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Les diagrammes suivants illustrent la mAthode. 1 2 3 1 2 3 4 5 6 3 a, ft. o > 92 GEOLOGICAL SURVEY OF CANADA G. M. DAWSON, C.M.G., LL.D,, RR.S., Dibkctor EEPORT 'A < < O o w X ON THE AREA OF THE KAMLOOPS MAP-SHEET PS o ■< M OS ?f i •A a BRITISH COLUMBIA BV GEORGE M. DAW80N OTTAWA PRINTED BY 8. E. DAWSON, TKINTER TO THE (/UEENS MOST EXCELLENT MAJESTY 1895 VI m^-^''^!''WMS^ S.„,_Th. be.ri»p th««gho„t.h. r.p.r.«. given «ith ,^.^- magneUo mia and Ore^n. The name Caitcadti Range h'uu Home maps extended to them from the mountaing of Oregon and Washington to which it rightly applies, but this is wholljr inappro|>riate, as the two mountain systems are entirely distinct, both in trend and in composition. H i 11 imiTI8H COLUMHIA. Tlif liitt-rior Plattiau. ItM uharactol<)giual Survey of CAiiiulit, 1878-70, np. 4(1 li, 18 i< ; Anriiiiil Rc])i)rt, (leoloificul Survt-y of Cniioda, vol. II. (N.H.) p. 15 b ;'IranH. Koyal Soc. Cnii., vol. III., 8fC. IV., i>p. (1-7. .- n of the u. illera are (vnges are, ) iwljivceat \) seem to nd to have id of the ire almost the same imbiiv, may lied miles, re hundred ,00 feet, but ,ion, so that cerned, con- r contrast to d, that this pointH along y or in places it is found to LH of plateau- liffering con- son to believe the Interior the condition ■suited from a leiglit of the the streams to vel of erosion," ;od to unwater ,n. After this ,till upstanding end, these also )lutely flat, the lain or what is 1(1 1), W It ; Aiiimiil = 5 •f. t: r. ■= C:7. .u ■] TtIK INTKRIOR PLATEAU. 6 R It appears further that the peneplane at this time formed has never Ju liiHtory. since been entirely obliterated, although it has passed through several stages of elevation and depression and has even been subjected to more or less deformation due to earth movements. At certain periods, it has been an urea of deposition of strata and the theatre of great volcanic eruptions, the results of which have been, in some places, to level up previously formed irregularities in the surface, in others, to produce local elevation. At intervening times, the natural forces uf waste have been engaged in reducing these supenvdded irregularities toward the old plane, but during the latter part of the Pliocene Tertiary, with the country standing at an elevation higher relatively to the sea than at present, the greatest erosive changes tending toward the destruction of the ancient plateau occurred. At this time, the main rivers cut deeply into its surface, while their smaller tributaries were actively engaged upon the edges of the intervening blocks of plateau, degrading these, and, in some cases, producing considerable widths of lower hilly country along the larger river- valleys. In the general description of the Tertiary geology of the region (p. 66 b) and in the subsequent discussion of the various periodi. jf erosion in connection with the auriferous drifts further particulars of the evolution of the surface features at different stages are given. Addi- tional details, with an extension of the same inquiry over the entire area of the province of British Columbia, may be found in a paper elsewhere published.* Thus our idea of the Interior Plateau as an entity must include some preHent a|>- reference to its origin and former condition. But even as it exists at lu*"'!"^"' the present time, it °s not unnatural to designate this ragion gener- ally as a plateau, for, standing upon any point of sutiicient elevation, the great lower valleys are entirely lost to view, while the high, r tracts run together everywhere in the distances to form a nearly level hori- zon line, above which the rugged forms of some of the adjacent moun- tains may stand out. It was indeed the recognition of this fact which led to the conclusion that the many existing isolated areas of plateau are but parts of an originally single feature, and which induced an in- vestigation of its cause and age. Further, it may be added that the several existing plateau areas, though differing considerably in elevation, do not do so materially as between adjacent parts. They do not re- present blocks of country which have been bodily uplifted or de- pressed by faulting, but parts of a gently inclined and undulating sur- face, so that in such a view as that above referred to, the differences in height are not at all apparent. •Trans. Royal Soc. Can., vol. VIII., sect. IV., p. 3. 1^ 6 B-L-' BRITISH COLUMBIA. Hlope of the IMati-aii. IiTfgularitieM. i Within the area of the Kamloops sheet, near its middle linf/, the normal level of the plateau may perhaps be described as declining north- ward from about 4500 feet to about 3500 feet, and it is very possible that the early Miocene drainage of the country took place in that di- rection. On this particular line, however, it will be observed that the volcanic accumulations of the vicinity of Savona Mountain and of the Arrowstone Hills, superadded during the later Miocene, to some extent interfere with the regularity of the main old pre-Miocene plateau. Further to the east, the high 8il-whoi'-a-kun Plateau forms another ir- regularity of the same kind. Toward the western edge of the map, it will be found (even in omitting from notice the deep but relatively modern valleys of the Fraaer and Thompson) that the plateau does not regularly abut upon the Coast Ranges. Its regularity is here interfered with by several subordinate elevations, which are of two kinds — higher projecting ridges of the old rocks, and local volcanic accuinulationsof the Miocene period. The Marble Mountains and Pavilion Mountains are referable to the first category, the Clear Mountains to the second. But as the western edge of the plateau rises gradually toward the Coast Ranges, particularly in the south-western part of the area of the map, none of these stand out very boldly above it. It will be understood from what has already been said, that the great valleys by which the Interior Plateau is now conspicuously trenched — those of the Eraser, the Thompson and their main tributar- ies — are relatively modem, being referable to the later part of the Plio- cene Tertiary. This system of valleys is superposed upon an older one, believed to date from the earlier Pliocene, of which parts may still be traced meandering upon remaining blocks of the old plateau. Still 6lder drainage systems, of which the streams took quite different courses, undoubtedly lie buried beneath the volcanic accumulations which are referred to the Miocene or middle Tertiary. Thn bunoii- All the lower and larger valleys in the plateau region, up to an ele- grram country, nation of 3000 feet and sometimes considerably higher, are, in conse- J quence of the dryness of their climate, either free from forest or dotted over with irregular groups of open wood or with single trees, of which Pimia ponderom is the most characteristic. The terraces and slopes are naturally covered with bunch-grass (Agrojjyrum tetierum). This is the case in the valleys of the Fraser and Thompson, also in the valleys of the North and South Thompson to the limits of the map, / amd in those of the Bonaparte as far as the Chasm, the Nicola, Junc- tion Valley, Hat Creek nearly to a point abreast of Cairn Mountain, Diffurent Bystcmg of valleyH. i s. »;, the north- oesible lat di- nat the , of the I extent plateau, (therir- Bvon in \ of the at upon y several rojectiiig Miocene referable it as the Bangea, ^ none of that the jpicuously 1 tributar- f the Plio- older one, may still >au. Still different amulations to an ele- B, in conse- )t or dotted !8, of which and slopes tw> This also in the f the map, icola, June- Mountain, 2 2, \ r. : X± J - - \ H .5 9 I : i MWtON.] CHARACTER OF SURFACE. the lower part of Pavilion Creek, the valley of Loon Lake, Semlin Valley, the Deadman as far up as Gorge Creek, Copper Creek, Guichon Creek to the mouth of Meudow Creek, the lower part of Cherry Bluff Creek, Peterson Creek, Reservation Creek, the wide valley running south of Kamloops to Nicola Lake and the Upper Nicola River. In these lower valleys, nearly all the land available for agriculture is Tillable land, situated, and in most of them irrigation is necessary to produce crops. The open bunch-grass slopes adjacent to these valleys are al- ways most extensive along their northern sides, and in some cases country of this character extends far beyond the immediate valley in- to lower hilly tracts of the adjacent plateau. This is notably the case in the vicinity of Ashcroft, in the hilly tract on both sides of the North Thompson near Kamloops, in the vicinity of Stump Lake, on both sides of the Upper Nicola valley, and on the western slope of the Pavilion Mountains. In the higher parts of all the mam valleys above enumerated, and Partially woodod in those of very many of their tributaries, the country still continues country. to be open or but sparsely wooded, with an abundance of graes on the slopes or on the terraces and flats about the streams. Here, however, the bunch-grass is found only on the rlopes most exposed to the sun, while various kinds of flat-leaved gra8se.s, with wild peas, vetches and other species of herbaceous plants are mure abundant elsewhere. A change of the same kind is indeed found to occur with increasing eleva- tion in all parts of the country, so that, in climbing from almost any one of the lower valleys, the nearly treeless slopes are exch mged at a certain elevation for open woods, consisting of Douglas fir (Pseudotsuga Douglasii) or yellow pine {Pinua ponderosa). The width of thb belt varies much with the exposure, and depends also largely upon the steepness of the slopes itself, but in the aggregate the area thus char- acterized is very considerable. Conditions of the same kind obtain over some of the lower parts of the plateaux themselves. This is especially the case on the Green Timber plateau, where open grassy country is inter- spersed with areas of forest, in this case largely composed of small black or bull pine (/'. Murrayana), and in which innumerable small lakes, some of them saline, occur. The Bonaparte plateau, with open woods, somewhat resembles the last, while similar, though less consid- erable, areas of the same kind are found about Toon-kwa Lake to the south of i^avona, near Uren's on the Upper Deadman River and along Meadow Creek. Many sudaller patches of a like character might be enumerated. The various classes of country above described constitute the chief Pastoral grazing grounds of the region, upon which large he^-ds of cattle and ^" "° 8 B BRITISH COLUMBIA. The forest country. I, Alpine ]vurk land. horses are maintained. The lower tracts are naturally the liest wiatei* ranges, and these it is now becoming customary to fence, in order to reserve them for winter feeding ; while in many of the higher valleys, abounding in natural meadows, hay is now annually cut and stacked in the summer, in order to provide a reserve against the occurrence of an exceptionally severe winter. Much the larger part of the plateau area is, however, covered with dense forests of trees of medium or small size, including, in order of abundance dr nearly so, black pine (P. Murrayana), white spruce {Picea Enyelmanni), Douglas fir {Pseudotsuga Douglasii) and balsam spruce {Abies gubalpina). In such tracts, narrow irregular borders only along the banks of streams or swamps, produce any grass ; few trails or practicable routes for horses are found, marshy spots aro frequent and great regions of almost impassable " windfall " occur. For the last- mentioned impediment to travel, the recurrent fires are responsible. These in consequence of carelessness on the part of both whites and Indians have devastated great tracts. In some places where such fires have passed more than once, the woods have been locally almost completely removed, but the soil, being by the action of the fire itself much deteriorated, even then produced as a rule but a scanty growth of grass of indifferent quality. In other instances, an almost im- penetrably denBo crop of young trees springs up immediately. In the course of years, these dense forests of northern type will undoubtedly for the most part disappear, and although this will facilitate travel, and render the examination of all parts of the region much easier than it is now, it appears certain that no great concurrent advantage will result in regard to the extension of grazing grotinds, while the supplies of the streams which now yield water for purposes of irrigation will be seriously impaired. At or about an elevation of 5000 feet, the dense character of the woodland country aliove described begins to change. The fore-st, which is composed chiefly of black pine, white and balsam spruce, with (in the south-western part of the region) the white-barked pine, begins to open out. Without any marked decrease in the size of individual trees the forest covering becomes more sparse, and as some- what greater heights are reached, the trees arrange themselves in separate clumps with grassy intervals. In many places park-like country of this kind is somewhat extensive. This is particularly the case between 5000 and 6000 feet on the Nicoamen Plateau and Lytton Mountains, in the Clear Mountain range and on the Sil-whoi'- a-kun Plateau. The Marble Mountains and higher parts of the Pavilion Mountains, are so bare of soil that such conditions are not that I side( runs I selval this and has watpi rangri stratil Excel F>art •] TIIK COAST RANGES. 9 U jt wintei' order to r valleys, tacked in nee of an I covered , in order te spruce id balsam rders only few trails 3 frequent or the last- whites and where such ally almost e tire itself ,nty growth almost im- ;ly. In the indoubtedly B travel, and aier than it vantage will the supplies ation will be acter of the The forest, alsam spruce, i-barked pine, the size of and as some- ,hemselve8 in ices park-like rticularly the Plateau and I the Sil-whoi- parts of the itions are not act:' reproduced upon them, and the same is generally true of the Coast Ranges. In the Sil-whoi'-a-kun region, as the name itself denotes, this high open country was, within the memory of Indians still living, a home of the caribou — an animal now found no nearer than the uplands and mountains in the vicinity of the Clearwal«r branch of the North Thompson. The aggregate areii of such alpine park land is not inconsiderable, and during a few mouths of summer it is always singularly attractive, watered by innumerable rills, and covered with gay alpine flowers. During that season, it is capable of affording nutritious pasturage to cattle, and although it has not yet been utilized for this purpose, there can be no doubt but that it will be so employed in the near future. The upi)er limit of the growth of any trees in an arboreal form, may Timber limit be stated for the region as being about 7000 feet, and, at this height, the more hardy forms, last enumerated, survive only in the sheltered valleys. In i-egard to the upper limit of thick forest, it is pretty clear that this is defined by the amount of the snowfall. Above a certain CauBOM of height, varying somewhat with locality and exposure, the depth of the ,|I^'pJft,, winter snow is so consi lerable that, if the forest l)ecame dense, the snow would not disappear from beneath its shade soon enough to enable any appreciable growth to occur. Thus any tendency to a thick growth in naturally checked, for only a certain number of trees, or clumps of trees, to a given area find the necessary conditions for permanent existence. A different cause must, however, be found for the sparsely wooded condition of the lower valleys, and this it appears is the absence of sufficient moisture. A ]imite 48i: -8-7- 21!) 14 (■: o(i-8 74 o; 2!)(i500 ll-427!> 4(>\y;02 4 10 -SI !>■(! 2() 538 •!» 18 2'22 12.S ,0 5(i-8 52-8i45-7 «8 0'58 0,()3 ^ S = 3 (iO-2(!8-2 77-2 83 7 84-2 .30-7I45-5I49 7 r..-)-2l.M!) 73 Tl?!!-!'!)^- '7-3i!t4 I S'7'48-7!o5-2 28 0.'13 13!i 22!I27 5 28 o2!l3iL»7!l 4()0:53 4:48 45 3,5 12o;n 4 48-2.')0-4i47-8 570 0!)0|780 07 03 10 03 40 60 21 03 It is unnecessary to repeat the description of the causes and results Chinook of the flow of relatively warm and moist currents of a'r over such a * " barrier as that of the Coast Ranges, and their liubsequent descent to a lower country, which have been given in my former reports on other parts of British Columbia.* It is sufficient to state that the effect is that variously known as the foehn or Chinook, now well understood and described in te.\t-bix)ks of meteorology. The air, already dried in its passage over the range, is mechanically warmed in proportion to the amount of its descent, and is thus rendered still more susceptible of absorbing moisture and incapable of affording any rainfall. This effect is naturally most in- tense in the immediate lee of the mountain range, as is very clearly seen in this particular district. Standing upon some high point, as for instnnce, one of the summits of the Clear Mountains, the Coast Ranges may not infrequently be seen to be buried in clouds, which as they detach themselves and drift eastward are gradually absorbed, a L'lear sky obtaining over the western part of the plateau. Naw bodies •Report of ProgresH, (Jeol. Surv. Can. (Jeol. Surv. Can., vol. III. (N.8.) p. 22 B. 1879-80, pp. 70 u— 78 u ; Annual Report, 14 B BRITISH COLUMBIA. t Distribution of rainfal). Tre(« as an index of cli- mate. Altituegd reached by soveral trees. Peculiar cli- matic condi- tiona. of cloud, from which local showers fall, may often at the same time form about the higher parts of the plateau itself. A study of these conditions, with the aid of the contour-lines on the map, will show how it happens that the lower valleys and those nearest to the Coast Ranges are the most arid parts of the district, while the humidity of many of the higher parts of the plateau, particularly those situated to the eastward, is at the same time still con- siderable, enabling them to be the sources of perennial streams which may be employed in the irrigation of the lower and drier tracts. A complete meteorological survey of the region would undoubtedly supply numerically accurate proof of these conditions, but in the absence of such data, much may be gathered from an examination of the natural vegetation, and more particularly of that of the native ti ees. A number of observations on the heights attained by various plants will be found tabulated in one of the appendices to this report. It is of course impossible to say how far the limiting range in height is determined by temperature, and how far by humidity, the effect being in each case a resultant principally of these two causes ; but in respect to the other resultant known generally as *' climate," and particularly in regard to the bearing of climate on agriculture, the indications thus afforded are important. The Douglas fir (Pseiulotsuaa Doiiglasii), and the yellow pine (Pinua ponderosa), because of the facility with which they are recognized and observed, may be regarded as ready indexes of this kind, and an ex- amination of the heights at which these trees were last seen in various parts of the region, will show that the upper limit of the first-named tree declines from the vicinity of the Clear Mountains to the eastward — a distance of some fifty miles — from about 5500 feet to 4500 feet, while the yellow pine similarly declines from about 5000 to about 3500 feet in the same distance. It may further be noted, that the white-barked pine {Pinug albicaulia) is practically confined in its range to the dry alpine country characteristic of the Nicoamen Plateau and the Clear Mountain Range, immediately to the east of the Coast Ranges, where, between levels of 5500 and 6000 feet, it is one of the most abundant and characteristic trees. The actual elevation observed in each par- ticular place is largely governed by the subsidiary effect of the exposure or direction of the slope of the country, but this also has an equally marked effect on agricultural possibilities. Many local climatic effects, which are of considerable importance and interest in the districts in which they occur, are naturally found in a country with boldly marked physical features like this. Thus, in the upper part of the Botanie Valley, a place resorted to every year by J o a O i I I _ .3 Hi S '>-' % O .3 as =: -< — o x: 'li ^7 s 2 o I l^^ ■6 \ II •] AURICULTURB. 16 B the Indians at the seaaon for digging edible roots, the vegetation is not only notably luxuriant, but unusually varied. The cedar {Thuya occiden- talis), white pine (Pinua mmUicola) and devil's club (Fatgia horrida), all plants seldom met with in this region and rather characteristic of a damp climate, are found here ; while at the same time there is a large extent of open slopes, and no such continuous thick forests as might be expected with the conditions for the growth of these plants. It appear" however, that as the result of causes not very well understood, the winter snowfall is here unusually great. The Indiana say that it lies on the ground to the depth of three feet and that in particular winters it is much deeper. Owing to similar local conditions, a strong up-river wind developes Local winds, almost every afternoon in summer in the lower part of the Fraser Valley, while during the winter season a frigid down-river wind fre- quently prevails. Similar land and sea breezes blow through all the main valleys in the Coast Ranges,'" but there is some evidence to show that these affect only the lower strata of the atmosphere. Thus, on one occasion, while upon the summit of Botanie Mountain (6620 feet) the afternoon was characterized by a light westerly air, while in the Fraser Valley at Lytton and even in the Botanie Valley immediately below, a violent southerly wind was blowing. The upper limit of agriculture in the region depends principally up- Limit of on the elevation at which killing night frosts occur during the summer ftgrwulture. months, or season of growth of the crops. Practical experience has shown that, in so far as wheat is concerned, this limit seldom exceeds 3000 feet above the sea-level, while it is often found to be at consider- ably lower levels in consequence of local circumstances. Barley and other more hardy crops may of course be grown at somewhat greater altitudes, but as a rule the surface of the plateau generally is much too high for sgricultural occupation The highest areas upon which wheat is successfully grown occur near the wagon-road on the southern and western slopoi of Pavilion Mountains and on the upper part of Hat Creek, the elevation being in the first case from 3500 to 4000 feet and in the second about 3500 feet. The highest farm upon the part of the Pavilion Mountains named, is situated a little above 4100 feet and here, though barley and oats may be grown successfully, «'heat and potatoes are not profitable crops. It will be observed that all these places occupy sheltered positions near to the inner margin of the Coast Ranges, where, as already stated, the /oehn ufiect is most notable. Annual Report, Geol. Surv. Can., vol. III. (N.8.), p. 22 b. 16 B BRITISH COLUMBIA. CropH of the lower valleyM. Mininimn temperatures at varioiiH lieightm. Larger auiRiaU. In the lower valleys, such as those of the Fraser and Thompson, notwithstanding the occasional severity of the cold of winter, the summer heat is very great and nocturnal frosts are not known at this season. The extent of arable land in these valleys iti not very con- siderable, but, with a proper supply of irrigation-water, many of th» benches and slopes may be rendered exceedingly productive. Orapes, water-melons, inusk-melons and tomatoes grow luxuriantly, and may be cultivated as Held crops ; fruit trees of all kinds flourish, and con- siderable quantities of beans for the local market are produced by Indian and Chinese cultivators. Where southward-facing slopes occur upon which water can be brought, it is certiiin that by terrar ; the surface, extensive vineyards might be established ; and as it well known fact that the better qualities of light wines are produi near the northern limits of the vine, it appears possible that a not unim- portant future may await the intelligent development of some parts of these valleys for this purpose. As a general rule, it is found that the temperature of the atmosphere decreases in ascending to the amount of about one degree Fahrenheit in 300 feet. This, of course, applies to the mean temperature, while the lowest nocturnal temperature during the season of growth is the important one in limiting agriculture in this region. As throwing some light upon this question, the minimum readings, extracted from the meteorological observations kept during the progress of the explora- tions, have been tabulated in accordance with the elevations at which they were taken, for comparison with those registered simultaneously at the Kamloops meteorological station. The resulting tables appear as an appendix to this report. A note may be added respecting some of the larger animals of the region. As already stated, the caribou {Rangifer Caribou), once an inhabitant of the high plateau between the head-waters of the Dead- man and Tranquille and the North Thompson still known to the Indians as Sil-whoi'-a-kun, is now locally extinct. The wapiti (Cermis Canadensis) was also not long ago abundant within the area of the Kamloops sheet, and weathered antlers of this animal may still be found, particularly in the hills near Stump Lake. Its resorts being in the open or lightly wooded tracts of the lower country, it was soon and easily exterminated by hunters. The black-tailed deer {Cariacus macrotia) is still abundant in the district, and the white-tailed deer (Cariacits Virginianus) is occasionally seen. Work done by beavers is frequently met with in all parts of the region, but the animal itself is now rare. The black bear {Ursus Americanus) is not uncommon, and the grizzly {Ursus horribilis) also occurs, particularly in the vicinity the ■] TIIK MAP AND METHODS OF SURVEY. 17 H of the Nicoamen Plateau. The mountain go&t {Aplo-f^rtm monlanun) is rather abundant in the higher parts of the Coast Ranges, and tho big-horn, or Rocky Mountain sheep (Ovin nitmtaiM), may often l)e seen in the mountains near Bridge River. Wolves {Cards liipiiM) are met with occasionally, and coyotes {Cnnin latrans) are in most years abundant below the main limit of the forest country. The rattlesnake inhabits only the lower and dry valleys, the greatest height at which it has been observed being 2520 feet, at Tso-tin Lake in the Pass Valley. The natives inhabiting the entire region covered by the map, belong Nativon. to the Shuswap stock, and speak a single language with dialectic variations. Such particulars as I have been able to ascertain con- cerning them have been made the subject of a separate paper.* THE MAP AND METHODS OF SURVEY. When the Gejlo^cal Survey of Canada first extended its work to Pnvious geii' British Columbia in 1871, the geology of that province was practically vaTions"**"^ unknown. In that year, lines of reconnaissance were carrie general topography of the DifficultieH en- country, it will be understood that, as a whole, it is not an easy one to *'"""**'"' • examine. While the larger valleys and lower tracts are generally open 2i 20 B BRITISH COLUMBIA. Routes Degree of acoiracy of the majt. (Jeologioal JKolation of Uritish Col- umbia. grass country, or are but !ightly wooded, the higher plateaux and rough hills are frequently densely covered with forest, or encumbered with alien trees in such a manner as to render them almost impassable. Other considerable tracts are characterized by high rugged mountains, the elevations met with within the sheet ranging from about 400 feet above sea-level to over 9000. The district is crossed by the main line of the Canadian Pacific railway, and is traversed besides by several roads and by a number of '' trails " or travelled tracks ; but large intervening blocks of country, which uve seldom or never visited save by Indian hunters, have had to be explored for possible rouies with considerable expenditure of time and labour ; and although tht length of route examined in the course of a day was seldom more than hiuoen miles, and frequently much less because of physical obstacles met with, li ■>vf«'« not often that the same camp was occupied or returned to on two consecutive nights. It may be added, that the crushed and greatly weathered character of most of the rocks, together with the fact that in the Interior Plateau region they are often completely disguised by a crust of lichens, in most cases renders the recogn-tion of rocks at any distance or from mere in- spection almost impossiMe. The exposure must be actually reached and attacked with the hammer before its nature can be ascertained, and this is often a matter of difficulty, and one involving time and labour. It has been considered necessary to outline the methods of survey, as above, in order tr indicate the degree of accuracy which may be supposed to attach to the results. Nearly all the routes followed, whether travelled trails or mere exploratory lines; are indicated on the raap, this being the best way of showing where the geological features have actually been examined on the ground. A certain average stand- ard of accuracy has been aimed at, and although at every point iidditional detail and more Jiiinute examinat'on present themselves as desirable, each step in this direction increases many fold the time and labour necessary to the completion of a map. As it now stands, the map is offered as the best possible under the circumstancbs and on the scale adopted. It is believed that it will be of practical utility as an aid to the development of the mineral wealth of the district, and it is hoped that it may also be found to be a substantial contribution to the general geology of the exceedingly complex western part of the Cordillera of North America. In regard to the systematic geology of British Columbia generally, it must be understood that our knowledge of this, so far as it goes, has been developed by slow degrees within the limits of the province itself, ■] ARRANGEMENT OF GEOLOGICAL MATTER. 21 B id rough red with passable, juutains, 400 feet n Pacific umber of country, ve had to of time 16 course nuch less , the same laracter of r Plateau IS, in most n mere in- sached and ained, and nd labour. of survey, h may be 3 followed, vted on the ■al features rage stand- very point jinselves as e time and stands, the and on the tility as an ct, and it is lution to the )art of the a generally, 1 it goes, has Dvince itself. beginning almost from first principles. This has been necessarily the case because of the absence of established general sections of the formations met with in any part of the length of the western portion of the Cordilleran belt. The early explorations of the geological pioneers in California, together with those of Prof. Whitney and his assistants, were scarcely ' f a sufficiently definite character to aflbrd a basis of reference for any rocks below those of the Cretaceous system, while the systematic and detailed work done by the Fortieth Parallel Survey was almost entirely confined to the territories east of the Sierra Nevada— a region not structurally comparable with that to the west of this range, or with that which forms the greater part of the area of British Columbia. Within the past few years, however, and to some extent concurrently witli the ob.servations here reported on, geological work of a definite character has been undertaken in California by the United States Geological Survey, the results of which, in so far as they have been made known, lend to show a close relationship as to com- position and structure between the rock-series there, and that of which the main features had already been developed in British Columbia. Reference is made in the sequel to such analogies and points of difference as have so far been brought to light in the Course of this later work in California. With special reference to the Kamloops map-sheet, it may be added, Tlie Kaniloops that while the earlier and more extended examinations previously '""'''■ made of this and other parts of the province enabled its investigation to be begun with a general knowledge of the sequence and character of the formations, the more detailed section now presented has been practically worked out within the area of the sheet or in its imme- diate vicinity. Thus, while this section may be accepted as a type in the further progress of the geological mapping of neighbouring regions, no one is more conscious than the writer of its essentially provisional character in some respects. ARRANGEMENT OK GEOLOGICAL MATTER. In the following pages, under the heading of General Geology, an Divisions of outline of the main features relating to the several formations met with "' "'""^ " in the area of the Kamloops sheet is given, the evidence upon which each has been referred to its position in the geological scale is set out, and the relations of the several formations with others known in the western part of the continent is discussed. In this part of the report the formations are treated of successively, beginning with the Cam- brian, which is the oldest recognized in the district. 22 p. BRITISH COLUMBIA. elation to the ap. Classification of th« older looks. Order partly geofjfraphicul. The next division of the report is occupied by what may be termed Descriptive Geology, being a more detailed treatment and examination of the various principal sections afforded by the region, with local notes and facts relating to the geographical distribution and composi- tion of the various rock-series. This necessarily occupies some con- siderable space. If it were possible to present a map drawn to a large scale, resulting from surveys and examinations so complete that the details of the composition and character of the rocks could be adequately represented upon it, much of the descriptive portion of the report might be omitted. In the actual circumstances this must, however, be relied upon to supplement the map. In other words, the descriptive matter required stands very nearly in inverse proportion to the completeness of the map which it is intended to accompany. With the knowledge now gained of the region included by the Kam- loops sheet, it is generally easy to distinguish the Tertiary, Cretaceous and Plutonic rocks from each other and to separate these from the remaining rocks of the region. Where points of doubt are still found in the.se separations, they are chiefly due to imperfect exposures or to the incomplete examination of certain parts of the district. When, how- ever, all these have been coloured in upon the map, the remaining mass of older rocks presents much greater difficulties. They may, in fact, be described as forming a ' complex,' of which the unravelling has so far proceeded but to a limited extent. The results of the work carried out on them appear to show that Cambrian, Carboniferous and Triassic strata are present, but they do not exclude the possibility of the ex- istence of other formations which should intervene in the normal geological scale between these. It has been endeavoured, so far as our information concerning these basal rocks of the district allows, to separate them under the heads above named; but this separation is not yet so satisfactory as to admit of a strictly chronological treat- ment in every part of the region. Thus, in the pages which deal with the descriptive geology of these older rocks, the arrangement adopted is, almost necessarily, in part based on the districts in which they occur, though the developments believed to represent the Palanizoic rocks are in the main described first, while those rocks classed as a whole in the Triassic system are taken up subsequently. The typical development of the CAche Creek formation is first noticed, as being that which is best understood, while its less definitely known representatives, with other associated rocks, are next referred to. The rocks which have been excluded from it as Cambrian, in the north- east part of the sheet, are then described. Finally, the great mass of •] TABLE OP FORMATIONS. 23 B strata which is referred to the Nicola (Triassic) formation is discussed, but with these it is found convenient to treat also of some rocks at- tributed to the Cache Creek formation, because of their regional proximity and the fact that they form parts of general sections, which it appears to be best po notice in each case as a whole. Both of the above mentioned sections of i he Report relate, how- Surface geo- ever, to what may be termed the ' solid geology ' of the region only. A separate chapter is devoted exclusively to the ' surface geology,' or the examination and description of the superficial deposits or ' drift ' ; the character and distribution of which are largely due to action dur- ing the glacial epoch, assumed to mark the close of the Tertiary period proper. No recapitulation of this part of the report is included under the head of General Geology, and it may be regarded as constituting a separate essay, subsidiary to the first two divisions, although the facts disclosed by it are scarcely less important, particularly in their reference to the character and distribution of the gjld-bearing gravels of the region. In each of the three foregoing divisions of the Report, the bearing of Kconomio the ascertained facts on economic questions relating to mineral deposits and mining is constantly alluded to ; but in order to facilitate easy reference to all the economically important facts, so far as they are known, a fourth division of the Report is devoted to the summary treatment and enumeration of theso, and to the details respecting various metalliferous districts which may prove to be of immediate importance to the prospector and miner. THE TABLE OP FORMATIONS. As a key to the geological structure of the region, the subjoined Arran^eiufnt syr.nptical table of the formations met with is given. From this all iet :.s have been eliminated, leaving only the main facts presented in the most concise form. In expli>,nation of the table it may first be stated that it relates to what has been termed the ' solid geology ' alone. The known unconformities or breaks in the series are indi- cated by the horizontal lines, but it must be understood that the value of these is very une(]ual, some representing long, while others represent comparatively short tinio-intervals, to an extent not fully ascertained. It will further be observed that in some cases local names have been adopted for the groups or formations. This has been done where it appeared to be necessary for the purpose of description, and particularly in cases where the precise limits, above or below, of a geological series are not known. The introduction of such new names 6??' 2-1 B BRITISH COLUMBIA. m Thickness uf rock-8prie». ARgregate tliit'kne»B. (treat abuiul- aiieeof volca- nic materials. has, however, been minimized as far as possible. Thus it is believed to be sufficient to designate the upper and lower volcanic rocks of the Tertiary, simply as Upper and Lower Miocene of the Kamloops sheet, ratlier than to affix to each of these series of rocks some local name. It is further to be noted, that the maximum observed or esti- mated thickness is given in each case in the table. But it by no means follows that this always represents the actual maximum thick- ness, for in several cases theie is reason to believe that the volume ef strata, if accurately knoxn, would much exce-"^ the figures given. On the other hand, cases are not wanting in which a very small thickness of beds appears as the representative of what is elsewhere a very massive series. This is particularly found in the volcanic rocks of the Tertiary, where, in some instances a single flow of basalt spread over the surface of the older rocks is all there is to show for the more than 3000 feet elsewhere representing the Upper Miocene. Again, in the case of the Cambrian rocks — the whole thickness of these actually known by sections l.i the Kamloops sheet is about 11,500 feet only, but in the sections on Adams Lake the volume of the upper member of the CamVjrian alone is about 1 7,000 feet. These sections are so closely related to those of the Kamloops sheet tiiat there can be little doubt that the entire thickness of the corresponding beds in it would be found to be nearly the same if fully displayed. It is some- what different, however, in regard to the lower member of the Cam- brian, for the thickness given under this head in the general section is derived from the section in the Selkirk Range, at aconside>able distance, and it may very well ho that, within the limits of the sheet, the actual thickness of this member is different — possibly less. It will thus be apparent that the vast aggregate thickness of the rocks, amounting to 7fi,600 feet, need not be supposed to have ever been in any one place superposed as a single section ; but it is very clear that, average the thicknesses determined as we may, we have an enormous volume of strata to reckon with in this part of the Cordil- leran belt. In a paper read before the British Association for the Advancement of Science in 1880,* the writer pointed out, as one of the most signifi- cant facts of the geology of the Cordilleran region, the recurrent accumulation there of great masses of volcanic materials at different stages of the geological scale. Subsequent investigations have served to confirm this indication and to increase its importance, and of this *Geol, Mag., April and Mav numbers, 1881. "•] TAIILE OF FORMATIONS. 25 B believed s of the ps sheet, il name. or esti- it by no mi thick- olume of ven. On thickness •e a very !ks of the iread over the more ickness of s about ime of the se sections lere can be beds in it t is some- the Cam- 1 section is le distance, the actual ness of the have ever t it is very we have an the Cordil- ivancement :nost signifi- e recurrent at difiFerent have served and of this no better evidence can be given than the general section for thu Kam- loops region presented herewith. Further corroVjoration to the same effect, is also now coming in from various sources, as the investigation of the rocks of the Western States of the American Union is being proceeded with in the light of the comparatively recent recognition, for that region, of the existence of volcanic rocks older than those of the Tertiary. Assuming the section here given to be some index for the Interior Kxtraviwation Plateau region of British Columbia as a whole, an assumption con- piateau. sistent with the facts already known beyond the particular area of the Kamloops sheet, the writer believes it to be well within the limits of probability to estimate the volcanic materials from (and including) those of the Cambrian at about 20,000 feet in total tliickness. In order to give detiniteness to our ideas, it may be supposed, as a mini- mum, that the width of the belt characterized by this development of volcanic rocks is about one hundred miles. It foUo'vs, almost inevit- ably, that so vast an extravasation must have been accompanied by enormous subsidences, and, so far as can be ascertained, the main line of such subsidences must have corresponded generally with the pre- Probable sub- sent position of the Coast Ranges. Here, more than elsewhere, it Coast Ranges, would appear that thousands of ieet of strata have been engulfed — forced down by superincumbent additions, or depressed by flexure below the surface till they reached the zone of granitic fusion. But the movement affecting the area of the Coast Ranges has not been continuously one of depression. Recurrent periods of elevation have resulted in the production, at more than one period, of a chain of mountains along this line, which has again more than once been broken down and carried away by denuding force.s, till at the present day we find the existing mountains, low in comparison with some of those of the further interior, but consisting for the greater part of granitic rocks of deep-seated origin, with but scanty remnants of the older members of the Paheozoic series resting upon their flanks or remaining as infolds in their mass. Very often, and over large areas along the littoral of thefe ranges, the beds which rest directly upon the granites are of Triassic age ; but from this it is not to be argued that the older formations have never existed there, for these may only have passed beyond recognition by entering as component parts into the subjacent granitic magma. , ffl ;i y)^'¥.»»g'» «wMMi.,M 26 B BRITISH COLUMBIA. m ■oio'/oiJivx i CAMBRIAN HOCKS. 27 B u GENERAL GEOLOGY. In the following pages a brief general outline is given of the char- acter and relations of the several formations under which the rocks of the district are classified. Cambrian. *5 X 3 It has of late years become evident, that rocks of the Cambrian sya- Evidence of tern have a great extension in British Columbia, and are, at least in some here indirect. places, developed in enormous thickness. No direct evidence of the age of the rocks classed as Cambrian within the area of the Kamloops sheet has, however, been obtained within the limits of the sheet, and their recognition here depends on several intermediate terms, by which they are connected with the great Cambrian series as developed in the cor- responding part of the length of the Rocky Mountains proper. To make this clear, it will be necessary to enter into some short explana- tion of the facts. These rocks, vith others believed to be Archaean, constitute a great part of the section examined in 1877 on the Shuswap Lakes, of which some account is given in the report for that year (p. 96 B et seq.), but respecting the age of which nothing could be t,aid definitely at that time. In 1 888, an examination of the shores of Adams Lake, a body of Kocks of \d(iiiis water thirty-seven miles in length which lies to the west of the Great jsiiuswai) and Shuswap Lake, afforded a better and less complicated section than had ^T^s""^ previously been obtained of rocks of the same old series. In 1889 similar rocks were again found and studied in the vicinity of Kootanie Lake. The lower or presumably Archii'an series was there recognized, as well as a great thickness of overlying rocks, comprising black micaceous argillitea, followed above by green and gray schists. The rocks here met with were evidently the same with those previously known on Shuswap and Adams lakes. In the report made upon the West Kootanie region, a general section was given, combining the results of work in this region with those obtained up to that time on the Shuswap and Adams lakes, and the several rock-series were distinguished under the provi' ional names of Shuswap (Archiean), Nisconlith and Adams Lake (Cambrian) series. It was also stated that " The gray and greenish schistose rocks [of Kootanie Lake] con- stituting the second group may, with confidence, be affirmed to be essentially composed of altered volcanic materials, and their present 28 B BRITISH COLUHIilA. Similar rocks in the Helkirk Range. TboHe forming aconnectinu' link. schistose character may probably be regarded as in the main due to the enormous pressure to which they have been subjected during the movements of the earth's crust, which resulted in the uplift of the mountains of the region and the extrusion of the great masses of granite here everywhere found."* It was further noted, in the same report, that although some evidence of this chansre .Vpendent on dynamic metamorphism occurred in the Kootanie district itself, the best evidence upon this point had been obtained in th<' region l>etween Adams and Shuswap Lakes and the North and South Thompson rivers ; the allusion here being to part of the district adjacent to the eastern edge of the Kamloops sheet which had been examined in the previous year. Having arrived at this point, it became eminently desirable that a connection should be established between the older rocks of the In- terior Plateau of British Columbia, the Gold Ranges and the western Hanks of the Selkirk Ranges, and those to the eastward, in the Rocky Mountains proper, which had already been carefully ex- amined along the Bow River Pass by Mr. R. G. McConnell, t.iid reported on by him .n 1887. f Thus in the autumn of 1890, an examination was made by the writer, on the line of the Canadian Pacific railway, across the whole width of the Selkirk Range. As a result of this examination of the intermediate region, it became possible to establish a fairly satisfactory correlation of the diflferent develop- ments of these older rocks, and of this a short review was given in a paper read in December, 1890, before the Geological Society of America, in which a comparative table was also presented of the rocks as found : — (1) On Kootanie and Adams Lakes. J (2) In the Sel- kirk Range on the line of Canadian Pacific railway, and (3) on the west side of the Rocky Mountains, as observed by Mr. McConnell. The comparison thus instituted rendered it possible to correlate a large part of the rocks previously observed on the Kootanie, Shuswap anfl Adams lakes, as well as a part of those of the Interior Plateau of British Columbia, with the recognized Cambrian strata of the Rocky Mountains proper. It is, however, in the last-mentioned section alone, that any paheontological evidence is available by which to fix the pre- •Anniinl Report, Geol. Surv. of Can., vol. IV. (N.S.), p. 30 b. t Anmml Re|>ort, Geol. Surv. of Can., vol. II. (N.S.) tBuU. Gefil. Soc. Am., vol. II., pp. 165-17(). In the table tiiere given, as well us in that given in the reixtrt on the VVest Kootanie district above alluded to, the thick- ness of the Adams Lake series and its overlying beds was, by an error in the scale, made just one-half too smaU. This error is corrected in the table accompanying the present report. •1 CAMBRIAN ROCKS. 20 n Tnlil.- of Ciiinliriai) roc'krt. cise ftge of tlie strata, and the correlation made between those rocks of the Rocky Mountains and those of the further western region, neces- sarily proceeds upon lithological and stratigraphical grounds. In order, therefore, to justify the inclusion of a portion of the rocks met with in the area of the Kamloopa sheet under the Cambrian, it becomes necessary to refer to the intermediate terms by mean.s of which they are connected with those of the Rocky Mountain spction. This will be mo.st easily accomplished by reproducing, with such changes and corrections as have since become necessary, the com- parative table which formed a part of the paper last referred to. Before proceeding to speak particularly of the Cambrian rocks of the table, it must be noted that jthe beds included in the upper com- partments of two of the three columns, are not known to be equivalent in any strict sense. They are so placed, only becau.se tliey follow the rocks here described as Cambrian in ascending order. Thus these beds in column 1, very probably belong in large part to the Carboniferous formation, while the age of those occupying a corresponding position ill column 3 is much greater, as known by their contained fossils. In explanation of the table, the following general notes may be given, extracted wherever included between quotation marks, from the paper already referred to.* The first column of the table represents the rocks met with in the Colmnn 1 i.f western part of the Selkirk and Gold ranges, chiefly in the vicinity of Adams Lake, the Shuswap Lakes, and on Kootanie Lake. The lowest rocks in this column, the Archsean, were found best displayed on Kootanie Lake, and the thickness given is derived from the part of this system exposed there. The thickness and description of the over- lying Cambrian divisions are practically those of the actual section measured on Adams Lake, or in its immediate vicinity.f These rocks run into the eastern part of the Interior Plateau of British Columbia, the section above the Fish-trap Rapid on the North Thomp- son (see p. 107i).) being directly connected along the strike of the rocks with Adams Lake. " The third column in the table represents Mr. McConnell's published C"!'""" •' <>f section in the Rocky Mountains proper, in which certain horizons, ranging upward from the Lower Cambrian, are definitely fixed by fossils. It was found, in working out the section in this part of the •Bull. Geo). Soc. Am., vol. II., pp. 165-17G. + The thickness of these rocks previously given has been corrected, as already stated. IIRITI8H COLUMBIA. .2 •| s It e 3 S 05 e 1^ -^ s I •I 3^ as PS- S>3? ..'=8 ^1 - rt SO e3 S a 1 8 I •NviH.ms ONV NVH1.TJ18 imiiwvo •NVlHaHV3 ■MVMHOHV " s « * i',- 1.1 -.", fe ^ ,r <3 S 5 " ? 2 •Si S £-2 i^ c js; 15.5 a : a " 5 * S c« C a ■" ^_-= ■5^ «•? ss s I'Ea : i S-|« : Us . : •5 * §.5 * a • ■/ S S =« ' t -a * 3 ^ 'S - ■gawae J3.i.'Jf »'og' c ?» i OJX >> Si ^ 4-> X i2 =2 " i a C ^ 2 c 4-» 1 T. 1 1 4,- T3 L. ^ m 2 3'5'SbS s a -V a cr o •»*iu»(( ^-it^iPS 5 >-. «)T3 ■i^ a a j: 2 o <« Ss g » i I, a S'"-a| n2 *•■ ? S S ' a »: i ij m •St.JI.iJS '*'-a •Kjwas di>.nsnys 2 8 •- ^tc O O •8Jl.t38 -I a) e » 1{ftpiO091 1^ a 1-2 ■nfun diMim-qS! "■] CAMDKIAN HOCKS. 31 U Rocky Mountains, that a considerable difference exists between the section of the eastern as compared with that 'of the western part of the range, the present width of which (whatever that originally occupied by the rocks composing it may have lieen) is about sixty miles only, Tlje particular feature of this change which is interesting in the present connection, is that observed in the Castle Mountain (Cambrian and Canibro-Silurian) group, which although it is on the east essentially a limestone formation, is found on the west to consist in largo part of greenish calc-schists and greenish and reddish shales and slates ' No granitic rooks or true crystalline schists are seen in any part of this section." The section represented by the middle column in the table is tliat Column 2 of found along the line of the Canadian Pacific railway in the Selkirk TaWf- Range. " It occupies, geographically, as it does in'the table, a position intermediate between that of the eastern border of the Interior Plateau and that of the Rocky Mountains. In this, as in the section given in the first colunm, no horizons have yet been fixed paheontologically, and the position given to the rocks therefore depends principally on the comparison of the section with that known in the Rocky Mountains pro' ' It is probable, from the composition and condition of the rock that they may be found to hold fossils ; but in the meantime it is believed that the lithological resemblance of the formations to those met with in the Rocky Mountains, is in itself suflicient to enable some important general conclusions to be arrived at respecting the roclcs of the Selkirk Range, while the analogy of the rocks of the Selkirks to those of the first section is also such as to'afford some clue to the age of the formations represented in it." " The Niscordith Series. — Overlying the basal holo crystalline Nisconlith (Archaian) series in the Selkirk section, is a mass of rocks of which the Series, thickness is estimated at fifteen thousand feet. These are dark coloured and generolly blackish argillite-schists and phj'Uites, representing various stages in alteration between true argillites and micaceous schists. The rocks are usually rather finely fissile, with glossy and sometimes wrinkled surfaces, but often with much minute yet visible mica on the division-planes. These planes are in some cases evidently due to cleavage, but are often true bedding-planes. The rocks are usually calcareous, and frequently hold thin layers of dark-bluish or black impure limestone, together with occasional layers of dark quartzite. The coloration is evidently duo to carbonaceous matter, and pyrites crystals are very common in certain zones. The only notable •Annual Report, Geol. Surv. Can., vol. II. (N.8.), pp. 24 i), 25 d. 32 B BRITISH COLUMBIA. (M Selkirk Series. Reprcsenta- tivea else- where. diversity met with ia the otherwise homogeneous mass of rocks is found towards the base, where (at the lower end of Albert Canon) a bed of pure blue-gray crystalline limestone thirty feet or more in thickness occurs, and a short distance still lower in the section, a series of beds of over one thousand feet in thickness, consisting chiefly of granular pale gray quartzites. The quartzites are sometimes flaggy and generally more or less micaceous, and are interbedued as well as overlain and underlain by blackish micaceous argilliti?s and layers of coarsely micaceous schists." " These rocks undoubtedly represent the Nisconlith series of the first column, of which no extended sections have yet been found in the Interior Plateau, while to the eastward they certainly correspond, in the main, with the Bow River series of this Rocky Mcr.utains, for which a thickness of ten thousand feet was there ascertained, though the base of the series is never exposed in the Rocky Mountains." ^^ The Selkirk Series. — Between the foregoing s( ries and the next overlying mass of beds in the Selkirk section no distinct line of divi- sion, even of a lithological character, has* been observed, there being, apparently, on the contrary, a considerable thickness of passage beds, in which the dark schists of the lower series alternate with gray glossy schists characteristic of the upper series. The estimated thickness of this overlying .series is 25,000 feet ; and of its rocks the higher central peaks of this part of the range, comprising Mounts Sir Donald, Mac- donald, Tupper, Hermit, Cheops, Ross Peak and others, appear to be wholly composed. Lithologically, it consists of a great volume of gray schists and gray quartzites, which are occasionally somewhat dolomitic. The quartzites probably preponderate, and vary in colour from nearly white to gra^ and greenish-gray, being seldom dark in tint. They often, however, weather to pale brownish colours and pass into coai-se grits and fine-grained conglomerates ; and these grits and conglomerates have become more or less schistose in structure as a result of pressure, which has also led to the development in them of much tine silvery mica. 1 1 schists vary in colour from pale neutral-gray to greenish-gray, and from dull to silvery and lustrous, being in many cases apparently true sericite-schists." These rocks undoubtedly represent, at least in a general way, those of the Castle Mountain group of the Rocky Mountain section, to the eastward. For this group Mr. McConnell ascertained a minimum thickness of 7700 feet, but found reason to believe that its total volume in the western part of the range approached 10,000 feet. They likewise also correspond, in the main, with the rocks previously named rocks is Canon) a more in , a series chiefly of les flaggy as well as layers of [)f the first nd in the espond, in ntains, for ed, though ains." i the next le of divi- here being, ,ssage beds, gray glossy hickness of ;her central onald, Mac- ,ppear to be unie of gray it doloniitic. from nearly They often, '•se grits and lerates have ssure, which t mica. y\ ay, and from arently true il way, those sction, to the a minimum lat its total 10 feet. They iously named ..] CAMBniAN ROCKS. 33 U the Adams Lake series, differing from them chiefly in the great de- velopment of quartzites and quartzose conglomerates ; though the dis- covery of some thickness of precisely similar quartz conglomerates in rocks of the Adams Lake series, near their typical locality (seep. 108 b) tends to bridge over this difference. Under the circumstance.s, in 1890, it was thought best to name the series met with in the Selkirk Range the Selkirk series, rather than to affirm a precise equivalency of these ?!['!"''',?"*' *° rocks either with those of the Adams Lake or Castle Mountain series, ftmua. In regard to this comparison with the last-mentioned series, " the line indicated between thi:; and the underlying (Nisconlith) series in the Selkirks is based entirely on genei-al lithological differences, while there is every reason to believe that a plane of division drawn to correspond with that between the Castle Mountain and Bow River series in the Rocky Mountains wo. id lie several thousand feet above the recognized summit of the Nisconlith series in the Seikirks. In the Rocky Moun- tains, the Lower Cambrian (Olenellun) fauna is known to be common to the lower part of the Castle Mountain and upper part of the Bow River series ; * the separation being there made at the base of the dis- tinctly calcareous upper part of the Cambrian, while certain rather characteristic quartz-conglomerates observed in the upper part of the Bow River series of the Rocky Mountains are paralleled by similar con- gloiiieratps which abound in the upper series of the Seikirks. No un- conformity has been observed between the upper and the lower masses of strata in either place." " Though i.i the Selkirk .section the lowerof the two great series which Sulkirk antl have been described resembles the Nisconlith of the Interior Plateau so geVi'yg" "" " closely as to warrant extending the .same name to it, the fact that the overlying mttiiber of the section difl'ers considerably from the Adams Lake series of the Interior Plateau, while on the other side it probably represents not only the whole Castle Mountain group but also the upper part of the Bow River series of the Rocky Mountains, renders necessary the application to it of a provisional distinctive name. It is therefore proposed to refer to this rock-mass as the Selkirk Series." It is very probable, however, that it may eventually be found pos- sible without inaccuracy, and therefore ive ' >.:.i ujade, the following statement was given respecting the ch.n ;.' 'J iv.\. ' ogical character of these Cambrian rocks when followed i'r> .. e.-,f c to west across the component ranges of this part of the Cordillera : — "The comparatively pure limestones of which the Cambrian of the eastern part of the Rocky Mountains is composed are repln ;ed in the western part of that range by rocks largely clastic in origin. This change in lithological character appears to continue, and to become still uiore marked and to be accompanied by increasing thickness in the Selkirk Range. Much of the clastic material is siliceous, and the introduction of an increased proportion of such material may be ex- plained by considering it as a result of approach to the shoreline of Archit'ttn rocks on the west. While the principal development of con temporaneous volcanic products, whether in the Palasozoic, Mesozoic or Tertiary, is confined to a region west of the local Archivan axis, tli;: writer is inclined to believe that a portion of the remarkable differ^i j found to occui in the western extension of the Cambrian, may b- u <" to the inclusion in its rocks, on this side, of volcanic ash deposi > . other hne-grained volcanic materials, of which the composition wp? such as to favour the subsequent production of sericitic or sericitelike schists." Subsequent investigations appear fully to sustain the view thus advanced, showing as they do tiiat in the rocks representing the Sel- kirk series in the vicinity of Adams and Shuswap lakes, the prepon- derance of quartzose clastic material is not maintained, but that gr. -en and gray schists which can be traced into diabases, diabaso:>gfrlom- erates and other rocks of volcanic origin, form the great bulk t- ' eae rocks. Thus it would appear, that while the miissive limestones ol . :e Castle Mountain series were in course of deposition in the region now represented by the eastcrr slopee ul the Rocky Mountain Range, the calrareous material: I^mcojtjc ''V'";ely intermixed vith volcanic detritus and arkose matte, f uitiie. ic fftt west, producing under metamorphism the great mass of cal'' ociiists found in the western parls of that range. In the Selkirk re.[,Lon< local granitic and gneiasic shores H.] CAMBRIAN ROCKS. 35 B ) made, ■jgical supplied great quantities of coarse sediments, while volcanic ash or other material resulting from contemporaneous volcanic action became to a still greater extent a constituent of the rocks. Htill further to the west, in the vicinity of tlie region now occupied by the Gold Ranges, and also apparently to the southward about Kootanie Lake, massive volcanic rocks became entirely preponderant at this time ; the quartzose and iiikose constituents are sparingly ropresented and pure limestones a'.e no longer found. Rocks still represented by massive diabases and 'oy diabase-agglomerates, where not affected by great dynamic alteration, are now found in the form of the green and gray schists of the Adams Lake series, and can actually be traced into connection with their massive originals to the west of the flanks of tho Gold Ranges. Even here, however, the argillites and limestones of the Nisconlith series continue as the lower number of the Cambrian, representing a period antecedent to that at which the great and evidently long continued volcanic eruptions of the later Cambrian occurred. The establi.shment, by observations in the field, of the fact of tho Foliated and incks of Adams Lake, Kootanie Lake and the Holkirks generally, I am inclined to believe, that there is usually a coincidence between the foliation and bedding such as to render estimates of thickness of the kind alluded to fairly trustworthy. The fact that alternations in character of material occur in layers parallel to the foliation, favours the belief, while on Adams Lake, for instance, the difference observed between the generally gray schists of the lower part of the formation and the generally green schists of the upper, shows that there is no bold overturn and repetition of the whole mass of these rocks. It therefore only remains possible, that portions of the same part of the original series of beds may have been locally folded together and com- pressed in such a manner as to involve a partial repetition of beds. But where this may occur, any increase of thickness accruing is probably more than compensated for by a general attenuation of other parts of the formation which must have resulted from the extreme degree of pressure to which the beds as a whole have been subjected. If this view be correct, it follows that while some undue prominence, which it is impossible to eliminate, may be given to certain classes of rocks in the section, the aggregate thickness and general character of the section as a whole has been little affected. Reverting to the particular area of Cambrian rocks outlined upon the Kamloops sheet, in the vicinity of the North Thompson ; it must be confessed that it is not without some hesitation the attempt to define these rocks has been made. Their limit may be said to be drawn entirely on lithological grounds of difference observed between them and the strata adjacent, which are referred to the Cache Creek formation. The area coloured as Cambrian, however, is certainly coextensive, par- ticularly in its southern part, with one of metamorphisin much greater than that ordinarily found in the same region, and should it be found necessary in the light of further investigation to change the position of the line, it has, as now drawn, at least a certain value in differentia- ting this metamorphic area. It is by no means improbable, as elsewhere stated (p. 109 b), that a considerable tract to the west of the North Thompson and north of Whitewood Creek, should be included with the rocks just referred to, but the balance of the evidence at present appears to me to be against thii. •] NEWEB PALiEOZOIC ROCKS. 37 B Reference must also bo made to the possible existence of Cambrian rocks in the much disturbed and altered western edge of the Palseo^oic series in the vicinity of the Coast Ranges, as mentioned on page 43 b. Newer Palaozoic Rocks — Chiefly Carboniferous. As the result of his own investigations and those of Mr. James History of the Richardson in British Columbia, concurrently made in 1871, Dr. Sel- ^JlJ^'^jJ^^J]*"'' wyn was led to propose two groups (constituting the fourth and fifth groups of his preliminary general section) with the names of Upper Cache Creek and Lower Cache Creek respectively, under which he included a large part of the older locks of the interior of the prov- ince. The Upper Cache Creek group embraced the massive lime- stones of Marble Cafion and of the Marble Mountains, with some asso- ciated " red and green shale, and epidotic and chioritic rocks, with others which closely resemble rocks of the Quebec group in the East- ern townships of Canada." The Lower Cache Creek group was made to include the cherty quartzites, argillites, greenstones, serpentines and associated limestones t'ound to occur al(.)ng the Thompson and Bonaparte valleys in the vicinity of the main wagon-road.* It was at this time suggested, because of the occurrence of a foraminifer recog- nized as of the type of Loftusia in the Marble Cafion limestones, that the Upper Cache Creek group was of Eocene or Cretaceous age, while the Lower Cache Creek group, on the evidence of the fossils examined by Mr. Billings, was known to occupy a position somewhere betwein the base of the Devonian and the summit of the Permian. In reporting on a portion of the northern part of the interior of Northern British Columbia in 1875, the writer assigned .some of the rocks there tiitivo»! met with to the Lower Cache Creek group, on lithological grounds alone, for no fossils were discovered in them.f In the following year, as the result of further and more extended work in the same northern region, the peculiarly Carboniferous fossil Fusnlina was found to be Discoyi'i-y of abundant in the massive limestones of Stuart Lake, and these lime- stones with certain quart /.ites, argillites and green schistose rocks, were together classed under the Lower Cache Creek group ; while their relations with rocks of the southern part of Vancouver Island and with those of a portion of the Rot;ky Mountain range, were also pointed out. J • Rei«)rt of ]'i-()H[rc98, Oeol. Siirv. Can., 1871 73, pp. 60-02. \ ReiH)rt of I'rogroBH, (it-ol. 8uiv. Can., 1870-VG, pp. 24V-25(). Reiiortof ProgreHS, Qeol. Surv. Can., 1876-77, W- 55, 8!l. ■mpPMUHIII mfsmim^^ 38 B BRITISH COLUMBIA. ConHohdatioii of the Upiwr and Ijower CAchc Creek gn>ui)8. Interlocking* of characters. Relations of Ciicho Crock ard Boston Bar grou|>H. \Jt will be observed that no rocks referable to the Upper Cache Creek group had been found during the explorations of 1875 and 1876, and when in 1877 a further and more detailed examination was made by the writer of the southern part of the interior of the province, upon which the original classification had been founded, the con- clusion was arrived at that the so-called upper and lower groups are not strictly separable on stratigraphical or lithological grounds, while Fusu- lina was found to occur in association with the massive limestones of Marble Caiion as well as in the limestones of the lower group. In the report on the work of the season, the whole of the rocks pre- viously placed in these two groups were referred to under the name of the Cache Creek series,* and further investigations have since served to bear out this consolidation of groups. Thus in the present report, as in that last referred to, the Cache Creek series or formation must be understood to embrace the rocks originally included in the Lower and Upper Cache Creek groups. There can indeed now, I think, be no doubt that the Marble Cafion limestones, which constituted the greater pai t of the Upper Cache Creek group, are in fact the higher member of the formation, and between these and the underlying rocks it may eventually become convenient to draw a line of division. But impor- tant bods of limestone also occur in the lower part of the formation ; there is a stratigraphical and lithological interlocking between both parts, and the palreontological evidence, so far as it goes, indicates the reference of both parts to the Carboniferous. It must further be explained that, in mappingthe Palieozoic rocks of the area here described, it has been found practically impossible to separate the rocks originally spoken of as the Anderson River and Boston Bar groupf from those of the Cache Creek formation. Dr. Selwyn was, at the time iic proposed this name, unable to assign any age to these rocks, but the order of the group in his report shows that it was understood to lie below the Cache Creek formation. This reference proves to be a correct one, for it can now scarcely be questioned that these rocks either underlie the greater part of the rocks classed as the Lower Cache Creek group, or correspond in part with the lower portion of that group. But while upon the single line of route originally examined, these rocks are widely separated by other groups from those of the Cache Creek formation, the two series have since, in different localities, been traced into connection, and in such places no means have been found of defining a line between these rocks. Some details on this point are given later, (p. 43 B.) • Report of Progress, Geol. Surv. Can., 1877-78, p. 169 r + Rejxirt of Progress, Geol. Surv. Can., 1871-72, p. 02. ..] NKWEK PALEOZOIC ROCKS. 39 a \ The Cache Creek formation, as shown on the present map and as Cache Creek now understood, must therefore bo regarded as including a very thick detinod. series of Paht'ozoic rocks, of which the greater part is definitely refer- able to the Carbo!iiferous period by means of its fossils, but of which it is scarcely probable thatthe upperand lower limits agree precisely with those of the typical Carboniferous. It may very possibly be found at the base, particularly, to transgress these limits and to include beds older than those of that system. In attempting a brief general description of this formation, it must Its shattered in the first place be observed that, the extremely broken and disturbed character of its rocks, almost everywhere renders it next to impossible to learn much about their attitude or sequence in any one locality. It is very generally impossible to determine whether the dip of the beds is normal or has been overturned. It is thus only by following the general association of the rocks from place to place and by piecing together facts observed at many different places that it becomes practi- cable to outline the salient features of the whole. Tiie western part of the Kamloops sheet, between the Thompson The marble and Bonaparte rivers on one side and the Fraser on the other, is the stones. typical area for the Cache Creek formation, and the most definite fea- ture which can be traced throughout, is the belt of massive limestones already several times referred to. Beginning to the north in the Marble Mountains, these gray and whitish limestones, sometimes marbles, are continued in the Pavilion Mountains, cross Marble Canon, and after an interval in which they are concealed by Tertiary rocks, reappear in the western part of the Cornwall Hills, extending south- wards to White Mountain and to Blue Earth Creek. Further south the Tertiary volcanic rocks are continuously spread across tiieir line of strike. Practically the entire mass of the Marble Mountain range is com- Chariutirof till* IX)CkH posed of these limestones, as well as the whole eastern part of the Pavilion Mountains. They include comparatively insignificant inter- calations of argillite, cherty quartzite and niateri.vls of volcanic origin. Further south, in the region to the east of Hat Creek, such materials become more abundant and form thick beds am ng the limestones, particularly the cherty quartzites and the green stones. In this region it is probable that the lower part of the great limestone series is most prominently displayed, and that higher beds are more characteristic in the north, particularly in the Marble and Pavilion Mountains. The earlier stages of the grecat period of limestone deposition appears to have been marked by frequent interrup ions, during which argillaceous and ■.■TT!"»Knrg. . ^.■.,i.y..,.|,B'^,n' ^^~™?"^^F^^KB^ 40 n BRITISH COLUMBIA. A great nyii- cline. Minor irregu- larities. liower mem- bers of the Cftche Cret'k. The 'chcrty quartzites.' volcanic products were laid down ; while in its later stages, the deposi- tion of limestone must have been almost unbroken. The interlocking of the diflferent classe < of materials is such, however, as to show the close connection which obtains between the Marble Ca3on limestones and the lower parts of the Cache Creek formation. The limestone belt above described, has, within the limits of the map, a length of above sixty miles. There can now be no doubt that this re- presents a great syncline, upon both sides of which the older members of the Cache Creek formation are displayed ; but superimposed upon this general at icture are very numerous smaller folds, which generally run in more or less exact parellelism with it, but often in varied directions. The limestone has thus been, as it were, heaped together by repeated folding, in such a manner that it occupies a width much greater than that which can possibly be due to its thickness, with the high dips which are usually found. Similar complex folding affects the under- lying rocks of the formation, and it is due to this fact that it is almost impossible to obtain any good estimate of its total thickness or of that of its parts. This folding is not generally of the tightly compressed and linearly direct kind met with in, and near, the mountains of the Coast Ranges, but is just sufficiently irregular to make it very difficult to follow. Occasional instances are also found — as for example on the upper part of Jack's Creek, between the Thompson and Hat Creek and in Glen Hart — where the rocks rest at very low angles ; but these are in immediate contact with others in which the same beds are found to be nearly vertical. In speaking of the lower part of the Cache Creek formation, it will be convenient to refer firdt to the rocks on the east side of the main syncline, near the Thompson and Bonaparte ; next to those lying to t!ie west of the syncline, and last to those in the neighbourhood of the North Thompson and in the eastern part of the map generally. Along the Thompson and Bonaparte, these lower rocks characterize a belt of country some forty-five miles in length. They consist of cherty quartzites, volcanic materials, argillites and limestones about in the relative order of importance in which these are named. The rocks which are for the sake of brevity spoken of throughout as ' cherty quartzites,' are of a somewhat peculiar character. They gene- rally occur in well defined beds of a few inches only in thickness, and often form great masses of strata. They are very fine grained, re- sembling hornstone or chert, usually gray in colour, passing to black in one direction and to yellow-gray and nearly white in the other, but occasionally greenish-gray. Almost < ry where they are traversed by H.1 NEWER PAL/EOZOIC HOCKS. 41 II iimuraerable veinlets and threads of white quartz. The bedding planes are often black and lustrous, and black glossy argillite-schist is fre- quently associat.ed with them. These rocks have evidently been silicified subsequent to their deposition, but perhaps very soon after, for it is pretty clear that they were much in their present condition before the main period of disturbance by which the formation has been aflFected. Their microscopic structure throws very little light on their original character, but they have in all probability been laid down as argillites or silts. It is worthy of remark that they closely resemble in their character cherty or hornstone-like rocks found in different parts of the world in association with contemporaneous volcanic beds, afiFording ground for the belief that their condition may be connected with the circumstances of volcanic action. It may be mentioned here that cherty beds, which may be of a True chertH. di.ierent character, are not infrequently found in the limestones of all parts of the formation. These are often lenticular, and it is quite probable that many or all of them may represent original siliceous concretions of the nature of flinc. The volcanic materials comprise contemporaneous effusive rocks, Rocks of vol- agglomerates or breccias and ash rocks or tuffs. The effusive rocks gene- '''^""' "■'•?'"• rally vary in colour from dark gray green to green, They are usually rather fine-grained, and on microscopic examination are found for the most part to be very much decomposed diabases in composition. The coarsely porph^'ritic and uralitic diabases, so abundant in some parts ■of the Nicola formation, were scarcely seen. The agglomerates are mjide up in the main of fragments of the same character. The ash rocks and tuffs are often gray, but sometimes green, and whon fine-grained it is difficult to separate thom by the eye from the traps proper. Where tliey have been locally subjected to grent pressure, the effusive rocks tend to pass into green schists, the agglomerates into rough gray schists, and the ash-rocks into gray speckled schists, in which the constituent particles are often drawn out into linear forms. With the volcanic rocks, the serpentines, which form a characteristic Serijontines. feature in this lower part of the formation, must be included. They are often seen to be closely associated with the agglomerates and decomposed diabases, and have evidf >.tly resulted from the alteration of some highly basic volcanic rock. The argillites are generally hard and dark coloured, ranging from Argillittis. black to gray. They are often schistose, and sometimes show more or less slaty cleavage. In some places they are largely siliceous, and 42 B ItRITISH COLUMBIA. FuHuline limeatoiiea. Rocks east of main Ryncliiw. West of main syncline. Development wcKt of Fraser evince a tendency to pass into the cherty quartzites. In the black varieties, graphitic or anthracitic carbon appears to be present. The limestones found in the lower part of the formation, to the east of the main syncline, are seldom more than a few hundred feet in thickness and often much less. They frequentlj^ prove on microscopic examination to be composed chiefly of crinoidal debris, but often con- tain Fitimlina'. and other foraminifera, as well as frag^ "^nts of polyzoa and molluscs. The cherty quartzites and argillites uppear to constitute the bulk of the lowest part of the formation as displayed in this region, while volcanic rocks with associated limestones preponderate higher in the series, in that part of it which approaches the base of the Marble Caflon limestones previously described. Tiie volcanic rocks, with lime- stone, occupy a considerable area near Cattle Valley, McLean Lake and Medicine Creek. To the west of the main limestone syncline, the lower rocks of the Cache Creek formation come to the surface in the Edge Hills and their vicinity and in the western part of the T'avilion Mountains and Mount Martley. In their general character the beds here represented are much like those on the east side of the syncline. Argillites, generally schislose, are somewhat more abundant, and the typical cherty quartz- ites are not quite so well represented. The intercalated limestones appear to be somewhat less important, while rocks composed of volcanic materials are not found immediately beneath the massive limestones in so great volume as before, but appear to be rather more important at a somewhat lower horizon, which crosses the lower part of Pavilion Creek and is found with identical characters along the Fraser above Leon Creek. As a whole, the rocks are somewhat more altered than before. The argillites are more distii'iCtly schistose, and the limestones are more often crystalline and marble-like. Further to the south, and west of the Fraser, rocks of the same character, and believed to be of the same age, are found in the vicinity of the town of Lillooet, extending along their striko to Intl-pam Creek, and again seen on In-koi-ko Creek. They consist here of schistose and slaty argillites, cherty quartzites, well bedded decomposed diabase- tuffs and serpentines. These being included in the eastern strict folds of the Coast Ranges, are all somewhat more notably schistose than elsewhere, but show no other important points of difl'erence. Somewhat further back from the line of the Fraser, on Cayoosh Creek, Texas Creek and in the higher parts of the Askom Mountain, as elsewhere described in greater detail, the rocks become indistinguishable It is tri their repr the lower near Fish- to cnrrel,! this theor' volcanic n the sectio I elation wi I mode of a local cause loompositio I and uplift No pal I Boston Ba jtliis region -] NEWER PAL.KOZOIC HOCKS. 43 li •ka of the i and their md Mount jented arc , generally irty quartz- limestones of volcanic limestones important )f Pavilion aser above Itered than limestones the same the vicinity pam Creek, jf schistose sed diabase- strict folds istose than on Cayoosh lountain, as iinguishable in character from those of the Boston Bar series of the original Attcinptu ° to Nepuratc (1871) scheme. On the assumption that those last-mentioned rocks OAchc Cwk might be of Cambrijin age, an attempt was made to define a line Canucks.' which would separate them from those referred to the Cache Creek formation, but it prov d to be impossible to draw any such line to accord with the facts, and the points of diflFerence successively relied upon have broken down under investigation. The ojily notable and easily observed difference, is one dependent on the more schistose and slaty character of the rocks, which gives to them when examined in the field, a different general aspect. But this difference manifestly depends on the amount of compression to which the rocks have been subjected as infolds in the granitic masses of the Coast Ranges. It is in fact an extreme stagt; in the transition of which the earlier steps have already been referred to. Fundamentally the composition of these rocks, as well as that of the Boston Bar rocks in their typical locality, further south, is the same with that of the lower part of the Cache Creek formation on the Bonaparte and Thompson. Argillites, altered diabases, ash rocks (though now often passing into chloritic and epidotic schists and porphyroids), and limestones are equally present in both. Clierty quartzites are much less abundant in the Boston Bar rocks, but they are still to be found, and it will be remembered that the present character of these rocks is probably an iidventitious and subsequent one. Even the serpentines may be represented by the talcose rocks which occur in some parts of the Boston Bar series. It is true that the present appearance of the Boston Bar rocks and ,^f*'}}"gl'''*"j}'^, their representatives within the Kamloops sheet is much like • • ;' of rocks t<> Cain- the lower rocks of the Cambrian, as found for instance in th. ' .on near Fish-trap Rapid, (p. 107 h.) This indeed led to the attempt to correlate the Bo.ston Bar rocks with that formation ; but against tliis theory, it may be remarked that the great superior thickness of volcanic materials characteristic of the upper part of the Cambrian in I tlie section near Fish-trap Rapid and elsewliere, is not found in asso- ciation with these rocks in the Coast Ranges, while the state and mode of alteration of the other rocks may well b<, accounted for by local causes, and would have affected equally any rocks similar in I composition which existed there prior to the great period of folding [and uplift of the Coast Ranges. . No paheontological evidence is available for the IBoston Bar : ories, and as already explained, no attempt is made in Itliis region to draw any hard and fast line as that of the base of the rocks of the No fossils found. 44 B BRITISH COLUMlilA. i !?'■:■ Aviriftrous cliaraotpr. Kiickti near North Thom|) son. It!': An area of doubtful age. p. Caiii|)bell Creek bf 'i«. C&che Cretl' formation. It is quite possible that some part of these rocks may belong to horizons much lower than that of the Carbon- iferous, b'lt in the present state of knowledge there appears to be no escune from the decision to unite them, at least provisionally, with the Cache Creek formation. One point of particular interest with respect to the schistose and sL\ty rocks of the Boston Bar series and their representatives in the ar ja of the present map, is their auriferous character. This feature i.'i returned to on a subsequent page. Turning now to the rocks of the Cache Creek formation, which are shown on the map to occur in the vicinity of the North Thompson — These rocks are found, on the lower part of that rive ^ be associated with limestones known by their fossils to be of Ca ^rous age, but they are widely separated from their representat. . ..i the western part of the map, between them and which no single connecting link ejcists within the area here reported oii. Thus, besides the scanty palwontological evidence, we have only lithological characters upon whish to rely. We find here a great series of argillites, often highly siliceous (but seldom with the hornstone-like characters of the typical cherty quartzites), with limestones, grauwacke sandstones, conglomer- ates and contemporaneous greenstones. These, there is every reason to believe, represent the lower part of the Cache Creek formation, or some portion of it. How far the series may extend downward, there is no means of ascertaining, but in so far as original similarity of com- position may be taken as a guide, there appears to be some reason to believe that part of the local development may represent the rocks of the Boston Bar series. To the west of the northern part of the North Thompsou included by the map, a considerable tract of country is characterized, in so far as it has been possible to examine it, by dark schistose rocks, in part con- sisting of finely micaceous argillites and in part of rocks which may originally have been .olcanic in origin, some of which show points of resemblance to the Campbell Creek series, subsequently described. No limestones have been found in association with these rocks, and although th^ have been provisionally included in the CUche Creek formation, this reference is very doubtful. Lithologically they are not unlike some of the Cambrian schists of the lower part of the Fish-trap Rapid section. To the south of the line of the South Thompson, on Campbell Creek, near Douglas Lake and elsewhere in t.ie south-eastern part of the map, the series of rocks designated as the Campbell Creek beds occur. ] NEWER PAL.F.OZOIC K0CK3. 45 II These consist of dark argillites and fine-grained, bedded, black, slaty amphibolites, with some layers of grauwacke sandstone and .'■onie ap- parently interbedded masses of green uralitic diabase. With the ex- ception of the amphibolites, these rocks closely resemble those found about the North Thompson, but this exception is of so marked a char- acter, while the distance separating the localities is iauonsiderablo, that it appears necessary to assume it to mark some difference of hori- zon. The circumstances of their occurrence render it evident that the Campbell Creek beds must belong either to the upper part of the Cache Creek group, as locally developed, or to the lower part of the Nicola formation ; for it is clear that these bed hold a position strati- graphically intermediate between the two formations named. It has been decided to be most in accord with our present knowledge of the I'rovisionally facts, to include the Campbell Creek l)eds_with the Cache Creek forma- Cilcbr Creek, tion, and thus the thickness of this series of beds, (or at least a great part of it, for there may be some overlap of horizons) should be added to that estimated for the Cache Creek formation on the North Thomp- son in order to represent the total volume of that formation in this eastern part of the map. As elsewhere explained, there is some appearance of a passage with- CiviiiipIhOI out break between the Campbell Creek beds and the lower beds of absent to tho the Nicola formation, for no really definite line has yet been satis- ^^»"''■• factorily determined between them. In the case of the unconformable junction of the Cache Creek rocks with those of the Nicola formation on the North Thompson, not far to the east of the margin of the present map,* no rocks resembling the Campbell Creek beds are found, and it is therefore probable, to which ever of these formations the Campbell Creek beds may ultimately be attached, that the strati- graphical break at this place is an important t)ne. Neither are recog- nizable representatives of the Campbell Creek beds found in the sec- tion to the south of Ashcroft (p. 112 n), Imt the distance which sep- arates this from the typical localities of these beds is so consideroljle that the argument for unconformity by overlap, which might there be based upon this circumstance, is less cogent. On the other hand, no trace of the massive upper or Marble Cafion Marble Cafion limestone of the Cache Creek formation as represented in the western sent to ttie part of the map, has been found in the eastern part. To account for ''''**'■ this fact it may be conjectured : (1) That if deposited here this lime- stone has since been removed by denudation ; (2) that the upper part of the formation has no representative in this region ; (3) or that • See Report of Progress, Geol. Surv. Can., 1877-78, p. 80 B. •pmsmmmmim 46 B BRITISH COLUMBIA. it is represented by other rocks, as for instance by the Campbell Creek beds. The amount of pre-T riassic denudation implied by the finst hypothesis is so great that considerable hesitation is felt in adopting it. The abundance of grai-.wackes and the occurrence of some conglomerates n this eastern part of the Cache Creek formation, appear on the other hand to suggest the occurrence of an approach to littoral conditions, which would favour the acceptance of one or other of the two last named hypotheses. Probable total The extremely unsatisfactory condition of the rocks of the Cache thicknesR of . ■' •' Ciiciie Creek. Creek series for all purposes of measurement, w'!' be understood from the foregoing remarks as well as from the further local details given on later pages. Thus, in endeavouring to give some idea of the total volume of the formation, no even proximately correct data can be quoted. The subjoined summarized section is tlierefore merely an attempt to indicate the general oider of succession, and to some extent the im- portance of the format:ion, in ilie western part of the area of the map. The order is descending 1. Feet. Miissive limestones (Marble Canon limesttme) with some minor intercalations of volcanic rocks, argil- lites and oherty quartzites. At least 1000 feef seen in some single exposures. Total thickness probably at !.- as" 3,000 2. Volcanic mate, lals and limestones, witii some argil- lites, cherty quartzites, etc. Minimum thickness about 2,000 3. Cherty quartzites, argillites, volcanic materials and serpentines with some limestone. The thickness ' of these beds, or of a part of them, was roughly estimated in two places as between 4000 and 5000 feet. Minimum total thickne.ss say 4,500 9,500 The thickness of the lower members of the above section depends upon their development on the east side of the main limestone syncline. It will be remembered that the character of the rocks is somewhat different on the west side, where, in particular, the volcanic materials do not appear to be so important immediately below tlie Marble Cafion limestones, tliough perhaps more largely developed at a somewhat lower stage. To the numerous known fro seiited. ported on stones, arf i-'li.iracteri! daily deal In tho ''ran NystPi SEWER PAL-EOZOIC ROCKS. 47 n \ 1 depends limestone the rocks ho volcanic below the iveloped at lo the south of the area of the present map, the thickness of the rhickness of ,.,,,., . , T. w^ ,. 1 ••II- "o»t('ii Bar rocks mcludea in the typical lioston J3ar group or the original chussi- groui). fication alone, is estimated at between six thousand and seven tliousand feet (p. 102 b). The thickness of the beds referred to the Cache Creek tonuafion on the North Thorapdon, is roughly estimated as about seven thousand five hundred feet (p. lOi u), but, if as above indicated a con- siderable part — say live thousand feet — of the Campbell Creek beds may be abided to this, we obtain a total volume of twelve thousand five hun dred feet for the Cache Creek formation in the eastern part of the map. Thus, the entire volume of the rocka of the Cache Creek formation as this is now defined, may be assumed to be about ten thousand feet as a minimum, while I am inclined to believe that it really exceeds lifteen thousand feet. The existence of rocks referable to the Cache Creek formation in the C;Uhe Cirek northern parts of British Columbia has already been alluded to in con- ,.,,1 Britiali nection with the general definition of the formation. These rocks have ''^^'unil^'*- in fact now been found to occur at intervals from the southern boun- dary of British Columbia north-westwards to the upper waters uf the Yukon, characterizing particularly a belt of country which lies to the east of the Coast Ranges, ard which corresponds more or less closely with the Interior Plateau of the southern part of the province. Their lithological composition, throughout this length of over 800 miles parallel to the general structure of the Cordillera, is everywhere much the same ; massive limestones, cherty quartzites and volcanic products being characteristic. A few characteristic fossils have been obtaine'1 in a number of places beyond the limits of the present map. At >' .art Lake (lat. 54° 30'), Dease River (lat. 59' 15'), Frances River ' .... GO 30') and on Tagish Lake (lat. 60°), fusuline limestones have been observed. To the westward of the Coast Ranges (in which it is probable that On tho coast, numerous infolds of Pahvozoic rocks will yet be found) a formation known from its fossils to be of Carboniferous age is again well repre- sented. This has, so far, not been very minutely examined or re- ported on in detail, but it is known to comprise thick beds of lime- stones, argillites and volcanic materials, the latter being even more characteristic and iv. greater development than in the region here spe- cially dealt with.* In the Rocky Mountains proper, or eastern member of the Cordill- CivrlioniferouK , . , . , , , , , . , of the Hocky ^'ran system, the section which must now be regarded as the typical Mountaitw. • See Geol. Mag., dec. II., vol. VIII., pp. 218, 219. mm 48 B BRITISH COLUMBIA. Region be- tween Kam- looi)s area and Rocky Mountains. Oarboiiiferous rockn of Cali- fornia, etc. U' one for these latitudes, is that worked out by Mr. R. G. McConnell.* In this section the Carboniferous period is represented by the BanfiF limestone series which, including two shaly zones, has a thickness of 5100 feet.f This has yielded a number of fossils, and these show that the series as a whole represents the lower part of the Carboniferous, passing below into Devono-Carboniferous. The later part of the Carboniferous period seems either to be unrepresented, or if represented at all, to find but a partial equivalent in the upper shales. It is thus very probable that before the close of the Carboniferous the present position of the Rocky Mountains formed part of a land area. Thu.s, the absence of the great Marble Canon limestones of the Cache Creek formation in the eastern part of the Kamloops sheet, with the appearance alrefidj' noted of an approach there to littoral conditions, may indicate that this land area of the later Carboniferous extended westward nearly or <}uite to the eastern edge of what is now the Interior Plateau region. It must, however, be noted, that in some portions of the region between the Kamloops sheet and the Rocky Mountain range, as on Adams Lake and Kootanie Lake, the upper part of the genenil section includes thick beds of limestone, with greenish and gray schists and black ar'.;illites, which are believed to be at least in large part referable to the Carboniferous period. J But it is not known to what part of the Carboniferous these belong, and it may very well be that they more nearly represent the horizon of the Banll' limestones than that of the Marble Canon limestones of the Cache Creek formation. Carboniferous rocks closely resembling those of the western part of British Columbia will probal)ly eventually be found in the correspond- ing western portions of the >States of Washington, Oregon and Cali- fornia, where limestones of this age have long been known in a number of localities. Mr. J. S. Diller has lately described the occurrence of important volcanic intercalations in the Carboniferous rooks of the Taylorville region of California, thus bringing those into line with the long recognized character of the Carboniferous of British ColuHibia in this respect. He finds reason to include (though in part doulii fully) a thickness of over fifteen tiiousand feet of beds in thi." system at that place.§ Further east, in the Middle Nevada and Wahsatch sections, Clarence King has found the Carboniferous system * Annual Report, Geol Su.'v. Can., vol. II. (N.8.) t Op. eit., |). 17 I) et seq, i See p. 2!* B, also Annual Report, Oeol. Surv Can., vol IV. (N. S.), p. 31 n. S Bull. Geol. Soo. Am., vol. III., pp. 372, 374-370. * Geoa f Aiiii| 4 ■■ny ■J TRIAS8I0 ROCKS. 49 B to consist., in descending order, of the (1) Upper Coal Measure lime- stone, two thousand feet, (2) Weber quartzites, six thousand feet, and (3) Wahsatch limestones, seven thousand feet, with a total thickness of fifteen thousand feet, the lower portion of the last named formation passing down, howevci', into the Devonian.* With our present information, it would appear that the Marble Canon limestones probably represent the upper member of this section, while the lower parts of the Cache Creek formation are equivalent in a general way to its two lower members. It has already been noted that the lower portions of the Cache I'osHibif Creek formation may be older than the Carboniferous period. |If''|')"von'ian The very general bh-nding of the Carboniferous and Devonian systems Silurian, etc in the West, shows that no well-marked line need be anticipated at the base of the Cirlioniferous. The separation of any beds of Devonian age can only be made in the event of the future discovery of characteristic fossils. The same may be said respecting the possible existence of Silurian or Can liro-.Silurian beds. Where complete sections have been examined . the wostern parts of the continent, these usually form a comparatively thin series, intervening between the Cambrian and the Devono-Carboniferous, Itorli of which are very massive formations. In a great mass of strata liki- that hero reported on, there is ample place for such representative^ of these rocks, but so far, in the southern part of British Columbia, no fossils of this age have been detected to the west of the Rocky Mountain range. In the far north, however, on the Dease River (Lat. 59' n't ) graptolites of Cambro-Silurian age have been found. f Tr lassie . Stratigraphy and General Relation^. — In the Preliminary Report ui lli.. Nicoht 1877, the existence of rocks of Triassic age in British Columbia was f""""*'"" for the first time made known. The statements then made rested chit^Hy upon the facts met with in the vicinity of Nicola Lake, and the formation was in consequence named the Nicola series. The deter- mination of the age of the rocks depended almost entirely upon tho interpretation given to the few fossils obtained from the limestone of McDonald River (Quilchenna Creek) and the relationship established between this limestone and the as.sociated great mass of volcanic rocks. It thus became possible, at that time, to describe the general character * Geology of the Fortii-th P.irall(>l, vol. 1., p. 2-18. t Annual Report, (Jool. Snrv. Can., vol. III. (N.S.), p. 94 n. i 50 B BRITISH COLUMBIA. Fossils originally fouiid. Ijatei-Mis- ctwariea of fossils. of the series very much in the same terms which might be employed to-day.* Further search has net resulted in obtaining any additional characteristic fossils from this particular limestone, and it may thus be appropriate to quote the original statement made concerning it, as follows : — "The limestone of McDonald's River, Nicola Lake, was at first sup- posed to be Carboniferous, but the most diligent search failed to bring to light any characteristic forms of this age, and, on the contrary, resulted in the discover}' of the scattered joints of a crinoidal column, closely allied to Pentacrinites asteriscus, Meek, of the Jurassic of the Black Hills. It differs from this form, however, in some particulars, but in these it approaches to, and is piobably conspecitic with, a PentacHnites doubtfully referred to /'. aateriscus by Hall and Whit- field, and procurefl from beds of Triassic age in the Pah-Ute Rani;e of Nevada.! Apart from other con.siderations, this might form a rather uncertain criterion of age. but in the same limestone a Terebratula al.so occurs which can be referred, with very little doubt, to the ratheir variable species T. IJumbnldtensis, which is also found in ass-^ciation with the crinoid above named, in the same locality in Nevada. "| The onlj' additional fo-:sil since obtained from this particular locality is one described by Mr. Whiteaves as a species of Cijrtina or ^jpirij'erina with a very high area, not specifically determinable. In 1890, another fo.ssiliferous locality was found in the limestones which outcrop near the mouth of the Deadnian River, the collections made including two species of Pelecypoda, not determinable, and portions of the guard of a slender Belemite which might be referred to the Triassic period or to one somewhat later. In the same year, in the hills a few miles to the eastward, and at a horizon which appears to be several thousand feet higiier than the last, some fossiliferuus argiilites were discovered. Professor A. Hyatt, who has kindly made a preliminary examination of tlie fossils obtained from this and a few other localities, designates these as distinctly Triassic, enumerating a Myacifes like uV. IJuiiiboldtfunis, *.iaV)b, a Daonclla like D. Loinaiieli, a Triyonodns, a Cardita and other fragments. In. 1894, a somewhat minute examination was made of the rocks along the east side of the Thompson, south of Ashcroft, in the course •R('IK)rt of I'l'ogrfBs, (icol. Hiirv. Can., 1877-78. + U. S. (leol. Exploration of tlie Koitii-tli Parallfl, vol. IV., p. 280. X 0)1. fit. p. 171 H. Pfntiicrinitin has since l)wn found in three placoH in California in ftsHociation with undoubtwl Triacsic fossils. J. 1'. Smith. Bull. Utxil. Soc. Am., vol. v., p. 250. "•] TRIASSIC ROCKS. 51 B of which fossils were found at two different horizons, separated by about twelve thousand feet of strata. Of these, the lower yielded a Daonella like that last noted, and a Panonea like P. Remondi, Gabb, Fossils of . Ijowor .) uraH- while the upper is believed by Professor Hyatt to be of Lower J urassic sic age. age, equivalent to the Hardgrove sandstone, and possibly to the Mor- mon sandstone of Taylorville, California, from which fossils have lately been obtained. Professor Hyatt enumerates two species of Rhynchonella, one like R. gnathophora, a Pecten like /■*. acntiplicatus, Gabb, an Entolium like E. equabilis, Hyatt MS. and Lima parva, Hyatt, MS. In a small detached area of limestone near the 89-mile stable on the Thompson, a few fossils have also been found to which Professor Hyatt attributes an age similar to the last, although the species repre- sented are difierent. > The above statements summarize all that is really known respecting Strata yield- the age of the Nicola formation from palreontological evidence up to wj^arabL from the present time. It will be observed that the original reference of Triansic. tlie series as a whole to the Triassic has been gradually strengthened by later discoveries. These, taken in connection with the strati- graphy, in fact seem to show that while the great bulk of the Nicola formation is undoubtedly equivalent to the Triassic, it passes up in a few places into rocks of Lower Jurassic date. The structure and lith- ology do not appear to afford any means of separating the two faunas or of drawing any line through the great mass of rocks, chiefly of vol- canic origin, in which they oi:cur, and it is therefore approj>riate and necessary to treat of the Nicola formation as a whole, although recog- nizing the fact that it probably extends higher thah the typical Trias. In several parts of the soutliern interior region of British Columbia, Unconformity pretty good evidence exists of an unconformity between the rocks of Q^cek. the Nicola formation and those associated with limestones holding characteristic fossils of Carboniferous age. Such an unconformity is believed to exist in the hills on the north side of the South Thompson, about ten miles above Kamloops and beyond the limit of the present map.* It is also supposed to occur in the rocks near the Thompson River below Kamloops Lake (p. 120 a) and there are indications of its oxistence in the vicinity of Ashcroft. This unconformity may not, however, be universal, even within the limits of the area here under notice, and the character of the older rocks renders it always very tliificult to determine. RoiHiit of Progress, Geol. Surv. Can., 1877-78, j). 80 b. 52 B BRITISH COLUMBIA. Definition of the Nicola formation. Mapping of the Nicola. Date of ^an- itic rocks. SI y The Nicola group, as originally defined in the report for 1877, was in- tended to include merely the limestone of McDonald River, with the attached and overlying great aeries of volcanic materials found in the section on Nicola Lake, as yet out on page 77 b of the report cited. Subsequent investigations have, however, shown that greenstone rocks essentially similar to those of the original section, also underlie the McDonald River limestone in the same vicinity, and that they there hold probably at least one other similar thin limestone. These rocks are therefore also now included in the Nicola formation, which here finds its provisional base where they rest upon the dark Campbell Creek beds, already described. y In attempting to define the limits of the Nicola formation on the map, it has had to be separated from the often lithologically similar rocks of the Cache Creek formation on the one hand, and from those of the Cretaceous and later formations on the other. The latter separation is generally not difficult, but when the Nicola rocks are found in association with some of the altered volcanic products of the Lower Miocene, it is often far from easy to decide upon a line, which must proceed upon lithological grounds alone. The reasons in accordance with which it has been fixed in each part of its extent, together with the doubts attaching to it, are fully explained in the .sequel. As already stated, it is quite possible that a practically continuous sedimentation, or effusion of volcanic products, was raantained in some parts at least of the district throughout the later Palaeozoic and the earlier stages of the Mesozoic. The more important granitic masses of the region, are evidently later in date than the Nicola rock.s, while they are unquestionably earlier than those of the Cretaceous, and their existence and relations to the other rocks frequently affords important information in regard to tht^ upper limit of the Nicola formation. They are [inibably contempor- aneous with .some of the larger granite ma.ss! s found on the coast of British Columbia,* and there can be little doubt that the close of the period of Triassic deposition was brought about by crustal movements either consequent on or productive of the great gi.\tiitic intrusions of both regions. There is thus undoubtt^dly a distinct unconformity between the \. ighest members of the N icola formation and *he lowest, beds of the detaceous, and though this is often more or less masked by subsequent folding and disturbance, it is marked by a distinct change in the character of the materials composing the respective formations, * Annual 'luport, (leol. ►'(ui'v. Can., vol. II. (N.S.), pp. 11 n, 15 b. ■] TRIA88IC POCKS. 53 B \ as well as by a great limitation of the area of deposition in Creta- ceous as compared with that of Triassic times. The Nicola formation, where it has been recognized, appears to Area of Nicola attain its greatest development along the central part of the Interior Plateaii of British Columbia. It is most widely .'lish and green ; a few small lime- stone beds near the base Chiefly green diabase agglomer- ates, often coarse. Several calc.ireous beds and lime- stones. Dark felsites at base. Approximate total.. . . Feet. 20 1,800 7,840 .3,!»30 13.590 Vicinity of Nicola Lake. Feet. Fine grained felspathic rocks, generally well bedded Diabases, chiefly effusive and sometimes amvpdaloidal ; some tuffs ; two thni l>eds of limestone near the base. . .. Chiefly green diabase agglomer ates, occasionally aiiiygdal oidal. Thickness at least 2,t>00 feet, and i)ossibly «,000 feet (say) Approximate total (tiiinimum). 1,200 3,700 2,000 7,500 Trias of tiue« icola rormation, but otlier- Vancouver. wise the resemblance between the two, both in regard to their origiiwil mode of production and their present appearance, practically amounts to identity. Notwithstanding this fact, it is believed to be appro- priate to retain distinctive local names for the two great develop- ments of Triassic rocks in British Columbia. In both cases the lower and upper limits of the formation remain more or less inde. finite, chiefly because of the absence throiigliout great masses of the strata of any organic I'emains, and thus one may extend in its lower or upper beds through a part of the geological time-sjale consideral)ly greater than the other. It is morever found to om a general rule in this part of the Cordiller.a, that exact equivalercy of formations is scarcely to be sought for at any coiisiderab'e dist'.taee, across the prev- alent north-west and south-east trend of the loi'.in orographic features, and in this case, the nearest recognized representatives of the two formations are separated by a gap of about 150 miles transverse to this direction. It is unnecessary in the present connection, and in the as yet in- Triat^^ic tA thy complete state of our knowledge of the Tritissic rocks of the west, tt) enter into any extended comparison of the Nicola formation witii other rocks believed to be of the same age. It may sufhce to point out that characteristic Triassic fossils, like those of the Nicola and Vancouver formations, have now been found in a number of places very far to the north and north-west of these typical localities, as on the Stikine, Liard and Peace rivers and even in the Alaskan pen- insula ;t and that it is evident that in this northern region the Triassic sea extended eastward completely across the Cordilleran belt. To what extent volcanic materials are mingled with those of ordin- ary sedimentary origin in these northern localities, remains in most * Iliiil, l).8u. tSee Anmial Ki'ixirt, (Jcol. Surv. Can. vol. 111. (N.S.), pago 54 ii ; Ihiil., vol. IV., page l!)l); Rt'ix)rt of Pixjgre.fs, (ieol. Surv. Can.,, 1870-70, p. 97. liull. (ieol. Soc. Am., vol. v., p. 122. 56 B nRITISII COLUMBIA. Koc'ky Moun- tain r»'cl hvdii. cases still to be determined. It may further be noticed, that no rocks like those of the Nicola formation are found in that part of the Rocky Mountains proper which is situated in latitudes similar to those of the region here particularly described, but on the contrary, that about as far north as latitude 49° 30', certain red beds, the deposits of an inland sea, are there beHeved to represent the Triassic period. Between the northern part of th.o inland sea and the extension of the ocean in which the Nicola and Vancouver formations were laid down, land, occupying approximately the position of the Selkirk Range, appears to have formed a barrier.* Comparison To the southward, in the corresponding portion of the Cordilleran witJi Bouthern j^gjj. ^f ^jjg western part of the I'nitefl States, the nearest available term of comparison for the rocks here described is found in the Taylor- ville region of California, some 700 miles distant. It is not intended to suggest that the intervening portion of the Cordillera diflfers in its structure, but it has not yet been carefully examined or studied, and in regard to all formations older than the Cretaceous, it remains practically unknown. Such cursory observations as T have been able to make in travelling through this intermediate region, comprised in the states of Oregon and Washington, lead me to believe that rocks representative both of the Nicola and the Cache Creek tormaLions of British Columbia will ultimately be found to extend without any important break to California. The Taylor- In the Taylorvillo region, f near the fortieth parallel, in northern ville sections. California, the rocks have been examined in detail, stratigraphi- cally and paheontologically, by Mr. J. S. Diller, Professor A. Hyatt and others. The results arrived at by the two gentlemen named are given in a summarized form in papers contained in the Bulletin of the Geological Society of America.]; It is there shown that the Triassic rocks are unconformable on those of the Carboniferous, that these rocks as locally developed are all referable to the Upper Trias, later than those of the Aspen Mountains, Idaho, or of the Star Peak Range, Nevada, while they are supposed to be limited above by a second un- conformity which separates them from beds containing Jurassic fossils. § No unconformity corresponding to the last has been recognized in * For a further discussion of tliis jwint see Trans. Royal Soc. Canada, vol. I., sect. IV., {). 14.S et scf/. f An area about 12 miles in length by 6 miles in width. t Vol. III., 1802, \>\>. >SC9-412. § Iliid., pp. 378-379. 8ee also vol. V., p. 39i». The evidence of the Jura-Tria« unconformity as ^ven by Mr. Diller, does not appear to be entirely satisfactory for a region so much distiirlx-tl as tliat of Taylorville. ] TRIA8SIC HOCKS. a I II British Columbia where, on the contrary, the fossils referred by Professor Hyatt to the Lower Jurassic, occur in beds which appear to 1)6 conformable with those of the Triassic and which arc included with them in the Nicola formation of this report. A great otogenic movement, however, took place previous to the deposition of the low- est Cretaceous beds, which is probably equivalent to the important un- conformity in California elsewhere referred to by Mr. Diller.* Nothing beyf)nd the few fossils above referred to, of supposed Lower Jurassic age, has yet been found in British Columbia to bridge the gap between the Triassic and Cretaceous, for the beds on the Iltasyouco liiver (Lat. 50', Long. 126"), atone time supposed to be Jurassic, have been united by Mr. Whiteaves with the Cretaceous. f The most interesting circumstance met with in the comparison of Volcanic nm the sections examined by Mr. Diller with those of the Nicola forma- tion, is the considerable proportion in which materials of volcanic origin enter into the composition of both, and the evidence thus afforded of the widespread character of volcanic action at this time. J It is, however, probable that the lower rocks of the Nicola forma- tion are considerably older than any of those nicognized in theTriflSsic of the Taylorville district, and that tiie formation as a whole may corre- spond more closely with the period represented by the Triassic rocks (if the Fortieth parallel region to the east of the Sierra Nevada and between that range and the Wahsatch Mountains, as described by Clarence King. The rocks of this system are there divided into upper and lower Nevada sec- series, designated as the Star Peak and Koipato groups, respectivel)', with a total thickness of some 16,000 feet. These mcks generally rest upon an Archiean foundation, but pass conformably upward into the Jurassic. They are to a great extent composed of materials of ^ ordinary .sedimentary origin, but the imj)ortant development in them % of materials described as " porphyroids " and in some cases as "ehloritic schists," induced me long ago, in the light of the composi- tion of the Nicola formation, to venture the suggestion that such rocks really represent contemporaneous volcanic materials, although in the Geology of the Fortieth Parallel their character is accounted for as the y result of some peculiar metamorphism. This sugge.stion has not yet, • Ibid., vol. IV., p. 221. t Report of Projfi'esR, Geol. Hurv. Can.. 1876-77, p. 15S. (ieological Magazine, decade II., vol. VIII. (1881), p. 218. Wliiteaves, Mesozoic Fossils, vol. I., part III., )). 2r)8. t Bull. (leol. Soc. Am., vol. III., p. ,'{7fi, etc. See also J. K. Mills on an ad- jacent part of California, p. 420. The rocks described by him are shown by Mr. J. 1'. Smith to be Triassic. Ibid., vol. V., p. 250. \ 58 B imrrrjH columhia. Metainor- phiHm of vol- cAiiic r<)ck8. SO far as I am aware, been borne out by any later investigation of the rocks, but it appears to me to be, in connection with t}ie facts now established in the Taylorville region, more than ever probable.* Conditions of Mefamorphism qff'ecling the Oldrr Volcanic Roth. In order to understand the diflTerent forms in which the volcanic rocks of the Nicola series now appear, it is necessary not only to refer them to the original materials which they may be supposed to repre- sent, but also to examine into the causes of alteration . vhich have since operated upon them. In such an examination, the metamorphisni of the ordinary sedimentary materials and of the limestones, which coustitute a relatively small part of the great Triassic series as here developed, may be passed over, as being well understood and pr»^ I'tit- ing no features not easily recognized. It is in respect to the mass of rocks of volcanic origin, of which by far the greater part of the form iion is built up, that questions surrounded with greater difficulty and doubt arise. Anipliiboliteg nf Campbell Creek. The fine-grained amphibolites, which in association with hard slaty or schistose argillites constitute an important feature in the Campbell Creek section and in the vicinity of the Douglas Lake granite mass, (pp. 122 D, 136 ii) although assigned provisionally to the Cache Creek formation, may be mentioned in connection with the remarks here made on the Nicola volcanic rocks. This is appropriate by reason of their association in the field, and also because they seem to illus- trate what may be merely another form of metamorphism to which such volcanic materials are subject. Miscroscopic examinations of some of these rocks made by Mr. Ferrier, lead him to believe that they have resulted from the dynamic metamorphism of basic igneous materials, which may have resembled the diabases common in the # Cache Creek formation, or those which constitute the greater part ot Their mode ot ^^^ Nicola formation. There are, however, other varieties, difficult origin. of study under the microscope, but which in the field, evidently grade into hard black argillitps and into grauwacke sandstones, and in which no evidence of a foliated structure as distinct from the beddinjr pianos are found. It does not, therefore, appear probable that these dark-coloured, fine-grained rocks have revolted merely from the meta- morphism of the ordinary diabase porphyric. When evidently subjected to dynamic metamorphism, these ordinary diabases are observed to produce green and gray, lustrous, chloritic and sericitic schists. Where *See Trans. Royal Soc. Can., vol. Parallel, vol. I., pp. 268, 271-272, 275. I. (1883), p. 145. Geology of the Fortietli H.] TRIA88IC R0CK8. S9 B \ f the Fortietli affected merely by the temperature consequent on contact with granitic masnes, they are found to pass into gray rocks of gneissic appearance, but free from quartz. It is in fact supposed, that these amphibolite schists may represent highly altered basic tuft's, which have been deposited in water with frecjuent admixture of ordinary clayey material, and that their appear- ance of bedding really depends upon tlieir original arrangement as sediments rather than upon any subsequent foliation. In any case, they appear to constitute, an the Stump Lake and Upper Nicola region, a set of beds with recognizable and somewhat peculiar characters which are of classificatory importance from a stratigraphical stand- point. It may, however, still be argued that these amphibolites have been produced from the ordinary diabases of the region by a combination of temperature (or contact) and pressure effects, differing from that of either of these factors acting separately. I am not prepared to deny that this may be the case, although some of the circumstances cited above are opp(jsed to such a belief. Reverting to the other forms of alteration which are met with in the region, a few words may now be said respecting the kind of change which is clearly referable t(j the proximity of extensive granitic masses and may be described as a contact phenomenon. This is not equally apparent in the ease of all co itacts of these old volcanic rocks with the granites, a circumstance for wliicli the reason cannot be given with certainty, but which very possibly depends largely upon the angle which the intru.sive mass makes with the present surface. For, upon the assumption that the effect in the matter of alteration is equal in the case of each contact, it is obvious that this etlect would be apparent for a relatively small distance when the plane of contact is vertical to the actual surface, while it might extend very nmch fur- ther when this phine cuts the surface obli(iuely. But in addition to this, it must be noted that a much greater degree of heat, of hydro- thermal action and of pressure may have attended some of the con- tacts than that found in the case of others. In the southern and stratigraphically higher part of the section t'lianpps ol> which has been referred to as the Campbell Creek section, what is contact'."^^'" believed to be the normal change attending a contact of the diabases of the Nicola formation with granite is very well exemplified. The nature of this alteration is explained in .some detail elsewhere (p. 1 23 u). It may suflice here to say that the green colour due to the general Metaiiior- pliisiu near (,'ranitu t'oii- tfvcts. ■MR CO B HRITISH COLUMBIA. Various grmv itfc coiitactd. Dyiiiuuic met amorphisni. alteration originally suffered by the diabases, and resulting from a <;hp.iige of a part of the augitic constituents into chloritic minerals which have become diffused through the mass of rock, has in this place and in others similarly situated, been eliminated. The ferrugin- ous and basic constituents of the magma have rearranged themselves into black or dark-coloured new crystals of hornblende, while the felspathic constituents have recrystallized in colourless forms. The general tint of the rock thus changes from green to gray, and when nearly in contact with the granite it assumes a gneifsic structure, though free or almost free from quartz. Mica is also very frequently developed along the planes of bedding or foliation, but this appears to result chiefly from the effect of pressure superinduced on that of the metamorphism due to mere increase of temperature. Along the zone of contact of the diabase series with the granites on the line of Moore Creek (p. 129 h) pressure appears to have played a considerable part in the aggregate change of the rocks. The neighbouring parts of the granite are often foliated, and gray mica- ceous-looking schists are frequent, though many of them when care- fully examined are found to have the characters of amphibolites or epidiorites in so far as the bulk of their constituents is concerned, x'he same phenomena are repeated near the head of Clapperton Creek (p. 143 li), in some places on Guichon Creek (p. 144 h) and to the west of Jacko Lake (p. 138 u). When, at any considerable distance from the granitic ma.sses, the altered rliabases have been i^ubjected to great pressure alone, they tend to pass, as already noted, into the green and gray chloritic or sericitic schists, which are often lustrous and sometimes contorted and wavy in their planes of foliation. All intermediate stages between such rocks and massive and distinctly porphyritic diabases may be found in different parts of this lield, and along the southern side of Nicola Lake (where this particular kind of alteration was chiefly notsd as affecting the Triassic rocks) it is observed to be best marked in the vicinity of the compressed anticlinal axes. It is there also ob- served that the rocks so affected are usually highly calcareous, nnd it is possible that materials originally containing a cou.siderable propor- tion of lime have passed most easily into such glossy schists. It may here be remarked that, in the case of such schists within the arc of the Kamloojis sheet, no ciiteria have been found which, apart *r' n stratigraphical evidence, suttice to determine their age. Under . : o conditions, rocks of originally similar character whether TriHSf'", Carboniferous or Cambrian in age, have been changed into 1 TRIASSIC BOCKS. 61 B V green and gray schists in themselves indistinguishable. Neither is it possible in hand specimens, to make any distinction between the green- stones or altered diabases of these several and widely separated geo- logical horizons. Respecting the original chartacter of the materials of the Nicola Original char- formation, now found in the various stages and kinds of alteration above la rocks.^ referred to, it may confidently be stated that they have appeared as vol- canic rocks not necessarily different from those which now reach the sur- face in regions of vulcanism. The great bodies of volcanic materials which at recurrent intervals appear to characterize so many different stages in the entire geological history of this part of the Cordillera, in them- selves afford a practical clue to every step in the alteration of such deposits. The greenstones, or groen altered uralitic dia- bases, now so abundant in strata of Triassic age and older, have un- ( loubtedly at one time reached the surface as dolerites or as basalts, which in some cases have been effusive, in others of the character of volcanic breccias, or the finer forms of volcanic ashes or tufl's. Such deposits, whether thrown down sub-aerially and afterwards covered by later Ktrata, or scattered and spread abroad in the waters of the sea of the period, are essentially the same. Under the last-named c mditions, they are often well stratified, but unless subjected for prolonged peri- ods to the leaching action of water, or intermixed with considerable proportions of calcareous or ordinary earthy deposits (both conditicms which can only have prevailed when the rate of supply ui the volcanic material was slow) they are the same in composition and remain sul)- jeot to a similar series of changes. In the Tertiary volcanic rocks which cover so large a part of the Analogy witli same urea, we find without dithculty the little changed or practically ^..^„|^. ,.,V.Us. unaltered representatives of all the older volcanic rocks. The massive basalts, dolerites, nielaphyries and augite-porphyritas, with agglomerates composed of those rocks, afford the materials which, by a breaking down of their original constituents and some concurrent recrystallization of them, lead to the production of diabases By a further change, affect- ing principally the augite of the diabas*? and resulting in its conver- ,siou into iiornblende, wholly (■.• in part, the characteristic " green- stone "' or altered diabase of the region may be formed, of which the 'itill further changes have already been traced. In a similar manner, the bedded tuffaceous rocks of the Tertiary evidently represent the clastic materials of many of the older rocks. The acidic volcanic rocks need not be considered here in detail, for tliough rocks of this character are present in the Tertiary accumulations, they have not so 62 B BRITISH COLUMBIA. far been recognized as playing any important part among the older rocks of this particular region. Eastern limit of Crc'taci-(jus. Areas ill map shoet. CoMiiHwition of the FiK-ka. Cretaceous. Strata referable to the Cretaceous period, occur in the western half of the Kamloops sheet alone, and there only as insets among the older rocks due to folding, or folding and faulting combined. These rocks have not been recognized to the east of the Ashcroft Cretaceous area, and a more general survey of the conditions in British Columbia renders it probable that the Cretaceous sea at no time extended much further east in this latitude. The deposits consist largely of coarse clastic materials, including massive conglomerates, which in all proba- bility indicate a sinking sliore-line. But it is further evident thai we can now possess but residual fragments of a formation whic.'i must at one time have been much more extensive, for the conditions imply that at the time of the deposition of these beds the Coast Ranges were either non-existent, or that they were broken and discontinuous, so that the Pacific Ocean of the period obtained free access nearly to the centre of the region which now forms the Interior Plateau of British Columbia. The residual Cretaceous areas of the Kamloops sheet, wliicli have I'scaped the great post-Cretaceous denudation, may be designated as the Fraser River area, the Ashcroft area and the Botanie Creek area respectively ; the last-mentioned being quite inconsiderable in dimen- sions. The excessively crushed and disturbed condition of all these Creta- ceous rocks, has so far rendered it impossible to obtain any complete general section of them ; but it would appear that in the Fraser Kiver area, hard black argillites and black fine-irrained .sandstones or (juartz- ites form the lower part of the .series, while gray and green-gray sand- stones, with massive conglomerates, prevail in its upper part. In the Ashcroft area, on the other hand, tlio lower part of the formation seems to consist chiefly of green or gree.i-gray sandstones or (juartz- ites, while dark, shaly, and fine-grained sandstones are more abundant in its upper parts, conglomerates being less important at all stages. In the Ashcroft area there are, however, some coarse sub- angular grits and conghmierates towards or at tiie base which appear, to represent true " basal conglomerates." These, in one place (abo- idtion. Kosisils ob- tained. entered largely into the composition of the Cretaceous beds and par- ticularly into those of the Earlier Cretaceous.* Respecting the precise geological age of these rocks, it may here be sufficient to state that the)' are, for the most part, the local representatives of a great Earlier Cretaceous series which is very widely spread in British Columbia, and of which the fossils from a number of localities have now been studied in detail by Mr. J. F. Whiteaves. To this, the name Queen Charlotte Islands formation has been applied as a general one, as from vhese islands the greatest body of palivonto- logical evidence, with the best general section of the rocks, has been derived. For further details on the equivalency of this with other recognized Cretaceous areas, earlier publications by the writer and Mr. Whit- eaves maj be consulted. f Within the area of the Kamloops sheet, the whole number of Cretaceous fossils so far found is very small. In addition to the few plants elsewhere mentioned, on'y two species of molluscs have actually been determined. These are Aucclla Moxqitensis var. coiirenlrica and Pecten ( Syncyclonetna) Mcekiana. No fossils have yet been obtained from the Ashcroft area. Beyond the edge of the present map, however, the Cretaceous rocks run alon^r the Fraser valley for many miles to the southward, the trough terminating in a mountainous country to the east of Boston Bar and North Bend. I This southern extension of these rocks was examined by Dr. Selwyn in 1871, and the rocks were then provisionally referred to by him as the "Jackass Mountain Group," though their age was un- kpown.§ Subsequently (in 1875) these rocks were, on lithological grounds, correlated by the writer with those of Tatlayoco Lake (of which the age had been fixed by fossils)]] ; but in 1877 they were found to yield some fossils in Dr. Selwyn's original locality, and these bore out the reference just alluded to. T'le fossils oljtained at that time, which may be taken as equally characteristic of the rocks of the Fraser River area within the present sheet, are Bi'h'.mnites iiiijtresHKn, Gabb, I'ecten ( Syncyclonema) M<'ekiana, Wh., Ancyloceras percostaium, Gabb, ♦ R*<|X)rtH nf ProtrroBH, Oeol. Siirv. Onn., 1870-77, l>. 5H ; 1878-70, p. 09 B ; Annual Ki-lKirt, (i«ol. Hnrv. Can. v(il. I. (N.S.), p. 1(14 u. t See CHpfciallv Am. .lourn. Sci., vol. XXXVITT., \>. 120; Trans. Koyal Hoo. Can., 18!t3, Hect. IV., p. 3. \ RpiM)rt of I'rcigresH, Gool. Hm-v. Cm., 1877-78, p. 107 u. § RpiKU'tof Prot?ru88, Geol. .Snrv. Can., 1871-72, p. 00. II Reiwrt of PvogreHH, 1875-70, p. 253. i ! •1 CRETACEOUS ROCKS. 65 B \ Crioceras latus, Gabb, PImladomya Vancouvpretwix, Wli., an Area like A. Garteroni, D'Orb., and a CuculUva* The small coUeotion of fossil plants which is reported on by Sir J. Win. Dawson on a following page (p 148 b), goes to show that beds as late as the Dakota period must occur in the Fraser River area, and this is quite in accord with the general views previously enunciated of the limits of the Earlier Cretaceous series of British Columbia, j We have here in fact beds equivalent to those of the Queen Charlotte Eiuivalettoy Islands formation (including the three lower subdivisions of the gen- eral section in these islands;];) together with higher beds, which like the conglomerates of the Queen Charlotte Islands (subdivision B) and other conglomerates found on the Lewes River and iu the Kootanie district, represent the Dakota period with possibly some part of the IJenton period, of the province of the Great Plains. Further, these Earlier Cretaceous rocks correspond in a general way to the group long known in California as the Shasta group. The molluscs above finumerated appear to be essentially those of the Kno.wille or lower rli vision of that group. It has been found impossible to determine any of the fossils in a Upiu-r limit Hinall collection obtained on Stein Creek, but these appear to be fresh- watev forms. Whether they represent a stage during which the sea was actually excluded from a part of the region, is not known, nor can the stratigraplncal relation of the particular beds in which they occur to the others be stated. It is of course quite possible that these beds, or others which may yet be discovered, may be found to be related to parts of the Cretaceous even higher than the Dakota horizon. The late (leterminatioa, by Messrs. Diller and Stanton in California,*^ of the t'act that tho Shasta and Chico form parts of a practically unbroken series there, tends to indicate that similar conditions may prevail here also, but no fossils characteristic of the Chico period have so far been found on the mainland of British Columbia. « In concluding these general remarks on the Cretaceous, something Ui^liitioiiH of should be said on the possible relation to it of the conglomerates else- ,^,''j 'qIm^ where referred to the Coldwater gi'oup and described as probably Oligo- «iit<'r wm- cene (pp. 68 n, 76 n). The question has several times occurred, whether these conglomerates may not actually represent local developments of * Report of ProKrcHB, Geol. Surv. Can., 1 ffT 7H pp. 10« i), 10!) n. t Am. Jourii. Hci., vol. XXXVIII., i). 125. % Trans. Royal Soc. Can., 1803, sect. IV., ji. 15. § Bull. Cieol. Soc. Am., vol. V., p. 435. 5 66 B BRITISH COLUMBIA. Economic featurcH. parts of tho Cretaceous series elsewhere represented in the region, or an upper member of that series. Tliis suggestion cannot be quite defi- nitely negatived, but I believe the eviddnce to be almost conclusive against it. In its favour, the very high angles at which the oongkim- erates in question are often found, and the occasional occurrence 'n them — particularly as basal beds — of conglomerates litliologically closely resembling those of the Cretaceous, may be cited. On the other hand, we Hnd them in aspect and composition generally, to differ much from the Cretaceous conglomerates, while the associated sandstones are also very different in the two cases. Still more con- clusive, however, is their apparently definite association with undoubted Tertiary lignite — and coal-bearing rocks at Hat Creek and on the Niola. The fact that these conglomerates occur on Plat Creek in a position geographically intermediate between the Ashcroft and Fraser River Cretaceous area.?, while (juite unlike the rocks of either, and unaffected by the severe compression which has atl'ected both of these areas, is also significant. It remains, however, still possible, that isolated areas of conglomerates due to the Cretaceous period may have been con- founded with tho Coldwater congli)merates proper in some cases. The Cretaceous formation as represented in this region is not entirely without economic interest. The evidence of tho fossils shows that it represents a stage of the Cretaceous at which in the Queen Charlotte Islands on one hand and in ''e Kootanie region of the Rocky Moun- tains on the other, important coal-beds were in process of deposition. No coals have yet been found in these particular rocks, but the occur- rence of carV) (naceous shales and of plant reuiains, serve to show that a slight change in the conditions in some part of the extent of the formation might have led to the production of coal, which may in that case yet be discovered. Again, the massive conglomerates of the Cretaceous have possibly had something to do with the supjily of gold in adjacent parts of the Fraser Valley, for these conglomerates, representing as th(!y do an extensive Cretaceous erosion, may well have become in certain layers chnrged with gold derived from the older rocks, which may subsequently have foand its way, in the course of latei' erosions, into the bed of the present river. This subject is, however, returned to in the sequel. Tertiary. Earlinr o'is«, and there can be little doubt that the conglomerates found on the plateau to the west and south of Savona, as well as these forming small outliers on the Garde Lafferty, rep- resent further remnants of the basal conglomerates of the same series. In the case of the sedimentary dej)osits of the North Thompson, situ- ated near thb north edge of the map, no distinct Hthological identity can be appealed to, but there is at least nothing to show that they differ in age from those of the Coldwater group. The Coldwater group as a whole, evidently represents the remnants Original tx- of a once more extensive formation, most of which has been removed t^in ""'"' by denudation, and of which what still exists is often covered by the later volcanic materials. It may in part be regarded as filling hollows in the pre-existing surface, but this surface has since been considf^rably modified in its relief by later fiexures and by .some faulting, and it is thus g-^nerally in synclinal folds, or where let down by faults, that the Coldwater beds are actually found. It is, therefore, impossible now to determine whether the remaining beds of the series represent portions of a deposit once largely spread over the area of the Kamloops sheet, or, if more restricted, what areas such deposits may originally have covered. That these deposits antedate the period at which volcanic activity oidi-r than on a great scale began, is rendered evident by two circumstances. They ti"„?y ""^ include in their material no characteristic volcanic Tertiary rocks while they appear without doubt to be afifected by more pronounced folding than that affecting the volcanic rocks. In some places these beds are now nearly or quite vertical. This is Attitude of particularly the case near Clapperton and Copper creeks ; but in other *'"' '''rata. \ 70 B KIUTISH COLUMBIA. localities, as for instance on the plateau to the west and south of Savona, the basal conglomerates are found to be still nearly horizontal) or inclined at comparatively low angle-; like those normal in the case of the later volcanic I'ocks of the Tertiary. In the place last mentioned, not only are the basal conglomerates nearly flat, but they differ but a few hundred feet in elevation from their similarly undisturbed repre- sentatives in outliers on the Garde Latterty — twenty miles distant. Thus it would appear, that after the Coldwater beds had been laid down, a period of orogenic movement occurred, by which these beds were attected particularly along certain lines, running in north-north- west by .south-south-eitst liearings, while large intervening blocks of counti-y preserved their rigidity ; that a period of denudation followed, during which a great part of the Coldwater beds was removed, and that the denudation had been long in progress before the first beds of the succeeding volcanic series were formed. Relation to Nicola rockH. Character of conglomer- atcH. Origin of cherty peb- bles. In connection with the relations of the Coldwater beds, it may further be noted that, though unconformable on the rocks of the Nicola formation, they are found near Clapperton Creek, and south of Lac a la Fourche to rest on certain puiplish porphyrite rocks which are believed to occupy a position not far from the sunnnit of that forma- tion, a fact showing that the beds of the Nicola formation may not in some places have suffered very extreme disturbance before the time at which the deposition of the Culd water beds began. It has already been noticed that the basal beds of the Coldwate" group, consisting chiefly of conglomerates and breccia-conglomerates, but with some grauwacke and arkose sandstones, have derived their materials largely from the immediately underlying surface. The con- ditions are such as to imply a somewhat rapid working over of that surface by the gaining waters of the lake or lakes in which the Cold- water beds were formed. Al)ove these, and by a gradual passage, the conglomerates become charged with well-rounded pebbles, pre- ponderately of cherty materials, and these congloraferates are per- haps the most characteristic lithological feature of the series, having a great thickness, particularly on the lower part of Hat Creek and on Copper Creek. The cherty pebbles have evidently been derived from the Cache Creek beds, referred to the Carboniferous period, which are found to have their greatest development in a zone of country running southward from Clinton, in the vicinity of the Bona- parte and Thompson valleys, to latitude 50' .30'. Still further to the south, this zone appears now to be entirely covered by the later volcanic- rocks of the Tertiary, but its occurrence in that part of the region ina\ -•1 TERTIAUY ROCKS. ^1 U be aif^ued from the composition of the conglomerates near Clapperton Creek and Liic a la Fourclic. It is further apparent, ' hat tlie rocks of this zone must, at the lime of the formation of thesn conglomeiatea, have occupied a position more prominent than they now do with respect to the general relief of the suiface ; while the appcnrance of so great a proportion of the cherty material in the conglomerates, where these are now found at some distance from the beds yielding this material, indi- cates the existence of rapid streams, actively engaged in the erosion of the strata of the cherty xono and capable of carrying their debris away with ease. The volcanic rocks of the Nicola foi'mation, of which the main development lies to the eastward of the line occupied by these conglomerates, although they had contributed so hirgely to the Cretaceous rock.s, were not at this time supplying much material to the conglomerates, nor are the limestones of the region west of the , Thompson often represented. All this argues considerable orographic change both l)efore and 'I''edB. were also no doubt other lesser foci of eruption at the same time in diflFerent parts of the Interior Plateau region. The rocks of which the Clear Mountains are principally composed, may be described as consisting of hard, gray, greenish and purplish augite-fKjrphyrites with occasional examples of diabase-porphyrite. These comprise both effusive and fragme'-.tal materials. Other rocks met with in these mountains or in their vicinity are noted in connection with the more detailed descriptions givm in a later chapter. In the vicinity of the Nicola Vqlley, the products of the earlier eruptions are represented by very similar porphyrites and porphyrite- agglomerates, passing into tuffaceous agglomerates and including many other varieties of volcanic materials in lesser quantity ; the aggregate thickness being about 5300 feet. One of the detached minor vents which appears to have been active to some extent during this earlier period of vulcanism, is that of Kam- loops Lake, where the most abundant material discharged at aliout this time haS taken the form c" a dolerite. It is likely, however, from the close connection of this rock with the succeeding Tran(|uille beds, that it was poured forth only toward the end of the earlier period of activity. From the beginning of the Tertiary eruptions till their close, though the eruptions were doubtless more or less irregular and spasmodic, the accumulation of materials of volcanic origin in the plateau region probably never entirely ceased. The occurrence of water-bedded rocks, con\posed almost altogether of rearranged vol- canic dt'bris, indicates the formation of lakes which endured for con- siderable lengths of time, and tl e blocking up of the old drainage channels of the country by the lava-flows or other volcanic products, may to a great degree if not entirely, explain the impounding of these waters. '^here was, however, apparently, one such very notable interlude, of which the water-arranged deposits are believed to bo recognizable over a wide area. To the deposits then formed, the name of Tranquille bed/i has been applied. They are largely developed in the vicinity of Kamloops Lake, particularly near the mouth of the Tranquille River, and the persistent zone of stratified tuffs met with on the Nicola River, is believed to pertain to the same horizon. Volcanic action was not entirely quiescent during the formation of these beds, for they include much material whic' .ppears to represent volcanic .ash, while they are often found to graduate almost insensibly into tuffaceous gglomeratos. That the time represented by these deposits was •] TERTIAHY ROCKS. 73 U of some duration, is shown by the fact that they include thin bods of coal near Kamloops. Other localities in which beds supposed to be referable to this horizon are found, are mentioned in the succeeding descriptive portion of the report. To this important lacustrine episode, succeeded a second great Sf^wiiKi vol- period of volcanic action, or which the products are in the main basalts and basal t-brecciaa, with smaller ijuaiitities of nielaphrye, mica- trachite, miea-andesite, etc., and some porpiiyrites and other rocks resembling those of the first period. The old volcanic foci of the Clear Mountains have suffered so greatly from suljsequent erosion, that it is not possible to decide to what extent they may have supplied the mate- rial of these later eruptions, though basaltic flows are still found jiatched upon their slopes at considerable elevations and sometimes lyinn at incli- nations which appear to descend from their axis. It is in fact probable that much of the basaltic material was ejected from minor and less regularly aligned vents ot fissures, scattered over various parts of the Interior Plateau. The Kamloops Lake vent, of which Battle and c.nt,.,,.., ,jf Cherry bluffs reprejent basal remnants, was evidently one of the uruption. more important local sources of the basalts. This is indicated by the thickness of the basaltic agglomerates in its vicinity, the large size of their component fragments, and the (juaquaversal dips still found to characterize them. Similar circumstances, though less pronounced than in this case, indicate that Porcupine Ridge, as well as one or more places in the Arrowstone Hills were also centres of basaltic eruption, while there were probably many lesser sources. There is no evidence such as to show that any prolonged period of Relations of rest occurred in the course of these later eruptions. Neither is there any direct evidence of orogenic movement between the first period and the second period of great volcanic activity ; for althotigh it is true that the older vole mic products are now more fretjuently found resting at comparatively high angles of inclination, this may in part be due to the original slopes upon which they w-ere deposited, in part to the fact that in con.sequence of much later erosion, they now often occupy the peripheral portions of the volcanic areas, where they are in contact with the old rocks, and where whatever flexure has occurred is always found to be greatest. In any case, much the greater part of the area now occupied by the basalts is characteristically flat and un- disturbed, or inclined at slopes so light that it is very difficult to tell to what extent these may be original and to what extent superinduced. The thickness of the upper, or preponderantly basaltic part of the ThkkiicKs. Tertiary, in the vicinity of Kandoops Lake is about 3000 feet. In V 74 B BRniSlI COLUMBIA. ChansfOH in 'li()( tim I'lioceiii Plioceni! tli-- posits. I'liociiic de- udatiuii. the Nicoaviicn Plfttpau about 3100 t'oet ; but in many other places and overgi-ciit areas of the map, these rocks form a comparatively tliin and unifoi'm covering of the surface of the plateaii, consisting of wide-spread Hows, with which little agglomerate is associated. When this second epoch of great volcanic activity ended, the great later Tertiary period of denudation and erosion began. The Interior Plateau ceased to be an area of deposition and b(>came one of waste. It is, nevertheless, probable that the volcanic forces died out slowly, for some subordinate basaltic Hows appear to have occurred after cei - tain valleys had again been cut out to a eunsideralile depth. Possibly some uf thesfl later Hows may be more correctly referable to the Plioc(uie, but no suHicicnt evidence of this has 3'et been found ii. the southern part of British Uolumbia. Some fragments of evidence have been found in the area of the Kamloop.s sheet, such as to show that about the time of cessation of the main period of basaltic eruj)tion, or perhaps at a somewhat later date, but antecedent to the glacial period, lakes were again formed over certain parts of the surface, and tiiat in these a certain amount of .sedimentation occurred. These lakes were, however, doubtless small, and as comi)ared with those of earlier dates, transitory; for it is proitable that before the great erosion of the latest stages of tiie Tertiary advanced far, the surface became supp'ied with a completely developed drainage system. On the upper part of Hat Creek, where conglomerates chiefly 'om- po.sed of basalt pebbles occur, and again on the south-west slope of Pavilion Mountain, the deposits of such newer lakes are believed to be I'epresented. In fact, the contour of the country and the elevation of these deposits at the two places, is such as toshov,- that they may be attributable to a single lake, though some twenty ndles apart. If the later covering of drift deposits could be sti.^iped from the surface, it is very probable that more beds of the kind just mentioned would be found in some of the vnlli'ys, l)ut the instances cited are th(^ only ones ,so far met with. On the assumption that the main period of vulcanism closed about the end of the Miocene, such later lake- basins must be referred to the early Pliocetie ; but the history of the Pliocene or latest period of the Tertiary is written almost (>xclusively in erosion. It was a time of waste, in which the land stood high, and during whi-h nearly all fh'. existing river- valleys of the Interior Plateau were cai-ved out. Probably many reuniants of depo.^-it- due to this period of denuda- tion, and of the nature of river-grivols 1, £t behind on terraces or in TERTlAUY ROCKS. (i) H \ sheltered nooks of the hirger vallej's still remain, but they iniist be, ns a rule, now entirely concealed by the !.i' pr glacial deposits, from which it would moreover be difficult to sepa'-aii! them in many eases. Hut a single apparently definite instance of .such deposits has been met with in the area here treated of. This is a small patch of coai'se river- gravel, now hardened into a conglomerate, which remains on the east side of the Eraser Valley near the mouth of Fourteen-mile Crei k. Since the time of its depcsition, the river has cut down its valley by about 1000 feet. Attention has so far been directed merely to the composition antl l'rolial>li> age , •' . nf Tcrtiiifv. relative order of the mon\bers of the Tertiary system within the area of the Kainloops sheet. A few words may now be adde(l with refer- ence to what little is known of their actual age and the positions they may be assumed to hold in '■he geological scale. Nearly the whole oi the fossils which have been collected from the Fussils. Tertiary of various parts of the interior of British Columbia are the remains either of plants or of insects. The greater nundier of such fossils so far obtained from any part of the southern portion of the int( rior, are derived from localities in the Siuiilkameen V'alley, near the conliufiiie "f tiie Tulam.een. These localities are parts of a single Tcrtiaty basin wi.icli has not yet been traced into conrn'ction with any other, and which may have beon originally a distinct lake. It lies nearly fifty ;iiiles beyond the uoathern edge of tlie Kamloops sheet, and is now included in the drainage basin of the Columbia River. What has been, said with regard to the e.sistence of two well marked ('oinparisoii horizons of stratiiifnl deposits within the area of the ivamioops sheet, juluu beds. ^ and ir. respect to the causes to which these are flue, .appears tj render it piobal)le that the Similkameen beds mii_^ corr(!Sj»ond in time with . one or other of these horizons, and their aj>poarance and mode of occur- rence acc(jrds best with the hypothesis that of these two they repre- sent the lower or Coldwatcr horizon, but for the present this correlation stands merely as a probable conjecture. In a review of the Tortiaiy liora of the region, whieii has been oii^focciif dcscribfid by him, Sir J. Wm. Dawson finds reason to believe that f'""*'''"- the Similkameen plants ai'o referable to the Lower Miocene or to tin- Oiigocene.* Of ninctecni species of heiuipterous insects fdund in the Tor- tiaries of British Columbia, sixteea come from t he .Similkameen li icalities, and although all the species but one are new, their general facies is, acctirding to Dr. S. H. Scudder, rather indicative of an Oiigocene age, 'TniiiM. Koviil S(.i>. Ciiii., vol. VII 1., Ki-ct. IV.. p. !M». (iMli'l'lll Tertiary 8equ Mice. Tertiary |H)«it8. 76 a BRnisu columhia. altli(mgli some ulenients of il-.o fauna show relations to that of Rado- hoj, whicli is regarded as Middle Miocene.* Lastly, among a few poorly preserved remains of pink colour on tlie map. Or those che greater patt may be claasetl mnii. as true granites, but con.siderable areas of dioritic rocks also occur, with some of gabbro. (Jur knowledge of these rocks in this district is as yet in.sullicient to enable the several ohw.ses to be separately indicated on the map. This must, indeed, always remain a very difficult task in some cases, for a passage of g,-anitic rocks into diorites may often be noted, particularly about the margins of the granitic areas, where thesa appear to have absorbed '.arge portions of the more basic materials of adjacent old volcanic rock'i of the stratified aeries. As elsew here explained, a similar practical diffictdty has licc!! found in drawing any exact lino beiween some (,f the granites and the gabbros and inica- diorites of the Cherry Bluff mass. All the rocks thus grouped togntlier bear very similar relations to Vgi' nf grunit the stratified rocks of the district, having altered and otherwise "' '^"''"'' uifected tho.se among which they have been intruded. Tliey are, liow- ever, not all of one age. The larger granitic masses of the Coast llaitge.s and of tiie Interior Plateau are evidently due to a period subse(|uent to that of the Micola (TriasKic) formation and aiitecodent to that of the Karlier Cretaceous. In this respect they agree with the great granitic masses which have been studied on the outer margin of the Coast Ranges along the Pacific border of Ilritish Columbia.* They are probably coeval with these and due to the same orogcnic cau-ses The Cretaceous rocks are, however, also in some places broken through by granitic masses, rendering it evident that a portion (tf the granites must be much more recent in d;ite. Granites of tliis ago may occur in many places where the alwence of the Cretaceous rocks renders it impossible to determine their ago, for no means has yet been found of dilierentiating these granites petrographically f re m tiiose of the earlier period. It is also '-ortain, that granitic rocks due to periods much earlier than the Triassic must occur in some pa.ts of the region, for oven in the Cambrian strata, rocks largely composed of granitic debris are found (p. lOS ii). Hi, me of the gabbros and dioritirs again, are believed to represent the deep-seated products of th<' Tertiary period of volcanic activity. Perhaps the most notable fact which appears on assend)ling the N"t"i;V''' '""'"' " ' ' " l)lmi1. Surv. Can., vol. FI. (N.S.), 15 1 k 78 H HKITISH COLUMBIA. Their proli- al)le oiipiii. l'«ri|)heral if fects t)f |)it'.s> «ni. which hifjhiy hornhlendic rocks, often true diorites, are specially pre- valent. The first of these runs near to and parallel with the Fraser River, though generally on its east aide. It may be regardeii as including a great part of the Lytton Mountains, Botanie Mountain and it.s noi'thern continuation, the plutonic rocks met with between the vicinity of Fountain and Pavilion Creek and those found near Leon Creek. The second zone of the same kind, runs nearly parallel with the Nicola and part of the Thompson lliver from the Promontory Hills to the vicinity of Ashcrott. The first of these zones is undoubtedly connected at no groat depth with tilt! trul}' granitic rocks of the Coast Ranges on the west, the second blends to the eastward with the largo mass of true giviniies which occupies the area between the Nicola and (Jiuichon Creek. In the first, numerous cases occur where the intrusive material is inextricably mixed witli much-altered greenstones and otlier bedded rocks, while infolds and lenticular masses of now crystalline schists, (some at Icust of which doubtless represent bedded materials) are abundant in it. In the second, these conditions are not so clearly apparent ; but in both, it is probable that the present character of the rock is lai'gely ihie to the absorj)tion, or granitic fusion neatly in place, of great masses of the basic materials of the older formatit)ns. In some other instances, the plutonic I'ocks are clearly eruptive, sharply defined and quite difi'erent in cliaractor from the older materials which they break through, while many cases of an intermediate character present themselves, where no sound judgment appears possible as to the relations in this respect of the two classes of rocks. It is very generally observed, that the i)orders of tlie areas of gran- itic and other plutonic rocks, afford evide)\ce of intense pre.ssure, both in the foliation im})arte(l to these r. cks themselves and in the effects produccil in the iieighb airing stratified ro(>ks,one of which is a tendency to parallelism of tiie sti'ik(! of these rocks to the liiic of junction. This is not only the case in the strictly folded region of the Coast Ranges, whore both classes of rocks appear to have been subjected, perhaps at several periods, to a gommon compression, but also in that of the plutonic massf. ' )f the plateau region, where the evidences of a general compression are much less distinct. Whether these peri- pheral effects are due to a pressure exerted by the plutonic rocks themselves, or whether the extrusion or granitic fusion to which such rocks must bo attril)uted relieved a formerly existing pressure when it occurred, the facts appear to be iuautlicient to decide. PLUTONIC HOCKS. (0 n \, Jn later pages such brief details as appear to be necessary are Connection given for the several plutonic areas. Tiie clearly apparent fact i„g veins, that tlK> development of -Wis holding metalliferous minerals is largi^'ly dependent on pro- i.-i^y to such areas ami the hydrotliermal or other similar action which has been set up during the formation or intrusion of these masses, renders their definition a matter of some economic importance. It is, further, hiylily probable, that when the metalliferous veins ai"e better known and more extensively woikcd, it will be found possible to trace dilFerences in their character depen- dent on the differing com,position of the various crystalline mas.ses near them. Intrusive rock.? of the chavacter of dykes, occur in great numbers J)yl;f rock.-i. in many parts of the entire region, and in almost endless variety in respect to composition ; but in the present preliminary state of our knowledge of the region, it is judged to be uniieces.sary to detail observations upon these rocks or to enter at any length into the exami- nation or description of them. At some future period a study of these dyk'e rocks may be undertaken, wliicb may not be without results of importance, but, in conunon with many other detached lines of investigation, it has been found necessary to relegate this to later observers. DESCRIPTIVE GEOLOGY. In this divi.'sion of the report, such local details as appear to be of (Irdcrof trent- iniportance are given, and the data relied upon in laying down the geological linos in different parts of the field are discussed. The observations referred to are ginuTalized as far as possible, but ihey are reipiired in order to supplement the broad indications afforded by the map. The order of description adopted is not strictly that of rebitive age throughout., as it is more convenient to arrange ^ho matter in some cases in correspondence with locality. (!eneially sjieaking, hosvever, tlio Palieozoic rocks ai'e flist noticed, and these arc followed by the Triassic, the Cretaceou-i and the Tertiary; rocks cOasseil as Plutonic coming last, Thi" drift deposits or Pleistocene are noticed in II subset] uent chapter. PALiGozoic Rocks. Thotnpnon Vitlley — In-ki-kiih Crcfh fo Cdi-hf Crrrf,. Rocks referred to the Cache Creek formation, are first mot Mith in iiiKtiirlM-rl ascending tlic Thompson A'ailey about fix miles above Spences Bridge, J'**'^'*"" *•"'■ mm BfllTISH COLUMBIA. FosBilifcrouK liincstotH'. Vennblos Val ley. Hliatti'i'cd aiK (lKCom|)OKC(l roek.M. where they eme'-;^.; from l>eneatli the Miocene volcanic materials and occupy .1 narrow interval between this and the great granite mass to the eastward. They occur on both sides of the river, and numerous exposures may be found, but a!l are so much broken and disturl)ed that nothing can be said with certainty as to tluir general arrangement. The main direction of strike is about N. 20 W., and most of the- observed dips are to the westward : it is therefore pi'obable that the higher beds occur in that direction. There is reason to believe that faulting has occurred along the line of the Thompson or that of Venabels Valley, and perhaps in both places. The rocks consist of gray limestone, with greenstones, sometimes more or less schistose, cherty qunrtzites, wiiich often show locally an extreme stage of alteration and shattering, and hard, black slaty argillites. The bed of limestone which appears on the wagon-road two miles and a half aliove the 89-mile stable, is that particulai'ly referred to in Dr. Selwyn's oiiginal report, from which some fossils were at the time collected by .Mr. Richardson. Among these the following genera were recognizerl : — Cyrtitia, Spirifera, RhynchoneUa, a small Mi/alinu and a £uoiti/)Iin/iis. liespccting the.se Mr. Billings wrote : — "Although none of the above have been determined specific- ally, they indicate ;i.lmost cartainly a horizon between the base of the Devonian and the summit of the Permian."* Along Venables Vall'y, greenish, somewhat schistose rocks, with gray and blackish argillites were found. These appear to underlie massive limestones, '.vhieh occur ir, the hills on the west near the head of Twaal Creek n;id in White Mountain. China-Btone. In following th" wagon-road northward, the rocks all along this part of the Thompson Valhiy are found to be excessively shattered and de compo.sed. Red, yellow and white crumbling baids above described, runs parallel with this part of the Thonipson for fifteen miles or more, generally to the west of the river. The dynamic forces which have acted upon the rocks have in some places protiuced scliists, while in others, and generally more or less lenticular areas, tlie strata have become crushed and comminuted. Tiraal and Bhu -earth Crmka. The hills about the sources of TNvaal Creek and those along the-north KxtenHive .side of Ulue-earth Creek, are almost cxclusivelv composed of iimescone. '""""tone e.>:- In the last mentioned locality, gray limetjtone which is in part converted into marble, forms bold whitish (diO's facinir southward, much reseml)!- ing some of the cliffs along Marble Canon. The openings of M«veral caves or grottoes were ob.serve(i high up in these cliffs, iit the lower end of the little lake in which Blue-earth Creek ris^- ^rray, |iiob,ibly concretionary chert is as-sociated v.-itli the liniestoii<- inni in this there occur many spwiimens of Lufttiam with some 1 nmdiua, beautifully preserved. At the mouth of Blue-earth Creek, the limestones are founei to dip westward at high angles. They run thence to the north, along tlie Hat Creek valley, still forming bold cliffs to the untrancf of the pass which leads eastward by way of Jack's Creek to the Thompson. At the Section ulon^ intranco to this pass, on Hut Creek, the limestone was again found to 6 82 B BRrriSH COLUMBIA. dip westward, at a very high angle. Beginning at this place it was endea- voured to obtain a general section across the range of hills to the Thomp- son Valley, but with unsatisfactory results. The rocks seen are chiefly liniestoues, hut, where their attitude could be ascertained, they appear to lie generally at low undulating angles, in such a manner that no great thickness is brought to the surface. With the limestones are interbedded hard, fine-grained, green, felspathic rocks, some of which are much de- composed diabase-porphyriti^s.* These are sometimes slightly schistose in structure and usually very much slickensided. There appear to be at least two important beds of this kind, one of them probably l?00 or 400 feet thick, the other forming the lowest rock seen, but only in part expDsed. Black schistose argillites and cherty (juartzitei? were also seen, but not in great volume. Rocks of this kind were particularly noted near Limestone Amphitheatre, and again near the small granitic intrusion to the eastward, and between these places the beds appear to have the form of a shallow syncline about two miles in width. Home cherty masses occur in the limestones themselves, and in these crinoidal remains have been preserved. To the east of the granitic intrusion just mentioned, the much altered rocks of the Thompson Valley begin, as previously explained (p. 81 u). Limestone cliffs are characteristic of the north side of this valley as of that of Blue-earth Creek, and at the Amphitheatre they assume re- markably picturesque forms. Medicine Creek, McLean Lake, Cornwall Creek. i Cornwall Hilla .and vicinity. Nort'i of Med- icine Creek. Continuing to the northward, the older rock-i observed in a few places to the east of the Tertiary of Hat Creek and south of Medicine Creek, are chiefly gray limestones, with some diabase-like green rocks resembling those last described, and occasional exposures of cherty quartzite. The dips are generally higli and varied in direction. The summit of the Cornwall Hills (G600 feet), was reached by ascending from Jack's Creek along the ridge overlookinj; the Thompson Valley. The higher part of the hills is open sub-alpine country, with numerous bare limestone outcrops and some minor ex- posures of greenstone and cherty ([uartzite. These rocks as a whole are probably about the horizon of the base of the Marble Cauou lime- stones. Noith of Medicine Creek, between the two areas of Tertiary .shown on the map, green altered diabases, .sometimes agglomeritic, with •Apijendix I., No. 0. PAL.F.OZOIC OF HOXAPARTE VALLEY. 83 II clierty quartzites, were the only rocks actually seen, but limestones may not improbably also occur hi're. The strike is pretty constant ut about N. 40° W., and the beds are nearly vertical. The interbedding of the greenstones with the quartzites was clearly seen at one locality. In the vicinity of McLean Lake, the older rocks consist, so far as Mdican observed, cliielly of greenstones, probtibly diabase in composition, and gray limestones. The attitudes of these rocks are rather irregular, but a nearly east-and-west strike is found in some place.s. A mile and a half south of McLean Lake, quartzite-schist and greenstone agglomerate were found, the latter containing numerous limestone fragncents and some circular crinoid joints. One of these was observed to be over three-quarters of an inch in diameter. The hills separating the Cattle Valley from that of the Bonaparte, are likewise composed chiefly of limestones and interbedded greenstones, the latter being often more or less distinctly schistose. The strike is here on the average, about N. 35° W., with high south-westerly dips. The limestone areas shown upon this part of the geological map iuive not been strictly defined. It would be very dillicult to accomplish this here, and the intention is merely to indicate the existence of large bodies of limestone. The horizon is again, in all probability, about that ot' the base of the Marble Canon limestones. In following down Cornwall Creek, from McLean Lake, after a Coniwiill concealed interval of a couple of miles, the rocks seen are principally cherty quartzites, with some line-grained greenstone and a bed or beds of serpentine. A rather prominent little hill of gray limestone occurs on the north side of the stream before the wagon- road is reached. The surrounding rocks are cherty quartzites and quartzite-schists, but the whole so irregular and so much broken up that the order or rela- tions of the several rocks could not be determined. Civek. Cdche Creek to Mundorfs. . . • Between the western edge of the Ashcroft Cretaceous area and Mun- (ienera run (iorf's, on the wagon-road, a distance of some fifteen miles, the general '" " strike of the rocks, which is about north-north-west, carries them obliquely across the line of the Bonaparte River and that of the wagon- road. This general strike is, owever, subject to numerous subordinate irregularities, while the angles of dip met with are very varied, and it has so far proved impossible to define, with any accuracy, either the thickness of the strata met with or their general succession. It is thus necessary to describe these rocks as a whole and in general terms. It ' M B nniTisii roM'MRiA. ( 'ln'rty i|ii!irtzit(' would appear that mimerous smaller t'oliis are here superposed on the main flexures of the Ix-ds, and that there is thus a tendency for each zone of rfKik.s, to occupy occa.sionally, a narrow or wide belt of country, in such a manner that the actual thickness could only be a*!certained (if at all) hy a most minute survey of the wliole area. The most characteristic material is here a cherty quartzito or silici- fied argillite, which is generally found in thin beds of blackish or gray colour. The.se are separated by black, more or less lustrous aruillite- schists, or by gray, glo.s.sy schists ; and with them are interbedded one or possiljly two beds of green ()r blackish serpentine. These rocks appear to cross the Bonaparte with a north-westerly strike to the north of the small outlier of Tertiary rocks marked on the map and described on page '2\'.i H. Further west, they gradually turn to a north-eastward direction near Cache Creek, where they are much disturbed and cor- rugated. They next a.ssume a north- north-westerly strike, and with dips which are in the main to the westward, cross this l5onaparte alx)ve the Indian village and occupy the lower part of the valley of Hat Creek between the river and the fault which here appears to bound the older Tertiary rocks to the eastward. The thickness of the rocks included in this belt, chiefly cherty (juartzites, may be stated as prob- ably from 4000 to 5000 feet. To the westward, near the Tertiary outlier above alluded to, and on the western slopes of the hills near Campbell Hill and declining to the Cattle ^^alley, the cherty quartzites and their associated rocks are followed, and apparently overlain, by interbedded green and green-gray diaVjases and limestones, in beds of small or medium thickness, which are carried by their strike beneath the older Tertiary rocks. At five miles and a half below Hat Creek, about half a mile west of the wagon-road in the Bonaparte Valley, some exposures were found of a peculiar coarse greenish-gray conglomerate holding rounded pebbles. This rock has sutl'ered considerable metamorphism, and appears to have been included in the flexures of the older rocks, but, as it holds some cherty quartzito pebbles, it may represent an outlier of some newer bed — possibly referable to the Nicola formation. i;.«-l;.s imiU- Yor about two miles to the north of Hat Creek, on the west side of (Hi;iit/.iteM. the Bonaparte, the hills continue to be chiefly composed of the cherty quartzites. Beyond this point, to Mundoff's, the character of th(^ rocks becomes more varied, and they are, in all probability, referable to a somewhat higher stage in the formation. As no persistent attempt to work out the stratigraphy in detail has yet been made, the rocks as a whole may be described in the following general terms, quoted from my report of 1877 (p. 93 b) : — Coiii^loiii .■nvto. •] PAL.KOZOIC OF UONAFARTK VALLKY. S5 II "Between Hat Creek and 121-milo post (Munilorf'H) nninerous Hiiw.in \{n\ exposures in the roadside show the intimate association and inter MiiiidnifV. hcddinj^ of tlie cherty siliceous rocks with serpentines, j)ure iinil iin])ure, and ot' the latU-r with ventine. between their bedding planes. With these are interbedded green' stonng, often agglomeritic, together with gr%y ash rocks, now more or Oocurrencp of less schistose, limestone beds and serpentines. The serpentine bed (or beds) is evidently most closely associated with the rocks of volcanic origin, and is no doubt derived from the alteration of some volcanic rock. The strike is in the miiin north-west by south-east. The sub- joined section, sketched at a place two miles above Loon Creek, and which appeared in the report for 1877, is reproduced here because of its interest in connection with the mode of occurrence of the serpen- tines of this formation. The l)ed of serpentine here represented is about 100 feet in thickness. No characteristic fossils were found in the particular bed of limestone included in the section, but about a mile further down the river, in another outcrop which may possibly represent the same bed, good specimens of Fusnlina were discovered. This outcrop is associated with altered volcanic rocks but no serpen- tine was actually observed. The mass of the limestone is largely com- posed of crinoidal fragments, and weveral smaller species of foruminifera are present, including a form which is in all probability a IVovhammina. WMMS Mmmil m eh FIO. T. SKF/mi 8KCTI0V HIIOWING THE MODE OF OCCUItRENCE OK SERPENTINE IN THE CACHE CREEK FORMATION. (t. Spriientine. h. Quart/.ito. e. I'aleHcriioiitinouHHchiHt. t/. (irifiiiBh aniygdaloiii and lin-ccia. e. Liiiu'Htimc. Miimloif Maiden Creek. H to .ScliihtoHe nickH ill Marl. Olen Origin HchlRt*. th< In following the road from Mundorf's through Glen Hait, towani Clinton, the rocks continue to resemble those above doscribed, about as far as the mouth of Maiden Creek ; greenstones and tlierty quartzitt's being most abundant. Thence northward, their character becomes somewhat changed. A schistose or slaty structure is in most case.s observable, while very t' in and flat divisional plants are developef rojkH. ation-product of the ordinary greenstones or diiihiises ; but along this part of tlie valley the cherty quartzites Iwfore so common, were n«»t seen. The black glossy argillites precisely resemblo those found al.ng the Bonaparte Valley, and in regard to the gray schists, a less siiueezed material of the same kind, and more evidently clastic, was found to occur alx)ut a mile Ijelow Mundorf 's, in the Bonaparte Valley. The problem presented by the rocks here met with, is whether the} represent a peculiar condition of alteration of materials of the same age with those already doscribed, or whether they may belong to a different and an older series, for, if it Ije atlmitted that their present appearance is of classiticatory value, they very closely resemble litho- logically certain rocks found along the Eraser lliver (particularly those in the vicinity of Anderson River and Boston Bar, to the south of the Kandoops sheet) which were originally assigned to a very low stage in the Paliuozoic. So far as I can see from our present knowledge of the subject, no reason can lie urged for the supposition that these particular rocks are older than the rest. It would appear that they have been to a great extent exempted from the silicifying changes which has resulted in the production of the cherty quartzites from orflinary argillites, while they have been instead att'ecierl by pres- sure, giving rise to a dynamic metamorphism, which in all probability occurred at an earlier period than the siliciflcation. At the north end of the little lake situated about a mile to the south of Round Lk^ke, a bed of gray crystalline limestone about thirty feet in thickness occurs, and is interbedded in schistose rocks of the character just described. In ascending Hart Ridge from Clinton, .^cks like those of (Jlen Hurt Hi Ipc Hart are occasionally seen, though the surface is much covered by drift. Along .1 unction Valley, from Clinton to the Bonaparte, the rocks seen arc chietly quartzites and greenstones, resembling those of the Bonaparte, and offering no features of special interest. Marble Caiion and Vii'inity, In the report for 1877, an attempt was made (in section No. J3), to Section give a diagramatic representation of the relatit)ns of the rocks occur- ^^^^' ring between Lillooet, on the Fraser River and the mouth of Hat Creek on the Thompson, via Marble Caiion. Subsequent investiga- tions show that some of the features ^presented in the western part of this section re(,uire modification, particularly in respect to the now recognized Tertiary age of the pt\rphyrite rocks, which ^m 88 B BRITISH COLUMBIA. in 1877 were supposed to be attached to the Cretaceous series, but in the main, that part of the section which runs eastward from the west end of Marble Cation, is still believed to afford a general idea of t!ie structure. A short description of the older or Cache Creek rocks shown in the Marble Caiion section, from the Fraser at the mouth of Pavilion Creek eastward, will therefore here be given, baaed in part on that contained in the report of 1877, with the omission of some de- tails which may not require repetition and with the addition of some new fa))ts since ascertained. otolith «tance of about three miles and a half eastward, or to about a mile beyond the bridge crossing Pavilion Creek, the rocks may be described as consisting chiefly of hard green or gray-green altered diabases, of rather fine ^rain. With these rocks, a short distance alx>ve the fall, a couple of thin limestones are interbedded and some thin layers of quartzite, all very irregular. One of the limetones is again found to the southward, about half-way between Pavilion Creek and Eighteen- mile Creek, on the road. In the hills between Eighteen-mile Creek and the south side of Pavilion Creek, these rooks are very largely mingled, in a per- plexing manner, with greenish granitoid diorite. A careful examina- tion of the rocks, appears to show that in this place tlie plane of the present surface nearly coincides with that of the upper part of an intrusive mass, or that of a centre of alteration, where the diabase-like stratifie<)rt of Progrt-Hg, Oeol. Hurv. Can., 1877 -7S, ii.' 88 h. UuHrt. Joum. Oeol. .Sw., vol. XXXV., p. «9. ' , * 90 B imiTISII C.'LUMBM. KaHt pdiTH of lirai'stont* belt. ticiuTii) »r- raiigriiifiit Hiid tliicknnw. smaller Foraminifern, thn mass resembling a thoroughly hardened chalk. Through these a few more or less perfect Litflxutur may be scattered. Fintulince. appear to be very scarce in the Marble CaSon limestones ; they are much more abundant in those of other parts of the country, composed principally of crinoidal fragments. They seem to have preferred a bottom composed of the debris of the larger calcareous organisms to the fine oozy bed most congenial to the Loflusia.^' " The typical and most abundant form of Lojtunia limestone is a pale or dark gray crypto-crystulline rock, in which the more perfect specimens of Loftuaia appear thickly crowded together as paler spots, generally pretty sharply defined. The limestone breaks freely in anj direction, the fracture passing e(jually through the matrix and included organisms, which it is impossible to separate from the stone. The matrix generally seems to be composed in great part of granular calcareous matter similar to that employed in building up the test of the Loj\u»ia, but more irregular in .size of grain, and with an occasional fragment of a Crinoid or example of smaller Foraminifer." In following down the valley of Hat Creek, in a north-easterly direction from the eastern end of Marble Canon, similar limestones are found to continue for alwut three miles, or till they become coveretl by the Tertiary rocks in that direction. The limestones here include at least one bed, which must be over a hundred feet thick, of fine- grained gray-green felspathic rock, originally volcanic. Further down Hat Creek, a small projecting ridge of the older rocks which appears from below the Tertiary conglomerates, is chiefly com- posed of hard f^reen agglomerate, though to the north of the valley it consists almost entirely of limestone. The cherty quartzitea and as- sociated beds met with near the mouth of the creek have already been noticed (p. 84 b). The rocks included in the whole section above described, between the Fraser and the Bonaparte, are believed to hold in the main a synclinal form, though with many irregularities and minor compli- cations. The structure is at least undoubtedly a synclinii ne between the Pavilion Creek granite and the main western edge of the Tertiary rocks. Of this the limestones hold the whole central and stratigraph- icall}' higher part. Taking the actual distance across the strike, which is pretty uniformly north-north-westward, with the average in- clination given by the 'few observed dips, the thickness of the lime- stones would appear to be about thirteen thousand feet. But there ] PALAEOZOIC OF MOUNTAINS NEAK MAKKLE CANON. 91 11 is every reason to believe that they are in reality affected by numerous subordinate flexures, and that though very thick, the entire mass may not even reach half the amount stated. Mount Martley and Chi-pooin Mountain. The facts ascertained respecting the older stratified rocks in the adjacent mountains, necessarily somewhat imperfect, may now be briefly noted in connection with the Marble Canon section. The central parts of Mount Martley and Chi-pooin Mountain are Hm.kH ^m-. composed of a mass of gray granite. To the west of this granite mass, ''">"".|'"k'1 the rocks consist chiefly of cherty quartzites and hard blackish and gray argillite-schists, interbedded with limesttme, which preponderates towai-d the edge of the granite. The quartzites and argillites aie evidently continuous with those seen on Pavilion Creek near Captain Martley's house. The strike is about north-and south, and the beds are vertical, or very nearly so, wherever examined. To tin- north-oast of the granite area, a lower range of hills, composed app.irenlly almost en- tirely of limestone, separates it from Marble Canon. Where close to the edge of the granite, near Hat Creek, t'le limestone was observed to be locally changed into coarse, or tine grained, gray and white striped and blotched marble ; but this is apparently too much broken up to be of any value. Some quartzites and schists were also found interbedded with the marble in this vicinity. To the south of the same granite mass, on Chi-pooin Mountain and along the north side of Limestone Creek, limestones again preponderate. They are associated with some greenish or blacki.sh diabase-like rocks, and with small beds of black argillite-scliist and cherly quartzite. The limestones are altered, as in the case last described, near the actual edge of the granite. They dip southward at high angles. It will be observed that there is a tendency for the limestones and Diiwawiiy associiited stratified rocks to dip away from the granite in all ilirections. One very small outlier of marble was found patched upon the granite to the west of the sunmiit of Mount Martley, and it is probable that others of the same kind occur in this high region. from (fraiiitf. Pavilion Mountains, The southern slopes of the Pavilion Mountains, east of the Pavilion pavi! i Creek granite, are all remarkably free from drift deposits. Th"y were v'"""/j|j"* well seen from several high points, and appear to consist ei rely of limestone, though there are doubtless also minor intercal tions of 92 B BltlTISil COLUMIilA. other materials, as oUewliere found. In crossing these moantaiiM by the upper valleys of Pavilion Creek and Maiden Creek, limestone is again found almost to the exclusion of other rocks, though occasional exposures of hiaek st^hists, chcrty quartzite and greenstone also occur. The two last-named rocks were noted to lie particularly abundant near the sources of Pavilion Creek and close to the summit of the paiw, bat the higher hills and larger ex|M)8ures everywhere consist of limestone, precisely resembling that of Marble Caflon. Tsil-tsalt Hidge, *een only from a distance, where not capped by Tertiary volcanic rocks, appears likewise to consist of similar limestones. K()cks west «)f Clinton. Dixturliiuici! and ciimplica- tidu of beds. Junction ValUy. The rocks of the eastern part of Junction Valley have already been mentioned in connection with those of the Bonaparte and Glen Hart (p. 85 n). To the west of Clinton, this remarkable valley crosses the direction of the Marble and Pavilion Mountains and the general strike of their component rock^, nearly at right angles. Its vestem end is occupied by the lower part of Kelley Creek. For about four miles west of Clinton, the mountains on imth hides of the valley are practically wholly composed of limestone, and for a further distance of about four miles, nearly to the point at which the road turns up Kelley Creek valley, the same may be said with regard to the upper parts of the mountiiins at least. The valley itself is wide, and the exposures seen are few and poor unless the slopes are ascended. In an exposure midway between the forty-fourth and forty-fifth mile-posts from Lillooet, in the valley, scattered sjiecimens of Lo/tudia Columbiana were detected in a gray limestone, which hen- dips S. 64° W. < 60'. About two nrles to the east of Kelley Lake, on the northern side of the valley, a short section, almut two miles and a half in length, was carefully examined and measured in 1877, the exposures on the hillside at this place appearing to l)e more continuous than usual. A note on this section is given in the report for 1^77-78 (p. 95 b), but it proved to be impossible to arrive at certainty in regard to the thickness or order of superposition of the beds, l)ecau«e of the great amount of disturbance to which they have been subjected. It shows, however, the intimate association of the massive limestones with blackish to pale-greenish chorty quartzites or hornstones, quartz- ose and felspathic schists, and greenish or grayish-green decomposed diabases or felsites. Some of the beds are serpentinous in joints and cracks, and small quantities of chrysotile or ser^ientine-asbestus were observed in one place. The 8ectio>i as a whole is supposed to be near 1 PALEOZOIC OF FRA8ER \'ALLEY. oa II the base of the Marl)le Cuflon liniestoneH and very probably about the ^'orizon of that at the east entrance of Marble Canon (p. b9 n). To the west of Kelloy Lake, the msissive limestones are no longer K<«kH tof found. About the lake and along the road which ascends the slope of Pavilion Mountain to the south, the rocks consist chiedy of blackish argillites. generally more or leas schistose, often considerably silicified, breaking with a rough irregular fracture and weathering ru«ty. With these are cherty quartzites of the usual kimi, in considerabli- abund- ance, and at Kelley Lake some greenstone, prol»ably interbeddcd, was noticed. The general strike of these rocks along the road al)ove referred to, is a few degrees west of north, with westerly dips at- angles of from .'(0 to 70'. Similar rocks continue f)n the lower part of Keliey Creek, which falls rapidly in a verj- rough gorge to the Fraser, but cherty ijuartzites are, perhaps, more abundant here. They ,,• m- , . are all very much fractured, and near the edge of the Fraser contain iiiim-. a quartz-vein which an attempt has Iteen made to work for gold. This, known as the ]Hg Slide mine, is descril)ed later. Fraai'r Valley, Xve Leon Creek, the other almost exactly where the line of the edge of the map is drawn. Tlie first of these, under the microscope, shows evidences of great pressure, but crinoidal fragments are distinguishable ; the second may b*- callefl a marble. The strike of the rocks along this part of the valley, is pretty uniformly north-west ; the angles of dip are usually high and the t)eds in all probability form several folds. On the east side of the Fra.ser, in the corresponding portion of its length, the rocks are precisely similar to those just described, though argillites are perhaps a little more abundant, and some instances of distinct slaty cleavage were observed in these. Further to the north and west, beyond the edge of the present map, argillites and quartzites of a similar character, with some diabase and occasional tliin beds of limestone, aro^ut across nearly at right angles by Big Bar Creek. The valley of this stream appears to be a likely place in which to obtain a general section of these rocks. The Kclir«! Hills. Halle Mill. Valley between Edge Ililh and Marble Mmintains. The valley which separates the Edge Hills from the Marble Moun tains, has been cut out along the general strike of the rocks and almost exactly on the line of junction of the argillaceous schists and quartzites on the west, with the massive limestones of the Marble Mountains on the east. In the northern part of the valley, the :vctual junction of the two classes of rocks is covered by basalt, but along the upper part of Kelley Creek, which flows in this valley, the line can be closely traced. The Edge Hills, by which this valley is separated from that of the Eraser, appear to consist entirely of the argillites and quartzites with their associated rocks, as described in the foregoing pages ; the west- ern part of Junction Valley, with the Eraser Valley, that of Big Bar Creek and the valley last referred to above, completing the circuit of these hills. To the northward, the trend of the Edge Hills turns more to the west, in conformity with a general change in the strike of the beds. At the extreme north-western angle of the map, a locality of some interest is found at Haller's mill. A gray fine-grained limestone occurs here, striking about N. 5^ W. and dipping eastward at angles of 60° to vertical. The beds are so soon covered by basaltic rocks to the eastward, that it is impossible to tell whether this limestone actually PAL-EOZOIC OF MAItlILK MOUNTAINS. 9.') II fnrtnsu part of thoinas.sive series of liiiiestuiieH appearing in the Marble Mounttiins. but it ciinnut be fnr beneatli their hori/on. In the gorge of the streiini, Ix^low the mill, the liuieMtono is, however, found to be underlain by blue-gray cherty (junrtzites, which fonn a distinct anti- clinal fold. In the linie.stone, not far nlK>ve its junction with the ds are foi.iK? near Tn-koi kii C'rcck. These appear to have ; width of about a luile, ijfctween tlie Cretaceous edge and the granite, though it was fo'nd to be a little ditKcult in this place to draw a line between the Cn tacoous rocks and those of the older series. The latter consist of grceidsh and gray fel.spatbic materials, sometimes with calcareous layers, and of quartzites, which arc uiLon nearly white ai:d vitreous. The rocks are all muih disturbed and are cut by numerous granite dykes before the main border of the granite is reached. This band of rocks continue* northward, as shown on the map, gradually widening. Where it crosses Si-wlu Creek, it is com- posed chiefly of gray schistose quartzites, generally somewhat micaceous and corrugated, and of green rocks, also more or Ies.s .schistose, but evidently resulting from the dynamic metamorphism of some of the ordinary greenstones. Some distance further up thid creek, a small area was found by Mr. McEvoy of greenish and dark gray hornblcndic and micaceous schists, which appear to represent still further altered conditions of the rocks just noticed and closely resemble .some of those of Iz-man Creek. In the vicinity of In-tl-pam Creek and Askom Mountain, the widtli Askmii Moim- of the belt of Paheozoic rocks Ijecomes nearly three miles, and at a short ''""' distance to the north of the creek, these rocks come'down to the edge of the Fraser, the Cretaceous being locally conrined to the east bank. The rocks are here chieHy gray and black, hard, somewhat .schistose argillites, with cherty quB tzites of the same colours. With those are, however, included important intercalations of gray-green felspathic rocks, repre.senl)!ng the ordinary greenstones in an indurated condition. ^.. . ,• Two beds of serpentine (or two outcrops of a single bed) are also "'"I rfiixcmitc. included in the .section. One of these occurs a short distance north of Tn-tl-pam Creek, about half a mile from the river, the other about half way up the long ridge by which the summit of Askom Mountain was reached. The last-mentioned is distinctly schistose, and contains irregular harder layers, which, according to Mr. Ferrier, have the com- position of saxonite.* •Appendix I., No. 7. , 7 98 B BRITISH COLUMBIA. Condition and attitude of the i-ockn. Kvidently OAche Creek. Texas Creek. lielation to Onyixwh Crej'k expo- 8Uro8. Though somewhat irregular, the strike of all these rocks is generally north-north-westwurd, parallel to the main direction of the mountain ranges, with dips u.sually, but not invariably, to the westward. They are cut by numerous dykes, and are generally much shattered, with the development in them of considerable quantities of iron pyrites, the decomposition of which produces the general reddish colour by which Askom Mountain is characterized, in contrast with the usual gray colours of the granitic mountains of the region. On approaching the granite to the westward, the argillites become distinctly micaceous and glossy and are often corrugated, and together with the quartzites are everywhere cut through by numerous small quartz veins and seams. The broken and evidently crumpled character of the strata in this vicinity is such as to preclude any accurate knowledge of their order of succession or actual thickness, but the latter must be very con- siderable. The composition and association of the rocks at this place, however, leaves no room for doubt that the greater part of them at least, repre- sent that portion of the Cache Creek formation which is characterized by cherty quartzites and argillites, with some greenstones and serpen- tines, and of which the character, as displayed along the Bonaparte and Thomp,son valleys, has already been described. Their state of alteration and present appearance is, however, practically identical with that of the Boston Bar rocks, as met with in the Fraser Valley to the south of the area of the present map (see j). 101 i«). Still further north, on the lower part of Texas Creek, the Palieozoic ."ocks appear as a narrow band between the Cretaceous (here very much shattered) on the east and a miissive granite on the west. At the bridge by which the stream is crossed, they consist of gray -green felspathic tuffs containing films of interbedded black argilite, but all excessively twisted and kneaded together. To the west of the granite just referred to, which is quit^ narrow, the Pahvozoic rocks again appear, and wen- found by Mr. McEvoy to extend westward for a width of nearly four miles, when they are again bounded by granite. The rocks here con- sist principally of blackish argillites, generally .somewhat micaceous, and often becoming black micaceous schists. Some grey, possibly fel- sphatic, schists are also found and numen small quartz veins wer(> noticed. The rocks are nearly vertical toward tlio east side of th'-^ belt, but further west were observed to have westerly dips in a couple of places. The belt of Pala'ozoic rocks here crosseu by Texas Creek, is evidently the same with tliat found further north on Cayoosh Creek, and th:ro examined, and the auriferous character of the rocks on Cayoosh Creek renders their extension here important. f > 1 / ' a^l; ^HflHHp^^^^^^^^H '^.^.-tji Pi 1 ■^ j^*'^*J^^w r^^M 1 fidn'" 'flili^HWH^^Hl^^^ilS' 1 I^K^^^InC^ 'A7\1^^^^^^^^^^^(^BH r > ■ - jri . ^-' '1 i ^ a: = s = y. K OAW*ON. ] In foil Lillooet, 1 of serpen of these they con Cayoosh serpentii of Cayoc mile and town of evidentl} north. Cayoo! importan been fouj bridge, o nearly at consist, s they are which lie south war The sti to the Fr thus be s associate River ha; Hrst larg( tudes, bu and near angles, represent merely ct rocks are the condi The gr by Cayo( often lust ally micfl distinctly \ent of I 74 •] PALiGOZOIC OF COAST RANGES. 99 n In following the west side of the Fraser Valley from Texas Creek to Texas Creok Lillooet, much-shattered, gray, cherty quartazites, associated with a bed of serpentine, are found three miles north of Texas Creek. The strike of these rocks precisely accords with the direction of the valley, and they continue to appear along it at intervals for five miles, or to Cayoosh Creek. Hard greenstones also form a part of the series. The serpentines are particularly well shown near the road, about a mile south of Cayoosh Creek. The same bed of serpentine was again found a mile and a half beyond Cayoosh Creek on Hoey Creek, behind the town of Lillooet, and rocks of the character of those just noticed evidently run on in the eastern part of Mount McLean, still further north. Cayoosh Creek, which in late years has been the scene of somewhat Section on important placer-mining and near which veins of auriferous quartz have Oret'k!" been found, was examined for about five miles westward from the bridge, or to the Bonanza mine. It cuts across the strike of the rocks nearly at right angles. Near the bridge and mill, the stratified rocks consist, so far as seen, of blackish and g!-eenish quartzose schists, but they are much broken up and confused by large dykes of gray granite, which lie nearly in line with the granitic mass of Mount Brew, to the southward. The stratified rocks appear, as seen in the end of this range nearest to the Fraser, to have a general easterly dip at low angles. Thoy may thus be supposed to ftass beneath the horizon of the serpentine and associated rocks, the strike of which along the west side of the Fraser River has already been traced. Further up the stream, opposite the first large valley from the south, the beds assume nearly vertical atti- tudes, but still further in the same direction, they again flatten out, and near the Bonanza mine are found to have easterly dips at moderate angles. It is not known whether the zone of nearly vertical rocks represents a compressed anticlinal or synclinal form, or whether it merely consists of a number of compressed smaller folds ; but that the rocks are everywhere nmch plicated on a small scale, is evident from the conditions in limited section and even in hand specimens. - The greater part of the rocks met with in the cross-section afforded Clmractcr nf by Cayoosh Creek, may be described as black or blackish argillites, often lustrous, sometimes much wrinkled and corrugated, and occasion- ally micaceous with very fine i "ca. Many of them are more or less distinctly calcareous. Near the Bonanza mine, a rather notable develop- line.""""^ lent of black and probably slightly graphitic argillites occurs. Inter- 7i ■'V^r 100 B BRITISH COLUMBIA. bedded with these are some gray felspathic schists, which occasionally show the drawn-out forms of their original constituent particles, and have evidently, like the similar rocks of the northern part of Glen Hart (p. 87 b), and some of the Boston Bar rocks been produced by the action of pressure upon volcanic ash rocks or volcanic tuffs. Some green schists, chloritic and epidotic, are also found, as well as green rocks of the same kind not notably schistose, and still preserving the character of ordinary altered tuffs. Some of these are finely plicated and exactly like those seen at the bridge on Texas Creek (p. 98 b). Sau88iirit(>. In one place, not far from the east end of Seton Lake, a gray saussurite rock was collected, and at two miles and a half below the Bonanza mine, a zone several yards in thickness of greenish-gray talc-schist was observed to be interbedded with the series.* The auriferous quartz veins which intersect these rocks are described on a later page with other occurrences of economic minerals. S slicot. advisable to add some notes on the Anderson l-{iver and Boston Bar series, above referred to, in its typical development along the Fiaser lliver to the south of the present map. Some notice will be found of these rock in the reports for 1871-72 and 1877-78.* In the last-men- tioned report, for the sake of brevit)', the btjds in question were gene- rally designated merely as the Boston Bar rocks. In 1888 they were examined along the line of railway on the west side of the Fra.ser, where it was possible to obtain a better idea of the sciries as a wiiole than had previously been gained on the old wagon-road on the opposite side, CiintileviT luidmt to North Bend. Speaking generally, these rocks occupy the west side of the valley from a point about three miles below the cantilever bridge to one three miles below North Bend station, a distance in all of about nine- teen miles. They are separated by a mass of granite from the Cret- aceous rocks seen near the cantilever bridge, this granite being the continuation )f the main granitic area shown on the j)resent map to the west of the Fraser. The strike of the rocks crosses the Fraser valley at a very oblique angle, the belt of schistose or s^aty rocks be- ing continued to the northward, after leaving the Fraser, in the Salmon Hiver valley, and to the southward, east of the Fra.ser, along the Anderson Biver valley. The obliquity of the line yf examination does not favour the definition of an exact section, and the observations do not admit any precise thickness to be given f<»r eacii of t.iie various classes of rocks, but their order and charncter is approximately as follows : — The first, and presumably the lowest rocks, seen just south of Order ofMii- Quoieek Biver, arc dark gray, quartzose mici-sclii'-'cs. About four miles further south and probably considerably higher in the series, somewhat similar, but pale gray, highly quartzose schists were next seen. These are followed by greenish, rather lustrous schists, and thin- * ReiK)rte of Progress, Geol. Surv. Can., lrt71-72, i>. 02.rl877rH. ii. 73ii. 102 B BRITISH COLUMBIA. Thickness. Rockx near North B«iiil. ■I unction with granit«M. Bast »\Av of Kras«r. bedded cherty quartzites with slightly micaceous, shining, black divi- sional planes, and by massive gray indurated sandstones, verging on quartzite, but not cherty. Overlying these beds, are dark glossy schists and quartzites. Then, after a considerable concealed interval, dark argillit«-schist.s and schistose quartzite, the former somewhat graphitic. These rocks are seen in cuttings from a mile to two miles south of Reefer Station. At the south end of the Salmon River bridge, graphitic argillite- schists, with talcose and quartzose schists with a bed of nearly massive graj- talc, occur, the whole followed by more blackisli argilliteschists. Near the 134-mile post on the railway, the section is interrupted by the appe«vrance of gray gneissic rocks, which may be regarded as prob- ably representing a mass of foliated granite. If, as is supposed, the above represents an iiscending series, terminated above (and to the westwarrl) by the gneissoid rocks, the thickness displayed must be between 6000 and 7000 feet, of which the greater part is made up of argillites in diflferent stages of alteration. Beyond the gneissoid rocks, after a concealed interval, black argillites are again found in large exposures between one and two miles above North Bend station. These are very regularly bedded and banded with thin gray layers, and with them are some gray quartzite-like sand- stones. Two miles to the scuth of North Bend, black, shining argilliteschists, becoming chiastolitic in places and interbedded with dark gray mica-schist, are exposed. In following these ix)cks fi>r a short distance in the cuttings, the micaceous schists are found to become more abundant ami coarser grained, resembling gneisses, while many fine-grainen8 among these rocks near the line of contact, and that the whole composite ma-ss of granitic and stratified rocks has subsequently been subjected to great compression, such as to ijiduce a foliated structure in t'ae granitic material. In addition to the rocks above mentioned, thin lieds of gray lamin- ated limestone, green schists, and gray felspathic schists formed from squeezed volcanic ash, were observed in certain places on the east side «•] PAL.EOZOIC OF NORTH THOMPSON. 103 B of the Fraaer in 1877.* The gray schists are identical in character with those noticed in the northern part of Glen Hart (p. 87 u). Palmozoic liorks on and near the North Thompson Rivur. These are believed to be separable into two great groups, of which Rucksof Cam- 1 1 • 1 • 1 11 • /~i 1 ■(• 1 J i_i liriiiiiiuiil Cnr- the higher is wholly or in great part Carbonirerous, and rererable to ixmiffroiis the Cache Creek formation, the lower to the Nisconlith and Adams "^'^'• Lake series, correlated in a general manner with the Cambrian ; as elsewhere explained (p. 27 u). The nature of the provisional line of division which has been drawn on the map between the Cache Creek and Nicola formations is also referred to on another page (p. 124 b). In noticing the Palipozoic rocks of this vicinity, it will be conveni ent to begin with those assigned to the Cache ^reek formation, in order that the-e may be more closely compared with the rocks of the same formation, to the description of which the immediately foregoing portion of this report ' s been given. Rock» referrtd to thu Cdche Creek Formation. — An attempt has StfL-tion hIhhk been made, along the lower part of the North Thompson, to obtain 'fi,^'J[,,'„",u the necessary data for the construction of a section of the rocks there found and characteristic of the adjacent country on both • sides of that river. The sides of the river-valley appeared to be the only place in which sufficient connected exposures of these rocks occurred to offer any prospect of such a section, although it was known that the general direction of strike is oblique to the valley, being in fact about north-north-west. The information obtained along both sides of the valley has since been combined, but with very indifferent results, in so far as the main purpose of the examination is concerned, lioth strikes and dips proved to be exceedingly irregular in detail, and the rocks of the region generally are so much shattered and disturbed, that it is practically impossible to trace out single beds for any con- siderable distance. The diagramatic section (No. 3), which has been Sictioii No. 8. drawn as an attempt to represent the structure along a part of the valley, extends from the north side of Reservation Creek, northward, to the vicinity of tiie granite mass which comes out on the river beyond Sullivan Creek. The general character of the rocks met with may be briefly described Gi'iiural char- iis follows : — Blackish or dark gray argillites preponderate in the ' section. These arc usually shaly, tlaggy or slaty, but are so much cut * Op. oit., !>. 7.S n. 104 B BRITISH COLUMBIA. Limeotoiic beds. Thickiircs. up by jointage-planea in every direction, that they generally crumble away readily into rubbly slopes, like those seen descending from the higher parts of Paul's Peak. The argillitos are very often more or less calcareous, sonietirjes slightly micaceous near their contact with the granitic masses, and particularly so in the vicinity of the granite near Jamieson Creek. They are frequently somewhat silicified, and then be- come black or grayish, fine-grained rocks like chert or homstone. resembling the cherty quartzites of the Cache Creek formation on the Bonaparte River and elsewhere to the westward. With the argillites, hard grauwacke sandstones are in many places found to he interbedded. These are generally of paler colours than the adjacent argillites, and pass, in several places, into beds of fine-grained conglomerate or breccia, of which the constituents are rather varieve the upper li.Tiestone, diabase and similar volcanic intercalations are more abundant, constituting a great part of this portion of the series. The whole thickness of beds seen on this part of the North Thomp- son appears to be al)out 7500 feet. The tracing out in detail of the limestone beds contained in this series of rocks, appears to offer the only method of obtaining more exact knowledge of their stratigraphy and thickness, and the age a-^signed to the whole series depends chiefly upon that indicated by the fossils contained in the a.ssociated limestones, a reference which appears to be justified by the interrelation of the various component members of the series, as well as by their resemblance to the rocks already described to the eastward. •] PALAEOZOIC OF NORTH THOMPSON. 105 n The best exposure of the limestone IxkI, above designated as the lower (Kitcrojw i>f limestone, is found on the west bank of the North Thompson near Venn's, almost directly opposite the mouth of Sullivan Creek. The dip of the limestone is generally eastward, but just at this place the direction of its strike appears to change. It has been followed in a north-north-west direction along the higher slopes of the valley for about three miles. To the southward, it turn/* more to the west, and possibly abuts against the granite mass found near Jamieson Creek. The outcrop near Venn's is probably the best and most accessible source of lime for burning to be found along this part of the river. On the opposite side of the river, a mile north of Sullivan Creek, and almost in contact with the edge of the granite there, exposures of the upper limestone are seen. These run northward parallel with the main direction of the last-described Imnd, crossin^.^ the river, and are again seen on the west f^ide of the river two miles and a half fur- ther northward. In both cases the dips are to the eastward. Another outcrop, believed to be of the upper limestone, is found a mile and three-quarters south of Edwards Creek, on the east side of the river ; and between three and four and a half miles further south, on the same side of the river, several expcsures referred to the same upper limestone band occur. Still another prominent outcrop of limestone appears to the east of Fossilifcrous the North Thompson valley, in the Inner Vallej-, five miles due l'"""'^'"'- south from the upper part of Kdwards Creek. This may probably be the lower band, and is again undoubtedly the same with the limestone seen in extensive exposures in hills to the north of the South Thomp- son, about ten miles east of Kamlix>ps, a short distance beyond the east edge of the present map. The limestone of the Inner Valley is almost entirely composed of crinoidal fragments, and large round crin- oidal columns more than an inch in diameter ,, Kisli-triip Kii|>i(l. Thompson assumes a north-east and south-west trend, cutting across the strike of the rocks nearly at right angles, and affording the most satisfactory section of the Cambrian rocks met with in the area of the Kamloops sheet. Much of this part of the valley is narrow, and the rocks are fairly well exposed in it. The section as presented (No. 2) runs from the vicinity of Fish-trap Rapid to the lower part of I^ouis Creek, about six miles, and thence northerly to the vicinity of the Barriere River, about three miles further. The observations upon which it is based were made, for the first part of this distance, along the south-east side of the North Thompson and along the valley of Louis Creek for some miles above its mouth. For the second part, chiefly in the hills to the east of the North Thompson a couple of miles back from the river. The oldest rocks found appear in the form of a somewhat con- Cintral miti- torted anticline, of which the axis seems to slope down to the north- '^'"" ■ westward. These are referable to the Nisconlith series and consist of hard black argillites and argillite-schists, often rather lustrous from •Appenilix I., No. G. 108 B imiTISlI COLUMUIA. Ktickit to Huutli-weHt. RockH ti> north-enwt. Nortli of Bar- ri6re River. the development of minute mica crystals, and passing from these in some places into well characterized black micaceous schists. These black schists do not appear to l)e calcareous. The thickness repre- sented is aiiout 3100 feet, but the base of the series is not .seen. The higliest Ijeds appear to blend with the rocks of the next overlying series, which consists chiefly of greenish and gray 8chi8tt)se rocks result-' ing from the dynamic metamorphism of diaba.sc8 and diabase' agglomer- ates and representing the Adams Lake series, or a part of it, with an estimated thicknes-s of 9.000 feet. In the syncline at the south-west d of the section, about 6000 feet of the lower part of these rocks is Mien. They are here less altered than tiiose on the opposite side of the main anticline, and are clearly recognizable as ordinary green altered diaba.ses,or greenstones, becoming; more or less schisto.se in structure, but in some places still showing an original agglomeritic character. The prevalent colours throughout are greens and gray-greens. On the north-east side of the anticline of Nisconlith rocks, the Adams Lake series recurs in the manner shown in the section. Its rocks here have suffered greater mettimorphism and are chiefly repre sented by gray or greenish-gray often lustrous schists, with, in their upper part (and at a horizon higher than any represented in the first syncline) some rather considerable intercalations of blackish argil- lite-schists. The highest beds seen, in the centre of the north-eastern syncline, consist largely of quartzose schists, with quartzose and arkose conglomerates, more or less schistose, glossy gray or nearly white schists and some black argillite-schists. These have a thickness of about 2000 feet, in addition to that already stated for the lower part of the Adams Lake series. The exposures found on the lower part of the Barriere River, and along the east .-side of the North Thompson northward from that river, are insufficient to admit of the further continuation of this section, but it is believed that the greenish and bluish-gray altered diabases and felspathic rocks chiefly seen there, are also referable to the Adams Lake series, forming a still higher part of it and one which has escaped much of the dynamic change by which the beds above described have been affected. It is also probable, that the main strike of these beds here runs nearly parallel to the North Thompson valley, though the massive character of the rocks renders it very difficult to determine this. PAL.KOZOIC NORTH OF WIIITEWOOU CllKEK. 10'.» It Rocks asgiyned to the Cambrian, South of Finh-trnp Jiapid. The rocks in the hills to the eivst of the North Thompson, south <»t' ('ainliniiii the Fish-trap Rapid section, have not been sufficiently examined t(i j^',.'^''/l||'l'*' ' warrant any detailed description of them, ft has lieen endeavoured to draw an approximate line fjetween the Cambrian rocks and those ref- erable to the Carboniferous, but this depends almost entirely on the lithological characters of the rocks, without any exact know- ledge of the relations of the two series along their su[>poHed line of contact. It is, however, very probable that this line is a faulted one, due to one or more faults which may nearly follow the general line of the North Thompson valley. Between Sullivan and Edwards Creeks, and to the south of f<]dwards Xcm- ['..lllviui Creek, near the east border of the map, the rocks believeil to be Cam- ','!' •'■''"""I'* brian consist largely of greenish, diabase-like materials in various stages of alteration, often schistose, and passing over into coarsely micaceous schists of almost gneissic aspect. These last are, however, almost in contact with one of the granite msusses with which the struct- ure of this region is complicated, and may owe their excessive altera- tion in part to that circumstance. With the al)ove-mentioned rocks .some hard, micaceous argillites occur, and white banded quartzite was also noted. A bed of highly crystalline limestone is also seen in a couple of places, where it appears nearly to coincide with the line between the argillites, referred to the Nisconlith, and the green schists, referred to the Adams Lake serie.s, although no limestone was observed in a similar relation in the Fish-trap Rapid .sections. Between the south side of the Sullivan Creek granitic mass and Island Pond, near the edge of the sheet and fjeyond it, there is a con siderable development of schisto.se argillites, much broken, but prob- ably representing an irregular anticlinal elevation, which may be con- nected with the intrusion of the granitoid mass. Rocks of the Plateau to the North of Whitewood Creek. To the north of Whitewood Creek and west of the North Thomp- P'f,'.',"!' "'"■"' son, a belt of plateau country averaging about six miles in width, is Cntk. occupied by rocks of which the stratigraphical position is very doubt- ful. It must be explained that this region of country is exceedingly rough and difficult to traverse, by reason of its wooded and broken surface, and ihat but a few exploratory lines have fieen carried through it. 110 B BRITISH COLUMBIA. I J nigned to Cambrian. RockH'as- signed to cache' Creek. The trail which runs westward from the North Thompson to Bona- parte Lake, leaves the valley of the river about six miles above the mouth of the Barriere, and some three miles below the village on the Indian reservation. On this trail, near the foot of the steeply sloping side of the valley, and about 430 feet above the river, some brecciated gray limestone was first found, after which many fragments of dark argillites were observed, though not seen in place ; but in the main, for a distance of about three miles, green, slightly schistoso, altered dia- bases appear to be characteristic. These rocks are believed to form a continuation of those of similar character seen in the section near Fish-trap Rapid, and they are provisionally assigned to the Cambrian. In following the trail westward from the point last indicated, a great series of dark-coloured and often nearly black schistose rocks is met with, which continues all the way to the edge of the granites on Eating Lake, or for a distance of eight miles and a half. The strike of these rocks, wherever observed, is not far from north-and-south, and the dips along the line mentioned appear to be uniformly west- ward, at low angles near the edges of the diabase series, hut el.sewhere probably averaging about GO". The appearances thus indicate that these schists overlie the diabases, and if it be supposed that they form a continuous ascending series this would have a thickness of over 18,000 feet. It is, however, much more probable that folds or faults not recognized have to be allowed for, and that there is much repetition of beds, though their actual volume must in any case be very considerable. Tlieir clmrac- ter. Lithologically, these beds consist of argillites, schistose or slaty, more or less distinctly micaceous and approaching in character to phyllites, and of fine-grained black or blackish rocks containing a. larger propor- tion of bisilicate minerals, very much decomposed and altered and probably representing beds which have originally been volcanic in their origin. With these are occasional beds of hard fine-grained gray quartzite or grauwacke. The appearance of the^e rocks alone does not enable it to be decided / to what series they should be referred. They very closely resemble some of the strata common in the Cambrian, but they are equally comparable with the more highly altered beds of the Cache Creek f, rir'\tion, and are in some cases lithologically indistinguishable from strata described under the name of the Campbell Creek beds. The apparent absence of lime.stones constitutes a point of difference between them and the strata referred to the Cache Creek on the lower part of .] PALAEOZOIC NORTH OF WHITEWOOD CREEK. Ill n the North Thompson, but this may depend mcely upon the incomplete character of the examination made. Southward, from Eating Lake to Poison Hill, following a little to Continuation the east of the main edge of the basaltic and granitic rocks, similar micaceous argillitesand fine, black, mijceous schists are the predominant I'ocks, but the directions of strike r-iiJ dip are less uniform. Near the head of Skull Creek, where that itream was crossed on the route indi- cated on the map, these rocks are singularly contorted, being affected, besides their main flexures, by close parallel folding in undulations f lom a few inches to a few feet in diameter. They are also here traversed by numerou." small quartz veins, which show a tendency to follow the contorted bedding-pianos and are characterized by parallel marks of shearing, which indicate compression acting in a direction of N. 40^ E. c r the reverse. The isolated area of old rocks shown to exist to the west of Skoatl Near Skoatl Point, is so much covered by drift that its composition was very imper- fectly ascertiiined. It appears, however, to consist chicjfly of gray- green porphyritic diabase, much altered, and is provisionally referred to the Nicola series. Two miles southeast of Poi.son Hill, the micaceous argillites were Noai- Poiw.u foun.l to be interbedded with gray-green diabase-porphy rites,* in a manner precisely analogous to that observed on Campbell Creek (p. 123 b\ and it is probable that the horizon is about the same in both cases. Quai'tz veins were noticed to be abundant here, but specimens of them subjeL'ted to assay proved to contain nothing of value. Similar micaceous argillites, with some diabase, apparently inter- At Carihuu bedded, were found to characterize the tract of country, some miles to the south-westward, in which the basalts have been cut through and in which Caribou Lake lies. The general direction of stiike in all this region is north-west by south-east, and in the vicinity of Caribou Lake >juartz veins were again noted to be abunbant. It will be understood, from the brief description thus given of a Ape miccr tract of country some seventeen miles in length with an average width of '""' about six miles, that our knowledge of its geoio<:''cal structure is yet very imperfect. It is quite possible that the dark schistose rocks above described may (sventually be found to belong to the Cambrian, and to repre.sent an extension of the Nisoonlith series. In that case a line of separation would require to be drawn between them and the rocks of •Appi-ndix I., No. 5. . Jfe %\ 112 B BKITISH COLUMBIA. the lower North Thompson, and it is probable that such a line might be found to run from the vicinity of the mouth of Whitewood Creek to Basalt Point of the map. Kxaininsition of the section. FoHsilift-rous tieneral lie the Htriita. Tri.\8sic Rocks, and Sections Illustrating the Nicola Formation. Section South of the Ashcro/t Cretaceous Area. A notice of the rocks referred as a whole to the Triassic, under the name of the Nicola formation, may be begun by a short description of the section found along the east side of the Thompson, south of the Ashcroft Cretaceous area. This section was partially examined in 1877, and in 1888 some additional observations were made on it alon;.; the line of the rt ilwa}"^, but the results obtained remained fragment- ary. After all oth'^r parts of the area of the Kamloops map-sheet had been gone over, the unuoal regularity of the rocks at this place seemed to render it desirable that i/hey should again be examined, and two days were in consetiuence devoted to this in July, 1894. The section was found to be not so regular as had been anticipated, in consequence of the protrusion into it of .several masses of the granitic rocks of the vicinity ; but the effect of these has been elimin- ated as far a. pc.-tsible, and there can be little doubt that the general order and co'.iposition of the series is now fairly well understood. The discovery of fos.sils at two different horizons has also added materially to the value of the section as a whole. Professor A. Hyatt has been so kind as to make a preliminary examination of these and a compari m of them with some of the collections lately obtained by him from Californian localities, the results of which are of great interest. He tintls in effect that the fossils collected from the lower of the two horizons are undoubtedly Triassic, comprising a Daonella like D. Loinnie/i, a shell resembling I'anopea (1) Remondi, (iabb, and a. small ammonoid. Those of tlie upper horizon are probably Jurassic. This horizon is actually separated from the lower by about 12,300 feet of strata. The fossils found in it include TAma pnrva, Hyatt MS.. Entolium like B. equabiUn, Hyatt MH., Pecteii, like /'. aciitiplicatui<, Gabb, and two species of RhynchoneUit, one like R. gnathaphora. (,f The exposures which afford practically the whole of the measured secti n, occur on the east side of the Thomp-son Valley and in the adja- cent hills in a distance of a'jout four miles southward from the end of the Cretaceous area. The general dip is nearly north, or at right angles to the valley, the angles of inclination varying from about 15° to 50 . No evidence of important faulting was found, and it was po.ssibie to observe the angles of dip in many places, notwithstanding the generally massive character and originally volcanic origin of a large part of the *Mv: TRIASSIC SOUTH OF ASIICROFT. 113 B constituent rocks. The highest rock seen is a limestone, in small exposures in the hills about two miles south-east of the railway at Black Caiion. It is overlapped there by coarse basal conglomerates and breccias of the Cretaceous, consisting chiefly of granitic fragments with a calcar- eous cement. These exposures are somewhat removed from the main line of section, and are -omplicated by the occurrence of a small granitic boss, but there is little reason to doubt that the rocks ieen In them are conformable with those included under No. 2, of the section. The lowest member of the section is that numbered 9. It occurs about two miles north of Spat-!um station, where it is cut off by a projecting mass of granite, beyond which the regularity of the series becomes disturbed and the order of superposition doubtful. All the beds included in the section are believed to appertain to the Nicola series. The section Soctiim houtli obtained may be suuimarized as follows, in descending order : — Feet. (1.) firay limestone, of which at leivst 20 feet was seen. It often con- tainH numen)U8 siniill imgnlar fraffnieni.s of Hiliceous rocks and is f(etid, wlien struck. Contains fossils believed to be Lower Jurassic 20 (2.) Chiefly bluish and gray or greenish-pr.ay tine-grained felsite or [letrosilex, apparently jKissing into fine-grained decoini«)Hed dia- bases. Some agglomerate, comiK>sed of similar materials, is included in this jMvrt of the section, but nearly all the i-ocks break with u homogeneous sub-concoidal fracture 1,S00 (3.) Chietly puri>lisli and gray ratlier fine-grained agglomerates, occa- sionally greenish and often with .spots of epidote 1,.'?00 (4.) This |)art of the section is represented by few exiK)sure.s, but appears to consist chietly of bluish and greenisli-gray finegrained felsites, occivsionally somewiiat iJorphyritic 2,000 • (").) Chietly agglouierates, which are often tine-grained and imvss into miMlerately well iH'dded grauwacke or arkose sandstones, gen- erally indurated and often calcareous. Usual colour grayish. With these are assiK^iated (particularly toward thi> bivse) blackish argillite-like rocks and some thin l)e(Ls of limestone and t)f tine felsite-like rocks 2,!)0() (((. ) The upixir half of this memlxjr of the section is coni|K)sed of gray felsites with interbeatR\ini. At (ireat Itock-Hlide. •Report of Progrew), GwJ. Siirv. Can., 1877-78, p. 112 b. "•] SECTION IN THOMPSON VALLEY. 115 B ated rocks, which in falling have bounded clear of the general slope, strew the terraces along the foot of the slide. The great size of the constituent fragments of this breccia seem to show that it must have been formed at or very near to a centre oi volcanic eruption, and this eruption, it is supposed must have occurrec curing the deposition of the Nicola formation, to which the breccia itself is referred. j It is beUeved that the Thompson, in this part of its length, coincideaj Great line of with the line of a fault, which is accompanied by much comminuteci fracturing and crushing of the rocks in its vicinity. This faulting iai probably in relation to the general run of the edge of the granite, ancc may possibly have occurred at the time of its intrusion. In any case^ the rocks on the west side of the river are crushed, reddened, silicified!; and decomposed in a remarkable manner, elsewhere described (p. 80 u)., No distinct connection can be traced between them and those on the; east side of the river. They are referred as a v hole to the Cache* Creek formation, but may very possibly include broken remnants of^ parts of the Nicola formation j > well. In the hill above the old 89-mile stable, however, considerable Kxposures exposures of limestone occur, in which fossils have been found, tliese "t^bje '"' " Professor Hyatt refers to the same age as those of the highest bed of the section last described, or Lower Jurassic. These limestones further resemble that bed in character, and like it are charged with angular fragments of siliceous rocks. They are much broken up, and although associated with some greenish schistose rocks and with a gray spotted clastic felsitic or halletlinta rock, it is not certain that these are actually related to the limestone. The probable area of tiie newer rocks is indi- cated on the ap. It may be added, that a couple of miles above the 89-mile stable, on the road, another limestone occurs in which Mr. Richardson collected a few fossils evidently referable to the Cache Creek formation, Mr. Billings having determined them as of an age between the " base of the Devonian and summit of the Permian."* The fossils from the limestones near the 89-mile stable are described Fossils, by Professor Hyatt as including a Terebratula, two species of Entolium and a I'tcten, all closely resembling forms found by him in beds of Lower Jurassic age at Taylorvillo, California. Section along the Thompson Valley from Bonaparte River to Copper Creek. An examination along the line followed by this section appeared to Section No. l. be particularly important, as it constitutes the only direct link of con- •Report of ProgrcBs, Geol. Surv. Can., 1871-72, pp. (il-G2. 8* 116 B BRITISH COLUMBIA. Line followtnl by the sec- tion. West end of section. nection between the older rocks of the western and eastern parts of the map-sheet. Elsewhere these two areas are separated by wide masses of granite or by Tertiary volcanic formations. A satisfactory connecting section along this line would have been all the more valu- able l>ecau8e of the considerable lithological differences found between the Cache Creek and Nicola rocks of the two sides of the Kamloops sheet, but although examined with some care, and on several occa- sions, the section afforded has proved to be by no means a satisfactory one. The stratified rocks are broken up by large intrusive masses of a granitoid character, and, being fo^ ohe most part old volcanic mater- ials and much shattered, tbey do not supply the necessary data for working out the evidently somewhat complex structure. The section as presented (Sect. No. 1) must therefore be regarded as little more than a diagram, representing what is believed from the examinations made, to be the most probable arrangement of the older rocks. It affords a means of describing in outline the character of the rocks met with on both sides of the Thompson, and of bringing together the results of traverses made «long the wagon-road and the railway li-'*. as well as those of other traverses through the adjacent hills. The line of section approximately coincides with the east-and-west part of the Thompson Valley, running from its tributary the Bonaparte to Copper Creek, Kamloops Lake. It is to the wide and deep erosion of this great valley that the removal of the overlying Tertiary rocks is locally due. The actual length of the line of section upon which the observa- tions have been projected, is al)out twenty-three miles, from end to end ; but SIS drawn it is a couple of miles longer, because of the four distinct courses which it had been found best to follow in laying down the line upon the map. The line thus runs froni a point on the Bonaparte River just south of the minute outlier of Tertiary rocks there, in a bearing N. 79" E., to a point on the wagon-road about a mile beyond the crossing of Ei^ht-mile Creek. Thence, in a direction S. 70° E. to the Deadman River, near the bridge, approximately following the wagon-road. Thence in a bearing of N. 35° E. to the summit of the southern spur of the plateau, due north of Savona. Thence N. 68° E. to Copper Creek, which it reaches at a distance of about two miles from its mouth. Tl e approximate contour of the surface is indicated by the upper line of the section, the horizontal and vertical scales of which are identical. The section at its western end, where it leaves the Bonaparte River, shows the junction of the C&che Creek rocks with those of the Creta- ceous. The line of junction can be clearly seen along this part of the ■] SECTION IN THOMPSON VALLEY. 117 B Bonaparte. The older rocks are at angles of 60° to vertical, and here consist of greenish or gray felspathic or diabase schists, with serpen- tine in considerable mass, and probably forming a bed in the series, as tiiis rock is often found to do elsewhere in this part of the region. The Cretaceous rocks in contact with these, consist of greenish and bluish sandstones, which pass into coarse k'ough grits composed of het- erogeneous fragments, and all much hardened. These also, so far as could bo ascertained, stand at very high angles. It is probable that faulting accompanies the junction of the two formations, as represented on the section, but quite possible that the Cretaceous rocks here merely represent the western and overturned limit of a syncline. The Cretaceous rocks of the area crossed by the section are elsewhere Cretaceous described in greater detail (p. 154 u). The dips given to them in the sec- ^°^ "' tion, embody the observations made in the vicinity but not all upon the line of the section, and it is impossible with the information gained to show the actual folds or faults by which this area of the Cretaceous may be affected. The general westward dip, at angles of 40" to 45°, of a great part of the series in this vicinity, is, however, very clearly seen in distant views of the north end of the wide ridge which occurs to the south-west of the lower few miles of the Bonaparte. The hill crossed by the section in the middle of the Cretaceous area, Bas-alt cap- is capped by nearly 200 feet of black columnar ba.salt, of which the '""^' individual columns were observed by Mr. McEvoy to have an annular concretionary structure. A small wedge-like area of Nicola rocks, represented .somewhat dn- Area of Nico- grametically upon the section as intervening between the eastern edge of the Cretaceous and the large intrusive mass next met with, indicates the position of an isolated area of these rocks whicli occupies several square miles on both sides of tlie river, south of the wagon-road and near the lower part of Barnes Creek. These rocks consist of greenish, grayish, blackish and often purplish fine-grained diabases and felsite- like materials, which particularly on the north side of the river, are often .agglomerates. The gray and blackish felsite-like rocks frequently become porphyritic with small white felspar crystals. No limestone was seen, and very little of the ordinary coarse green diabase. The beds as a whole evidently represent part of the upper half of the Nicola series as shown in the general section to the south of the Ashcroft Cre- taceous area (p. 113 b). Ho far as can be made out, they dip weotward, passing beneath the Cretaceous at rather low angles of inclination. Their junction with the granitoid rocks to the eastward is hard to .Iimction with define, particularly to the south of tiie river, whene detached areas of the pranit* 118 B BRITISH COLUMBIA. Tertiary vol- canic rocxH crossing sec- tion. mm: A, Character eruptive masses. old volcanic materials appear to be included in the intrusive mass and to have been in process of- incorporati- ith it by fosion. The character of the intrusive material is itselt changed by this circum- stance, but a couple of miles to the eastward it becomes an ordinary mica-diorite. Reverting to the actual line of section, on the wagon-road, where the Cretaceous is directly followed by the intrusive mas-s, the latter shows similar evidence of having absorbed neighbouring part^ of rock of the Nicola formation. It is not homogeneous, varying con.siderably both in colour and texture, although generally dark greenish or greenish- gray and usually fine grained. A microscopical examination shows it to be a porphyritic diabase, much resembling some forms of the rocks of Cherry and Battle Bluffs on Kamloops Lake.* The area of Miocene volcanic rocks next met with, evidently occu- pies an old pre-Tertiary depression which here crosses the line of the Thompson River. The volcanic rocks have a width of about a mile in their narrowest part, at the rive., and serve to unite the large regions characterized by similar rocks to the north and south of this portion of the Thompson Valley. Further to the westward, the same rocks form a bold escarpment along the north side of Semlin Valley and their western outcrop, to the south of the Thompson, i.s also very abrupt and rugged. On the east side, they are found to overlap a granitoid diorite at the mouth of Eight-mile Creek, at a height of about 250 feet above the river. The lowest volcanic rock here seen is a coarse basaltic breccia. Effusive basalt is elsewhere developed, as well as gray tuffaceous rocks, which in some places become alm(j6t porcelanous in character, reddish porous rocks, probably melaphyre, charged with zeolitic matter, and some pale augite-porphyrite. It is possible that sedimentary materials, such as ordinary sandstones or conglomer- ates, may occur in the bottom of the old depression here occupied by volcanic rocks, but none such were actually seen. The area occupied by the eruptive mass next .shown, to the east of the Tertiary belt, near Eight-mile Creek, has not been very accurately determined, particularly to the south of the river, where few exposures are seen. It consists chiefly of a green-gray mica-diorite. The next, and last, eruptive mass of importance, which breaks through the sec- tion about midway between Eight-mile Creek and the Deadman, may be mentioned at the same time. It is chiefly represented by dark gray-green, much decomposed, dioritic and gabbrolike rocks, some of which are not unlike those of the last. It resembles generally the granit- * Appendix I., No. 84. "•] SECTION IN THOMPSON VALLEY. 119 B oid materials elsewhere found in the region, where near a contact with the stratified rocks, and on the east side of the mass, near the road, it includes a considerable quantity of diabase or similar material, derived from the stratified series. On tiie same .side, in the hills to the north, however, considerable exposures of a bright red hornblende-granite were found. This is so different in character from ^he rest, that it probably represents another intrusion of different age, although its outlines were not separately traced out. It is too much shattered to be of any value for purposes of construction. While the stratified rocks seen between Eight-mile Creek and the NIcHila'rockf--, Deadman River are almost entirely of volcanic origin, several broken ^ Deaclman. outcrops of limestone have now been ascertained to exist in this part of the section. None of these can be traced far, and it is not certain whether there is one bed of limestone or two. Most of the associated volcanic rocks are very massive in character, and are, besides, even more than usually shattered and disturbefl. It is thus almost impos- sible to ascertain the lie of the rocks from direct observation, but there are certain (iiffereiices of texture and colour moderately constant along some zones, which, taken in connection with the limestone outcrops, afford a slight clue to the structure, and upon these the hypothetical attitudes given to the beds in the section are based. it is unnecessary to describe the rocks themselves in detail. They Dialiasm and consist in the main of different varieties of greenish, blackish and gray diabases, sometimes fine-grained and resembling felsites. Agglomerates are common and in these purplish tints are often observable, while in some cases included fragments of limestone are abundant. Some of the agglomerates also pass into tine tuffaceous materials. Purplish grauwacke-like beds of this kind constitute a somewhat notable feat- ure. One of the freshest and most chiracteristic of them, collected one mile east of Penny station on the railway, has been subjected to microscopical examination with the result elsewhere detailed.* No distinctive fossils could be found in any of the limestones, although in the limestone outcrops near the road, aVwut four miles west of the Deadman, organic fragments are common, and a peculiar structure of oolitic aspect was observed under the microscope. This particular outcrop was at first supposed to represent part of an unconformably underlying series of rocks. It is followed on both sides by purplish agglomerate full of limestone fragments. Its resemblance to the lime, stone on the Deadman, however, appears to show that it nmst be '■ i *Apj>endix I., No. 35. Compare also Nos. 32 aiul 29, frf>in the north side of Kam- ix>i)8 Lake. 120 B BRITISH COLUMBIA. Apparent junction witi) CAcht' Crcfk rocks. Remarkable dyke. Relation to section near Ashcroft. Liine-stones and argillites, Dendnian River. regarded, like that limestone, as a part of the Nicola formation, and that it occurs here in the form of a sharp anticlinal, as represented on the section. Another point of interest in this part of the section, is found on the wagon-road, nearly three miles east of Eight-mile Creek, where the road approaches a northerly uend of the river and is protected by dry stone walling both above and below. At this place, there is pretty distinct evidence of the un( . informable superposition of rocks of the. Nicola series upon a projecting lx)ss of older rocks. Th^ lower rocks consist of greenish to nearly white granular tween Eight-mile Creek and the Deadman, correspond with some of those of the lower half of the general section south of Ashcroft (p. 113 b). Near the bridge by which the wagon-road crosses the Deadman River, on the east side of the river, are somewhat extensive exposures of limestone and argillite, with associated volcanic rocks which are believed again to represent those just referred to. The limestones are gray and fine-grained, while the associated argillites are often highly calcareous. The thickness of the limestones and argillites together appears to reach seveVal hundred feet, but both the direction and amount of the dip is irregular, varying from N. 10° W. to N. 6° E. and from an angle of 20° to one of 45°. Both the limestones and argillites contain obscure fossils, among which portions of the guard of a Belemnite, with the remains of two species of Pelecypoda were recog- • See Api)endix I. SECTION IN THOMPSON VALLEY. 121 B nized. The limestones are overlain by a pale felspathic rock, which weathers to a reddish colour, and \tfhich, though much shattered, seems undoubtedly to form a part of the same series with the limestones. The limestone here seen, is believed to be the same with one found some five miles up the Deadman, near the Indian village, which there dips eastward at an angle of 20". In order to ascertain what rocks follow the limestone in ascending Ri>cki< !»■- , , „ 11.1 1 T-x 1 twi'iiii Diiad- order, a traverse wius made from the bridge at the Deadman across man and Ct>i) the area of rough hills between that river and Copper Creek. The •'*''" ^''''^'*- rocks niet with on this traverse are represented in the eastern part of the section to which this description relates. BrieHy characterized, these rocks consist chiefly of altered diabases, sometimes apparently compact, but often in the form of agglomerates, and generally greenish or greenish-gray in colour. At a height of about 1800 feet above the Deadman, a, small patch of brown basalt occurs. The area of this is somewhat uncertain, but it undoubtedly forms a mere remnant of a more extensive flow, adhering to the surface. Two miles and a half from the Deadman, on this line of traverse, a Fossiiiffrous zone of hard highly calcareous argillites with some grauwacke-like '' sandstones was found. This is repeated at a further distance of about three-quarters of a mile, the interval being occupied by diabase agglom- erates containing some calcareous fragments. The dips of both out- crops of these argillites are very high, but there can be little doubt that they represent a somewhat compressed syncline. These beds contain a few fossils, among which Prof. A. Hyatt recognizes Triyonodiis, a Gardita and a Daonelfa like D. Lominell and apparently the .same with one found in the general section south of Ashcroft, the assemblage being clearly of Triassic age. In this part of the section, the only dips actually determined are Easteru cud those of the limestone at Deadman River and those of the argillites near the summit of the hills. The intervening indications of dip are therefore conjectural, but the return of the limestone on the east side of the syncline appears to be indicated by the facts detailed in con- nection with the section along Kamloops Lake (Sect. No. 5), which in part runs parallel to this one. The conglomerates at the base of the Tertiary, represented at the east end of this section, are the Coldwater conglomerates described in the Kamloops Lake section just referred to. They appear to be immediately followed by an overflow of igneous i-ock rich in olivine, probably a picrite-porphyrite, which seems to be the lowest of the Tertiary igneous materials in this neighbourhood. -SKS 122 B BRITISH COLUMBIA. TliickneBs. Caniiibell _ Creek ncction. ArgillittH and iimphilxjIiteH. Lenpth of the section The information so far gained on the straligraphical arrangement of the rocks referred to the Nicola formation in this section, is obviously too incomplete t<> afford any definite idea of their secjuence or thick- ness, although there would appear to be a volume of at least 5000 feet between the limestone of the Deadman and the fossiliferous argillites. Seftion on Campbell Creek. The older stratified rocks found to the south of Kamloops and the South Thompson- River, are, for the most part, believed to represent the Nicola formation, but some consideraljle areas have been separ- ated from these and referred to the Cache Creek formation. The grounds upon which this admittedly provisional separation is justified are elsewhere stated (p. 44 ii). In describing the rocks of the region named, it will be most convenipnt to begin with the section afforded by Campbell Creek, in which strata of botu these series appear to -."sented. Some account of a part of this section has been given in the report for 1877-78, but this included only the rocks seen near Shumway Lake, for which a thickness of about 500 feet was then ascertained. It is u; u'cessary to repeat this description, but it must now be noted, i't n-ijp ct to it, that a considerable part of the beds there spoken o? us 5>.itered argillites have since proved, on microscopic exam- inatiofi by Mr. Ferrier, to Ije very fine-grained amphibolites, which undoubtedly represent volcanic rocks of some kind, either tuffs or massive rocks dynamically altered. The alteration of the argillite.'; proper is by no means great, and is chiefly confined to the immediate vicinity of the granitic intrusive masses. The section hjis now been extended by an examination along the entire portion of the valley of Campbell Creek occupied by the strati- fied rocks, with a length of nearly two miles from the north end of Shumway Lake north-eastward to the edge of the granite in that direction, and ot alx)ut four miles southward to where the stratified rocks are again cut off by granitic rocks, near Nf^wman's house, at the mouth of Fish Creek. The first part of this section crosses the strike of the beds at a considerable angle, while the second part does so verj- obliquely. The general direction of the strike is about N- 15° W., while the dips are to the westward at high angles, varying from about 70° to 40'. Both strike and dip are notably regular or this region, and rock exposures are frequent. «•] SECT Beginning with the the .section, the rocks rep ing order : — (4.) Kinpff rained amphibi Ik'dded and jfeneri coming gfi-eetiisli-bii (3.) Mohsive, dark-gr((eni (poHsibly intrusive) (2.) Cliinfly iirffilliteM, wit ■..tertnl diat>a!(e (?) ii (1.) Chiefly green and gni with micaceous «chi Total. The rocks of Nos. 4 to referred to as the Campl The argillites are oft« with the fine-grained am texture, that it is freqt two classes of rocks. So brlding planes, from th s;. ic mica, but it is ci between the upper end of ation becomes consideral ance. This alteration i: dently connected with upper members of the s in character, and has pr extreme term of this al where the strike of the cont'oi-mity with the dir the road going north war be found changing into i all the difl'erent stages ii On the hills to the ei and on both sides of Fisl as lenticular masses in indicate these on the m but they evidently repro rocks. The upper part of t beds, is that which is *Api)endix T., No. 8. ProterobaHo or e]>idioritie, D.WSON.] SECTION OS CAMPUELL CfiKEK. 12.'? II Beginning with the lowest beds seen, at the north-eastern end of the section, the lockH represented may be described as follows, in ascend- ing order : — Feet. (4.) Fine-praiiK'd amphiholiteN and liaril, splintery urgillitcs, Uitli wfll bedded and penerally bluck or bliiekish.out occaMionally be- coming greenish-black 3,000 (3.) Mattsive, dark-greenish, rather coaine-grained dialiaHe-iKirphyry ([xiasibly intrusive) 000 (2.) Chiefly argillite«, with fine-grained amphilM>liteH and graygretn ■..terwl diabane (?) all well bedded.* 2,200 (1.) Chiefly green and gray altt reof conditions, and enables the separation on the map of a set of lower beds which in this region have peculiar characters and are pretty easily recognized wherever they occur. To the north-westward of the above-described section on Campbell Creek, and following the strike of its rocks, beds of identical character are found running on to the Thompson Valley. In the vicinity of Separation Lake and near the town of Kamloops, they consist chiefly of fine grained blackish amphibolite3 and argillites, with grauwacke sandstoneSj containing in some cases fragments of hard black shales. These dip in various directions, and appear to be considerably dis- turbed and fractured, probably as a result of the proximity of the se eral granitic intrusions in this vicinity. They evidently represent, however, the lower part of the section seen on Campbell Creek, or that to which the name of Campbell Creek beds has been given. The upper part of the Campbell Creek section is equally clearly represented by the greenish md gray diabases and diabase-conglomer- ates which lie below the Tertiary coal-bearing rocks near Guerin's, three miles south of Kamloops town, and form the ridge to the west- ward of the small stream which enters the Thompson at the old Hudson Bay house (at the west end of Kamloops), between ^h"' stream and the edge of tlie Tertiary. As already stated, the line drawn between these two series of rocks is not entirely a satisfactory one, and it must, in fact, be regai'deti for the present as a p»x)visional line only, for no unconformity nor any marked break has here been found. Had this particular tract in the vicinity of the town of Kamloops and Campbell Creek been alone examined, the two classes of rock:i would undoubtedly have been con sidered as the upper and lower parts of a single series ; but, being alrefwly in pos.:'i.ssion of the fact that the Carboniferous .strata of the Cliche Creek formation characterize the region to the north-eastwai'd, while those the south-w where betw of all the fi To the n. map in accc mentioned, together in To the s after an ir Tertiary ro reappear on Where thes close to the volcanic ro( exceptional shattered, o red bmks. micaceous r with less a their origin of miles oii scribed abo Creek, and j diabase is f< Further much shait The Tertiar ihese, and of the older ing Stump are folio wee ing the Car dip N. (10" S'luth-eastw whicli the scarcely pr.i ^is runniiii>' continued s TRIASSIC OF STUMP LAKE AND VICINITY. 125 B while those of the Nicola formation are characteristically developed to the south-westward, it becomes necessary to determine a line some- where between them, and that above defined appears, in consideration of all the facts known, to be the most natural one. To the north of the Thompson, the line of division is entered on the map in accordance with the same lithological basis, though, as already mentioned, it is very probtable that the two formations are brought together in the region of the Garde Laiferty by faulting. Stump Lake, Moore Creek and Upper Nicola. To the south of t.he section on Campbell Creek, above described, Nicoln rocks after a^ interruption c^ some miles, occupied by the granitic and Lake.' Tertiary rocks which surround Trapp Lake, the older rocks again reappear on the west side of Napier Lake and north of Fraser Creek. Where these rocks touch the shore of Napier Lake, they are not only close to the edge of the granite, but immediately underlie the massive volcanic rocks of the Tertiary, and have evidently been subjected to exceptional alteration by solfataric or similar action. They are much shattered, often highly silicified and pyritized and weather into rubbly red bmks. Gray somewhat silvery schists, with some rather coarsely micaceous rcjksof gneissic aspect, occur; but both these are associated with less altered poiphyiitic diabase in such a manner as to prove their origin fron' that rock Within the area of the granite, a couple of miles eastward, gneissic intercalations also occur, like those de- scribed abo'b near Newman's (p. 123 b). To the north of Fra.ser Creek, and again not far from the south edge of the gi'anite, dark green diabase is fouml, coarsely porphyritio, ami with uralite crystals. Further to the south-west, about the actual head of Stump Lake, are About mutii much shaitered and decomposed diabases, often highly dolomitized. stiimii llaki' The Tertiary volcanic rocks have evidently at one time extended over these, and the characters mentioned are often found in superficial parts of the older rocks in such a position. On the first small stream enter- ing Stump Lake on the east, to the south of Fraser Creek, these rocks lire followed by nearly black, very fine-gi'ained ainphibolites represent- ing the Campbell Creek beds. Those appear to be well stratified, and dip N. (iO° E. <. 80. From this place, Muiihir rocks have been traced siHith-eastsvard, nearly on tl)e'r line of strike, for about five miles, beyond . wliich the country becomes so thickly wocxled and broken that it was scarcely practicable to follow them. Ihey are represented on the map as running out in this vicinity, though it is possible that they may bo continued .somewhat further. They are generally>nearly or quite verti- 126 B nRITISH COLUMBIA. Stratigra|)ln- cal relations. UeveloiHnent to the .south. Stratigraphy obseuri'. cal, and the fine-grained black rocks are apparently in some beds true argillites, which occasionally show calcareous streaks and seem to be interbedded with green porphyritic diabases of the usual character, which to the south-eastward, became moi-e altered. Thus far, from the vicinity of Napier Lake to the li'io of outcrop of the amphibolites and argillites, we evidently i w^ rented the south-west side of a rather wide syncline repeat ri' l).> ks of the upper part of the section on Campbell Creek ; )ut lie thickness of the lower dark rocks here coming to the surface is very much less than that found iu the Campbell Creek section, rendering it probable that they occur here either on the summit of a compressed anticline, or that they are cut oflf to the south-westward by a fault. The latter appears to be the more probable hypothesis, and a line of faulting running in a direction of about N. 20° W. would best accord with the observed facts. It may be added, that such a line if traced northward, is found to correspond with that of a fault noted as affecting at least the older portion of the Tertiary rocks on the south shore of Kamloops Lake, nearly opposite the mouth of the Tranquille River. To the south and east of the line of outcrop of the older rocks u ; referred to, the region in.iluding Stump Lake, Moore Creek, the^'j'per Nicola and the Douglas Plateau is occupied by roeks to whic' tL '.. »_' is afforded by the section on Campbell Creek. Much the grei; "r i of this area is held by strata referred to the Nicola formation, inc'ii ing beds of that formation which must be stratigiaphically much higlie. than those of any part of the Campbell Creek .section. The remaining part of the area is occupied by the underlying dark arapiul)olites an', argillites which have been provisionally attached to the Cache Cre ;k formation. These are developed in greatest force about uhe Dorglas Lake granitic mass, and there probably include bed.s lower thoa any seen on Campbell Creek. They also, however, probably occur in minor areas near the edges of the granite on Moore Creek. This region is continuously bounded on the west by graj>' : -.lul extends to the east and south as far o,s the borders of the i. .r ,, tlio only notable exception to its j^oneral character, being found in the occurrence of the Douglas Luke graniu* tnass just alluded to. Tlic western portion of this tracl >'■ ou'int y. particularly abou Stump Ijake, lias been pretty closel}' exair.Ir j, i)u; with results which, in so far as any complete understanding, oi the geological structure is con- cerned, must be admitted to 1 j unsatisfactory. The massive character of many of the rocks, with «heir often shattered state, render the dip.s \ 1 TRIASSIC OF STUMP LAKE AND VICINITY. 127 B iUi, -.nd i in tho ;o. Tlic Stuiup and strikes very obscure in most places, and even when these are dis- tinct, they are found to be irregular and conflicting. The general direction of strike is about north-west by south-east, but strikes nearly at right angles to this are not infrequent, while the beds, though generally dipping at high angles and sometimes vertijal or nearly so, are occasionally almost flat. That which is certain is that we have in this region a great develop- Gpiioral char- liient of altered diabases, generally of green colours, and among which ^^ '"^ " "^'"^ *"' porphyritic (uralitic) varieties itre particularly characteristic. With these, and forming a lower part of the series, is a great thickness of fine-grained well stratified blackish and dark gray amphibolites, often simulating altered argillites andpitssing in places into distinct argillites of similar dark colour. The lower rocks last referred to are found in their greatest develop- Probable widi^ ment around the Douglas Lake granite mass, but are also seen along ^^'"^ '""' Woore Creek near tlie bordering granite on that side. It appears probable that a synclinal axis runs southward between these two places, in a sinuous course, beginning near the north-west part of Stump Lake, passing near Rockford, crossing the Upper Nicola, and appearing again plainly in the woU marked syncline examined in the Meander Hills (see p. 136 b). It is certain, at least, that a wide belt of diabase rocks of the general character above noted runs south ward from the north end of Stump Lake to and beyond the border of the map. On the west side of Stump Lake, a mile and a half from the shore Limostmii' and near the first small stream below the head of tlie lake, a bed of '^''^^■ gray limestone was observed in association with the greenstones. It is not thick and is much broken, but contains some obscure organic remains, and resembles that met with on McDonald's River (Quilclienna Creek) to the south of Nicola Lak(^ (p. 132 n). Although it oannot be traced out, and may even not be continuous, the occurrence of this limestone is interesting, as apparently fixing a horizon. Following the general run of the rocks, it is probable that the same limestone bed is that seen on the hills one mile east of the road and three miles south from Rockford. This strikes about north-and-south, and is nearly vertical. In thin sections this limestone has a greenish tint, which, under the microscope, is found to result from the inclusion of numerous small grains of a crystalline mineral. This has probably originally been pyroxene, but most of it is now changed to hornblende or to chlorite. The foreign constituent thus represented, has no doubt been introduced as a volcanic ash during the deposition of the lime- BBB WBB 128 B BRITISU COLUMBIA. Rocks near Dropping- water Creek. Valley of stone, the circumstances being the same as those met with in the McDonald River limestone, described below. It is believed that the two limestone outcrops referred to, represent points on the west side of the main syncline which has been juggested. No exposures of limestone on the opposite or east side were found, but, on the hypothesis advanced, the bed may be assumed to run along the hollow followed by tiie road to the east of Stump Lake, and to pass neiir to a point south-south-east of llockford, three miles, where a diabase charged with small calcareous fragments was observed. The following more detailed notes on the rocks of a few parts of this region may be useful : To the west of Dropping-water Creek, and beyond the line of the Tertiary volcanic rocks in that direction, the older series is chiefly represented by dark green, gray-green and occasionally purplish, hard volcanic ash rocks or diabase-tuffs. With these are volcanic breccias of similar composition and some massive leek-green altered diabases of the usual kind. The fine-grained fragmental rocks are generally more or less calcareous, and arc less indurated than most of the rocks in this region. Where the dip could be observed it is eastward at angles of 20^ or 30°, and it is quite possible that these rocks may immediately overlie the horizon of the limestone above alluded to. They are identical in character with some of those found near Kam- loops Lake and to the west of that lake in the vicinity of the Thomp- son River (pp. 119 b, 1 10 b). Rocks of the character above described form a belt which runs nearly parallel to the edge of the Tertiary, and occupy iimcli of the country between this edge and tho upper part of Moore Creek. They are rather notably less altered than most of the rocks of similar com- position found in the 8tunip Lake or Upper Nicola country ; and it is also to be remarked that, though they immediati'ly underlie the Tertiary volcanic rocks, they have not been shattered or dolomitized like tljose occupying a similar position at the head of Stump Lake (p. 125 b). To the west of Stump Ijake, between that lake and Moore Creek, the rocks observed, in addition to the limestone already mentioned, were green diabases, generally por[)hyritic with some exposures of a gray arkose grauwacke or qunrtzite. The valley of Moore Creek, running from north to south and ending MtHirr Creek. ^^ Nicola Lake, for fourteen miles nearly follows the junction of -1 TRIASSIC OF STUMP LAKE AND VICINITY. 129 » L the Nicola rocks with the granite. The occurrence of this line of erosion is evidently dependent upon the contact of tlie two classes of rocks, though the actual stream lies persistently at a small distance to the eastward of the edge of the granite, wliich is somewhat ttexuous. The granite border was traced out here in some detail, because of its possible bearings on the metalliferous deposits of the vinicity of Stump Lake. In going southward along the valley for the first ten miles, the rocks Clmiivctor <>f in contact with or near tlie granite border all appear originally to have ''""*^^."f " 'f'' been diabases or felspathic rocks of volcanic origin, like most of those in this field. These have sufiered considerable local altoi'ation in the vicinity of the granite and are thrown there into rather iixegular atti- tudes, in respect to their dip and strike. Tiie special alteration referred to is usually very apparent at a distance of a mile from the granite, but extremely altered forms are found only much nearer to it. Close to the granites, the rocks are gray, rather than green in colour, often gneissic in appearance, and fre(|uently become more or less schistose with the development of considerable quantities of black mica on the planes of foliation. Some of these rocks which have been microscopically examined have the composition of amphibolites in which traces are occasionally still visible of the usual p.irpliyritic character of the diabases from which tliey have been derived,* but few of the amphi- bolites here met with have the fine grained and regularly l)edded appearance of those characteristic of the lower pai't of the section oi. Campbell Creek, previously described. Where the stratified rocks from a bay in the granite edge, about riiiiiiilull four miles north of Nicola Lake, the rocks above noted are, however, ^'"'''''^ ''•''"• found to have in association with them some finely bedded hard argil- lite, of which the surfaces are verj' slightly micaceous. These are believed to be referable to the Campbell Creek beds of the Cache Creek formation. All these rocks are here traversed by numerous irregular and usually Kilgeof the ?-.arrow quartz veins, but no granitic dykes were observed to cut thtmi. S'''i'i'*<'- The granite, near its junction with the stratified rocks is also some- what modified, being in some places foliated parallel to the line of contact. In other places it becomes very fine grained and appeal's to consist entirely of felspar and quartz. It is also usually charged with pyrites grains, weathering red in consequence, and is often more or less silicified throughout its mass, besides being traversed by numerous small veins of (luartz. ' A|in<>ndix I., Noh. 11 and 12. 130 B BRITISH COLUMBIA. a«wsoH,l Rocks near The principal known metalliferous deposits of the vicinity of Stump Stump Lake ]jak»', are comprised within an area of about five miles in length witli mines. ' ^ ^ a maximum width of three miles, situated on the south-east side of ' he lake. Here a large number of veins containing silver ores, with .^o.je gold, have been discovered, and a considerable amount of work of a preliminary kind has been done on them. The greater number of these veins run in bearings between N. 15° W. and N. 15° E. Some notes concerning them have been given in the Summary Reports for 1888 and 1890, and a more complete account appears on a later page of the present report. The country -rock of the region traversed by these veins, is almost uniformly a dark green or green-gray diabase-porphyry, in which large uralite crystals are often conspicuous. There are, however, occasional bands consisting oi diabase tuff, well bedded, with others of a fine gray felspathic rock, also well bedded, and possibly a few layers of fine amphibolite. A diabase tuflf of the kiad referred to was found at the " Plai.et " mine, near the shore of Stump Lake. The felsite-like rocks were observed in the valley traversed by the road to the east of the lake. Near the metalliferous veins, the rocks are often much shattered and weather red from the presence of iron pyrites or dolomite with which they are frequently charged. Rocks sur- Along the north-western side of the Douglas Lake granite, the Doui^las^Lake country is deeply and nearly uniformly drift-covered, so much so that granite. ^\^Q boundary of the granite itself in this direction is somewhat uncer- tain, while very little is known of the rocks in its immediate vicinity, and the lines drawn upon the map must, in ct»nsequence, be considered as merely approximate. On the western and southern sides, however, the rocks are well shown in numerous places, and here the granite is found to be surrounded, for a width of about a mile and a half, with black and dark gray rocks of flaggy or schistose structure, consisting of argillites and fine grained amphibolites, with fine hard grauwacko .sandstone."*, sometimes calcareous. These rocks evidently correspond with those of the lower part of the Campbell Creek section, but inas- much as the distinction was not clearly made in the field between the fine amphibolites and the argillites, which they very closely resemble, it is not possible to state in what relative proportions the different classes of rock met with are present. In one place, about half a mile east of the eastern extremity of tlio granite, rocks such as those above descrilif^d were noticed to hold, apparently as interst ratified masses, altered diabase-porphyry of green- ish colour, the circumstances being the same with those noted in part of the Ca Lake, on The str the edge < this resp« away f ron that the g beds, here observed t (|uartz vei The th; roughly es and gray rocks are 1 general sec not seen ai formable o I In 1877 vicinity of end of the general str which was country m.' general sec made to su along the s iilong tiie c tiie south previous ol section giv( now presen ill regard t compositioi endeavoure .Meander results of t Though heyond the necessary ii H TKIAS8IC OF NICOLA LAKE AND EASTWARD. 131 B of the Campbell Creek section and also near the north end of Stump Lake, on its east side (pp. 123 b, 126 b). The strikes of these rocks show a tendency to run in parallelism to Relations! to the edge of the granite mass, and although there is some irregularity in f|^f,!i!|,g',,^" this respect, as well as in that of the dip, the predominant dips are away from the granite at high angles. The impression conveyed is that the granite has been thrust upward, bearing the lower stratified beds, here seen, to the surface with it. No extreme alteration ia observed along contacts with the granite in this case, though small (juartz veins are rather abundant near it. The thickness of these beds near the Douglas Lake granite, is roughly estimated as 7000 or 8000 feet, and they are overlain by greeA and gray diabases of the usual kind. The relations which these two rocks are believed to hold in this part of the region, are shown on the general section which is next described, but their actual junction was not seen and it is not known whether it is a conformable or an uncon formable one. General Section near Nicola Lake and Eastward. In 1877 it was found that the south side of Nicola Lake, from the Kxamina- vicinity of McDonald's River (Quilchenna Creek) westward to the lower tions made of , / , , , ,. / ., , , ,~ Nicola Lake end of the lake, a distance or seven miles and a half transverse to the »ection. general strike of the rocks, afforded a fairly good section of the series which was then named the Nicola series, The further examination of the country matle in later [years has led to the discovery of few better >;eneral sections of these rocks. In 1889 an endeavour was therefore made to supplement the results of the paced survey carried out in 1877 iilong the southern border of the lake, by means of a traverse running along the crest of the ridge which bounds this part of Nicola Lake on the south side. The results obtained, taken in connection with the previous observations, somewhat modify the outlines of the provisional section given in the first report, and aflford the data for the section now presented, which though still perhaps not entirely free from doubt in regard to its details, is believed to aflford a fairly correct' idea of the ciimposition and sequence of the rocks exposed. It lies further been endeavoured to extend the original section eastward through the Meander Hills to the Douglas Lake granite area and to combine the results of the whole in a single diagram. Though the greater part of this section (Section No. 4) lies a little Section No, 4, beyond the southern border of the Kamloops sheet, no apology seems necessary in connecting its results with the report on that sheet, as it 8i 132 B BRITISH COLUMBIA. Strike of rocks and trend of Kection. throws light on the general structure of the Triassic rocks of the region reported on. The main direction of strike of the rocks met with along the lake-shore and in the ridge behind it, is about N. 10° \V., and this is preserved with considerable regularity, though on following the beds across to the north shore, where they are found in contact with the southern end of the great granite mass, they are found to turn more to the westward. It is in fact probably in connection with the intru- sion of his granite that the beds included in the section have becoinc flexed cis they are. The section now given, is supposed to be drawn along the crest of the lidge and not along the lake-shore as was the ca.se with that of 1877, the discovery of four new limestone outcrops among the rocks met with on the ridge, having aflForded a clue to the arrangement ot the beds which was formerly wanting. As now presented, the section includes three synclinal and two anticlinal axes, and in describing it. the outcrops of the upper of the limestones believed to be comprised in the series — that first seen to the east on McDonald's River, — are assumed to be those defining the widths of the several synclinal and anticlinal folds. Limestonea at Beginning at McDonald's River (Quilchenna Creek), at a point McUonald » about a mile back from tiie shore of the lake, the first wide low syn- cline is found to have a width of about two miles and three-quarters, its western edge being more steeply inclined than its eastern. Thf eastern outcrop of the limestone and the rocks near it are thu< described in the report for 1377. Some of the details then given were for the purpose of establishing the fact that the limestfjn*' actually forms an intercalation in the great volcanic series here reprc sented, a fact which can no longer be regarded as in any doubt . — "The limestone bed above alluded to is seen on the west side of McDonald's River, about half a mile south of the wagon-road, where it forms a prominent bcre clitl' about sixty feet in height. It lia< been burnt here, and found to produce good lime. At first sight this bed appears to pass bilow the volcanic rocks with a low westward dip, but on more careful investigation it is found that it is separatfil from the mass of these rocks by a fault which runs alxjut S. 14 E.. with the downthrow probably on the west side. The existence "t this fault is so far unfortunate as it to some extent oljscures tin- relation of the limestone with the volcanic series, which is a matter ot importance. I believe, however iiat the very great probability- almost amounting to certainty — of the limestone belonging to tlie volcanic series can be shown in several ways. been ori^ lowed to sive or above thj rence of higher bd otherwise beds, abc •OnnI consist lari associatecl] tApiJ TRIASSIC OF NICOLA LAKE AXD EASTWARD. 133 U The vol- ^•''i'> .^vlc'i'iie nmteriivlB. "The limestone is very much brokea and disturbed, but on the Admixtm-f whole appears to dip westward at an angle of about 20 canic rocks on the west side of the fault seem, in so far as their atti- tude can be ascertained, to lie in a similar position. In its normal form the limestone is gray, granular, but not very highly crystalline, evidently composed of organic fragments, among which joints of crinoidal stems are most abundant. A few obscure larger fossils are also occasionally present, including a Tfrehratnln. In some places, liowever, it becomes filled with green granules, which project on weathering, and by examining various parts of the exposure these can he found at times to be much more abundant, so much so as to form ;i coherent mass after the whole of the calcite has been removed. In other layers the limestone is almost altogether replaced by this mate- rial, which is pale green in colour, and holds only scattered calcareous particles, among which crinoidal joints can at times be made out. On removing < he limestone by an acid, the residuum appears to be fels- pathic, and fuses pretty readily on the edges before the blowpipe.* It resembles the finer constituents of some of the volcanic agglomer- ates to the westward, and has, without doubt, Ijeen a %'olcanic ash or sand, mingled in varying proportions with the limestone toward the close of its deposit. * * * On the opposite side of the fault the first rock seen is an amygdaloid, which, though its cavities are in places charged with a siliceous mineral, is generally highly calcareous, and in some layers appears to be more than half composed of calcite. Though, owing to the fault, the precise relation of this rock to the limestone can not be made out, it would appear that calcareous matter was still very abundant at the time the amygdaloidal material was poured out over the bottom." The amygdaloid last noticed may thus be supposed either to imme- Overlying diately overlie the limestone or to occur stratigraphically at a very '""ytfa''""" short distance above it. The iPfiss of this amygdaloid is a purplish and greenish altered diabase, and it has evidently in some places been originally an almost frothy scoriaceous volcanic rock. It is fol- lowed to the westward, in ascending order, by a great series of mas- sive or brecciated diabase-porphyrites.f For several hundred feet above the limestone these are characterized by the frequent occur- rence of purple colours, though green colours are also present. The higher beds become almost entirel;, green or greenisli-gray, but do not otherwise materially differ from the lower. The thickness of these beds, above the limestone, appears to be about 2600 fe^t. *On :nicri)acoi)ical exniiiiiiatirm the ^eeii granules in the limestone are found to consist largely of hornblende, which is prohahly .in alteration product of pyroxene, associated with some felspar and a little quartz. , t Appendix I., Nos. 23, 33. 134 B BRITISH COLUMBIA. Limeatone west of first syncliiie. Rockii of firrit. syncline. Anticline witli two lime' Htone beds. Schistoge nxjks in anti- cline. Where the limestone recurs on the west side of this syncline, it is again found to be overlain by a considerable thickness of notably purplish, porphyritic rocks, but these are here slightly schistose in character, doubtless as a consequence of the greater pressure to which they have been subjected. The limestone itself is again about sixty feet in thickness, and its connection with the volcanic rocks next under- lying it is clearly shown. At its base it becomes •• erbedded with green felspathic schists, which still afford evidence of their original fragmental character and undoubtedly represent altered ash rocks or tuffs. In the centre of this first syncline and overlying the generally por- phyritic diabases previously described, are certain bluish or greenish- gray fine-grained rocks, which belong to the highest part of the entire series represented in this section. Their thickness, as they are found in this syncline, appears to be small, but they recur in much greater volume in the westernmost syncline of the section, in which they con- tinue as far as the lower end of Nicola Lake. No means was found of obtaining an approximately correct estimate of their thickness, but this must be at least several hundred feet. In some places they are very distinctly bedded and they evidently represent an altered con- dition of fine grained tuflfs which have been deposited in water. Thej' are believed to be equivalent to the highest beds met with in the Meander Hills, subsequently described. Returning to the last-described limestone outcrop. — This is followed to the westward by an anticline about a mile and three-quarters wide, bounded to the west by what is taken to be another exposure of the same limestone, with westerly dips at high angles. On this western side of the anticline, below the limestone mentioned, is another lime stone outcrop which, unless some unrecognized complication occurs, must represent a second and underlying bed. This was, however, not seen on the eastern slope of the anticline. The strata intervening between the two limestones appear to have a thickness of about 1000 feet, which is characterized chiefly by coarse greon diabase-breccia or agglomerate ; and where this runs out upon the lake shore, it contains in some places large quantities of angular pieces of limestone, holding crinoidal fragments, and otherwise resembling the limestones of this series. Beneath the lower limestone, in the central part of this anticline, a thickness of about 2600 feet of beds not elsewhere seen in this part of the section, come to the surface. They consist for the most part of bright leek-green altered diabases, generally distinctly porphyritic and MWtON.] TRIA8SIC OF NICOLA LAKE AND EASTWARD. 135 B Si'coiul Hyii- cline. Second anti- cline. occasionally brecciated. Epidote has fretjuently been developed in the more compact varieties of this rock, but a large part of tiie entire thickness of these lower beds has been converted by pressure into jjreen chioritic schists, bet *feen which and the compact forms transitional varieties occur. The schists are often highly calcareous, and it may be that the more calcareous beds have been those most affected by this alteration. In the next small syncline to the westward, beds recur like those already described jis overlying the upper limestone. These are here, as before, often purplish in colour and largely agglomeritic. Tlie next (and last) narrow anticline, to the westward, is belived to occur in the manner indicated, though the outcrop of the upper lime- stone which should appear on its west slope, was not seen. It seems that this anticline narrows and that its axis slopes down in a northerly direction, so that neither limestone comes to the surface on the lake shore, while the lower limestone can outcrop only to the south of the present line of section. In this anticline the rocks are again found to be rather schistose in character, in some places, particularly near ;he lake shore. In the last low syncline, at the west end of tiie section, the exposures Western low are very unsatisfactory, and its form as indicated is therefore largely'"''"'^'"*"' conjectural. The characteristically purplish rocks previously noted were here not recognized, but green rocks of the usual character and often breccias are abundant on its eastern side, while the fine-grained felspathic materials forming the highest member of the section, apjjear to occupy a considerable breadth in its central part. With reference to that part of the section in the viciunj Lake, above described, the following general points may be noticed. The diabase? of the Nicola series are here, in many places, unusually charged with epidote, a fact which may probably be attributed to the proximity of the granite mass which comes out on the north shore of the lake. A greater development of schistose structure is found here than elsewhere commonly encour*^^ered in the Nicola rocks of this part of the Interior Plateau, and this is juost prominent in the anticlines, especially toward their axes, where the beds stand at very high angles and appear to have had their original structure broken down by the intensity of the pressure exerted upon them. The two limestone beds are so inconsiderable in thickness that they may never have b«.on absolutely continuous throughout the area covered by the section, while the recurrent explosive forces indicated by the massive volcanic breccias may easily have destroyed or removed the limestone uf Nicola Generul char- acter of rocks. TiE 1 • 136 ItRITIHir COLUMHIA. Section fast of MiDomildV Ki\ ur. Svncline of ISlfandpr Hill». beds locr.lly. This, in fact, becomes more than a mere probability, in casen where limestone fragments in cjuantity are components of the b.-eccias. An endeavour »>ii.s been irade to continue the section above described eastward and northward through the Meander Hills and as far as the Douglas Lake granite mass, thus to connect the rocks of the Nicola Lake section with the dark fine-grained argillites and amphi- bolites which surround that mass. The result >f this attempt is shown in the eastern part of the general section presented, but in this part of the section it must \je understood that the data are very much less precise than in the case of the section along Ni' Lake. The syn- cline found in the Meander Hills, in which occur w 'ded fine-grained felspatliic locks almost certainly identical with tuv. -uilar rocks found to form the upper members of the series near Nicola Lake, may be described iis the ruling feature of this j art of the section. The.se upper beds are here confined to the higher part of the hills, south oC the Upper Nicola, and do not appeHr in the valley of the river. They consist ciiiefly of fine-grained felsites, of gray, greenish-gray and blackish tints when freshly broken, but which weather to various rusty colours. Some varieties break with a perfect conchoidal fracture. With these rocks, especially toward the base of this part of the series, are some fine-grained diabases, while the highest beds seen, resemble hard black argillites and probably contain a considerable proportion of ordinary argillaceous material. All these rocks are well and regularly bedded, in layers ranging from less than an inch to several feet in thickness. Like the rocks of the upper part of the Nicola Lake section above igies ,e H. (jgggpjjjgj^ they resemble very closely the felsitic strata found in the \icinity of the Cretaceous area near Ashcroft, elsewhere noted (p. 113 b). To the west of the syncline thus occupied, between it and the line of McDonald's Ri^er and the shore of the upper part of Nicola Lake, hard gray-green and leek-green altered diabases of the usual kind prevail. These are generally more or less porphyritic and occa- sionally very markedly so. In one place, west of McDonald's River, considerable exposures were found of a hard green amygdaloid of which the base is coarsely porphyritic with uralite crystals. It i> difficult to ascertain the attitude of these rocks, but where this was observed, they appear to lie at low angles, being in some cases nearly horizontal. The granite shown to under'ie these rocks in the section, does not appear at the surface on the line of section, but occupies a cof^siderable area near tV.^ jhore of Nicola Lake half-way between the mouth of the Upper Nicola and McDonald's rivers. The limestone Undeilying reeii dia- h C>W«ON. J TRIA8SIC SOUTH OK KAML00P8 LAKE. 137 It tioiiof Bi-ctiedded rocks, chiefly felsites ; thickness seen in Meander Hills (alxnit) 1,200 2. Altered diabase rocks, generally ixn-phyritic, often brecciated ; for the most pai't green )>ut often purplish toward the base 2,0<; made here of a remarkable vein of siliceous dolo- Dolomitie mite which travt-rses these rocks near Duffy Creek. This appears to ^''"'' begin about one mile and a half south of the iSSrd mile-post on the railway. It runs thence south-eastward along the slope of the hills for a couple of miles, to DufVy Creek, where it turns to a south-westward course, and was followed by Mr. McEvoy for about two miles further, along the north-west side of the creek. The vein is often a quarter Traces of of a mile in width, and, as specimens collected from it yielded a trace ^ of gold on assay, it ni;iy be worthy of further e.vamination. It pre- cisely resembles in character the dolomite veins elsewhere found in this district, as, for instance, those of tlie southern part of the (lardo Lafferty near Kamloops, but is much lai 'or than any of these. It is probably referable to the same date » i the other similar veins, and this, there is reason to believe, is later than that of the oldest Tertiary deposits (p. 163 u). Near Savona, the rocks are chiefly green diaiiase-.iiTglomeratp- Savdim, often notably coarse and porphyi'itic. About the head waters of Cherry Bluft' Creek, greenstones of the tMu'in liluff usual character are found, but there is here also a small ani of a diorite-like rock which is pretty evidently an intrusive mass, uid is therefore indicated on the map under the same colour with the plu- tonic rocks gonei'ally. The tract forming the south-west slopes of the Timbered Hills. \ alley of with the plateau country southward to Meadow Creek, was exaniintd Cieck. along the exjiloratory line shown on the map and along the vidlcy of Meadow Creek. The whole upper part of this valley, is wide and deeply filled with drift deposits, showing only here and there small isolated exposures of the underlying rock. The west edge of the granite, near Trout Lake, is entirely concealed, but near its assumed position green, schistose and slightly micaceous, much altered, dia- base was found. This resembles some of the rocks .seen in similar contiguity to granite on Peterson Creek (p. 138 h). Elsewhere along the valley, the rocks seem to consist of green and gray-green, with occasionally purplish, diabases, which are sometimes agglonieritic, but present no features of special interest. On the north side of the vallev, three miles east of Guichou Creek and to the east of the ^;SE9B9P 142 B BRITISH COLUMBIA. Choo-whels Mountain. IJreenRtone Creek. Rock soutli Meadow Creek. projection of Tertiary volcanic rocks which occurs there, brownish and purplish grauwacke-like volcanic ash rocks are found, much like those of the vicinity of Three-mile Creek alre.ady described (p. 139 b). On the route from Trout Lakt; to Choo-whels Mountain, nearly all the rocks seen are greenstones of the usual character, which seldom show distinct bedding, though often consisting of coarse or fine diabase- agglomerate. In a few places the diabase was observed to assume a slightly schistose character. One of the agglomerates contains numerous fragments of limestone, most of which has been converted into greenish or reddish marble. Some of these are large and still show distinct traces of crinoid stems and other very obscure fossils, generally silicified. There are also some rounded pebbles present, which appear to show contemporaneous water action. The southern point of Choo-whels Mountain, which was occupied as a transit station, is composed of a dark leek-green augite-porphyrite, somewhat less altered in appearance than most of the rocks of this region. From this point to Face liake, diabases are seen in numerous exposures. These are usually greenish, but include also a notable pro- portion of purplish or reddish rocks of the same character. Similar rocks prevail along Greenstone Creek, but they are here nearly all green or gray-green in colour. About i. mile and a half below Big-fish Lake, on this creek, where its valley makes a right- angled turn to the south, there are, however, some exposures of rocks differing in chiiriicter. These are gray or blackish in colour, well bedded in thin layers, and are found on microscopic examination to be composed of siliceous and tutfaceousmatterintermixed.* Mucroscopically they much resemble some rocks noted near Peterson Creek (p. 138 n). In certain layers they contain numerous small calcareous fragments, and with these rocks there appears to be associated some slat}' or schistose argillite, though this was not actually seen in place. The dips are eastward, at rather high angles. It appears not improbable that the horizon here represented uiay be the same with that of the argillites noted in the hills to the north of Savona (p. 121 b) though no fossils were found at this place. „f Several excursions were made from Sfeadow Creek into the country to the south, but this is not only for the most part thickly wooded, but also heavily drift-covered. These diiHculties are especially great toward the edge of the granite on the east, and about the head of the west branch of Moore Creek, so that the line between the Nicola rocks and the granites in this region is far from being very definitely fixed. OAWION. ] In the rod feature is t which are These are < often neiirl some calcit four miles tion, grad miles. Tl; above the attitude of eastward o on Greenst repeat the the summi Among Guichon C Marait La' was found greenstone stones of tl far from evidence o intrusive r though no Furtlier stone serie generally i characteri; Clappertoi where the found in v and elsewl in appearr The strike lire f reque veins or d seldom we iussociated Creek, ale •Appen •Appendix 1., No. 3(5. OWION. 1 TRIA8SIC SOUTH OF KAMLOOPS LAKE. U3 i. In the rocks met with to the south of Meadow Creek, the only notable feature is the unusual abundance of aniygdaloidal diabase-porphyrites, which are sometimes green, but more commonly purple in colour. These are comparatively little altered. The amygdaloidal cavities are often nearly spherical and are lilled chieHy with zeolites together with some calcite.* Rocks of this class appear near Meadow Creek about four miles above its mouth, and run thence in a south-easterly direc- tion, gradually departing from the line of the stream, for about six miles. Thoy closely resemble the purplish amygdaloids found not far above the limestone on McDonald's River (p. 133 u) and though the attitude of the beds could not be determined, it is possible that they dip eastward or north-eastward and pass beneath the rocks last described on Greenstone Creek, ir which case the section here might be found to repeat the conditions of that obseived between the Deadman River and the summit of the hills north of Savona (p. 121 ii). Among masses of rock brought down by a stream which enters N,.ar Mmnit Guichon Creek from the east between Meadow Creek and the head of '-''•"^'^■ Mamit Lake, gray fine-grained limestone with obscure traces of fossils was found. This was seen to be associated in the same fragment with greenstone rocks, and it is probable that an outcrop of one of the lime- stones of the Nicola formation occurs to the cast of Guichon Valley not far from this place. It may further be observed here, that some Possibly Tci- evidenco of the probable occurrence of a small outlier or outliers, or of ''"^'^ '"'"' intrusive masses of Tertiary volcanic rocks was met with in this vicinity, though no such rocks were actually seen in place. Furtlier south, on Ray Creek, the rocks seen all belong to the green- l{iiy Crook, stone series. They are hard and often contain some ppidote, and are generally much shattered by jointage planes. Similar rocks appear to characterize the whole region in this vicinity. At the extreme head of Clapperton Creek and on the adjacent crest of the Little Timbered Hills, where the Nicola rocks form a bay in the edge of the granite, they are found in various stages of alteration, sometimes resembling dioritcs, and elsewhere, near the actual border of the granite, becoming gneissic in appearance or forming thinly foliated and highly micaceous schists. The strike is here, locally, neaily east-and-wost. Small (juartz veins are frequent in these altered rocks, and they are also cut by granitic veins or dykes. On the lower pnrt of Clapperton Creek, the rocks are seldom well seen, but they appear to consist wholly of diabases or associated materials,' generally greenish. To the west of Clapperton Creek, along the border of the projection of Tertiary rocks shown on > i| (^lapnortoii Crook. •Appendix I., Nob. 24 and 27. ^ESSSS^S 144 B BRITISH COLUMBIA. Junction with (franites on (inichon Creek. t;he map, the Nicola series is represented by bright greenish amygdaloids and agglomerates, the latter passing into tuffs, and then becoming some what calcareous. On the west side of the same projection, the underlying rooks, where seen, consist of brown and purple-brown augite- porphyrite, with abundant felspar crystals and a little quartz. These are elsewhere referred to in connection with their relation to the Tertiary rocks (p. 195 b). The wide and deep hollow now occupied by Cluichon Creek, like the corresponding depression of Moore Creek, has been excavated along the line of junction of the Nicola rocks with the granite. Its existence has undoubtedly been determined by that of this junction, and although the stratified rooks are usually hardened on their approach to the granites, it may be supposed that the facility of excavation evidenced has lieen due to the much shattered state in which these rocks are often found when thus situated. In general, this valley is now deeply filled with drift deposits, but sufficient exposures of the older rocks have been found to enable the line of junction to be traced with approximate accuracy. Opposite the mouth of Meadow Creek, alor.g the base of the hills which border (xuichon Creek valley, the actual contact of the Nicola rocks with the granite is pretty well seen. The diabases be- come schistose and almost gneissic in appearance, while the margin of the yranite itself has been crushed into a fciiated material of gneissic aspect and gray colour. It was also observed here that the granite, at some distance from its actual edge, is charged with angular fragments of the greenstones, still plainly distinguishable from it.* Speaking generally of the large area of rocks of the Nicola founation to which the foregoing brief notes apply, it may be described as being characterized throughout, so far as our present knowledge goes, by altt'red volcanic products. It is in fact a great region of " greenstone." which is usually found to have the composition of an altered tliabaso. and often appears in the form of agglomerates, souutimes as amygdaloids, and occtusionally as fine ash rooks or tuffs. The occurrence of limestone, as near Three-mile Creek, and ot iHul rtitfillitee. argjUitelike materials, as on Greenstone Creek, with the evidence nt underlying limestone afforded l)y the ealcareouj agglomerate of the south-east slope of Clioo-whels Mountain, are quite exceptional. These at the same time must be regarded as most importan, exceptio.is. for they appear to offerameaiis of eventually determining and tracini; out horizons, and of bringing these into comparison with those recog- nized on Nicola Lake and elsewhere. The attitude of the beds is so A j?i\ at aroa of priH'n- sUme. Liintstono .seldom ol remains ii main a sy masses, and the '. Big-fish 1 however, i no evi(.!en( bance, exc Jiocki Passing above Asli descriptior of the gene iiig the olc River and tiary volca to the Nici The vail with that » and into, t exception < creek, coni= bably for ' green, gra^ Two mil Headman along it f McEvoy, a by Tertiar again foun eight miles the mouth of about a : chiefly of g limestone, in characte I'ock seen north by a 10 -] TRIAS8IC NEAR UPPER DEADMAN RIVER. 145 H seldom observable, that the order and thickness of the series here General remains indeterminate. The structure appears, however, to be iti the strwotnre. main a synclinal one, resting between the eastern and western granitic masses. The general direction of strike seems to be about N. 40' W., and the highest beds found are probably those of tlie vicinity of Big-fish Lake. The general synclinal structure, if such it be, is, however, evidently complicated by seve'ral superposed minor folds, but no eviiience has been discovered of acute crumpling or of great distur- bance, except in certain places toward the edges of the area. Jiocks of the Nicola formation, seen on and near the Upper Deadinan River. Passing over the region in the vicinity of the Thompson River above Ashcroft, and that of the western part of Kamloops Lake, a description of which has already been given in connection with one of of the general sections, (p. 115 b) it remains to add a few words respect- ing the older rocks shown ahmg the northern part of the Deadman River and its branches where these streams have cut through the T(,'r- tiary volcanic strata. The rocks thus shown arc believed to be referable to the Nicola formation. The valley of Criss Creek, for about ten miles above its junction with that of the Deadman, appears to be continuously cut down to and into, the older rocks. These, ,so far as observed, and with the exception of one thin bed of limestone near the lower part of the creek, consist entiri'ly of greenstones and porphyrites, and are j)ro- bably for the most part diabases in composition. In colour, they are green, gray and bluo-gray. Two miles above the mouth of Criss Creek, the main valley of the Deadman is found to iio floored by greenstones, which continue iilong it for aljout a mile and a half. These, according to Mr. McEvoy, are dark green diabases. Aftir a short interruption caused ')y Tertiary rocks extending .tcoss the valley, the older rocks are again found, and they continue iu the 1 ottom of the valley for abcve eight miles, or nearly to the lower end of Deadman Lake. Just about the mouth of Gorge Creek, extending thence up stream • a distance of about a mile, is a hard breccia or sub-ingular conglomerate, composed chiefly of greenstone fragments with some of granite and of finegrained limestone. This has a calcareous cement, and is somewhat different in character from the conglomerates usually met with, reaembiing the rock seen eivst of Three-mile Creek (p. 140u). Tt is followed to the north by an ordinary dark green diabase-agglomerate ; and rocks of 10 Criss f 'reck. Dcivdiimii RiviT .nbove Oris.- Creek. 146 ii BRITISH COLUMBIA. BoiiaiHirte River. Uren's. Granite Lake. the same character, though often apparently massive rather than agglomeritic, continue to floor the valley to the puint alx>ve designated, where the Tertiary rocks again extend completely across IL To the north of Deadman Lake, the old rocks reappear in the bottom of the valley and seem to be continuously .shown, according to Mr. McEvoy, for more than seven miles. They consist of greenstones, differing from those seen further down the valley only in being some- what more highly indurated and altered. They become coareely crystalline on approaching the edge of the great granite region on the north. In this vicinity, a few miles to the north westward, on the Bona- parte below the mouth of its north branch, a small area of fine grained green diabase was observed to occur in the river-valle}-, between the margin of the granite and the overlapping edge of the " Ttiary rocks on the west. Following the main stream of the Deadman to the eastward, above Hunters Creek, it would appear that the volcanic rocks of the Tertiary have been removed for a considerable area near Uren's, as marked on the map. This area seems to be occupied in part by bedded greenstones, in part by diorite, but it is so heavily drift- covered that its extent as well as the relative proportions and out- lines of the two classes of rocks are doubtful. Still further up, th« valley, for a distance of nearly three miles below Granite Lake, is again floored by old stratified greenstones, which, so far as their attitude could be observed, appeared to strike about east-and-west and to b^ nearly vertical. These rocks are some- times more nearly blackish than greenish in colour, and appear now to be fine-grained diorites rather than diabases. They are occajiidn- aliy schistose, and probably owe their present appearance to their proximity to the great granitic mass of the Bonaparte Lake region. Granite Lake is itself surrounded by granitic rocks, but in these, on its south shore, are numerous lar-ge fragments of greenish dioritio rock, with sofne of hornblende-schist, the appearance l)eing that fre- quently characteristic of the vicinity of the border of the gninitio masses where they meet the stratified greenstones. It is entirely doubtful whether the greenstones found in this particular area should be classed with the Nicola formation, as no definite evidence as to their age could be obtained. The tuffaceou lite. W rocks ha^ but bet\ accuratel On St miles to i the river main rai vail ; bu the rocks 1( 0.w80h. ] cretaceous op fraser river area. 147 u Cretaceous Rocks. Fraser River Area. The principal area of Cretaceous rocks included in the Kamloops (jenural lel,"- sheet, takes the form of a narrow band, which, entering the southern rl'^"*'" .'„"^'"'' edge of the map, pursues a remarkably direct course of about N. 20° W. till it passes obliquely across its western edyc. The whole length of this band, within the map, is aljout fifty-six miles, its greatest width about seven miles. It may be regarded as defining the inner or eastern margin of the wide mountainous zone formed by the Coast Ranges. In a general way, it must be understood to occupy a syncline on the eastern side of these ranges; but its occurrence there is also, no doubt, largely due to faulting, parallel to its general direction. The actual position of the Fraser River, within the limits of the map, has evidently been determined chiefly by the existence of this Cretaceous band, or by the folding and faulting which have here defined it. For a distance of over forty miles, from the mouth of Bridge River to the southern edge of the map, i;he Fraser almost exactly follows the main strike of the Cret-aoKias rocks. Above Bridge lliver it breaks across the Cretaceous be t and thereafter, to the western edge of the map, its valley lies to the eastward of this belt. From the southern edge of the map, as far north as the mouth of R<«i()n south the Thompson, the Cretaceous rocks are chiefly represented on the west side of the Fraser. The main direction of strike is generally nearly parallel to that of the valley, but to this there are numerous exceptions. The beds are much disturbed and broken, and probably consist of several crushed folds, ivs dips occur both in eastward and westward directions. The rocks are chiefly greenish and gray-green, hard grauwacke or tuffaceous sandstones, with some conglomerate and a little shaly argil- lite. Where crossed on the route to Kl-ow-a Mountain, the Cretaceous rocks have a width of a mile and a half to the west of the Fraser but between this point and Stein Creek their width has not been accurately determined. On Stein Creek, the Cretaceous rocks have a width of nearly two miles to tho west of the Fraser, occupying not only the flat land near the river, but forming also the lower tier ol' hills along the base of the main range. Sandstones and shaly beds of the usual character pre- vail ; but in this vicinity, on both sides of the river, entire masses of the rocks have become reddened and decomposetjl by action subsequent lOi u A On Stein Civi'k. -3BC^ 148 B BRITISH COLUMBIA. Fresliwater foBxilH. M m to their deposition. The beds are all much shattered, and lines of faulting in this place undoubtedly run along the valley, one of which apparently bounds the Cretaceous trough on the east side of the valley. The conglomerates here hold rather more granitic material than usual. Below the bridge on Stein Creek, where the rocks are several times folded, a bed of gray, crumbling, sandy shale was found to contain numerous fossils. These are, unfortunately, badly preserved, but art' apparently fresh water forms, one of which may be a Goniobasis. Some fragments of large tir; opines of a Selachian fish were also found, measuring more than half an inch in greatest diameter, and either nearly triangular or laterally compressed in cross-section. Fossil iilantK. On the east side of the Fraser, about a mile above the mouth of Stein Creek, numerous exposures of Cretaceous rocks occur in a number of transverse gullies which are crossed by the trail. Blackish, shaly, and evidently carbonaceous beds, are here somewhat more abundant than usual, and from these a few fragmentary plant remains were collected in 1877, and a somewhat better, though still very small, collection, was made in 1890. Sir J. Wm. Dawson has described the first collection as containing two indeterminable dicotyledonous leaves and one flabellate leaf resembling that of a Sal i.tbitryu,.'^ On the second collection, he supplies the following note : — " 1. Platanns oblusiloba, Lesq., or closely allied. This is a species found in the Dakota group in Nebraska. " 2. Probably Magnolia tenuifoHa, Le.sq., which is found in the Dakota of Nebraska and also in the Dunvegan group of Peace River. " 3. Menispermites, allied to M. grandis of the Dakota group, but probably specifically difierent. "4. Laurophyllum. Several leaves referable to this genus, and near the Dakota species. " 5. Sequoia, a fragment which may be S. Rechenbachii. " 6. Gra.ss-like stem or Phragmites, Carpolites, etc; — scarcely deter miuable. "The whole probably belongs approximately to the age of the Dakota group or near to this." Stein Creijk to Further up the Fraser Valley, the principal devolopment of Creta CretS! *'*"" ceous rocks continues to lie to the west of the river as far as La-lco- wissin Creek, and these often rise into hills of 2000 to 3000 feet in height on the flanks of the mountains there. The rocks met with are * Rejrart of Progresa, Geol. Surv. Can., 1877-78, \i. 110 u. •] CRETACEOUS OF FRA8ER RIVER AREA. 149 11 all so much like those already described, that it is unnecessary to enter into any detail respecting them. Evidence of great disturbance and crushing are everywhere found in the shattered condition of the beds, the recurrence of reddened zones, and occasionally of friction, or crush- breccias. Beyond La-loo-wissin Creek, the greater part of the Cretaceous belt Thcnco to lies to the eist of the Fraser River, though detached selvages continue to appear on the west bank also. In one of the latter, three miles above In-tl-pam Creek, numerous specimens of Aiirel/a Afos(/uenniti var. concentrica were found, in a hard black flaggy argillite. These are all considerably distorted by pressure. At this place and in the next considerable strip of Cretaceous on the west side of the river, near Texas Creek, hard, black argillites and fine grained blackish sand- stones are more than usually abundant, and it is probable that the lower part of the formation, corresponding with that seen near, liillooet and Bridge River, is here chiefly represented. At the mouth of Texas Creek, below fhe bridge, clifFs are found Breccias at composed of completely shattered black Cretaceous argillites, in which ^''''"* '"''^ ' the fragments have since been re-cemeiited by the introduction of ferruginous material. These rocks have evidently been shattered in place, and they may be regarded as. representing a species of friction-breccia. The shattered zone, which is of considerable width, crosses the Fraser River to the southern end of the Great Rock-slide, this remarkable feature being in fact due to the comminuted character of the rocks which have supplied its materials. Fountain Ridge, appears to be entirely composed of Cretaceous rountain rocks, bounded by the newer volcanic rocks of the Tertiary on the "'''' east, along the line of the Three-lake Valley and by Pala?ozoic rocks on the west ; the line here nearly coinciding with the Fraser, till in the vicinity of Lillooet it crosses the river obliquely and includes the north-eastern slopes of Mcl^ican Mountain. The general structure of Fountain Ridge is that of a syncline, which appears to be simple in its southern part, but becomes wider and more irregular and com- plicated to the north. Moie or less faulting is suspected to exist iilong both the eastern and western bordei's of the Cretaceous, evidence of which seems to be given by irregidarities of strike, and the broken and often silicified character of the rocks in many places near these lines, as for instance in the neighbourhood of the bridge at Lillooet. Some miles above Lillooet, the Fraser River breaks completely l{(K;ks alnivc across the belt of Cretaceous rocks, from east to west, a circumstance ^mmmi 150 a BRITISH COLOMBIA. probably due to the existence of an imperfect transverse anticlinal flexure, by which the rocks here appear to have been affected ; but though both sides of this part of the river have now been exai'ined, the irregularities found are such that no really satisfactory general section has been obtained. About half a mile north of Lillooet, rocks evidently belonging to the Cretaceous series, consisting of hard, blackish argillites are found. Further north, near the Lillooet Bridge, similar rocks occur, in asso- ciation with blackish quartzites, and materials of the same kind con- tirue along the west side of the Fraser to the mouth of Bridge River. The-e are usually blackish, gray or greenish well-bedded quart-'.ites, often much shattered and pyritized, and thus producing by wc'theringt bands of a rusty colour. These rocks, between Lillooet and jI: icigo River, have, as a rule, easterly dips, at an average angle of 60°, but varying from about 50° to vertical. They are all very much disturbed and irregular and have been highlj' uilicified. Bridge River. At the mouth of Bridge River, where a considerable area has been stripped of its superfi'-ial deposits by placer miners many years ago, extensive exposures are found of black, gray and banded quartzites, with hard, black, shaly beds, and some thick layers of gray-green sandstone which pass into tine conglomerates. Bands of pyritized rusty rocks run Iwth with and across the strike, which is here pretty uniformly S. 25° E., the beds standing vertically. The valley of Bridge River has been cut out along the strike of these rocks, as far as the edge of the present map and further. The beds found along it are either vertical or have high north-easterly dips ; but in the hills to the north-east of the river, the angles are lower, and hard, greenish- gray sandstones and conglomerates prevail. At the summit of the mountain ridge which runs parallel to Bridge River on that side, these dips become reversed, and the same beds occur in nearly vertical attitudes. Transverue A short distance above the mouth of Bridge River, what is Brfck'e Klvei-. pi'^^^y evidently a compressed anticline crosses the Fraser, and in this, blackish l)eds are again seen. This is followed to the eastward by a second syncline, of which Fountain Peak, forming the northern and culminating point of Fountain Ridge, occupies the central part. All the higher parts of this peak and its dependent range appear to be compased of the greenish-gray hard sandstones and conglomerates. Mouth of To the east of the peak, near the lower part of Fountain Creek, Cr^lc. varying and confused dips are again found. In the gorge at the mouth of the creek, the beds dip away from the stream on both sides, oawion. I iind it at fir Tertiary sar strata on t1 those on tl Cretaceous of the gorg that the ro I'iited charai position eff( consequent To the eas are found ii They are he highly silicii in their app and the disi supposed til Cretaceous the light of grounds for Thus, spi laay be saic and conglor gray coloui rocks, larg greenstones stones whi- colour. Fe subsequent The argillit jjy lighter The conglo those of ch( most abunc also repres sc irce. M Tlie paste < grauwacke *A collect Kidge, near ally examine mice, iiB fo granitcK, wi J CRETACEOUS OF FHA8ER HIVEU AREA. 151 B iind it at first seemed probable that here an unconformable overlap of Tertiary sandstones occurred, upon upturned Cretaceous beds ; for the strata on the east side are comparatively soft and crumbling, while tiiose on the west side have the usual liardened character of the Cretaceous rocks. It appears certain, however, that on the east side of tlie f^orge a compressed and partly overturned anticline occurs, that the rocks on both sides r.re Cretaceous, and that the less indu- rated character of those on the east side is due to subsequent decom- position effected by acid vapours or by some form of solfataric action consequent on the volcanic eruptions of tiie Tertiary period. To the east of Fountain Creek, Cretaceous rocks, generally sandstones, .SiluiKwl Cro- are found in various stages of alteration, but with low southerly dips. '''"=*^"'* rocks- They are here not only much shattered and reddened, but also as a rule highly silicified ; and it was in consequence of the changes thus produced in their appearance, that no precise line was discovered between them and the distinctly volcunic rocks next met with, in 1877, when it was supposed that the latter constituted an underlying part of the same Cretaceous formation. A niore detailed examination of the region, in the light of furtlier study of the formations elsewhere, has since afforded grounds for reversing this opinion. Thus, speaking generally of the Cretaceous rocks of this area, it (Jcnoral ch.-ii- inay be said tliat they consist of hifhly indurated sandstones, argillites ''*'^''"'"' '•Jc''''- and conglomerates. The sandstones are most commonly of greenish- gray colours, passing on one hand into coarse, distinctively green rocks, largely composed of arkose materials derived from the older greenstones and granites, on the other, witli fine-grained blackish sand- stones which grade down imperceptibly into argillites of the same colour. Few of the sandstones are distinctly siliceous except where subsequently silicified, and many of tliem hold pebbles here and there. The argillites are generally black or nearly so, but often notably banded by lighter colours along the bjdding planes and not seldom carbonaceous. The conglomerates are composed of well rounded pebbles, among which those of cherty quartzites and gi-anitoid rocks are probably, as a rule, the most abundant, though greenstone?, black argillites and phorphyrites are also represented, and limestone, though occasionally found, is notably PC irce. Many of the rounded masses are as much as a foot in diameter. The paste of the conglomerates is, usually, a coarse-grained greenish grauwacke.* *A collection of [juliblcs, niatU^ froin the Cretaceous congloinerateH of Fountiiin liidge, near the northernmost lake in the Three-lake Valley, has been inacniscoi)ie- ally examined by Mi. Ferrier. The m.iterials rei)re8entect are, in order of ini]H)rt- auce, as follows: — Fine-grained ern])tiveH of various ^ kinds, diabases, diorites, graniteK, with one siiecimen of api)arently an impure limestone. Order of kii- perpoHitioii. A line of weakness. ThieknoKB of the series. Pyritoiis zones. 152 B imiTISH COLUMBIA. Post-Cieta- ceous granites. Outlines uii ma]). llespecting the order of superposition of these beds, it may be stated that the blackish sandstones, quartzites and argillite form the mass of the lower part of the formation, while the greenish and gray sandstones and quartzites, with the conglomerates, characterize its upper parts, and constitute the higher crests of Fountain Ridge and othei- mountainous elevations. None of t.iese rocks are, however, confined to the upper or lower parts of the formation, for blackish argillites occui- at varioushorizons throughout and the same is true of the conglomerates. The whole of this great ma.ss of rocks, is here found crushed together in a series of rather strict folds on the eastern edge of the great elevation of the Coast Kanges, the area which they now characterize having, for some reason, proved to be the line of least resistance and minimum strength during one at least of the periods of Cordillerian folding. In I'espect to the thickness of the Cretaceous rocks, the beat evide-;ice to be founil in the area of the Kamloops sheet, though admittedly very imperfect, is that obtained in this particular district. To the south of Lillooet, on the east side of the Fraser, the Cretaceous rocks form for some miles a great range of vertical nliffs, in which the beds have rather low easterly dips. ThcoC cliffs show sheer rock-faces of about 2000 feet, and these, taken in conjunction with the outcrops nearer the river, must represent a thickness of at least 3000 feet of strata. But an examination of the sections as a whole, shows that the rocks thus ex- posed can constitute but a portion of the entire volume, and indicatts that this must exceed 7000 feet, while ii is very probably 10,000 feet or more. The occurrence of pyritized shattered and now rusty zones in these rocks has already been remarked. This is not uncoumion, and has attracted attention in consequence of the possible occurrence of gold in such zones, although assays made of a few of these materials have- not shown the presence of any gold. Another interesting point, is the occurrence of granitic intrusions, of the nature of large dykes, in these Cretaceous rocks, a fact which shows that some at least of the /granites of the region must be of post-Cretaceous ages (p. 241 b).* It uiay also be noted, that the green colour andarko.se character of mar, y of the sandstones, renders it occasionally difficult to distinguish them in bi'oken or poor exposures, from the greenish tuffaceous rocks of the Ttffi ry on the one hand and from the tuffaceous greensto.ies of the otJer series (from which their material has been derived) on the other, "his is especially the case along the Three-lake Valley, but the See .■\p|.encli\ I., \os. .'W, ;«( and 40. CRETACEOUS OF BOTANIE CRELK ARKA. 153 li line of division as now established there, is believed to be practically correct. The only fossils obtained in this part of the region are a few speci- Fussjls. mens of Pecten ( Syncydotiema) Meekiana, found a short distance to the west of Fountain house. To the north of the vicinity of Fountain, the Fraser lies nearly along Rocks nortli tlie east edge of the Cretaceous for about five miles, after which this " """t'l""- edge gradually leaves the vicinity of the river and runs up the wide valley of Red Creek. Hai-d greenish sandstones of the usual cluiracter are the most abundant rocks along this part of the Fraser Valley? though some carbonaceous shaly layers also occur, as well as beds of conglomerate. The dips are generally westward. At a short distance below Black Hill Creek, and thence onward along the river and trail. At Black Hil the sandstones are somewhat diffeient in character. They are com- pletely shattered and rubbly, apparently considerably decomposed, and almost entirely formed of paler, greenish-gray, arkose material derived from granitic rocks. The apparent decomposition of these rocks may of course be due to the fact that tliey have never been penetrated by the silicitying matter to which the general induration of the sandstones is attributable, but it is equally probable that they have bien affected by emanations due to the Tertiary volcanic period, in the manner sug- gested in the case of the similar rocks at the mouth of Fountain Creek (p. 151 n). The shattered condition of the rocks is ahnost certainly due to their proximity to the zone of volcanic action, and is very probably accompanied by faulting. It is thus uncertain whether these softer and paler arkose rocks represent a special horizon, but they very closely resemble some of the Cretaceous rocks met with on the .Skagit River in 1877.* Cliffs of these rocks, of striking appearance and bold- ness, occur about the mouth of Black Hill Creek. Along the west side of Red Creek valley, the Cretaceous rocks form |^,,,i c: !i rather bold escarpment, dipping westward, generally at higli angles. They appear to consist almost entirely of gi-ay-green sandstones, and in l.'irge part of arkose and not highly indurated beds, like those above described. The Cretaceous rocks of the Camelsfoot Mountains, to the westward of the Fraser and Red Creek, were well seen from distant high points, but hiive not been examined in detail. The dips appear generally to be comparatively low in the central })arts 'if this range. .■k. Botanie Creek Area. The small detached area of ■ Cretaceous rocks shown to occur near Botunic ('nil the mouth of Botanie Creek, about two miles from Lytton, consists of * Ki'port of IVoi^rcsH, (icol. Sm-v. f'iiii., 1877-7S, p. KXi h. 154 B BRITISH COLUMBIA, blackish and brownish shaleH, hard gray sandstones, and conglomerates, all much disturbed. The conglomerates particularly, are also com- pletely reddened, while the other rocks are generally shattered and slickensided. These beds, on the east side, are evidently faulted do« n against the granitic rocks, while a second fault probably runs along the west base of the small, scarped granitic ridge which is a prominent feature from the river. The actual area of the Cretaceous beds here is indeterminate, for they may extend further up the Botanie Valley than is now known, beneath the flat terraced land which occurs in it. A few small fragmentary fish-bones were here found in some of the shales, with what are apparently the crushed tests of minute Ostra- coda. Ashcroft Area. Asluroft area. 'This Cretaceous area may be referred to as the Ashcroft area, the town and station of Ashcroft being situated nearly in its centie, in a comparatively wide and low tract of land which is dependent on the existence of the Cretaceous rocks. It is. about four miles in aver- age width, with a length of about eleven miles, and for the greater portion of this length the Thompson River follows its axial line. (iimeral The rocks consist of sandstones, conglomerates, and dark shales, the iirranpemi'Dt. g}j.i}gg i,e,.p apparently preponderating in the upper part of the series, and occupying in the main the central part of the area, while the sand- stones and conglomerates are more abundant and characteristic in the lower parts. Thei'e is, however, throughout, a considerable amount of alternation of all three classes of rock.s, and no easily defined line of separation has been observed in the entire series. The general lithological character of the strata in this area is closely akin to that of those of the more im])ortant Cretaceous region of the Fraser Valley. The sandstones are usually greenish or greenish-gray in colour, being largely composed of debris of the underlying (liabaNCS and felspathic rocks, and seldom or never purely siliceous. Thev vary in texture from very coarse grits mid grauwackes, to materials of which the constituents are indistinguishable to the unaided eye. In many cases they are extremely hard. The shales are blackish, and their sombre outcrop along the Thompson has given its name to lilack Cuiion. With the shaly part of the series, some nearly black sand stones occur, but it is also in as.sociation with the shales that the dis- tinctively gray smdstones are usually found. The conglomerates were nowhere in this area observed in great thickness. Their material is very varied in origin, but like the grits. Saiidftoni'H. Shales. (Jclll(flolll«.'I- att'H. angles of structure western Hi acting fro and numc] the entire possibly 111 On the be added of miles, conglomer airijady re wagon-ron about 1 5 greenish "■] CRETACEOUS OF ASHCROFT AREA. 155 H into which their finer varieties pass, largely composetl of diabase or felsite. Pebbles of cherty quartzite, granite nnd gray limestone, are also abundant in some places. The component fragments are often well rounded, but in some beds are angular and unworn. This is especially the case near the base of the series, which appears to have been rapidly built up of materials produced by sub-aerial waste of the older I'ocks of the vicinity. Breccia-like rocks of this character, but slightly wator-rounded, and liieccias. somewhat calcareous, are well shown in the ridge to the east of the wagon-road on the west side of the river, about a mile south of H Cornwall Creek. The^' rest directly upon a rather finegrained purplish calcareous agglomerat':, which is more compact than the Cretaceous I'ocks above it, and Is almost identical in character with that described as occurring in the Nicola formation, near Penny station (p. 119 b). The lower agglomerate is here also believed to be referable to the Nicola formation. Similar breccia-like rocks are abundant near the margin of the Cretaceous in the valley of the Bonaparte, about three miles above the mouth of that river. No fossils have been found in any part of this area, but it3 litholo- gical identity with the Cre;-aceous of adjacent parts of the Fraser Valley, is sulhcient to fix its Cretaceous age. The rocks are nearly everywhere nmch disturbed and crushed, and stnictuiL'. no satisfactory genei'al section has been obtained of them. Nearly all the observed dips are to the westward, but as a rule those on tlie eastern side of the middle lino of the area are comparatively low, ranging from 10' to 45", while those of the western side are often at angles of 60 and from that to vertical. It is thus probable that the structure of the area as a whole is that of a syncline, of which the western limb has been more or less completely overturned by pressure iicting fnmi the west. There are, however, undoubtedly, minor folds, and numerous indications of faulting are also found. The thickness of the entire series may be stated as at least 5000 feet, although it is very possibly much more. (See Section No. 1). On the western edge of this Cretaceous area, the following notes may \v,..st,.in Ihh-- bo added : — From the vicinity of Jack's Creek northward, for a couple '''''"' ""^' of miles, the margin of the Cretaceous appears to be formed by a coarse conglomerate, generally with very high westward dips. At tlio place already referred to, about a mile south of (Cornwall Creek and on the wagon-road, tho rocks are t'ouml dipping eastward at an angle of about 15^ ojdy. The breccia and conglomerate described here is greenish and gray, and is believed to lie at the actual local base of the wmmm 156 n UKITISH COLUMBIA. Rocks ne'. r ■Cftche Ori'ek. Basal con- glomerate south-east of Black Cunon. formation. Further north, on the Bonaparte, where the line of junction was next clearly seen in detail, both the Paheozoic rocks and the Cretaceous are nearly vertical, and faulting was suspected. That such faulting is probably not very considerable, is, however, indicated by the similarity of the beds of the Cretaceous here found near the contact, with the basal beds just alluded to. Still further north, on the west side of Cache Creek, just where tliat stream issues from the Tertiary escarpment into the wide Seraliu Valley, gray Cretaceous sandstones were found dipping westward at an angle of 60°. They ap- pear to rest unconforraably on a gray, fine-grained and somewhat dolo" mitic limestone, which dip. S. 45° E. to 45°. The limestone is asso- ciated with greenisli schists and evidently belongs to the Cache Creek formation. It would appear that these old rocks came up on a small subsidiary fold or along the line of a fault, and that they form an isolated area within the main western edge of the Cretaceous. On the east side of the Thompson, near the river, the rocks of th(^ southern edge of the Cretaceous area are found to have a nearly east- and-west strike, dipping at high angles, apparently crushed against the older rocks in several folds, and very probably faulted. Further back from the river, a small projecting area of the Cretaceous was, huwever, observed, in which the beds are inclined at an angle of about 20° only, with varied direction of dip. Tlie exposures, though not large, are of unusual interest, as they appear to represent the actual local base of the Cretaceous at this place in a little disturbed condition. The lowest bed, seen at one place, is a rough breccia, composed almost entirely of granitoid fragments of a single kind. This passes upward in a few feet, into a conglomerate with well rounde 1 pebbles of the same kind, the change being gradual, and the cement in both cases calcareous. The conglomeritic bed re?ts in one place upon a green altered diabase near the junction of the latter with a granite mass. At another, it apparently rests upon the limestone described as the highest member of the section on pagt H 3 u. Above, the conglomerate passes into gray sandstones. Tkutiaey ]{ocks. Kamloops Lake and Vicinity. Infonnation The shores of Kaniloops Lake were .somewhat carefully examined s"ctioi''Nc>''5 ''^ 1877, and some account of the rocks, together with a general section. were given in the report for that year. In connection with the more detailed investigations since undertaken, further examinations have •1 TERTIARY OP KAMLOOPS LAKE AND VICINITY. 157 n been made, notably along tlie shores of the hike, but also in the neighbouring country. It was proved in 1877, that the best general section of the rooks is that aiforded by the north side of the lake, tiie exposures being there more connected than elsewhere and the irregu- larity and disturbance of the beds less troublesome. The section now presented (Sec. Mo. 5) follows essentially the same line, and is based upon that of 1877, but with the addition of many new facts. It is now believed to represent, with proximate accuracy, the general structure and probable volume of the Tertiary and its component members in this vicinity. It would appear, that the original surface upon which the Tertiary Oiixiiml de- beds have been laid down was generallv lower in the vicinitv of the I']''*''!"" "'^■"" " " •' KillllloopM present position of Kamloops Lake than elsewhere in this part of the Lake, region. This is shown in part by the greater thickness of beds referable to the lower portions of the Tertiary hereabouts, and by the occurrence in the neighbourhood of various members of that part of the Tertiary not elsewhere found. These features are very clearly seen, in examining the Tertiary rocks southward along the valleys of Watching Creek and the Trancjuille River, or in approaching the lake shore, northward from the vicinity of Coal Hill. It is not, how- ever, supposed that the original depression thus indicated cori'e.sponded either in extent or trend with that now occupied by the lake. Con- siderable chiinges in the relative heights of various parts of the old surface must since have occurred, as shown by the inclinations imparted to even the later beds of the Tertiary itself, while further diflerences of level have resulted from faulting at dates later than that of the Tertiary beds represented here. It appears, in fact, to be now quite impossible even to determine in what direction the drainage of this part of the country discharged previous to the disposition of the Ter- tiary rocks. A reference to the map will show that Cherry Fluff, on the south ciwuiv ""<' side of the lake, with Battle Bluff and its connected rocks on the north ''i^"'« IJluHs. side, form two halves of what must originally have been a single mass of eruptive rocks and much altcM'ed greenstones. These are included under the colour employed for the plutonic rocks generally, though they differ considerably from the great granitic or dioritic masses, which more characteristically represent the plutonic rocks of the region. But in the case of these particular rocks, as we)! as in that of several smaller areas of a like character, it has been found to be impi'actioable, with our present knowledge, to draw a line of division between them and the granitic ■■ 158 B BRITiaU COLUMBIA. Their rocks. Probably mark .1 vent. ^ri^inal mass of volcanic accuHMi- lations. Vallev of tin- lake.' areas. They an; closely associated with these, and resemble them also in regard to their relations with the older stratified rocks (see p. 246 b). The rocks u£ Battle and Cherry bluflFs, consist chiefly of ji;abbro, diorite, mica-diorite and altered diabases- porphy rite generally, much decomposed and everywhere excessively shattered.* Epidote is abund- antly developed in some places,and veins composed of magnetite, together with trap dykes of various kinds, frequently traverse the ma^s. The mass as a whole must be regarded as an intrusive one, or one which at least holds the same general relation to the older stratified rocks as do the graii?tes, but it is probable that considerable portions of the oldrr stratified greenstones have also become included in it and are now inseparabk from it. On the north side of the lake, and resting on the north-west Hank of the Battle BluflF rocks, ther'e is, in fact, an area of hard purplii'h and gray diabases and diabase-tuflfs still clearly referable to the Nicoli formation (p. 119 b). A gieat part of the Battle Bluff and Cherry Blufif mass, above described, must be regarded as a portion of the floor upon which the Tertiary formations rest ,; but its position relatively to that of the Ter- tiary rocks, by which it is completely surrounded, with many other circumstances, appear to indicate also that it marks the site of a focus of volcanic activity of the Tertiary period. This was suggested in my report of 1877-78, and appears to be sustained by further investigation. The higher and central parts of tno volcanic accumulations which may be supposed to have orignated here, must have been situated directly above the middle of the present lake, but have since been removed by denudation, leaving now a proximately horizontal section of the old volcanic centre. There is, however; no reason to believe that the original volcanic cone was otherwise than obtuse in form, and, relatively to its area, low. The dips, (or slopes), of such of the peripiiei-id volcanic beds as seem to have been least disturbed subsequently, sliow that it may never have attained a height of more than about 4000 feet al)ove the present water-level of the lake. It is quite possible that volcanic explosions^ or faulting and shatter ins; of the rocks toward the close of the period of activity of this vent, may have assisted in producing the deep rift now occupied by thiit part of Kamloops Lake between Battle and Cherry bluffs. This must remain a matter of conjecture, but the position of the lake relatively to the old centre of eruption is a very remarkable one, and it is evidently in consequence of the formation of the hollow of the lake across • See Appendix I., N08. 06, 97, 00, No. 100 represents a stratified rock, caught upin the intrusive mass. H.] TERTIARY OF KAMLOOPS LAKE AND VICINITY. 159 n the central part of the old vent, by some such exceptional circum- stance, that the denudation of the volcanic cone has progressed from its central parts outwards, in a manner quite different to that seen in other cases. It is also probable, that the old pre-Tertiary surface, including both Piotmsion cif stratified and eruptive materials, when it became penetrated and in- ''''^'' "'"'*'*■ tersected in all directions by the deep-rooted channels of the Tertiary volcanic materials, was to some extent thrust upward in a dome-like form, giving rise to the nearly regularly oval slope of tlie present sur- face section. Besides the actual position and form of the Battle Bluff and Cherry Further evi- Bluff mass relatively to the volcanic beds of the Tertiary, further evi- v^JJ^*^ " " dence of the existence of a centre of vulcanism at this place is afforded by the extremely shattered condition of its rocks, their exceptionally decomposed character, and the existence of such minerals as epidote and magnetite in considerable quaiii.ities in them, all pointing to the presence here of some exceptional cause of disturbance and of rock decomposition. Much of the last mentioned effect may have been pro- duced by solfataric action subsequent to the main period of activity, and this appears to have been extended to the olivine rocks of the vicinity of Copper Creek, resulting in their change to serpentines and to the deposition of cinnabar and copper there. The great number of trap dykes seen in some places, as for instance along the lower part of he Tranquille River, may also be referred to in this connection. Reverting to the general composition of the surrounding Tertiary vol- (iicut ma.iM of canic materials, additional evidence to the same effect is given by the Ji'il^ttTJ "^^ "'"' great thickness of very coarse agglomerates or volcanic breccias, showing the recurrent action of local explosive forces, and the inclu- sion among them of flows of molten matter of various kinds. These rocks are well shown in the great escarpment to the north of Battle Bluff and in smaller exposures in Dufferin Hill, near Kamloops, and their inspection leaves scarcely any reasonable doubt that they actu- ally represent parts of the flanks of a volcanic cone. The statement previously made respecting the existence of a depres- sion in the vicinity of Kamloops Lake previous to the Tertiary period, cannot of course be maintained because of the exceptional thickness of beds of the character of those last a 'uded to, hut depends chiefly upon the equally exceptional volume of evidently water-laid deposits chiefly formed of the finer volcanic ejectimenta. The foregoing roirarks on the general conditions of deposition of the Suewrdinj.' Tertiary rocks .iurrounding Kamloops Lake, Ijave been made in order chnm'oioKicul 160 B HRITISII COLUMBIA. Coldwater group Oligo- cone. Banal con- glomerates. OoiiglDtn- eraten west f>f Kaiiilooiis Lake. to provide a clue to the geological features as a whole, and for the purpose of dispensing as much as possible with detail in what follows. The conclusions stated here result from much work in the field, as well as from the subsequent study of the specimens, notes and sketches accumulated, and if ultimately found to be subject to correction in sonic particulars, it is believed that they will in the main stand, although many additions may have to be miide in future. It will now oo possible to speak of the Tertiary rocks in chronological order, a-ssemblin;;^ in this way the observations made in various years, and over an extent of country some twenty-five mile.s in length by about ten in breadth. The older rocks, upon which those of the Tertiary period were depositetl, will here be regarded together, merely as the floor upon which the latter lie. In a previous chapter of this Report, the several main subdi\'isions found to be applicable to the Tertiary rocks have been noted, and it has been pointed out for what reasons the lowest conglomerates and sandstones have been referred to the Oligocene, under the name of the Colclwater group, and are regarded as being separated by some lapse of time and unconformity from the lowest Miocene beds. The lowest part of these conglomerates may be rr erred to as the basal conglomerate, merely for the purpose of convenience in describing its characters and supposed distribution. Hocks referable to the Cold- water group, are found only in certain parts of the area assigned to the Tertiary on the map, and even in these places the basal conglomerate-! are not always recognized and are sometimes clearly absent. These conglomerates are peculiar in the large proportion of material derived from the older rocks of the immediate vicinity in every case. They aii' generally dark-brown or greenish-gray in colour and vary much in the degree to which their constituents have been rounded by water action. South of the Thompson River below Karaloops Lake, conglomerates of this character cap the lower hills for a distance of nearly eight mile.s. To the south they are in turn overlapped by Miocene volcanic rocks. They are here usually dark greeiiish-gray in colour, but often weather reddish. The pebbles are pretty well rounded, sometimes becoming boulders of as much as two feet in diameter, and comprising a consider- able variety of greenstones of the underlying Nicola formation, as well as granitoid rocks of various kinds and souic black cherty quartzites. With the conglomerates are gray and gray-green sandstones, moderately indurated, and in these some carbonaceous fragments were found at one place. The beds dip in various directions at low angles. They are often running with an a •] TERTIARY OF KAMLOOPS LAKE A\D VICINITY. 161 IT A thickness of j^i;:^^;;:--^ very well stratified and the whole thickness displayed in variou ! places probably exceeds 500 feet. A specimen of these basal conglomerates, holding large well rounded Tiii(.i's(if gold. pebbles, on assay proved to contain traces of gold. The specimen was obtained from outcrops aljout one mile south of tlie Thompson River, opposite the mouth of Deadman River. It is very possible that a small area of conglomerates of the same kind, occurs at a nearly corresponding level on the hills due north of Penny station, on the opposite side of the Thompson. Large drift frag- ments were noted here, but the formation was not actually observed in nitn. To the south of; Savona station, no conglomerates of this kind could be found, the Miocene volcanic rocks apparently resting at this place directly on the Nicola formation. A small exposure of similar conglomerates occiirs on the road along C'oiigl( Cherry Bluff Creek, between Roper's and Hughes's, about fifty feet is here seen, extending from the level of the stream to where it is covered by a purplish porphyritic agglomerate, assigned to the Miocene period. Both rocks are very much fractured at this place. The stones in the conglomerate are more varied than usual in character and include a few specimens of cherty quartzite. They are well rounded and sometimes as much as a foot in diameter. The area of conglomerate exposed at this place appears to be small, but it is quite possible that more exposures of the same kind may occur in the wooded and generally drift-covered area to the west of this part of Cherry Bluff Creek. Crossing the lake to the north side, we find one of the most inipor- ronK'loni- tant developments of the Coldwater conglomerates and sandstones •■i''"'"*:i"d running back nearly parallel to Copper Creek for more than ten miles, "''luCopper with an average width of about a mile and a half. In the immediate vicinity of the shore, these beds appear to be overlapped and almost entirely concealed by dark greenish augite-porphyrites and agglomerates of the Miocene. But a single small mass of the conglomerates ajtpear- ing from beneath these was seen on the shore, the beds dipping S. 45" E. < GO', and themselves apparently resting upon rocks of the Nicola formation. There is much evidence of faulting and extreme disturbance in this vicinity and the details of the structure are by no means well under- stood. It is in fact supposed that several faults run nearly parallel with the belt of Coldwater beds, following their main strike, and in each case throwing the beds down to the eastward. It is probably in consequence of such faulting that the beds themselves are found to lie 11 Creek. 162 B BRITISH COLUMBIA. Cherty pel Lies. at such high angles and to be sometimes even vertical. Such an effect is often seen in this region, even where tiie Tertiary rocks are generally undisturbed. The observed dips are in nearly all cases to the east- ward, but towards the extremity of the formation, on Criss Creek, some westerly dips were noted and lower angles of inclination are more com- mon. From the above statements it will be gathered that the attempt to show the arrangement of the strata uiK)n this part of the section is little more than diagrammatic and largely hypothetical.* The conglomerate beds supposed to be the lowest in this place, show something of the same dark coloration and local character of material generally characteristic of those in that position. Higher up, and constituting the great mass of the rocks, are conglomerates with well rounded pebbles of moderate size and of light to dark gray or yellowish colour. With these are sandstones of similar tints, and both sandstones and conglomerates are preponderantly composed of cherty qunitzites. These quartzites (evidently derived from the Cache Creek formation) are not known to occur in places in this neighbourhood, and their great abun- dance in the mass of the conglomerates, shows conditions markedly changed in comparison with those during which the basal conglomer- ates were formed, and in which the material was conveyed by rivers from a considerable distance and thoroughly rolled in transit. The local restriction of these characteristically cherty conglomerates as compared with the greater spread of those referred to as the basal con- glomerates, further indicates a narrowing of the area of deposition after the period in which the lower beds of the series, regarded fis n whole, were formed. Traces of gold. \ specimen of these conglomerates collected near their western edge, on the trail north of Kamloops Lake, again showed traces of gold on assay. The identity of the cherty conglomerates of this locality with those of Hat Creek and the Nicola is elsewhere referred to. In all proba- bility they here represent the delta or flood-plain of some early Tertiary river having its sources to the westward, rather than beds formed along the shores of a large lake, which appears to be the most probable origin for the basal beds generally. The total thickness of the Coldwater beds in this vicinity, is undoubtedly very considerable, and probably exceeds a thousand feet. To the east of the main edge of the Tertiary rocks, in the somewhat peculiar tract of country named the Garde Lafferty, which occupies Outliers on (Jarde Lafferty. * See also Section No. 1. •] TERTIARY OP KAMLOOPS LAKE AND VKIMTY. 1G3 n the angle between the North and South Thompson rivers, two small outliers referable to the basal conglomerates of the Tertiary are marked on the map. Other Kmall patches of thj same kind may occur in this vicinity, for the surface is often heavily drift-covered, and the known outliers show a tendency to characterize hollo\ys in the contour of the older rocks. The conglomerate is here composed of rai tier small, well round(>d pebbles, of all varieties of the older rocks, and includes a good nuvny fragments of quartz derived from veins. There are also occasional thin layers of hard quartzose sandstone. The lowest layers of tho conglomerates are highly charged with dolo mitic matter, much indurated, .ind weather to reddish and yellowish colours. A similar dolomitization of the lower layers of the Tertiary Dolomitii- rocks is found in a number of places in the district. 1 ' is here accounted "^•"'"' for by tho occurrence in the older rocks, of numerous veins of doloiiiite< which evidently mai'k the conduits by which dolomitic matter found its way to the surface at sorao time in the later Tertiary period. The basal conglomerates, though here found so near the main eastern outcrop of the Tertiary, have not been seen in actual connection with that outcrop ; but the line of junction of the two series of rocks is almost always covered by debris frorj the bold escarpment of the overlying volcanic rocks of the Tertiary. It is probable that the con- glomerates occur along the base of the Tertiary outcrops in tho vicinity of Pass Lake and Lac le Dois. Further sc uth, to the east of Mara Hill, the Tertiary finds its limit at a fault, with downthrow to the west. A specimen of the conglomerate from the Garde Lafferty showed no trace of gold on assay. I In many other places in the vicinity of Kamloops Lake, various Overlaixi' higher members of tho Tertiary series, lie directly on the surface of "J-'""^''' ',",''" the older rocks, by overlap. This is the case for instance to the south tiaiy. of Dufferin Hill and .about the Battle Bluff and Cherry Bluff mass. It is probably also the case in the valley of Cherry Blutf and Alkali creeks ; but this part of the southern boundary of the Tertiary is so poorl)' exposed that its position as laid down on the map is little better than conjectural. It will be seen that the Coldwater beds, here almost exclusively repre- sented by conglomerates, are very irregularly and partially distributed, even in the comparatively small area about Kamloops Lake. They are wanting in some places, very inconsiderable in thickness in others, but very thick in the vicinity of Copper Creek ; these differences being due to original inequalities of the pre-Tertiary surface and to the positions of rivers and lakes antecedent to the beginning of the deposit of (ii'iif'ial (listriliutioii ;i;i(l chaiacttT (if ColdwiktiT beds. 164 B BRITISH COLUMBIA. l'l>|HT mem- bers of Ter- tiary. Dolerite. Tnffaceous beds. Dolei it< s and tufTs. the great ma-ss of the Tertiary. They show no evidence of contem- poraneous volcanic action, such debris of igneous rocks as they include beingreferabletothe underlyingPalti'ozoicandTriassic strata. The beds here classed under this general term, may thus vary considerably in agf, and some of them may represent a time long antecedent to the beginning of the period of Tertiary vuL^anism. They are the traces of an epoch of erosion, which was in progress before the great period of Tertiary deposition had been inaug'.:ratefl. The close resemblance of the cherty conglomerates of Copper Creek to those of I[at Creek, those of the Nicola near the mouth of the Cold water and to those at a locality ten miles south of Nicola Lake (beyond the area of the Kamloops sheet), is, however, such as to lead to the l>elief that their deposit occurred synchronously and under precisely similar conditions (see p. 69 b). The most satisfactory knowledge of the remaining members of the Tertiary series in the vicinity of Kamloops Lake, is that obtained by an examination of the sections about the eastern end of Battle IJlutl" and on the lower part of the Tranquille River. As already mentioned, the coldwater Conglomerates (1) are here wanting. (2.) Resting directly on the flanks of the Battle Bluff mass and dip- ping away from it to the eastward and north-eastward at an angle of 15', is a coarse gray dolerite, often regularly columnar and resembling a basalt, under which name it was noted in the report of 1877 (p. 117 u). This is 100 feet or more in thickn^^ss. (3.) Above the last, is a series; of yellowish and bluish-gray, hard, thin-bedded and fine-grained tuffaceous shales and shaly sandstones. These hold numerous fragments of plants in a very poor state of pre- servation and some obscure fish remains were also found in them. The thickness of these beds is probably more than 200 feet near the lake shore, but their outcrop appears to narrow rapidly when followed north-westward and westward along the strike, till it disappears. This particular intercalation of water-bedded material was not certainly recognized elsewhere, though it is possible that it may recur in some pait of the broken section along the south shore of the lake between the eastern end of Cherry Bluff and the head of the lake. It is probably quite local, and may represent the position of a small lake, held in for a time by the growing volcanic accumulations of the vicinity. (4.) Overlying these stratified materials, are more dolorites, coarse grained at the ba.se, but finer in the upper layers. Tliese probably re- present a series of flows of molten matter, and are arranged in bed.s of varying thickness, some of which are finely columnar. The thick- (6.) divi.sii) materi gray ai which rathc> ticular, •Ti-i ■J TERTIARY OF KAMLOOPS LAKE AND VICINITY. 16."; 11 ness represented by these flows at this place is at least several hunil- red feet and very probably as much as 1000 feet, in all. The strictly igneous flows constituting this series, pass above into water-bedded tuflfaceous sandstones, largely composed of doleritic debris, in such a manner that it is ditticult to draw a distinct line of division between the two classes of rocks. ('}.) The tuflfaceous sandstones last mentioned, together with yellow- Traiin\iill( ish tuffaceous agglomerates, of which the material appears to be largely .i!4i',',,,,",.;jtl.'H! doleritic, constitute the next number of the section, with a thickness of at least 500 and probably of nearly 1000 feet. These appear, with dips of 10" to 1.")" to the eastward, where the Tranquille River issues from its nfirrow valley to the head of its delta-ilat, at a distance back from the lake-shore of about half a mile. A short distance fur- ther eastward, they flatten out, and run along the southern face of Mara Hill, near the line of the wagon-road which leads fi'oni Tran- quille to the ferry at Kamloops. These beds, representing an im- portant interval ir. which volcanic materials were being laid down in the waters of the lake, have been named the TranqKille bedx. In the stratified materials of this subdivision, small collections of Fo^siU iilants. plants have been made from the lower part of Tranciuille llivtrby Mr. A. Bowman, and from corresponding beds on the south side of Kam- loops Lake (those at the east end of Section No. 5a.,) by the writer. In these the following have beer, recognized by Sir J. "VVm. Dawson. * Pimis ti-unculus, Dn. Taxodium distichum, Heer. Ailanthophyllum incertum, Dn. Comptonia Columbiana, Dn. Salix Kainloopsimia, Dn. UlniHs like U. Braunii, Heer. Sequoia, Sp. Imperfect remains of fishes have also been found in these beds in this vicinity. (6.) Overlying the last, and apparently not separated from that liasalts ar.rl division of the section by any distinct line, is a great thickness of agglonionitcs. materials predominantly basaltic, consisting of brownish, ])lackish, gray and reddish basaltic agglomerates with occasional basaltic flows, which are, however, rarely columnar. The bedding of this series is rathe'" massive and irregular, and the component beds are often len. ticular, though from a distance the aggregate presents the appearance •Trans. Royal Soc. Can., vol. VIII., sect. IV., p. 75. 166 B UIUTISII COLUMHIA. ThiokuoHS. DiKtrllMitinii of loW(!T Hull- (iivisions. of a rpwiilavly stratified formation. The upper part, which is here the highjs- nioml)er of tlie Tertiary, shows a preponderance of ratiier soft., yollowish-gray agglomerates of a tuflFaceouM character. The component fragments though often vesicular, are frequently dense black trachytic material with the fracture of obsidian. The observed thickness of this highest member of the series is here about 2000 to 2.J00 feet. The entire thickness of Tertiary beds displayed in this vicinity, may thus be stated at about 4800 feet. Having described the section in this typical locality in some detail, it will now be in order to endeavour to trace the occurrence of its various meui jers throughout the county in the vicinity of Kamloops Lake. For this purpose the local stratified intercalation designated as No. 3, may be disregarded, and the dolerites, forming numbers 2 and 4, may be considered as a unit. These rocks run round to the north of the central Battle Bluff mass for some miles to the westward, and were in some places observed to become concietionary in structure. They were not found at the westevi end of the older central mass, where the next overlying and bedded series (No. 5) seems to overlap directly on the rocks of the Nicola formation (p. 158 ») which are here at- tached to the Battle Blutl rocks and may be co.isidered structurally as forming a part of that older mass. How ruiire- Still further west, beyond a wide syncline occupied by the rocks of CopiicrCriiek. subdivision No. 6, the older members of the Tertiary series again readi the surface near Copper Creek. The dolerites appear here to bfj repre- sented by igneous rocks rich in olivine, of the character of picrite-por- phy rites and by augite-porpliyrites, which so far as can be ascertained immediately overlie the cherty conglomerates previously described, and intervene between them and certain bedded materials, which are believed to represent No. 5 of the typical .section, v "h a thickness of possibly alx)ut 600 feet. One of the olivine bearing rocks, where com- paratively unaltered, has been determined by Mr. Ferrier to be an augite-picrite-i)orphyrite.* Tiiese rocks, together with the overlying bedded materials largely derived from their waste, have, in the vicitiity of Copper Creek, suffered a remarkable amount of decomposition and change due to solfataric or hydrothermal action operating from below, and probably connected with the excessive faulting and fracture met with at this place. I'ainti"! '^'i^ Pain'.td Bluffs, oi tlie east side of Copper Creek, are composed HluffH. ^^{ ther-'e much decomposed rocks, apparently including parts of the *App«idix I., No. 67. TERTIARY OF KAMLOOPS LAKE AM) VICINITY. U17 If overlying bedded series No. a. Green, yellow iviid red colours prevail in the sloping and clay-like banks o.' . • irten rock, iiniongst which rounded masse.s, and irregular layers of tiie undecouipo.sed trap stiil exist. The olivine has become in inatiy instances completely changed to ser- pentine in the decayed rock, while the felspars are more or less com- pletely kaolinized. The whole section is traversed by dykes and by many small veins and seams of calcite. Near the mouth of C( rper Creek, on the lake, portions of the beach Mim'iftl . . „ , i i' '"I'liirencrs. are largely composed or green sands, consisting tor the most part ot more or less worn small crystals of pyroxene. Tiie nature of Uie alter- ation suffered by the olivine rocks at this place is fully described by Dr. B. J. Harrington in ihe Report of the Geological Survey fo'" 1877- 78, p. 41 li. The occurrence of cinnabar and of copper in connec- tion with these rocks in this vicinity is elsewhere noted. A reddish breceiated rock, v ith greenish markings and cavities and Clicin- lilnir ' well developed green hornblende crystals, which appears to lie near the base of the section above described, close to Copper Creek, was, it is believed again recognized on the lower part of Cherry Bluff" Creek, on the opposite side of the lake, adjacent to the Cherry UlufF rocks and dipping ■>i' hem. Some serpentinous and olivine-bei'ring i-ocks were also seen in the valley of this stream, and it is probable that rocks ivpresenting the part of the section now under discussion occur here, poasibly in some force, but no good exposures of them have been found. Opposite the typical .section of the iNIiocene Tertiary rocks first KdcJcs cist of described, on the .south side of Kiimloops Lake and to the east of *-'"''■'>■ '"" Cherry Bluff", dolerites referable to No. 4, and possibly in part to No. 2, are seen in several places along tiie shore (Sec. No. 5a.). They also run round behind the rocks of Cherry !>luff" more or less continuously, and at one place, a short distance soith of the word " iJluff," as engraved on the map, are so coarsely ciystallino and massive as to suggest the idea that they represent the place of an actual source of emission. The stratified tuffiiceous sandston(\s designated as the TraiKiuiile DistiilputlDii beds (No. 5) probably run continuously round behind the liattle Bluff" ;;[J^'''""i"'"'' locks on the north, following a hollow along the base of th" higiiir cliff"s and hills further back. They reappear on the lake shore near Red Point, with a breadth of about a mile ; being thrown into a couple of light synclines and traversed at Red Point itself by a small fault. At this place, or very near it, a sniali b;'d of lignite was found duiing the progress of tlie Government railway sui'veys in 1878. 'I'he sand- stones are here yellowish and gray, like tlibse near the Tran(|uilli'. 168 B BRITISH COLUMBIA. KilBt of f Mierry Blutf. Coal-lM'ariiip nicks Kinith < K&tnlooiis. Their further outcrop is concealed by the lake, till they reappear in the Painted ]iluffs near Copper Creek, where, as already explained, they are much altered and f^enerally reddened. To the east of Cherry Bluff, the same tufifaceous sandstones are found in several places, associated with the dolerites already alluded to, but the section (No. .";a) is here so much bj'oken that it has been found impossible to satisfactorily unrpvel it with the information avuii- al)le. The widest and least disturbed .-exposures of these .sandstones and shales here met with, are near mile-post 244 on thf railway, where they dip northward at an angle nf about 20', and w . .( . few fo.ssil plants we.e found. It is believed that these beds run •, ^ this place inland, in an easterly direction, following the hollow along the south base of Duft'erin Hill, and that they connect with those of the coal locality near Guerin's, where they terminate in a feather edge upon the underlying old rocks, at a point about three miles due south of the town of Kam'oops. The exposures are not continuous along the line of outcrop tlus traced, but there can be little doubt that the beds as^^ociated with the coal at tiuerin's represent the Tranqnille beds (No. o) of the general section. These particular beds, where found near Gueriti's, require special mention, because of the interest con.se(|uent on the discovery of coal in them, and the fact that some exploratory work ha;, been carried out in the search for workable seams. The beds containing the coal here rest directly upon the pre-Tertiary sunace, by overlap, the underlying members of the Tertiary being absent. The floor consists of a rough surface of diabase-agglomerates, upon whicii the Tertiary materials lie in the form of a shallow syncline which runs along the northward slope of Coal Hill. The exposures are almost entirely c(>nfined to the banks and bed of the small stream which tlows past (iuerin's house, and even with the aid of information obtained in the cour.se of driving an adit into the measures, give but an inijicrfect idea of the s(ction. The actual area of this projecting tongue of the Tertiary is shown on the map as closely as the fact^ observable on the ground admit. Its width is somewhat less than a mile -probably not more than three-quarters of a mile, while th< thickness of the measures comprised in the syncline mf •/ as great (IS r)00 feet, but is possibly nmch less. The beds actual j ...ssociated vvlth the coal outcrops which have been uncovered, dip N. 25° W. v: .'18°, but proliably flatten out to the northward and lake the posi- tion shown in the annexed section. T!ic measures, so fa> as exposed consist of greenish and yellowish tufliice lus and ugglomerate-l ke materials more or less distinctly bidfled, which weather to soft clayey stuflF, often re varying from iu all about f J?]g. Tlip liiu' of !■ liouHe. Thii Mi( '■? the Nicola foi The beds w I'e basal ..ic i ward, and if t nes.s, this wou the southwarc locality were In 1892, th visited by ^l\ on the dip o seventy to eij. in the charact The sectior descending or Con/.. Siin'..; Con/. (May.. Cm/.. Shale. Con/. Shall' Cm,/.. Shalo Coal. SaiiiLst Con/.. * Kroiii (Sim ■J TKHTIARY OF KAMLOOPS LAKE AND Vlt'IM lY. 109 1) stuff, often reddisli in colour. There are several tliin layers of good coal, varying from mere iilms up to a foot in thickness, and characterizing in all alwut fifty feet thick of the measures. Fij. 2. SECTION ;ncludi>"ii c.oxl, near kami.oops. Tlip line of sectiiiii is iilxiiit iiortli-cust and Noutli-wcst, passing thiouph (iijirinV liouse. Thf Miocene IxkIh c. 10. K.xtei.t f)f llii'Si- iied.K eontaininj.' eoid. Section. 170 n imiTIHII COLUMBIA. Fiirtlier tegtf requiied. I'SaccK rccoin- iiiniided for Ixiring. The quantity of clay is variable and some of the shale partings arc not continuous. The aggregate thickness of coal at this place is 30.), inches. The fuel found here is a true coal rather than a lignite, burniin; well and producing a coherent coke. If in seams of really workable thickness, it would possess considerable economic imp'. K c = u H Ui X w' via i c5 0. S-i '' 172 B BRITian COLITMUIA. EHCHr|>iiicnt<>f The hif^hest of the Tertiary series in the vicinity of Kamlodjis siitHlivi.si.int>. Lake, descril)ed a.s No. 6 in the general section, ha.s a notable efleit in giving form to the topography of the district. It consists in the main of rough basaltic agglomerates and ba.salt flows, which have a tendency to form steep, rugged cliffs where the outcropping eiij^p.'; are worn away. A remarkable and continuou.s range of high, Ixikl cliB's and escarpments, encircles to the north the lower hilly country occupied by the Battle Bluff rocks and the lower members of the Tertiary. This runs, with a curving Kweep, from the vicinity of the Tranquille lliver to that of Red Point and then up the valley of Copper Creek. Similar escarpments occur along the main valley nf the Tranquille, on Iwth sides, at least as far up as the position of tlie waterfall sliown on the map. The upper parts of Mara and Opax hills are formed of rocks of the same series, which are again well shown to the .south of the lake, in Dufferin Hill. Elsewhere to the south of the lake, these higher rocks have apparently been almo.st entirely removed by denudation, except in Savona Mountain. The summit of this mountain stands about P'TOU feet above the level .)f the lake. It was ascended on the north side, and notes obtained upon which the annexed section is based. TIip lower and upper limit of each stratum could not in all cases be ascertained in siich a manner as to enable its precise thickness tn he stated, and the beds themselves evidently vary much in this resjwci in short distances, so that the section must be considered as more or less diagramm.atic, although giving a sutiiciently correct idea of the general StrvonaMt. R(«ctioii in Savoiiii Mountain. ClmriictiT of itK-kn. N.29W. Fig. 4 S ACTION FROM S.VVONA STATION TO THE SU.MMIT OK SAVONA MOI'NTAIN. Mioccno volcanic rooltH overly iiitr tliouc of the Nicola formation. Letters rifer to tile ilescriptiou in the text. Scale, U m. 1 incli. se rock ((/). The trachyte has been determined by ^Ir. Ferrier to be a mica- trachyte with a tendency toward andesitc* The obsidian-like layer lias a thickness of about 100 feet. Above these, the summit of the mountain is composed of a second great agglomerate (c), with a thick- ness of nearly 1000 feet. The fragments composing both agglomerates are generally large, ("'nnrsi' and their material differs much in character, but so far as observed con- sists entirely either of igneous rocks referable to the Tertiary or of the diabase-like rocks of the older Nicola formation. The upper agglomer- ate holds masses as much as six feet in di;imeter, which are geiierally •somewhr.t rounded, but not more so than ma" be accounted for by friction in the vent from which they must have been expelled. The matrix is a gray tuffaceous material often resembling mortar. This agglomerate forms cliffs near the summit of the mountain, tending to wear out into pinnacles, each capped l)y one of the larger fragments which has served as a protection from the action of the weather. The basalts in .some places hold numerous agates, which are often green or * greenish in colour and sometiinos very handsomely marked. The entire series of beds included in the Savona Mountain section Thiikncw. iiiiiy be referred to No. 6, of the general section. Their aggregate tliickness is about .3000 feet. The great size of a large proportion of the fragments here, togecher with the thickness of the agglomerates, appears to indicate the immediate vicinity of some local centre of eruption. The same beds seen on the noi th .side of Savona Mountain, are continued southward along the west side of Three-mile Creek, where they form bold and picturesque cliffs. Recapitulating the general section of rocks about Kamloops Lake, licciipiml and giving to each member its probable maximum thickness, the follow- 'j'*'''" j,,,]^'^!"" iiig scjieme may be presented. It will, of course, be undei'stood that ^fotion. tlic scM'ral subdivisions vary much in thickness, and an; morco\'er not all present in any single place. The order is descending. — Fwt. No. 0. Agglomerates, cliiefly linfiiltic, witli snmr bnsiilti'i and trachytio tlciws ; all riuk'ly Ix'iMed. Thicknt'sa in Savona Moiintiiin S.IKH) * Api)endix I., No. 68. 174 B BRITIHH COLUMBIA. No. 5. TraiKiuille beds; tiiffaceous sandxtoncs and shales, with some soft tiiffacuoiis agglomerates, all more or less .i. south shore of the lake is very imperfect, particularly to the west of Cherry Bluff Creek. To the east of the massive rocks of Cherry Bluff the exposures are much better, but they are complicated by a number of small faults, which appear to throw the strata down to the west, ward. The partial section (No. .~)a.) given for this part of the soiith shore, will serve to indicate its general character, but in a diagrammatic way, as the positions ;ind number of faults are very imperfectly known. In this part of the section, a total downthrow to the west- ward of about 1000 feet may easily occur. The basaltic rocks shown as coming in at the east end, are the lower parts of those which form Dufferin Hill, which is situated about three miles to the westward of the town of Kamloops. 17G u imrrisn columfjia. Nicola Sec- tion, No. 7. l)iita «mi- ployMl. Dcproo of accuracy obtained. (Jeneral features. Section of Tertiary Rocks alon>lieved tc to which tl is in consi to be com tion, has l» it i.s a gr as porpliyi fresh apjie often MO m usually pre the TraiKju generally o The volcf are sometin eonstitutin^ of the two so that no St Tn regard whole is boi l>ears to he west side, side. The along it, be( materials tiie poi'phyi aijove allud The lowest about this At or ne; I'i^di angles, lias a low s( if small tr; lows a line iii)0ut three of the outci he traced materials, tlie Ime of and recross 12 ■1 TKKTIARY OP NlfOLA liiVKR. I I II separated by a horizon characterized by certain jiale-cohiured, often soft and frefiuently well-bedded tuttaoeous materials. These are l)v>lloved to correspond with the very siinilar beds on Kamloops Lak(>, to which the name Trani.raii(l are sometimes clearly effusive, but perhaps moi'e frecjuently fragment'il, l'.'"»''' <'i^i- constituting agglomerates or volcanic breccias, and the rock species of the two parts of the series art; nob altogether mutually exclusive, so that no strict line of lithological division can bo drawn between them. In regard to the general structural featun^s, the Tertiary series as a Onut fault to whole is bounded to the north-east, in this region, by a line which ap- u""!' 'i^Nt- peai's to be that of a continuous fault, with downthrow on its south- west side. This follows the edge of the great gi'anite mass on that side. The line of faulting runs about N. ."io W., bj' S. 35' E., and along it, beds of tuifaceous sandstones and other water-bedded volcanic materials are found in several places. These are believed to underlie the porphyrite lOcks and to be quite distinct from tiic Tranquille beds ab(jve alluded to, although denoted by the same colour on the map. The lowest rocks seen near the mouth of the Nicola seem to be at about this horizon. At or near the fault, the Tertiary rocks are often found inclined at Hilatii)iii>f liiirh angles, or even vertical, but the series as a whole, in this region, ; 'iv.',\„,,'';ii'?' has a low south-westward dip, upon which are superimposed a nundier ^teih. of small transverse undulations. Tn the main, the Nicola Valley fol- lows a line parallel to that of the fault, at an average distance of about three miles and a half from it. This line is approximately that of the outcrop of the Tranquille beds, and the position of the river may he traced to the existence of these softer and more easily eroded materials. In detail, however, the undulations just alluded to throw the line of outcrop of these beds into a series of zigzags, which cross and recross the actual line of the river. The Ijeds themselves show 12 IMAGE EVALUATION TEST TARGET (MT-S) Hi. 1.0 1.1 ■X Ui 122 1.8 - — 1 '-"^ 111'-^ ^ 6" t, Hiotographic Sciences Corporation \ 4^ •SJ <^ S. ^\^5< 33 WEST MAIN STRICT WEBSTER, N.Y. MStO (716) •72-4503 m 178 II IIRITIHII rOLUMIIIA. a tendency tdpass into tuHaceouH aj;;{I(ini<'ratos of a more or less eiirtliy character, and in which it is often scarcely possible to make'out any stratification. It is thus gt-nerally ditiicult to ascertain their thickness, even when the sections are ^txnl To the .south-west of this part i it' the Nicola Valhiy, is a wide .syncline, occupied chiefly hy the ba.sahi:' rocks of various kinds which (jverlie the Tran(iuille beds. These rocks form the Nicoamen Plateau of the map. Ofin-nil com- Thus, so far as the composition of the Tertiary series in this re<;ioii ieries! " ' '''"* '^•'" determined, it is made up as follows, in descending order : — Kfi't. ItiiHults, ImHult hrccciiiN, etc. (iilxmt) 3,1()0 l».-.f.liMl tutfH ('f"r;iniiiiifl.' iH'(fn) ( " )+r .'HH) I'orpfiyi-itt'M, etc. (iil«iiit,) 5,300 Tdtal 8,900 SiilxliviNi.iii iif T„ i\^f, following nmre detailed descriptive notes on the Tertiary '■ rocks found along the valley of the Nicola, the .section is divided inin five parts, each of wliicii follows one of the minor trends of the valli'V. and though the section may be descrilwd as a whole, as running fmiii north-west to south-eiust, it has bceti found convenient to change tlio direction in each case to cori'espond with that of the general bearing; of a cerUiin length of the valley. ( )n the annexed diagrannnatic section, these changes in direction an; clearly indicated. Parti. /'t the section, the lieds become undulating and are in the main not taf from horizontal. Nfiwor HK'kH The general effect of the attitude of the beds is, however, that ni awriiilmtf newer strata are found in order in ascending the valley, and the whole thickness thus exposed, to the base of the Tranquille beds, which form '■] TBiniAllY OK XirOLA ItlVEH. 179 II Pail the highest member here seen, is about 5300 feet. Of this the lower part, some 3100 feet, consists, so far as seen, of reddish, blackisii and greenish volcanic njcks, often lirecciated, occasionally vesicular, and in general to be classed a^ luirphyrites of various kinds An important bed of greenish, somewhat earthy, tuffaceous agglomerate or volcanic breccia tlien apjmars, which, witii various volcanic rocks of green, gray- green and dark colours constitutes the next 12200 feet in thickness of the section. As before, these rocks are in the main por|)hyrites. These are followed in ascending order by well bedded tuflfs or tuffaceous sand- stones, ap]iarently entirely conijioscd of fine-grained volcanic materials, which have been arranged in regular layers of water. No com- plete display of this mendjer of the section was seen, but it was noted to be at least 13i) feet in thickness, and it maj' very considei'ably exceed this. These stratified tuffs are referred to the horizon of the Trancjuille beds. /'(irf ..'. — This connects with the last, and runs in a direction of S. 30' E. to the mouth of Skuh'-un Creek, a distance of ex'.ictly six miles. It is the least satisfactory part of the entire section, inasmuch as the main direction of tin; ilip of the beds is south-westward, and the line of section coiLsequently nearly follows the genei'a! strike. It is further (Munplicated, near the mouth of Skuh'-un (.'reek, by several rather pro. nounced subsidiary flexures and possibly by .some faulting. This ])art of the section can thus oidy be regarded as a connect'.ng link, in which the beds are shown to lie in a position approximately correct. In the main, the river coincides with the outci'op of tlie Trancpiille IkhIs, crossing and recrossing it. 'J'he line upon whii'h this jiart of' the section is projected, lies a little to the north-east of the corresponding length of the river, and conse(iuently to the eastward and strati, graphically below the greater part of the sinuous outcrop of these beds, which are more persistently represented along the river itself than the section indicates. No great thickness tif rocks is clearly seen in this length of the I'or|>liyritfs. section, but here, as in the first part, the material immediately under- lying the Tramiuille hvxU is a hard greenish or green-gray porphyrite. Tiie water-bedded materials are greenish, pale gray and brownish in colour and generally fine-grained, but^ they j)a.ss in places iri,/0 green- ish tuffaceous breccias of earthy fractui'e, which do not show any distinct evidence of deposition in water. In tme place, a mile and a half below Skuh'-un Creek, the well bt^lded materials were ()l)served to b:i directly overlain by a blackish obsidian-like rock, probably a fine- grained augite-porphyrite. 12; Outcrop I if 'riaiKHiillo Uids. I . ■?,» n.j "' ' ^ 180 B IIKITIHII (OLUMIilA. BaHaltH. "^^^ highest dips, ohserved kxially, are at angles of 20" to 30 , while considerable parts of the formation appear to be nearly horizontal. The mountains along the south-west side of the valley seem to l)e almost entirely composed of massive basalts and bivsalt-breccias, with a general low westerly dip, but showing some light transverse undulations in their outcrops. In the part of this section nairest to Skuh'-un Creek, beyond the last outcrop of tuffaceous .sandstones in that direction, the attitude given to the beds is little more than conjectural, having been made to agree with the adjacent end of the next length of the section. A con- siderable thickness of the lower part of the formation must either come to the surface in the way indicated, or a corresponding change of horizon must be produced by faulting, with a downthrow to the north- westward, of which no direct evidence was observed. I'lirt 3. Part ,i. — This extends from the mouth of Skuh'-un Creek tn the vicinity of that of Smith's Creek (the next small stream frHy jiorphyriu-rt. Swii'f • Api ■] TEKTIAllY OK NICCLA HIVKR. 181 ' / greenish, hluisli and dull purplish poiphyrites, the latter preponderat- ing, /utenerally much freslier and with clearly defined felspar crystals.* Alxive these, just below the nmuth of a small stream wiiii-li enters from the south-west, is a gray augite-porphyrite, with a loliuted appear- ance, due to lines of tlow-structure in its niass.t Next in order is a red, rusty, shattered felspathic rock, now scarcely determinate, fol- lowed hy a dark greenish-black porphyrite in which some fragments of coarse gray gabbro were observed to have Ixjen caught up. This is succeeded in turn by much deconijwsed purplish porphyrite,^ grayish ])orphyrite, reddish porphyrite-agglomorate and dark greenish-gray, line-grained, much decomposed porphyrite with How-structure. Next in order are the Tranciuille binls, which here form a syncline Tnuuinillc near the south-eastern end of this part of the section. They consist, ,.,.itjt.' *'''" " in great part, of well-stratified, tine-grained rocks of gray and yellowish- gray colours, usually pale and sometimes much indurated, resembling felsites ; but also pass into coarse clastic and agglomorate-like tuffs, U'tween which and the finer and more regularly Iwdded materials it is often difficult to draw any precise line. In the centre of the syn- cline and f)verlying these water-laid materials dark brownish ba.salts are found. The rocks comprised in this part of the section, below the Tranquille VoimniMif lieds, evidentl}' represent those holding a similar position in the first •■f)fk«cx|Kisi'ed of better lig- nite is visible near Nicoainen a^ very low stages of the river, but this was not seen. The water-bedded intercalation here met with, is believed to represent Tiaiuiuillp the horizon of the Tranquille bed.s, and it is probable that these beds might Ije traced along the hillsiciii, gradually descending southward to t this phice, from the point previously mentioned at which the Big Slide has originated from them. The narrow margin of Tertiary rocks already noted as existing on the Tt-i timv edffc , ..." . west I if west side of the Thompson opposite Nicoamen, may here be referred to Tlumiiisdii. in j)assir!g. This appears to have a length of about a mile, and according to Mr. McEvoy's observations, the northern part consists of a brownish porphyiite, the southern i)art of gray arkose sandstones derived from the adjacent granite rocks, with some brown breccia, consideraoly de- composed. The horizon of the rocks last mentioned is pix)bal)ly about the same with that of the sandstones and shales at Nicoamen. The rocks forming high cliH's at the full of the Nicoamen, near its Bii.><.i1ti( soiits mouth, and seen in ascending tiie very steep hill on the trail to the ,|„,„_ north of the river, are chiefly vesicular and ainygdaloidal basalts, weathering to red colours. These are believed to follow the sediment- ary materials last descrilied, in ascending order. Higher up, and further east, in following the trail across the plateau toward tlie Nicola, much basalt-breccia or agglomerate is seen. All these rocks preserve a marked lithological uniformity, and from the fall Ui the summit of the plateau, on the trail, are nearly horizontal, in so far us the attitude of such massive beds could be determined. The trail crosses the plateau at an elevation of about 26(10 feet above that of the flat at the foot of tiie fall, while alxjve the transverse valley along which the trail runs, hills of the same composition rise to a further height of about oOO feet. Thus, on the assumption that the sedimentary and carbonaceous beds near the mouth of the Nicoamen represent the Tranquille bed.s of the Nicola section, we have for tiie upper prejwnderantly basaltic member of the Tertiary in this region, a minimum thickness of about 3100 feet. The basaltic rocks in this part of the plateau are frequently amyg- Agate«. daloidal, the cavities containing numerous well banded but pale-col- oured agates, with zeolites and green chloritic material. On i-eaching the steep slopes descending toward the Nicola Valley, '?»';"''•"*'" the basaltic rocks are found to have a very general south-easterly dij), at an average angle of about 10' ; and before getting down to the ttll.'V. TWW 186 II IIKITISII COLUMIIIA. ilif^livr parts oft Nii'oaiiii'ii Plateau. Za-kwiidki Mountuin, Cuinixjsitioii. river, on the line of route followed, bluish and purplish porphyritt's appear, similar to the rocks of the same kind in the Nicola Valley which have already l)eeii de8cril>enendix I., No. 54, TKKTIAHY OUTLIEHH OK LYITON MOUNTAINS. 187 It ■vith v;hich tlie slopes iiro strewn. This rock is vnry (iiUcreiit in iippearftnce from thn darker and more basic auj{ite-porpliy rites previ- ously described. Macroscopically it resembles a trachyte. The thick- iicHs of the mass of which Za-kwaski is composed must be HOO feet or iii)re, and it appears at this place to be the lowest representative of tlio Tertiary volcanic series, restinj^ directly upon the {granites, by overlap. Its precise relation to the Tertiary sc-ction as d. splayed along the Nicola is not known, but it may represent the !.<>ii/on of the trachyte-lik«! eruptions to which much of tiie material of the Tranquille l)eds is due, possibly here near a centre i)f eruption. A (listiint view of /a-kwaski from the northern part of Lytton Moun- tains showed its general relations to the granite and to the overlying basaltic members of the Tertiary volcanic scries more closely than these could be obstsrved on the ground itself. The second route, noted at tlu; beginning of this section of the report Nicuiiini'ii as running from the vicinity of Za-kwaski nc/rth-eastward to the Nicola, Ai^uto Ciwl". will be found indicated on the map. It follows a high ridge to the east of Agate Creek, of which Ml-meni-ooh, with a height of about fiOOO feet is the culminatinL; point. This point and tlie crest of the ridge fo" two niiles or more in length in its vicinity, is comj)osed of <;ray, generally pale-coloured rocks of trach^'tic appearance. All are apparently eruptives, and some are more or less amygdaloidal. The actual bare summit of Ml-mcm-ooh is composed of a hard but much de- composed porphyrite.* To the northward of this part of the ridge, basaltic rocks are characteristic, till in the inmiediate vicinity of the Nicola \' alley, the Tranquille beds are found, forming the upper part of the section extending eastward from the mouth of Hkuh'-un Creek, which has already been described in some detail (p. 1^1 it). The observations marie on this and the foregoing line of traverse, Di^turbanco together with what has been seen on Spioos River and its branch Prospect Creek (of which no description is incUuled in the present report) lead to the belief that the Tertiary volcanic rocks of the south- eastern part of the Nicoamen Plateau are somewhat complicated by low undulations, of which the position and trend have not yet been fully ascertained. I V of rooks. Tertiary Outliers in the Lytton Monnlains. Three isolated patches of Tertiary rocks lying to the south-west of the Nicoamen Plateau, may be mentioned here. *Api)eiidix I., No. 5i). -:"«,•■ 'r 188 II UHITI8II COLUMHIA. Patchi-H I if oiiiKloiix-rato and ImiwiU. Tprtiary JH-ds witli li|;nitr, Hour Frawr. At a height of about 4000 feet, on the north 8loi>e of Lytton Mouii tuin, a Hniall outlier of Tertiary conglomerate woh diacovered. This containM pebbles, and more or less perfectly rounded boulders of ftriwi- ites and of Tertiary volcanic rocks. It is probably a part of the df posit of some Ixnly of water which existed during the later stages of tlu' Miocene period of volcanic activity. A little further south on the sann- mountains, a much larger outlier of gra'ash and reddish Iwisultic rocks occurs. This is evidently a portion of the former edge of the flows capping the adjacent Nicoamen Plateau. The dip of these rocks nearly follows the slope of the hill, being, where observed, about N.aO E. < 15 . Another and in some respects a very remarkable outlier of i-ocks «( Tertiary age, occurs near the Friiser, on the west side of the Lyttcin Mountains, just beycmd the bordering line of the present map. This was examined by Mr. A. Howman in 18H."), according to whom it oi cupies a small flat area at a height of about 800 feet above the lino of railway, with a greatest width of po; DatvtON. TERTIAUY NORTH-EAST OP NirOI.A VAtXKV. 180 II tlie Houth-westwftrd. The same Wds were observed on their liiif of strike on tlie ojunmite side of the Thompson, with siniiliir dips. Litho- loLficallj- they resemble the Trtin<|uille ImhIs of t!ie Nicohi Viilley, hut it i>i (|uite po8sil)Io that they may represent a lower horizon. Tlieir con- iioction with the rocks of the Nicola Valley section has not been trnce (2.) Coal, liiiniiiated, rather soft I,") 4 (3.) .Sandstone, rivtlier soft, with soino shale 89 (i.) Coal r» 4 • Apjiendix I., No. 4(i. ither notably found to 1)0 Nicola. he Kainloo]is geogrupliical r. From the 1, the Niciil.i of the map, In this pnit but only two the limits of ide tributiuy latcau to till' a few words ,bout the cDii- tion of these .> it-rJGit) but he coal-seams ivial lands (if e of infereih-e jwn that the of the present canic Tertiary zai-ded in the n, is probably it the mass of on. found in C'oul half from the 77-78, it is as 'eet. III. "W 32 l.-> 4 S!l T) 4 o«w»ON.] NICOLA-COLDWATER CO.\L-FIELn. 191 II Feet. 111. (.").) Siiiiil.stoiio.s with a cdiisidfrable thickiiea.s of sliuly l)eil» at the Imse 1 H (yi) C(Mi! (aJ)oul) :} (7.) Suiiilstoiies, geiierally in tliiii beds I.3(i (■!<.) Coal (almut) 2 5 (9. ) Sandstones 424 1 The two upper beds designated as coals, might be more correctly described as lignite-coals, and it is not certain that any of the coal- beds in this section corresponds with that which has been wrought from time to time in a small exposure on the bank of the Coldwatcr, which shows a thickness of at least ■") feet 3 inches of workable coal, of pood (|uality and yielding a coherent coke. This is referred to a.s the " main seam " in the Report of 1877-78, which should be consulted. Since the above was written, the results of two test borings made in Hrsult (if r«>- the Nicola Valley in this vicinity by the Nicola Valley Company, in *^^'''" '""■'"K"- 1891 and 1893, have become available for publication. Il would be in- appropriate here to enter into details respecting the field, as it lies beyond the edge of the [ire.sent map-sheet and reipiires further i'lves- tigation, but it may be stated that a c(wl-seam undoubtedly representing the so-called ''main seam" has been found in both borings. These bor- ings were put tlown in accordance with my recommendation, in the Hat part of the valley, which is entirely covered by alluvial deposits. The first (No. 5) was situated on Lot 12'l,Tosvnshiji 91 ; the second (No. 7) on the east side of the north-west quarter of section 14, both being in the angle between the Nicola and Coldwatcr rivers. The level of the surface at both places may he consiilered identical. In No. a, the part of tho section sujiposed to represent the main seam is as follows : — • Fct. In. 0ml 'A S .Sandstone (1 Cml .■ 1 4 .Siiiulstnno (I 8 Coal 7 Total coal ."> 7 Depth of base of seam from surface, 19G feet 9 inches. ,,j;wM,r'arra3 192 B Til.' coal. KiK-ks fi'Din iMid iif swtidn to (iiiiclioii Cr.'fk. CoMwntiT ImkIh on (iiii- clioii ("ri'ck. HRITISH COLUMBIA. In No. 7, the corresponding portion of the section is as follows : — Feet. In. CoaJ (» S Shale 1 I Coal <» (i Slate 4 Coat 1 4 Total coal 5 6 Depth of base of seam from surface, 144 feet 5 inches. No. 5 was carried down to a depth of 600 feet, and No. 7 to 563 feet, cuttinj;, in each case, through several more thin seams not of workable dimensions. The coals obtained in these borings yield a good strong coke. Tlie two borings are distant from each other about a mile and a half, and although the natural outcrops to the south of the line joining the Iwrings sliow some stratigraphical complication, the result of tliese tests is to indicate that a considerable undisturbed and easily workable coal- field exists beneath the valley. From the above short note on the Nicola-Coldwater coal-field pro- per, we may return to the nortliern arms of rocks of the same age wliich, as already stated, i\ctually appear upon the map. A mile and three-cjuartei's eastward along the road from the project- ing boss of old rocks which terminates the diagrammatic section along the Nicola, another similar projection of old rocks appears in the bottom of the valley, with a width on the road of about eight-tenths of a mile. Tlie level of tlie river tlnoughout tliis part of its length, is evidently not far from the local base of the Tertiary, but no underlying sedimen tary deposits were actually seen here. At about two miles further eastward, within a mile of the bridge across Guichon Crck, a hil! of whitish trachy tic-like rock borders the road. This rock has a dull fracture, is in part an agglomerate and appears to be rudely bedded. Tt is believed to overlie directly the sedimentary deposits of the lower part of the Guichon Valley, next to be referred to. These i;edimentary rocks have been noticed in my report of 1877 (p. 126 n), in connection with the coal-bearing beds seen near the mouth of the Coldwater. A further attempt has since been made to acijuire more precise data respecting them, but with iiidifl'erent success, the whole of the low country which they occupy being more or less deeply drift-covered. The area actually held here by the Tertiary sedi- mentary rocks is, I believe, now defined with some approach to accuracy. "■] NICOLA-COLDWATER COAL-FrELD. 193 B though, as represented on the map," the outHnes are largely clap indent on the contour of the surface, taken in connection with observed out- cpjps of the older rocks which in some places fix maximum limits. The Tertiary rocks themselves, here consist of soft yellowish and Character of pale gray shales and shaly sandstones, with some beds of ratlier earthy, whitish, arkose sanilstonoof medium grain, containing much sub-angular quartz, min;:;led with decomposed felspar, and evidently resulting chiefly from the disintegration of granite. These are seen, apparently in place, in some of the gullies on the east side of the valley, between the wagon-road and tlie base of the steeper hill, but there is so much pvidence of old (probably pre-glacial) land slides, and the whole surface of these soft deposits has been so completely poached up during the glacial pericxl, that it is very seldom possible to be sure that any of the Ijeds are undisturbed. They are frequently incorporated in considerable quantity in the boulder-clay, which in consequence assumes yellowish tints locally. The broken shaly materials are found in several places, particularly Lignite and in bluffs along the immediate valley of the stream, to hold fragments ''""»t'"'i'- of lignite and of ironstone. . The lignite was not anywhere seen in place, and although beds of lignite or coal have been reported here, it is probable that the reports depend merely on the occurrence of such fragments. It is in the main, sufficiently clear, that the lower part of the ProliaUlere- Guichon Creek valley is Moored with these Tertiary sedimentary "'''|"""' "^ "'® deposits, which have been laid down when it formed an arm or inlet of the body of water in connection with which the coal-bearing strata of the vicinity of the mouth of the Coldwater were deposited. It is prt)bable that the beds here seen at the surface, represent those of the higher part of the section near the mouth of the Coldwater, which they closely resemble lithologically, as well as in the association with them of lignite, instead of tho coal found near the base of the formation at the Coldwater. It is further probable, that these higher beds here transgressively overlap the old locks, for if their occurrence were due to a subsequent synclinal flexure, the upturned edges of the harder and more massive sandstones and conglomerates of the lowt- r part of the formation, would almost inevitaiily have form' d bold outcrops about the edges of the basin. Thus, if these lower beds are here present, it may be presumed that they occupy the deeper part of the original valley without coming to the surface. This would indicate site nvmt that if a search is to Ije made here for the better fuels of the lower I!!!.'"'.'!'*' ^"^ beds, it must be conducted b-' boring somewhere near the middle line 13 Kiring-. ^ 194 H BKITISn COLUMBIA. CoUJwator ClupixTton Creek. SivndHtoiif uiitcrops. CoiikIohi- eratea. ^.oi the valley, in the vicinity of the present strram. It appears to be desirable that such a test should be made, and the circumst>inces .seem to show that tiie most favourable place would be about two miles above the bridge over (.luichon Creek, near the point of intersection of the creek with the south lino of the present map-sheet. The information gained respecting the second of these northerly projections of the Tertiary rocks, that to the west of Clapperton Creek, depends in large part on the examination of the Nicola Valley to the iiouth of the area of the map. Its form, as shown upon the map, is probably nearly correct, but the depth of cover upon this part of the plateau renders it to some extent uncertain. It may extend somewhat further to the north, and its western edge may al.so lie somewhat further to the westward than represented. It is also quite probable that additional, bui undiscovered, small' outliers of these rocks occur on the plateau beyond its nain area. Ju-:t beyond the bfirder of the map, a mile and a half west of Mr. Clapperton's hous(>, in the flat land of the valley, exjxjsui'es of griiy, siliceous sandstones like those a.ssociated with the coal at the mouth of the Coldwater are seen. These contain feome pebbly bands, and dip westward at angles of al)out 20°, toward the base of the neighbouring hills. The thickness exposed is fully 100 feet. About 100 yards further west, on approaching the base of the steep hills, and on theiv slopes for some hundreds of feet up, Tertiary rocks are again seen, with prevalent easterly dips, at high i.ngles, ranging apparently from about 40" to nearly vertical. The typical gray siliceous sandstones are not represented here, nor have they been recognized in any part of this area actually included in the map, which is occupied by rocks like those about to be noticed, which probably hold a lower posi- tion than the sandstones and represent the basal beds of the Tertiary at this place. These rocks are in the main conglomerates, but are accompanied by finer grained materials, and from their somewhat peculiar character and their relations to the lowest members of the Tertiary eLsewhere, require a few words of description. The upper beds are gray conglomerates, composed of well rounded pebbles thickly packed together. Tlu; pebbles are generally .small, .seldom more than a fcv inches in diameter. Compact cherty pebbles of pale tints predominate, but there is nlso a considerable i)roportion of hard black argil lite. In the lower beds, the character of the conglomerates is considerably changed. The material is much less perfectly rounded, in many places resembling a breccia, and although it is somewhat varielish rock. This is an augite-porphyritc with an abundance of felspar crystals and holding :i little quartz. It is easily recognized as forming a great part of the ni.iteriai of the conglomerates in its vicinity, and often occurs in large fragments in them. On the east .side of the Tertiary area, where it runs up on the plateau, hard brecciated, greenish, felspathic rocks appear to bound it. It is prol)able that the junction is here a faulted one the line of fault lunning nearly north-and-south. When last seen to Proimi,ie tlio north-west, on the plateau, the basal beds, here c )mprising a goofl f""'"- (Ifiil of rather soft brownish arkose sandstone, dip north-eastward at low angles. Elsewhere, the dips are almost invariably high, a circum- stance apparently due to local folding nearly parallel to the supposed lino of fault. -Vltogether, the stratigrapliical relations of the beds in this vicinity Cii.nora is confused and somewhat perplexing, but it issutliciently clear that wo '''''"'"""■ have here the overlap, upon the pre-existing surface, of a portion of the 13^ nL 196 B BRITISH COLUMBIA. Horizon. C'orremxmd- eiici' with other locali- t.ieB. lowest beds of the Nicola-Cold water coal-bearing rocks (Coldwater group), representing a part of the shore of the lake in which these beds were laid down. The thickness of the conglomerates and asso- ciated beds could not be precisely estimated, but must be at least sev- eral hundred feet. All the beds here p irticularly described are undoubtedly below the known coid-bearing horizons of the vicinity, and there is very little prospect of the discovery of coal in connection with them. This dot s not apply, however, to the gray siliceous sandstones seen in the flat land a mile and a half west of Clapperton's, and it is possible that coal ucanis might be discovered by boring in this part of the valley, The notes above given, will show how closely analogous the basal beds of the Tertiary at this place are to those already described in tlie neighbourhood of Kamloops Lake (pp. 160 n, 163 b). The basal con- glomerates are almost identical in character, with only such differences as result from the local nature of their material in each case. The over- lying cherty conglomerates are even more nearly alike, and the problem presented by the occurrence of cherty material in so great quantity is the same in each case. Here, as elsewhere, volcanic materials referable to the Tertiary period are entirely wanting in the conglomerates, as they are also in the sandstones of the Nicola-Cold water coal basin throughout its extent. Places StiitabU for Boring in Search of Coal. From a practical point of view, the main result to be derived from the working out of the stratigraphical order and details of the flexures of the Tertiary beds of the Nicola Valley, is a knowledge of the localities in that valley in which coal-seams may reasonably lie looked for. What has been said in previous pages, and more partiiii larly in the account given of the composition of the Tertiary as a whole, will have rendered it evident that the Coldwater beds, with which the coal is associated in this district, represent portions of a • sedimentary formation filling hollows, either those occurring in the preexisting surface, or those produced by the folding or faulting down of the formation. PoHsiWe exist- Some account of the Nicola-Cold water coal basin and of its exteii- ilower Nicok" '^'O" '" ''^^ lower part of the Guichon Valley has already been given. Further to the north-westwartl, the coal-bearing beds are nowhere seen along the Nicola Valley. Where, in a couple of places, the underlyinj; rocks come to the surface, the strata of the volcanic Tertiary, overl ip them without the intervention of the Coldwater beds, and these, if Position of Coldwater l)e ! basal con- differences The ovei- he problem juantity is ,1s referable imerates, as coal basin jrived from ails of the lowledge of isonably lie ore partieu jrtiary as a • beds, with jrtions of a ring in the ulting down if its exten- been given. lowhere seen 3 underlying iary, overlap md these, if present, occupy the lower parts of hollows of the old surface which liave not been exposed by the later folding and denudation. Thus, to the westward of 'Juichon Creek (where the site for an experiniontnl boring has already Ijeen indicated (p. 193 h), it is only possible to note a few places in wliich tlie lowest volcanic beds of the Tertiary come near to the surface, and where, by means of boring, it can be a.scertained, at least cost, whether the coal-bearing Coldwater beds underlie them or not. Further, were the Coldwater beds actually found to occur in any of these places, it does not by any means necessarily follow that they would continue to be coal-bearing ; for the coal-.seams are the result of the accumulation of large quantities of vegetable material, and the swampy areas in which such accumulation took place must have been bordered on all sides by higher and drier lands of which the vegetjition decayed as it was produced, and witli- out leaving any trace. The following places may, however, be mentioned as those in which it is desirable that experiments by boring should be made, and where, if coal should be found to exist, it may be more easily utilized, because '"'""g nearer to the main line of railway communi ion through the country. 1. Nicola Valley from thvee-quartew of a mile to a mile east of the road-crossing of Skuh'-un Creek. 2. Nicola Valley, near the bridge at its mouth, or within half a mile above the bridge. At botii these places it is believed that a boring would begin, at the surface, at a horizon low down in the volcanic ac- cumulations of the Tertiary, and would within a few hundred feet reach the base of these rocks. Whenever the older underlying rocks may be reached, in either place, the boring should stop, but some care would require to be exercised in the recognition of these rocks, as they do not always differ very markedly from some of the Tertiary volcanic inaterials. 3. Mouth, of the Nicoamen lliver, above the railway bridge and near the waterfall. It is not quite certain whether the beds contain- ing some lignite or coal near Nicoamen are referable to the Tranquille horizon or to that of the Coldwater, but in either case tlie discovery of workable coal or lignite at this point would be of importance. Tlie general section of the Tertiary rocks already given, will allord the means of deciding the horizon as any boring which may be made here progresses. It would be advisable to begin the boring as far up the stream as may be possible without materially imreasing the elevation, in order to avoid the zone of crushing and disturbance which here characterizes the junction of the Tertiary rocks with the granitic riiues .su)f- ({ivti'd fill- xpt'riiiicnt.il 11 '^ i it' Am. 198 B BRITISH COLUMBIA. PoHsibIc aiiri- rocks. The possible occurrence of a huried pre-Miocene river-channel feroun graveU. jj^^^ j^j^jg pi^ge, indicates the advisability of paying sjiecial atten- tion to any beds of gravel or conglomerate which may be met with in boring, as these might be found to be auriferous. Some other localities might be indicated as of subsidiary importance in connection with the search for coal, but those mentioned are, in so far as the structure oi the region is understood, undoubtedly the first, (to the westward of Guichon Creek,) at which systematic boring opera- tions might be made, and the results obtained should themselves go far to indicate both the advisability of further explorations and the places in which these should be conducted. Tertiary vol oauio range. Height of suniniitH. Tertiary Rocks of the Clear Mountains, Mount Murray, Arthur's Seat, Etc. The mountains above designated, form a nearly continuous range, which may be reganied as running from the vicinity of Spence'a Bridge on the Thompson for about twenty-six miles in a north-west- ward bearing. Chi-pooin Mountain and Mount Mattley, the two most northern summits of the Clear Mountains, are not included here, as they are composed of granites and other rocks much older than those of the Tertiary. The range of Tertiary mountains thus defined, is a most import- ant feature of the orography of the area included in the map-sheet. The Nicoamen Plateau may, in a general way, be said to form its further continuation to the south-eastward, but the heights at which the volcanic rocks occur in the range here particularly referred to, are greater even than those of the culminating parts of the Nicoamen Plateau — greater indeed than that of any other occurrence of similar rocks in the entire region. The elevations of the principal points in this range are as follow : — Arthur's Seat, 5500 feet ; Mount Murray, 6880 feet ; Blustry Mountain, 6740 ; Cairn Mountain, 7650 feet. Although it has now been determined that the rocks composing these mountains are referable to the volcanic series of the Tertiary, and that they represent the basal portions of great accumulations of that kind formed along the main line of eruption, chiefly during its earlier stages, this result has not been arrived at without prolonged and careful investigation of ail their relations in the field. Earlier views The area occupied by these rocks, being rugged and difficult of access, was necessarily left unexplored during the reconnaissance work of 1877, which was confined to a few mouths of a single summer. The A line of volcanic eruption. reBl)ectinK thesu rock) 0 ceous, and that although showing some points of resemblance to the ''•'•''iiiiiiwl. volf anio materials of Triassic and Carboniferous age so extensively developed in the region, they were distinct also from these. Eventu- ally, their intimate association with distinctly Tertiary volcanic pro- ducts was established, and their connection with the older Tertiary volcanic rocks of .the porphyrite class, as displayed along the J^icola River, became clear. Without entering into details respecting the character and nude of occurrence of the rocks at each locality where they have been examined, it will now be attempted to give a short general sketch of them. Arthur's Seat, so named by Mr. John Murray who has long resided AitluuV Seat. near its base, at Spence's Bridge, is a remarkably picturesque moun- tain as viewed from the Thompson Valley, to which it presents a bold front crowned by lofty mural cliffs. The rocks of this mountain were to some extent taken as typical of those of the whole range which is continued north-westward by Mount Murray and the' Clear Mountains. Its crest was not actually reached by us, -though this might easily be accomplished from the westward if desired, but very large blocks which had fallen from all parts of its face were examined on the side of the Thompson, its southern Hank was crossed at a high elevation, and the rocks of its northern side were examined and collected along the line of Murray Creek. Of the rocks obtained Cliaracteristio at these localities, a number have been subjected to microscopical '^'•''^''■ examination by Mr. Ferrier, and the greater part of these have been found to be augite-porphyrites, with some diabase-porphyrites and gabbro.f In colour they range from grayish-green to bluish-gray, and w * Roix)rt of PwgresH, (icol. Hurv. Can., 1877-7S, p. Ill ii. t Apiwndix I.. Nog. 47, 49, 51, 42. ii 200 B BRITISK COLUMBIA. Skoon-ko' Valley. in texture from fine-grained rocks of which the porphyritic struc- ture is scarcely visible macroscopically, to others with a fine- grained base in which felspar crystals are clearly discernible, and again to cry.stalline rocks of a distinctly speckled or spotted appearance throughout. Some of these rocks are evidently frag- mental in structuro, but most of them appear to repre.sent old Hows of molten matter. MurrayCrcek. At the waterfall near the mouth of Murray Creek, the rocks are very much shattered and conspicuously reddened. They consist of porphyrites and of a trachyte-like material, one being in all probability intrusive in the other, but the broken character of the exposures renders it difficult to determine which of them is the older at this place. On the upper part of Skoon-ko' Creek, to the west of Arthur's Seat, the rocks displayed are somewhat more varied in character and are distinctly arranged in somewhat massive beds, which dip at rather low angles, but of which the direction and amount of dip is irregular and difficult to follow. The order is in general, however, an ascending one, from lower to hii-her levels on the hills. The hill side to the north of the valley was ascended by Mr. McEvoy at two places indicated on the map. At the first of these, the general dip appeared to be southerly at angles of 10"" to 30°. The lowest rock seen is a bluish gray, much decomposed, amygdaloidal augiteporphyrite.* This is overlain by a fine-grained, greenish-gray agglomerate, followed by a distinctly bedded pale, tuflFaceous rock. At the second locality, some ordinary sedi- mentary sandstones occupy the bottom of the valley. These underlie the volcanic rocks and will be referred to again in the sequel. Above them is a tine-grained, yellow amygdaloid, then a pale gray trachyte- like material, then some brown and greenish rocks which were classed in the field as " basalts," but of which no specimens were brought back. ' Overlying these are l>eds of rather fine-grained agglomerate, composed chiefly of porphyritic fragments of gray, brown and purplish colours. Some of these fragments are evidently derived from massive rocks in the lower part of the series, seen along the valley of the stream between the two localities above specially noticed. The northern part of the Scarped Mountains, to the south of Arthur's Seat, appears to consist of rocks very similar in character to those of that mountain, in so far as they have been examined. Along the west side of the Thompson south of Skoon-ko' Creek, bluish and greenish-gray porphyrites of varied texture, generally massive, but sometimes agglomeritic, are characteristic. On the west side of these Scarped Mountains, • Appendix I., No. 50. •] TERTIARY OF MOUNT MURRAY. 201 n mountains, the general dip of the volcanic rocks in tlie mass, was very clearly seen from Botanie Mountain, whence their outcrops can be traced along the hill-side to the east of Hdtanie Creek. The dip is about east-north-ea.st at angle.s of from 15' to 30 . The rocks them- selves were not here closely examined, but specimens representing the lower memliers, near t(j the bottom of the valley, were obtained in three places, as follows : — Half a mile Wiow Botanie Lake, a fine- grained, purple-gray felspathic rock with tlow structure. Two miles below Botanie Lake, a fine-grained, dark augite-jiorphyrite (!) with green-faced divisional planes. Four miles and a half below Botanie Lake, a gray porphyrite. The southern line of the volcanic rocks, crossing the Scarped Mountains, ns shown on the map, depends chiefly upon distant views of these mountains from Botanie and Lytton mountains. It was not actually traced across this rugged range, and may therefore be held subject to modification in detail. The summit, niaiked " ."5860 feet," in particular, was referred with doubt, from its appearance, to the granitic series. The Tertiar}' volcanic rocks appear to liave been stripped from the southern pai t of the Scarped Mountains by denudation, but the under- lying granitic and gneissic materials bear evidence of the proximity of the great line of volcanic eruption in their extremely shattered and disturbed character. They are traversed by numerous dykes of trappean material, frartured throughout in every direction and much altered by heat or solfataric action. Mount Murray, at the head of Murray Creek, was occupied as a point of observation and a triangulation station. It iscomposed of rocks evidently the same as those seen along the valley of the creek and in Arthur's Seat. They are generally gray or greenish-gray porphyrites, usually massive, but often distinctly fragmental, and constituting agglomerates. Along the crest of the mountain, near the summit, some red fine-grained beds with small porphyritic crystals occur, which are nearly horizontal ; but generally it is not possible to determine the lie of the beds. The actual summit is composed of a gray augit«- porphyrite.* From Mount Murray, an execellent view of the whole surrounding region and particularly of the southern parts of the Clear ^lountains proper, was gained. liotanie ^•all..y. ."^tatc of un- derlying greiiiti'w. Mount Munav. ( 1| * Appendix I., No. 52. 202 11 UHITISri CULUWIIIA. Bntaiiit' V'hI- !.■>•. HaiKl- HtuiieH. Plivtfiiii near I^Hikuut I'oiiit. Character of line Vx'tween b|ktuilt.s and ixjrphyrites. West side ThomiBon Valley. The western ^H\]^e of the volcanic rockH, approximately follows the line of the valley in which Uotanie and Pasulko lakes are situated, and between the.st' lakes are some interesting outcrops of ordinary sediniei: tary materials which underlie the great volcanic mass. These appear to consist of sandstones and argillites not distinctly containing volcanii materials, but holding occtwional carl)onaceous fragments and obscure plant impressions. Conglomerates also occur, anrl these were par- ticularly observed on the nt)rth branch of La-loo-wissin Creek, whetc they pass into ordinary sandstones of pale yellowish colours. TIh^ approximate outcrop of these sedimentary l)eds is indicated on the mi). and though their precise age remains uncertain, it is probable thnt y may Ije regarded as forming an extension of the sedimentary betl I with in Hat Creek and described on another page (p. 207 »). To the north-eastward of Murray Creek and Mount Murray, the Tertiary volcanic rocks continue over a tract of country about five miles in breadth, extending from the Thompson Uiver to the head- waters of Hat Creek, with a length of some fifteen miles. This tract is high and rough, but with some tendency to a plateau-like character as seen from Mount Murray. Lookout Point, rising from it, reaches an elevation of 6600 feet. The greater part of this area is believed to be characterized by rocks referable to the earlier stages of the volcanic eruptions, and like those described in the foregoing pages of this section of the report. Its north-western part is, however, evidently covered by basaltic rocks in nearly horizontal flows. The attempt made on the map to outline these two classes of rocks in this region and in that of the Clear Mountains, must be accepted rather as an indication of their existence than as an actual definition of their areas, fof no sutticiently detailed examination of their boundary has been made. Tlit,' exploration of the tract of high country here particularly referral to, was in fact confined to the vicinity of Murray Creek, the Thompson River, Twaal Creek and Blue-earth Creek. The rocks met with on the line of Murray Creek have already been noticed, but a few words may be added respecting those seen on the other routes mentioned. On the west side of the Thompson, the north-eastern edge of the Tertiary is nearly opposite In-kai-kuh' Creek, where its beds are found in contact with black slaty argillites and quartzites of the Cache Creek formation. Porphyritic dykes, evidently due to the period of Tertiary eruptior, traverse the older rocks near the line of junction, and tlie Tertiary volcanic rocks near their margin are found to be much dis turbed. The junction is probably here a faulted one, the fault being •J TERTIAHV OF TWAAL AND HLUK-EAKTH CIIEEKH. .>0.{ II tlin s)iine witli timt wliich runs so persistently to the north-ciist of tlio Nicoirt Valh^. Near the edgo of tlu« Tertiary, a well l)cd(le(l intercahition of j,'re<'n- TuffivceouH gray tunaceous sandstoni! a[)|>oars, dippins; a. 35 W . < GO . Ino exceptionally high dip \h explaiiKid by the proxiiiiity of the fault. This stratitk'd intercalation was not recognized on the opposite or east side of the Thompson, but about a n\ilu further south (half a mile above Twaal Creek), another outcrop of similar tulfaeeous sandstone occurs on the west side of the river. This dips 8. (i.")' W. < HO'. Ft was estimated to be about one hundred feet in thickness, and is evidently the .same with that noted on the east «de of the river, opposite (p. 188 n). J^elow the mouth of Twaal Creek, considerable exposures are found Orthophyrc. of a peculiar gray con otionary rock not elsewhere seen in the Tertiary. This is described by Mr. Ferrier as a {juartzless porphyry (orthophyre) with well marked spher^ litic structure.* The other rocks seen along tiiis part of the Thomp.son are greenish and gray porphyrites of the usual character, occasionally fragmental. Similar rocks occur along the Twaal N'^alley, with the addition of Twaul Vallty. some reddish-gray porphyrite, and in one place of a gray dacite which contains numerous large grains of quartz with rounded outlincs.f The bedded tuffaceous layers seen on the Thompson were not founfl in this valley, but the hillsides along it are rather heavily drift-covered, and the exposures in consequence imperfect. At the head of the valley the volcanic rocks are in contact with the limestones of the / Cache Creek formation, but it war not ascertained whether the line of junction continues to be a faulted o'^e here. Blue-earth Creek heads in the same valley as that in which Twaal nim-farth . ( 'reuk. Creek rises, but Hows in the opposite direction, to Hat Creek. This part of the valley nearly coincides with the edge of the Tertiary volcanic rocks, which occupy the country to the south, while the north side of the valley is characterized by limestone, often in the form of bold cliffs. The step-like outlines of the high plateau rising toward Lookout Point, to the southward, indicate that it is chiefly com- posed of basalts or similar rocks in nearly horizontal flows, and differ- ent varieties of such rocks are found on the .'•lopes toward Blue- y,„cal base of earth Creek. At one place, just below the little lake in which the volcanic mcks. creek rises, the Tertiary rocks seen actually resting on the limestones, consist of yellowish and greenish-blue soft tuffaceous deposits, contain- I !| * Apiiendix I., No. 43, t Apjiendix I., No. 49. 204 B HRITISH COLUMBIA. ing fragments of basalts and hard concretionary masses of the same blue colour. This material appears to have been deposited against an originally steeply sloping surface of the limestone ; but there is nothing to show that it is at all near the true base of the Tertiary formation. Soutlieru part The valley which runs from the head of the north branch of La-loc- Mountains. wissin Creek to the head of Hat Creek, may be i-egarded as separating the Clear Mountains proper from Mount Murray and others previously described. As .seen from the summit of iNfount Murray, the higli broken region forming the southern part of the Clear Mountains sliows the well marked outcrops of massive volcanic beds dipping at low angles to the northward. The same observation was repeated in views had of the western side of this part of the range from As-kom ^loun- tain, on the opposite side of the Fraser, and from a ridge on the east side of the Fraser, in its valley and near the mouth of Cinquefoil Creek. From the two last mentioned places, however, the relation of these rocks to those of the granite series was also very clearly made out, the scarped liill sides sloping toward the Fraser Valley being cmn posed in their lower parts of granite and diorites, upon which, further back and at a greater height above the river, the volcaiiic materials rest often nearly horizontally. As seen from the Fraser Valley, tlic overlyinj; volcanic rocks often appear to form rugged and bold hills, but when viewed from a greater elevation, these are found to be merely the scarped ends of ridges and spurs fringing the broken edges of the central part of the range. Shiittcrecl uiulprlyiiig granitt's. SnmniitH of iho Clear M^iiintainH, Flfi. 5. — DI.AfJKAMMATlC SECTION NKAK THE MOUTH OF CINQUEFOIL CHEEK. a. Granitic and dioritic ruckw. (;. Cri'taceous. Volcanic rocks of the Tfrtiary. Along the Fraser Valley, from the vicinity of La-loo-wissin Creek to that of Cirquefoil Creek, the underlying diorites and granites are extremely shattered, and weather down easily into rubbly slopes of angular debris. These rocks are in fact affected in a manner precisily similar to those of the soutjiern part of tlie Hcarpeil Alountains (p. 201 u). and like them represent a portion of the old floor vpon which the volcanic accumulations occuTed, near to the central line of eruption. The summit of the Clear Mountains was reached, by following up tlir valley of a small stream which empties into Hat Creek oi)posite Blue earth Creek. So far as examined, the eastern flanks of the range, all -'i H.] TERTIARY OF CLEAR MOUNTAINS. 205 B 3s of the same lite J against an there is nothing iary formation. •anuh of La-loc- id as separating thers previously urray, the higli lountains shows dipping at low jpeated in views As-kom ^loun- iae on the east th of Cinquefoil the relation of ry clearly made alley being oni- n which, further ilcauic materials aser Valley, the and bold hills, und to be nici ely ken edges of the NQUEFOIL rUEKK. ofks (if the Tertiary. lo-wissin Creek tn and granites are rubbly slopes of manner precisi ly mntains (p. 201 h), vpon which tlie line of eruption. y following up tlie ;ek opposite Blue I of the range, all along the upper part of Hat Creek, are largely composed of basaltic rocks, while similar rocks occur high up on the north-eastern Hanks of Cairn Mountain, and also in several (or many) other placer along the range. On the map, it has been possible to indicate these occurrences only in a general way, or in certain special localities in which they have been observed. Here, as elsewhere, the distinction made between t'lr older and newer volcanic rocks must be considered as approximate m jrely,and as being nnuch inferior in accuracy to the outlines of the Tertiary rocks as a whole. The rocks observed on the higher parts of the Clear Mountain range, may be described as consisting in the main of gray, blackish, purplish and greenish-gray porp'iyrites, probably for the most part augite-porphyrites. They are often massive, and represent eruptive materials, but agglomerates of similar composition are also common. The occurrence of basaltic rocks on the eastern llanks of the range has 15a,siiliic out- just been alluded to. On the wesveni slopes of Cairn ^lountain, two or three distinct outliers of similar rocks were observed, which still preserve their slope, away from the axis of the range and toward the Three-lake Valley. Certain purplish porphy rites which are some- what less compact in texture than usnal, appear to immediately under' lie the basalts, while the dense and hard, gray and greeni.sh porphyr;te.«, occupy lower positions .n the series and are prominent about the crests of the range. A notable feature in the higher parts of these mountains and toward Musses of du- their axis, is the abundance of yellowish and whitish crumbling rocks, ^""ks.""^' which give rise to slides of broken material of the same colours, very conspicuous from a dis'ance. These, en investigation, proved to be merely portions of the ordinary porpiiyrites which had become highly charged with iron pyrites, and which, in part from the di'compo.sition of the pyrites and the actici of the libei'at.ed ucids on the containing rocks, in part apparently from solfataric action which may have occurred during the deposition of the pyrites, have become decomposed and bleached. Decornposed rocks of this character were found to be par- ticularly abundant in the vicinity of Cairn and Blustry mountains. Specimens of them were collected and subjected to analysis, in order to r,k1'"t''- Most of the boulders and pcblile-i consist of porphyrite rocks like those of the Clear Mountains, while some are granites. The height of this little outlier above the Fraser is about 1000 feet, and it appears to represent a remnant of an old bed of tlie Fiu^-^r, which, perhaps owing to some local induration, has escaped denudation. The height above the present river seems to indicate tiiat it may be assigned to one of the early stages of the period of Pliocene erosion. This, with Possibly any other similar deposits which may be found, appear to be worth ' examining as possibly containing gold brought down during the period of ancient river erosion. Tertiary Rocks of Hat Creek, ravilion Mountain and Vicinity. The upper valley of Hat Creek, which runs from south to north Hat Creek, along the east base of the Clear Mountains, is largely floored by sedi- mentary Tertiary beds — generally soft shales and sandstones. The whole surface of this wide va'lcy is, however, so thivikly covered with drift deposits, that it is impossible to detine the area of these Tertiary beds with any precision. The outline given upon the map is probably as nearly exact as is possil)le from observation of the natural exposures, butit is really only inthat partof the valley near Limestone and Medicine ■ Creeks, and thence uortliward, that the Tertiarj* sedimentary deposits are actually expoitid' Thus, the southern extent of these beds, and ~;. tlieir width i;i the southern part of the valley is particularly open to ; lioubt. ,' ':'■'''" The occurrence of an important dijposit of lignite-coal on Hat Orr.i!: bed of Creek, near the east entrance of Marble Cailon, has long been known. "S'l't*^- Tiiis locality was visited by me in 1877, and K-rpie description of it is jjivcn in the report for that year, from which the following is quoted : — " A locality of some interest in connection with the Tertiary is found D,.s' •'■i' ivit sedimentary Tertiary rocks of this part of Hat Creek valley, for extensive remnants of them occur at nearly corresponding elevations on the opposite or east side, where they form a step-like border to the Palieozoic rocks of the higher hills. The sedimentary rocks here observed, in their general appearance Ape of swli- nnd in the conditions of their occurrence, closely resemble those already "'^'"^'^''V l'^''"- U 210 B BRITISH COLUMBIA. lielation to beds of lower valley. Character of lig:iite. Site recoiu- niondetl for boring. described on Guichon Creek (p. 192 b). They were not observed to contain any contemporaneous volcanic materials, and it is highly probable that they are referable to the Coldwater series of the classi- fication adopted in this report. No determinable organic remains have been f. und in them. The natural exposures do not serve to satisfactorily connect the sedimentary beds of this part of Hat Creek valley, with the con- glomerates and sandstones of the lower pait of the vallny, whicli undoubtedly represent the Coldwater beds; a gap of more tha" a niilo occurring between them, for which there is no information. While it is possible that the two areas are continuous along the bottom of the valley, it has been thought better to represent them on the map us being disconnected. It is believed, however, that the beds .=een on the upper part of Hat Creek represent the higher parts, while those on the lower part of the creek represent the lower parts, of a single series of Tertiary deposits. The conglomerates were nowhere seen in place in the upper part of the valley, but large, loosp pieces of con- glomerate, identical with that of the lower valley, were found some miles above the lignite outcrops on the creek. The Tertiary volcanic rocks, last seen at about a mile and a half below the bend made by Hat Creek at the entrance to Marble Caiion, are basalts, apparently brecciated, underlain by purplish melaphyie identical with that described as overlying the granites near the mouth of Limestone Creek, and probably an extension of the same flow. In regard to the composition of the lignite here m ,t with, the fol- lowing assay by Dr. Harrington may be quoted from the report of 1877-78(p. 121n):- Water ! 8 • fiO Volatile combustible matter Hoii. Fixed carbon 4684 Ash O-O.'i For a lignite, the fuel is therefore of good quality, and the great thickness of the bed should render it of some importance, at least locally. As a result of the observations made on the mode of occurrence of the lignite and its associated rocks, it would appear to be desirable ti> abandon further exploratory work in the disturbed measures near tlie eastern efige of the valley, and to make a test by means of a l)oring, put down at a distance of a quarter or a third of a mile to the west- ward of the locality on the stream at which work has already been '•] TERTIAKV OF HAT CREEK AND VICINITY. 211 H done. From analogy with the Nicola Valley occurrences, it is quite poasihio possible that in beds beneath the lignite already known, fuels of the n Creek. Continuation of Clear Mountain axJH. Basalts over lying Hiintl- stoue. North of Leon Creek. Sources of basalt flows. On Leon Creek, two miloa and a half west of the Fraser, Tertiary porphyrites are again found to replace the Pala-ozoic rocks, which here border the river. They are generally agglomerates, containing many amygdaloidal fragments and showing evidence of considerable disturb- ance. These volcanic rocks here appear to occupy the eastern edge of a basin, and, further to the west, beyond the limit of the map, similar rocks seem to form hills of some height. Taken as a whole, the porphyritic rocks between Re • • -intercalation was not determined, but it is probably local. The sana.>it^^. < j yellowish and rather soft, often coarse and sometimes pebbly. It is composed chiefly of angular granitic debris. (See p. 211 b.) North of Leon Creek, basalts similar to those just described and forming an extension of the same flo>v o; series of flows, continue to cap the high hills on the west side of fchf> Vaser as far as the edge of the map-sheet. The last isolated patch ol' bvsalt shown, in this direction, is part of a very small outlier. Fui f iii-r to the west and north, the hills fall back from the Fraser in the vicinity of Watson Creek, porphyrites like those of Leon Creek are again seen in them, though the rocks immediately bordering the river are continuously Pala'ozoic, nearly or quite to the mouth of Big Bar Creek. The remnants of old basalt sheets found high above the Fraser along this part of its valley, together with those of the head-waters of Big Bar Creek, probably represent flows of proximately local origin, and have proceeded from sources diflferent from those which flooded the Green Timber plateau. In any case, their present appearance indicates a very great amount of river erosion since the date of their formation. South branch of Big Bar Creek. Tertiary Rocks of Big Bar Creek and the Green Timber Plateau. The northern part of the valley bordaring the Marble Mountains on the west, contains the sources v^f the south branch of Big Bar Creek. •1 TEBTIAHV OF OREEN TIMBER PLATEAU. 217 H It is occupied by a long narrow strip of basalts, the surface of which generally slopes gradually to the westward from the base of the moun- tains. Tlie whole valley is so much encumbered with drift material that little was seen of these basalts, but they appear to be of no great thickness. They probably connect with the basalts of the (Jreen Timber plateau, round the eastern end of the Marble IMf)untaina. Their southern termination, as shown on the map, is largely con- jectural, on account of the complete mantle of drift in the vicinity. It is also possible that they may occur to some extent along the west side of the south branch of Big B)u Creek, though no evidence to this effect was obtained. Between the source of the south branch of Big Bar Creek and Kelley Krllcy Creek. Lake, two streams from the eastward enter the valley separating the Marble Mountains from the Edge Hills. Near the mouth of each of these streams, basaltic boulders were observed to be very abundant, and it is possible that small basalt outliers may occur in these depres- sions, on the flanks of the Marble Mountains. The Green Timber plateau, of which the southern part is contained in the present map-sheet, being crossed from Clinton northward by the old Cariboo wagon-road, is oi. of the best known features of this part of the pro\ince. To the e^e, as viewed from any higher point, it is level and sea-like, but that part of it included in the map, really slopes gradually and somewhat irregularly from a height of 4500 or 5000 feet, near the north-eastern base of the Marble Mountains, to one of about 3000 feet near the North Branch of the Bonaparte River. The greater part of this eastern descent occurs, however, near the base of the Marble Mountains, the eastern portion of the plateau being not far from level. The whole plateau is heavily covered with drift deposits, but rock is occasionally seen in place, and where this does not occur, large masses or angular boulders of basalt of a single kind, are often found grouped together in such contiguity as to indicate that this rock is in place in the immediate vicinity. Along the southern edges of the plateau, near Clinton and on the Bonaparte Valley, sections of the basaltic rocks also occur, and there can be little doubt that the entire area of the plateau is underlain by rocks of this character, though it is possible that these may have been cut through t ) the older rocks below in some places. The source or sources of these great horizontal or nearly horizontal flows of basalt, have not been deter- mined, but their general contemporaneity with the basalts of Big Bar Creek, those of the vicinity of Leon Creek and the very widely ex- tended areas of basalt and basalt-breccia to the south and east of the (Jreen Timber plateau, can scarcely be doubted. The (ireeii Timber Plateau. ill 218 B BRITISH COLUMBIA. Bonaparte east of Fly Creek. Tuffaceous breccia. Fly Creek. On the lower part of Fly Creek, a tributary of the feonaparte wl)ieh forms a small canon before reaching that river, good sections of basalt are seeu, and rocks of the same character occupy the whole depth ot the Bonaparte Valley to within about a mile of the mouth of the North Branch, where they are found to be underlain by greenish tuffaceous sandstones, dipping about N. 45° W. < 40". The sandstones are imperfectly exposed and their thickness is not known. They rest upon greenish diabase, which is referred, though with doubt, to the Nicola formation, but this is soon replaced by granitic rooks which characterize the lower country about the forks of the Bona- parte. From Fly Creek eastward, nearly to the mouth of the Chasm, the Bonaparte Valley is similarly characterized by basaltic rocks, .»y denudation, but its general aspect seems to indicate, that the higher region of the Arrowstone HIlLs may represent th'.! source fiom which much of the volcanic material cover- ing this tract of country welled up. 220 B BRITISH COLUMBIA. Hocks largely A large part of this area is very inaccessible because of its thickly asa ic. wooded charactar. It has, however, been traversed on several lines by Mr. McEvoy, from whose observations it would appear that probably eight-tenths of its entire surface is occupied by basaltic rocks, eithe ■ in the form of flows or in that of basalt-breccias, often very uniform in composition and appearance for long distances. Volcanic rocks of other kinds observed, are chiefly those of the higher parts of the Arrowstone Hills and those found underlying the ordinary basaltic materials where these have been cut through. Thus, in respect to this area, attention has been chiefly directed to ascertaining the outlines of the Tertiary volcanic rocks as a whole, rather than to any detailed examination of different parts of the plateau. Possibly older eruptiuns. Notes on routes tra- versed. Obsidian-like rock. Hyalite. It is quite possible that some of the rocks met with, particularly those of parts of the Arrowstone Hills themselves, should be classed with the older Miocene eruptives, like those found in the Clear Moun- tains and on the Nicola Valley, but as there is no means of determinini; this point, it has been thought best to include the whole of the mass with the later eruptives, to which by far the greater part, at least, cer- tainly belong. The subjoined notes by ivir. McEvoy, relate to the routes actually traversed by him and shown upon the map. " The southernmost main elevation of the Arrowstone Hills, lies between the two branches of Cache Creek and the sources of Scottie Creek. In ascending from the forks of Cache Creek, purplish porphyrite is found, and rocks of a some- what similar character are abundant on this slope. In the higher part of the hills they become very hard and tough, and much resemble some rocks seen on the north slope of Mount Glossy. Some of these rocks are distinct augite-porphyrites. On the north side of this group of hills, which slopes down to Scottie Creek, there is an exposure of very flue grained augite-porpliyrite, resembling obsidian, associated with basalt*" The obsidian-like rock above mentioned, is very (^ommon in loose boulders and fragments everywhere in the vicinity of the Arrowstont Hills. It was formerly employed by thfl Indians for the manufacture of arrow- and spear-heads, and probably occurs in considerable volume in the higher parts of the Arrowstone Hills. " Cro&sing Scottie Creek and ascending the hill to the north, tlie country ia deeply drift covered. The top of the hill is gen' vfiUy cci;i posed of dark brownish basalt, often highly vesicular. C.i> a suiu.u i' one mile south of Hi-hium' Creek, this holds hyalite, both i i the ve^i■•'< - and between the layers of flow-stru'-^ure. The extent of tl,e area in "Apiiendix I., No. 74. 0W8ON.] TERTIARY OP BONAPARTE PLATEAU AND ARR0W3T0NE HILLS.' 221 B which the hyalite was observed to occur, is about one mile by half a mile, and some very fine specimens of this mineral, now in the museum of the Geological Survey, were obtained." " No exposures were found about the crossing of Hi-hiuni' Creek, but on the slopes of the hills to the north, vesicular basalt again occurs. The higher parts of these hills are composed of basaltic rocks* similar ir -0 alieady noticed in connection with the southern summits of the , . 1 one Hills. No exposures were found on the north s'.ope, in de- ending to Loon Lake, but the rocks are evidently basaltic." The valley of the Doadman River, with a general course from north Deadiiian to south, connects the Bonaparte Valley with that of the Thompson, Valley, and forms the eastern boundary of the region now under description. " From the source of its north-western branch as far as the mouth of Criss Creek, a distau-e of more than twenty-two miles, it forms a deep narrow trough, which cuts through the Tertiary volcanic materials and exposes the underlying rocks of the Nicola formation nearly through- out, though in one or two places the Tertiary crosses the line of the valley. North of the mouth of Criss Creek and as far as Deadman Lake, soft white tuflfaceous ash-rock is fouad exposed in vertical cliffs, Massive with a maxirau i observed thickness of 500 feet, the bases of the cliffs g^^.^ston^s, being gener.Ti'y ijir-ed by slopes of talus. The talus seems in some places to c -f.v £•. »' jH)sit of Tertiary conglomerate resembling that of Copper C ae«. i-r oot%veen the mouths of Criss and Gorge creeks, numer- ouj loose ieirts If < t iiuch a rock were found. Overlying the tuffaceous beds are basaif bre-'cias, with a thickness of some 800 feet, and capping these, at .i-. level of the plateau, are flows of brown basalt." The tuffaceou? rocks above referred to, are in some specimens Arkose ahnost entirely ' omposed of fine-grained felspathic matter of volcanic ■""'f'""- origin, but thjy generally include a certain proportion of arkose material wit'i angular or sub-angular quartz grains. In some speci- mens the quartz grains become very abundant and a large part of the whole t.' t-is appears to be of an arkose character, dp;ived from the decor. '«"i- u(ni of granitic rocks. Alon;r < ' jst side of this area of plateau, the Tertiary rocks come Parts of down to tiifc bottonj of the Bonaparte at one place only, opposite the ai'i'l'lCminsoa mouth of Hut Creek. They consist here of basalt-breccias and basalts, VallcyB. So far as ascertained, similar rocks appear to prevail in outcrops which occur high up on the sides of the valley. The Tertiary volcanic rocks outcropping on the south side, in the vicinity of the great trough now occupied by the Thompson River, have already been in part noticed in * Apjiendix I., No. 73. 222 B BRITISH COLUMBIA. Near Eight- mile Creek. Connection with Savona Mountain. the description of the general section from the Bonaparte to Copper Creek (pp. 217 b, 218 b). Along the north aide of the Semlin Valley, the volcanic rocks of the plateau are broken off in bold escarpments and cliffs. Thes 'n ve not been examined in detail, but they include both basalts and »- ; erials of a less basic character, all arranged in massive layers auu liering to reddish colours. The summit of the plateau to the west of Eight-mile Creek, in the angle between the Eight-mile Creek valley and Pass Valley, was found by Mr. McEvoy to be capped by dark-brown basalt containing very numerous crystals of magnetite, underlain by a volcanic breccia with a yellowish, earthy matrix. Near the mouth of the gorge of Eight-mile Creek, just above the wagon-road in the Thompson valle}', a white, banded, felspathic rock, probably a trachyte, with very fine lamination produced by flow-structure, was noted by Mr. McEvoy. The rocks seen along the Pass Valley, are all referable to the Tertiar; volcanic .series. Basalt-breccias and breccias charged with fine-grainei' augite-porphyrites resembling obsidian, being the most abundant. Apart from the somewhat peculiar rocks of the higher portions of the Arrowstone Hills, the Tertiary volcanic materials of this plateau generally closely resemble those of Savona Mountain and the plateau attaching to it, from which they have indeed been divided only by the deeply excavated valley of the Thompson River. Tertiary Bocks East oj the Deadman Valley and North of Kamloops Lake. Near Bona- parte Lake. Kuk-waus' Plateau. The Rim Hills, north of Bonaparte Lake, are capped by basalts in the manner shown on the map. These appear to rest directly on tli(! granites of the region, but they have been laid down from bearings and distant views only. The small outlier of Tertiary shown to occur to the north of the east end of Bonaparte Lake, was ascertained by Mr. McEvoy to con- sist of amygdaloidal basalt and brown dolerite. The Kuk-waus' Plateau, the Sil-whoi'-a-kun Plateau, the western pait of the Tranquille Plateau and Red Plateau, together form portions of a singlf great area characterized by a wide spread of Tei'tiary volcanic rocks. This it wiH be convenient to consider briefly from north to scmth, in the order above indicated. The Kuk-waus' Plateau, may be regarded, for purposes of description, as bounded on the south side by the upper part of the main stream ot' Deadman River and Hi-ak'-wa Lake. It has undoubtedly at one time ■] TERTIARY NORTH OF KAM LOOPS. 223 B been entirely covered by horizontal flows, which have also, in all pro- ' bability, extended across the hollow now occupied by Bonaparte Lake and connected, beyond the Bonaparte River, to the north-eastward, with the basalts of the Green Timber plateau. The surface had here. Levels of Uise as elsewhere in this region, lieen worn down to an approximate equality in elevation before the date of the eruption of the basalts, the base of which is now found at a heiglit of about 4500 feet on both sides of Bonaparte Lake, at about 4000 feet along the south side of the Bona- parte Valley near Young Lake, and at about 4600 feet near Granite iind Hi-ak'-wa lakes. The rocks underlying the basalts of the Kuk-waus' Plateau, are Xo sedimen- generall}'' granitic, but on the south side of the plateau older stratified rocks also occur. No evidence of the existence of any bedded Tertiary materials beneath the basalts, has been found in this region, and if any such occur they must be local and not of great thickness. The basalts fharactor of of this plateau are generally gray or brownish in colour, so far as observed, and offer no points of particular interest. They are occtasion- allj vesicular, but not often columnar, except toward the east end of the plateau, where this structure is more usual. Seen from Bonaparte Lake, they form flat cappings to the higher granitic hills, and as ob- served from the summit of Skoatl Point, the various, and now more or less disconnected remnants, of the basalt flows, run together in the dis- tance to form an almost perfectly level horizon-line. The western part of the northern outline of the basalts of Kuk-waus' Plateau, as shown upon the map, must be regarded as approximately correct only. All this region is covered with fallen timber and is very difficult to traverse. I)asalt rtows. Fig. 6. skoatl point from the west, about a mile distant. Skofttl Point, is a small volcanic outlier standing near the eastern Skoatl Point, margin of the Kuk-waus' Plateau, from which the basaltic flows, doubt- less at one time surrounding it, have been stripped away, leaving a tract of undulating hills composed of granite and old altered rocks, now i I 224 B BRITISH COLUMBIA. Sil-whoi -a- kun plateau. Near Caiibon Lake. Dome-like form of plateaw. more ox* less covered with drift deposits and dotted with lakes. From this, Skoatl rises very abruptly, with a steep conical form — somewhat narrower in its north-and-south than its east-and-west diameter. It affords a magnificent view of the frayed eiiatern edge of the basaltic plateau for many miles, and is itself a prominent and easily recognized point, which may be picked up from the summits of the higher moun- tains often at a distance of fifty miles or more. It is composed of a somewhat coarse-textured, dark-gray oli vine-basalt, with a finely developed columnar structure.* The columns average about a yard in diameter, and are curved in several directions, but with a general tendency to meet toward the apex of the hill. Those on the west side run from base to summit with a gentle sweep. There is every reason to believe that Skoatl represents the plug of an old vent, from which much of the basaltic material of the vicinity may have flowed out. The name Sil-whoi'-a-kun, though more restricted in its application by the Indians, may b" employed in the present connection to desig- nate all that part of the plateau to the south of that last described and to the north of Tranquille Lake. This is almost entirely covered with basaltic rocks. The rocks of its western edge, as they occur along the Deadman River, have already been noticed (p. 221 b). In the part of the region drained by Criss Creek, and along the upper valley of that creek, the rocks seen are all ordinary gray or brown basalts, often forming several superposed flows and occasionally columnar. In the valley in which Caribou and Tsin-tsoon'-ko lakes lie, the sheet of volcanic rocks has been cut through locally, exposing an iso- lated area of Palaeozoic rocks and granite. The basalts found in this vicinity are gray and blackish, not ofteii vesicular, and seldom dis- tinctly columnar.! Poison Hill, is a rather prominent bold spur of the eastern edge of this part of the basaltic area, rising nearly 300 feet above the low land at its base. It is chiefly composed of rudely columnar basalt, more or less amygdaloidal, with the vesicles filled with zeolitic minerals, but is capped by a similar blackish basalt with a laminated appearance due to nearly horizontal flow-structure. As seen from a distance, particularly ia a general view obtained from the summit of Pavilion Mountain, the w hole of this part of the plateau rises gradually to a wide doD>e-like form, of which the highest part is in the vicinity of Porcupine Ridge, in a manner highly suggestive of the belief that a great part of the basalts of the surrounding flowed out from, this as a centre. (Compare p. 219 b.) •Appendix I., No. 78. fAppendix I., No. 77. mr h TERTIARY OF SIL-WHOI -A-KUN. 225 B ^ The highest portion of the base of the Levels of base basaltic flows is likewise found near Por- "^ 'J'l'*"''- cupine liidge and Basalt Point of the map, at elevations of 5490 and 5400 feet respectively. From this vicinity, the level of the base of the volcanic materials declines northward to that already refer- red to near Hi-ak'-wa and Granite lakes, westward to about 3000 feet on the lower CD "I part of Criss Creek, and southward to even lower levels in the vicinity of Kam- J" loops Lake. No trace of Tertiary sedi- ments underlying the basaltic flows was 5 found in this region, except as already M noted along the Deadman River at its -.g west'irn end, but it is seldom that the '^ exposures are so good as to enaV)le it to ;| be stated definitely that beds of this kind ■f of small thickness may not occur. 1 ■s The most elevated part of the entire Povcniiine ^ Sil-whoi'-a-kun Phiteau is that at and ^''^»■• near Porcupine Ridge, where the height ijj attained is about 6000 feet. The summit g of Porcupine Ridge, though broken by 'p numerous minor irregularities, is in the 3 main nearly horizontal. To the south it •t is broken oiT abruptly toward the deep i vallejr in which Tranr(uille Lake lies. The ■^ rocks composing the ridge are chiefly 2 olivine-basalts of dark colours, verging on a black, and often lumpy and- irregular in g consequence of a fragmental or concre- 1 tionary structure — probal)ly the latter.* "= Some ordinary gray basalt was also ■^ found, and in two or three places areas of coarse brownish hornblende andesite with a lamination produced by flow-structure which dips at various angles irregularly, f The best marked occurrence of this rock is that forming a partly detached hill on m 16 •8eH Appendix I., No. 03. tSeo Appciulix I., No. (14. 226 B BRITISH COLUMBIA. A probable vent. Triinquille Plateau and vicinity. Near Lower Crisg Creek. IT filter Tran- quille Valley, the south slope, and tliis, as seen from the opposite side of the valley, much resembles the filling of an old vent or fissure of eruption. On the western flanks of the more massive rocks comprising the ridge itself, basaltic strata, often columnar, are seen, from the south, to rest upon the rocks of the ridge and to slope away from tiiem as a centre. These and other circumstances tend to show that Porcupine Ridge marks the site of one of the more important local sources of the great basaltic eruptions of the later Miocene. At the junction of Criss Creek with the Deadman River, the plateau runs out in a narrow and remarkab^ ■ bold point which may be called Split Rock. This is chiefly composvjd of rough basalt-breccia and is traversed in one place by a deep open fissure with vertical wallp. To the south of the region above described, is a large area of plateau chiefly drained by branches of the Tranquille River, of which the volcanic rocks of the Tertiary cover the greater part, as far south as Kami' ops Lake. To the south of Criss Creek and west of Porcupine Ridgt . a considerable district of this part of the plateau has not been examined on the ground. It is densely wooded or covered with fallen trees, but its contour, as seen from various points of view, and the mar- gins of the volcanic rocks which have been defined, indicate that it is probably occupied in the main by ordinary bacalts. The great quan- tity of large and small boulders of oli vine-basalt* met with in the val- ley of the Tranquille some miles above the fall, however, shows that a considerable area of rocks of this character must occur to the west of Porcupine Ridge. The summit of the plateau in the angle between Criss Creek and the Deadman River, on the east, at elevations of 3000 to 3.500 feet, iscom- poseid of blackish, basaltic rocks, sometimes very rich in olivine, but is so much covered with drift that they are seldom seen in place and their precise extent, particularly to the eastward, remains doubtful. After crossing the continuation of the cherty conglomerates of Copper Creek the country, to the Tranquille Valley, is chiefly characterized by basalt flows, both on the line of traverse by way of the Red Lakes and on that from the head of Copper Creek, but on both routes much of the ground is covered by drift. In the Tranquille Valley, a couple of miles above the fall, a white dacitef was found to form the lower slopes for 200 to 300 feet above the level of the stream. Overlying this are basalts and basalt-breccias to the level of the plateau on both sides. Following the valley down, •Apiieudix I., No. 70. t Appendix I., No. 70. miF •] TERTIARY OF T.' VNQUILLE PLATEAU. 227 B the dacite appears to extend nearly as far as the fall, but with this exception, the rocks seen on both sides are almost entirely basaltic, and chiefly consist of basalt-breccias, to the mouth of Watching Creek. The beds composing tliese are more or less lenticular, but the aggregate thickness is well preserved. They are nearly horizontal and frequently produce steep scarps and cliffs, which resemble both in their appear- ance and composition those met with to the north of Battle Bluff (p. 172 b) of which the beds seen here are the continuation. Near the mouth of the stream which comes in from the north side of Mara Hill, tliese rocks are underlain by the soft, yellowish, tuffaceous agglomerates, forming part of the subdivision designated as No. 6 in the Kamloops Lake section (p. 165 b). On the trail which runs eastward from the main valley of the Tran- Middle Fork- quille, crossing the Middle Fork and Watching Creek some distance Oreelf^^' '' "^ above their confluence, similar basalts and basalt-breccias are seen ; but where this trail crosses the Middle Fork, exposures of soft, yellowish, tuffaceous agglomerates, charged with fragments of brittle tachylite (?) and evidently representing those above referred to subdivision No. 6 are met with. From this point, a traverse was made up the Middle Fork and to I'latiau south the south side of Tranquille Lake. The summit of the plateau here i^ikr"^"'"' has an elevation of from 4500 to 5000 feet, and is more varied in the detail of its topography than might be supposed from distant views of it. The basaltic flows of which its whole upper surface appears to be composed, frequently form low plateau-like hills with steep broken edges. The rocks seen were basalts and olivine-basalts.* Along the upper part of Watching Creek, the volcanic capping of Tortiiny lusp tlie plateau appears to have been entirely removed by subsequent pro- Kiiwloui'ia '' o-'sses of erosion, and the stream flows over surfaces of the old Palu'ozoic i^'ikt-. rocks. From high points on its eastern side, it is evident that t'le base of the Tertiary volcanic rocks slopes gradually southward, and at about two miles above the entrance of the valley in which Pass Lake lies, they come down to the bottom of the Watching Creek valley. Below this point. Watching Creek, and the Tranquille River into which it Hows, nowhere cut down to the base of the Tertiary ; and the compara- tively thin covering of basaltic materials which occupies much of the plateau further to the north, in the vicinity of Kamloops Lake ,8 in- creased till it forms the seiies which has alreiuly been described in connection with the section in the vicinity of this lake (p. 173 n). It is thus evident, that near the present position of the lake, an original *Ap|)eiKUx I., No. 75. 15i II 228 B nRITISH COLUMBIA. An oripnal depreaHiun. Hilhif pikrite- ix»v|)hyrite. depression existed at the time in which the Tertiary sediments and volcanic materials were accumulated. This conclusion, resulting from the constitution anu thickness of the Tertiary rocks as a whole, is inde- pendent of any later change in relative elevations which may have tended still further to depress the country in the vicinity of the lakes. To the east of the lower part of Watching Creek, the level of the surface of the old rocks upon which the Tertiary was deposited, also rises rapidly, as will be apparent on comparing the level of the northern part of the Garde LaflFerty (with its small outlying patches of conglomerates) with that of the bottom of the lower part of the Tranquille Valky. The hill to the east of Watching Creek and north of Pass Lake, which was ascended and examined, is chiefly composed of pikrite-por- phyrites, blackish, greenish and greenish-gray in colour, and presentini; a peculiar spotted appearance. These are capped by blackish basaltic rocks. Opax Hill was not ascended, but it appears to be composed chiefly of basaltic materials about its summit, while rocks of the same character as those just noted may probably occur in its lower portions. The small detached area of Tertiary volcanic rocks shown to tlie east of Watching Creek, occurs in a tract of country rendered almost impassable by windfall. It was not actually reached, but from the character of the numerous loose masse i found to the south of it, is believed to consist entirely of basaltic rocks. Tertiary Outliers in the Vicinity of the North Thompson River. Indian reser- The most important of these detached areas of Tertiary rocks, is that ration on near the Indian village and reservation at the extreme north-east angle Thompson. of the map. This was particularly examined in 1877, because of the Basin of sedi- occurrence of coal in it. The Tertiary rocks here occupy a portion of rocks*-^^ t^P' trough of the North Thompson, and are hounded on both sides by ' the old rocks of the higher hills. The amount of drift in this part of the valley is very great. On the east side of the river, a few exposures occur of sandstones and shales, particularly along the small stream It8 area. named Coal Brook, but it is impossible precisely to define the area occupied by these rocks, which can be approximated to only on the assumption that they characterize the lower parts of the valley where the old rocks are not seen. On this assumption, the whole length of the Tertiary area to the east of the river cannot exceed five miles, while it may be much less. On the west side of the river, the only Tertiary rocks seen are gray and brown basalts, which occur quite down to the river-level nearly opposite the Indian village, and were also found on o»wiON. ] COAL-BEAHINO ROCKS OP NORTH THOMPSON. 229 H the lower slopes of the hills on that side to a maximum height of 620 feet above the river. The sedimentary beds in which the coal occurs, may of course underlie 'Jci'iiiToiice some part of the area in which only basalts are seen at the surface. A trifling amount of exploratory work has been done in recent years in the immediate vicinity of the coal outcrops at Coal Creek, but no 'dition has resulted from it to our general knowledge of the section, and it is improbable that any material addition to this knowledge will occur till boring operations shall have been undertaken. The sand- ijoiintf stones and shales show no traces of volcanic material in their constitu- '"^"''^'''"'J • ants, and it is probable that they represent an area of the Cold water series of the Tertiary, as previously defined. The basalts are probably referable to a much later date. The following description and section of the beds is quoted from my Bpscriptioii of report of 1877 (pp. 113b-114b.) " The area of this outlier, in so far as it can l)e defined by the section on the east bank of the river, is not great. It rests on the older crystalline rocks, forming a ridge about 600 feet high along the base of the tier of mountains which, rising to a height of 2000 to '' 3000 feet above the river, here forms the border of the valley. The length of the ridge is about two and a half miles, and it is where the little stream called Coal Brook cuts through it, that tlie Tertiary rocks are exposed, by the removal of the thick covering of boulder- clay and drift, which elsewhere shrouds it. The beds appear to form a syncline, nearly parallel in its main direction with the trough of the valley. " The following section, in descending order, includes nearly all the Section, beds seen in the brook channel. Some layers were measured, others estimated by the eye only : — Feet. In. 1. Sandstone, soft at least 2 2. Carbonaceous shale (5 3. Shale and sandstone 3 4. Cort/, shaly about 1 3 5. Hard clay C 0. Soft shale 1 3 7. Gray, fine shale, with fossil leaves 2 8. Coarse- and fine-grained sandstone 15 9. Hard, fine, gray clays 1 10. (Concealed) 10 11. Sandstone 2 12. Gray shales 3 13. Sandstone 2 Dip* Site for bor- ing. 230 U BRITISH COLDMHIA. Feet, tn 14. Soft, gray ahalo I .') ir». Coal 1 2 16. Sliale 'i 17. iSandntoiie and ohiily s^'ulgtones !l 18. C'Vf' V 1 1 •"> 20. CJray, uruinhling gandotoue 4 21 . Carboimot'oiis shale 1 in. to 4 22. Rusly, nodular suni'.Htonu 1 8 23. .Soft uindHtone in tain layers 8 24. Concealed 15 feet to 2<» 23. .Sandstone 4 2(1. Black shales 6 27. Sandstone 10 28. Shale, more or less carbonaceous, with a. little coal 4 29. Ironstone, nodular ,1 3f\ Thin-bedded clays, grayisli and brownish 2 8 iSl. (iray sandstone, generally coarse and ratlier soft. . 10 4 .32. Colli, shaly 2 .33. llrownish, sandy clays 6 9 34. Thinbeddeil sandy clays, rather hard about 20 .35. (,'oarse, pebbly sa»-'3tone about 8 3G. Browuish-gruy sandy clay, at bose 148 1 "At the base, the beds dip at an angle of 12^, further up at !•") , and again begin to dip at a lower angle at the summit. The direction of dip varies from N. 56° E. to N. 26" E. The lowest beds are first met with in .xscending the brook. Beyond the highest represonted in the al)Ove detailed section, a considerable gap occurs, in which the banks show no exposures. When next seen, the beds are poorly exposed, but one bank shows about twenty feet of sandstones and shales like those before met with, and includes two small seams of coal, the lower sev(?n inches, the upper nine inchc-s in thickness. These beds are doubtles-s the highest found in this locality. " It would appear, however, that in the sections, but a small por- tion of the entire thickness of Tertiary beds represented at this place, is seen. Their general character is much like that of those of other localities in the southern part of the province, the sandstones holding', perhaps, more coarse pebbly material than usual. Notwithsta,ndin^ this, however, there is no appearance of tumultuous deposit, and the coal-seams, though thin, show considerable regulaiity. The coal-bear- ing character of the formation appears to persist throughout the section, and a further examination by boring may at some time become desirable. OowMM.] COAL-HEAHIXO rocks of north THOMPSON. 231 a' The l)e8t locality for a bore-holo would probably be in the valley of the brook, at the lowest beds of the section." In 1892, Mr. MnEvoy revisited this localit}' and gives the following Later work , • -i. * <>1:i-. The Tertiary rocks of this vicinity have already been noticed, as far as the coal locality marked on the map (p. 108 is). Innnediately to tlie south of this, in the vicinity of Peterson Creek, the granitoid rocks are capped by several small basaltic outliers which are generally jitu- aied near the 3000-foot contour-line, but are not strictly confined to any particular level, resting as tliey do upon sloping surfaces of the older rocks. The apparent low dips by which tiey are affected, may probably represent the original inclination of the flows. At the road- crossing of Peterson Creek, these rocks are found at a rather lower level than usual and form a somewhat prominent little hill. The basalts are generally blackish or gray, and of the ordinary type Their thickness is not great, and they appear to rest directly upon the gran- itoid rocks, and to lie altogether beyond the margin of tlie old depres- sion in which the water-bedded materials iiolding the coal have been laid down. K much more important Tertiary area, with which the outliers just noticed have evidently at one time been continuou.s, is that which runs southward from the vicinity of Separation Lake to the head of Stump Lake, with a length of thirteen miles and a half and a maxi- mum breadth of about six miles. The northern part of this area appears to consist entirely of basaltic flows of the usual character. The eastern edge of the volcanic rocks gerterally forms a well-marked escarpment at an elevation of about 3000 feet, overlooking the long ■s M TERTIARY SOUTH OF KAMLOOPS. 233 li vdlley in. vhich Sliuniway and Trapp lakes are situated, but to the westward, the level of the phiteau rises gradually, though irregularly, till tK3 basalt rocks are found in some places at heights exceeding 4000 feet, '^n this I'egion, to the north of the head of Moore Creek, the edge of the basalts often ceases to he marked by a distinct escarp- ment, and a.f. the country here becomes thickly wooded their boundary is drawn with less precision than elsewhere. The southern part of the area is characterized by a greater thickness, l'n (lesoi'ibed an eoming from the vicinity of Stump Liiki'. lil ■] TERTIARY SOUTH OF KAMLOOPS. 235 H The area of Tertiary rocks shown at the edge of the map, to the east of Napier Lake, appears to consist entirely of basalts. Near Trapp Lake, where massive dioritic rocks are immediately overlain by those of the Tertiary volcanic series, the former are frequently decomposed and soft, the felspar being more or loss com- pletely kaolinized and the hornblende replaced by chlorltic or talcose minerals. On the east side of Napier Lake, the Nicola rocks im- mediately below those of the Tertiary, are decomposed and redtlened, and often highly charged with iron pyrites; wliile at the north-east angle of Stump Lake, the older diabases are very nmch ^hatteied and (iolomitized. At the last-mentioned place, the alteration produced in the appearance of the older rocks is so considerable tiiat the line be- tween these and the Tertiary volcanic rocks was drawn with some difficulty, and it is probable that small areas of dolomitized sandstones like those previously described on the Nicola \ alley (p. 195 b), may here, though in a more or less comminuted state, still rest upon the old broken surface. This dolouiitization of the lowest beds of the Ter- tiary has been noted in several places wheie these rest directly |Mjr> the old surface. To the north of Trout Lake, another small area of basalt ^^ as found. This forms escarpments toward Trout Lake and also on the hills to the south of Stake Lake. It is believed to be entirely separated by erosion from the larger basaltic area to the eastward, but this is not (juite certain. To ^he south west of Trout Lake, at an elevation somewhat greater than the last, a small patch of black basalt, containing some granitic fragments and showing How-structure, was found by Mr. McEvoy, In the upper part of the Meadow Creek valley, about midway lietween Trout Lake and (irreenstone Creek, hard, white, gritty, cal- careous clays are seen in several places, which may possibly bo of pre- glaoial age, and if so would be referable to some late stage of the Ter- tiary. These clays must in any case be of small thickness and cannot continuously occupy any considerable area. It is presumed that they are in reality a post-glacial lake deposit, and no attempt has been made to indicate them on the ma)). Tertiary Rocks on the Upper Part of Guichon .Creek and thenre to Axhcroft. The northern edge of the principal area of Tertiary rooks here referred to, of which Savona Mountain is a part, has already been noticed in connection with the sections near Kamloops Lake (p, 17'-' ii)- Kock-H ini- iiirdiati'ly bi'low till) Turtiiuy. Xi'iir Tiout Liikf. ^[|'ivll(lw• Crcfk cliiys. olidii (.'n'i'k. mmi 236 B BRITISH COLUMBIA. Tiiffaceous strata. Meadow Creek and Mamit Lake. Coiigloiuerato bouldern. «Hi The outline of the south-eastern part of this area, as shown on the map^ must be considered as an approximate one, for the whole of this country is so heavily covered with drift deposits that outcrops are seldom found. The outline given to the Tertiary volcanic rocks is thus largely based on the contour of the surface, taken in connection with the distrib-Llon and abundance of large blocks and boulders of these rocks. The exact point at which the line crosses Guichon Creek here, is, however, particularly indeterminate. On the upper part of Guichon Creek, west of Toon-kwa Lake, low exposures were found of soft tuftaceous rocks, whitish and yellowish, resembling those described on the Deadman River (p. 221 a). These are supposed to underlie the basalts which elsewhere appear to charac- terize the whole tract drained by the northern sources of Guichon Cieek, and are often extremely abundant in the form of loose masses and boulders. These generally present nothing unusual in their appearance, but are of brownish or gray colour, and not infrequently vesicular. The southern extremity of these rocks, north of the moutli of Meadow Greek, consists of olivine-basalt. Further south, to the east of the upper end of Mamit Lake, while the rocks actually seen appear to belong to the Nicola formation, some specimens of a material rich in fresh olivine and much resembling a Tertiary rock, have been collected. It is, therefore, possible that a Tertiary outlier may occur near here, and in fact, not improbable that several small patches of Tertiary volcanic rocks may yet be proved to exist in the country to the north-eastward of Mamit Lake and between the lake and the south side of Meadow Creek. The volcanic rocks of the Nicola formation are themselves here so little altered, that in hand specimens it is not always possible to distinguish them from those of the Tertiary. To the west of Mamit Lake, a small patch of Tertiary volcanic rock was found by Mr. Amos Bowman. It forms a perfectly flat little elevation, the limits of which have been fixed by distant views and bearings only. It may be added, that the occurrence of loose lucces of con- glomerate resembling that of the Coldwater series, in the valley of Guichon Creek above the mouth of Meadow Creek, suggests the possible existence of outcrops of this character to tin north-westward, in the drainage-basin of the stream. It may well be, however, that these have been carried southward during the glacial period from tho conglomerate area to the west of Savona Mountain, or even from that of the vicinity of Copper Creek. •1 TERTIARY WEST OF GUICHON CREEK. 237 B Forge Mountain and the hills attaching to it on the west, are chiefly Forge Moim. capped by basaltic rocks, nearly horizontal, but varying slightly in the '■'^'"■ Ifevel of their base from place to place. Toward Mount Glossy, the base-level of the basalts rises very considerably. The summit of Forge Mountain itself, was found by Mr. McEvoy to be largely, perhaps entirely, composed of a gray glassy basalt, containing fragments of granite and other older rocks. Cinder Hill is capped by basalts and basalt-breccias. The volcanic rocks on and about Mount Glossy, are chiefly brown Mount Olosny and gray basalts, often vesicular and occasionally brecciated. Between c,.,.,.i;.' Mount Glossy and Barnes Creek, the rocks met with are somewhat more varied, comprising basalts, red porous eruptives without macro- acopic characters and gray tuffs. On the north side of Barnes Creek, similar materials are found, with the addition in one place of a pikrite- porphyrite,* and at the base of the section of a small thickness (observed by Mr. ]McEvoy) of soft basaltic tufi\ The detached area of Tertiary volcanic rocks that overlies the Mica-ijorphy- ntc near Ash- Cretaceous to the west of Barnes Lake, near Ashcroft, is a peculiar croft. mass of mica-porphyrite, very homogeneous in its general character, but varying a little in appearance and hardness from place to place. It forms a rather prominent low hill on the side of the wide valley, and, as viewed from a distance, shows an appearance of massive bedding parallel to the general slope of the hill, indicating the existence of a pre-Tertiary depression near that now occupied by the river. That this rock here represents an outlier of a once more extensive flow, is shown by the fact that, a couple of miles further south, a narrow selvage of the same material! is found on the hillside, resting upon the FlO. 8. TERTIARY OUTLIER SOUTH-EAST OP' BLACK CaSoN. re. Crctiiceous. //. Mioa-poi'pliyrite. c. liusaltic tlnw, separated from the luBt liy a perioil of (Icniulation. slopintr and denuded edges of the Cretaceous rocks and capped by a Ttx icliition horizontal bed of columnar basalt. The mica-porphynte is here ' ApiieiuUx I., No. (W. t Appendix T., No. 44. 238 B BRITISH COLUMBIA. Granitic rock» of Const Ranges. affectod by a well marked flow-structure on a small scale, parallel to the inclined surface upon which it lies, and its upper surface has been levelled off by denudation between the time of its eruption and that of the basalt. Another small occurrence of the same rock, was found at the south edge of the Cretaceous, about a mile back from the river, but this is in all probability merely a dyke. Plutonic Rocks. The granitic rocks of the Coast Ranges, to the west of the Fraser, may be characterized briefly as a group, and require no detailed notice. They consist almost exclusively of gray granites of medium coarseness of grain, passing, in their composition, from biotite-granite through biotite-hornblende-granite, to forms in which hornblende pre- ponderates, and which may be named hornblende-biotite-granites. The biotite-granites are the most abundant, and thosri in which horn- blende is largely represented are not found to characterize large areas. Their charac- ter. Many local variations in texture are of course found, but on the whole, these granites are very uniform in character. They seldom weather rusty, while the schistose rocks associated with them almost always do so, and thus the ma.ssive granites are pretty easily distin- guished, eyen at a considerable distance. The outlines given to the granitic areas in the Coast Ranges, depend largely on such definition, re- sulting from examinations and sketches made from the several high points which were ascended. The actual forms of the mountains are often largely dependent on the nature and direction of the jointage planes, by which the granites tare aiTected in an unequal degree in var- ious places. About Klow-a Mountain, the jointage was noted to be particularly bold. Pegmatite veins also abound in some localities! and in other places the granites are found to be cut by numerous dykes, of which the more characteristic appear to be divisible into two classes, viz., gray dykes consisting of quartz-mica-porphyrite or of mica- porphyrite and dark brownish or black, basic dykes.* Dykes of the last-named character, were observed in places near to the summit of Stsin Mountain, to have a.ssumed a foliated ciiaracter as a result of subsequent pressure, becoming amphibolites. Both classes of dykes also cut the schistose rocks associated with the granites. Foliatfcl gran- The granitic rocks aro frequently more or less foliated in their struc- ""*• ture, passing into forms wi ich maybe called imperfect gneisses, but every giadation is found, in sou^e places, between these and the massive Dykes, •Appendix I., Nob. 03, 94, 95. '•J GRANITIC ROCKS OP COAST R.VXGBS. 239 B granites, from which they appear in most cases to have been produced by pressure. Such rocks are most abundant, as a rule, near the contact of the granites with the distinctlj' bedded Pala-ozoic strata, which in some phvces occur as isolated infolds in the granites ; and it is pro- bable in other cases where well foliated granites are met with, that the upper part of a compressed syncline, which has originally included Paheozoic rocks, has since been removed by denudation. It is not always possible, however, to separate the highly altered Associated bedded rocks, where these have passed into crystalline schists, from "'cks"'"' '' "^ the associated materials which are believed to represent foliated gra- nites. In these cases a separate colour appears on the map, but this luust be understood to indicate merely such doubtful rocks, and not to represent a separate formation. It will also be understood, that the outlines of these gneissic or foliated bands are necessarily indeterminate, and that in many cases the distinctive colour is employed rather to in- dicate the existence of such rocks than to define their actual extent. These remarks apply to the Botanie, Scarped and I;ytton Slountains as well as to those of the Coast llanges. An examination of some limited areas, might easily lead to the be- ProKaMy not lief that schistose and foliated rocks of the kind above described, con- ri,cks. stituted representatives of an Arclnean series, and it is of course pos- sible that remnants of such a series may exist here ; but there is, in my opinion, no sufficient evidences for such a conclusion in this particular region. In the Shuswap series of the Selkirk and Gold ranges, the circumstances are different, for there, rocks similarly crystalline in character are found unconfoi'mably beneath Cambrian strata and are interbedded with limestones and quartzites. The following notes on rocks of the character above referred to, in the Coast Ranges, may be added here : — Near Kl-ow-a Mountain, and just beyond the southern edge of the ^ear Kl-ow-a map, a narrow zone of blackish and gray micaceous-schist was found, l^I"""*'''"- -ko Lake, a small area of gray biotite-hornblende- Tsin tsndn'-ko granite occurs. The area of granitic rocks indicated on the map to the east of Bona- f econouiic importance. Near Edwards Creek, another plutonic msiss enters the area of the map from the east. This is a gray, to pinkish-gray, rather coarse-giainud rock, much jointed, with numerous blade-like and twinned felspaf crystals, considerably decomposed, and often containing uiuc-h iron- pyrites in scattered grains. It has been microscopically examined by ]\I v. Syenite carry- Ferrier, who describes it as a somewhat porphyritic syenite.* Its mggold. eastern edge, in some places, where in contact with the surrounding rocks, becomes a diorite Specimens of its pyritous and rusty portions subjected to assay, afforded traces of gold (p.312 b). It evidently repre- sents a truly intrusive rock, and the stratified materials in its vicinity are again found to be much altered. Three miles south of Edwards Creek, and also on the east side of the North Thompson, ' small mass of greenish-gray diorite appears in the bottom of the valley, but the detrital deposits prevent its precise tiefinition. The peculiar and somewhat diversified mass of crystalline rocks which forms Battle and Cherry bluffs on Kam loops Lake, is elsewhere de.'Jcribed in connection with tlie Tertiary volcanic rocks of tlic vicinity (p, l"i8 b) of which it is believetl, at least in great part, to have constituted the vent. To the south-cast of the Cherry Bluff exposures, after an interval of about three miles covered by Tertiary volcanic materials, rocks of the same kind arc again found in the ridge named Coal Hill and Coal Hill on the map. These are gabbros and dark diorites, coiitainiiij; \'cini ). some mica.f Further to tlie eastward, near Peterson Creek and Separation Luke, in the same area, these are replaceil by fine-grained gray granitoid rocks, and it is possible that plutonic rocks of two ilis- tinct periods are here represented. In some places, the rocks of this area, which is about ten miles long in all, have suffered considerable local alteration and decompositiiin> resembling that which is seon to have affected the rocks of Ciien y Magnetite. Bluff. At or near the west c tge of these rocks, "t their northern extremity, thin veins of mag» et:^) were found by Mr. McEvoy. •/VpiMidix I., No. 8!». fAnnual Reiwrt, Geol. Sur. m., Vol.V. (N.S.), 1). (K) It. ] GRANITIC ROCKS SOUTH OF KAMLOOPS. 247 B ;8 of two dis- On the edge of the mass overlooking Edith Lake, a very coarse diorite, containing viiagnetite in large crystals, was observed to occur. About seven miles to tlie southward of Kamloops, the northern end '"/Jl^''^' ^'''t of one of the largest granitic areas covered by the map is found. This Cri'fk. area runs southward by Trout Lake and parallel to the direction of Moore Creek, to the north shore of Nicola Lake, with a tot d length of nearly thirty mi'es. It is identified throughout with a rather high and somewhat broken plateau country, and except where overlapped by Tertiary volcanic rocks near its northern end, is everywhere found to be surrounded by rocks of the Nicola series. The eastern edge has been pretty accurately deteiuiined, but much of its western outline must be regarded as approximately correct only, as shown on the map, this part of the region '.eing in general not only thickly drift-covered, but also heavily wooded and dithcult to explore. Wherever examined, the rocks of this large area appear to be very l/itlmlujiicully uniform and homogeneous in their character, consisting as a rule of gray biotite-hornblende-granite of medium grain, generally with 'i con- siderable, and sometimes with a rather large quantity of quartz. True biotite-granite also occurs, but no highly liornblendic granites or diorites have been observed, except in the instance of a very coarse diorite, locally developed, near the west end of Trout Lake, liut which may not have the same date or origin as the main granite mass. The granite is .sometimes more or less distinctly foliated, for a Cont.ict narrow width near its contact with the stratified rocks, but this elTect is (]uite evidently due merely to the conditions of contact, which are elsewhere referred to at greater length (p. 1*29 ii). In this area, the granite was iu several places found to weather easily and to become superficially decomposed. This tendency, when in eoiaicction with well marked jointing, gives rise to miniature tors, and to the jiroduc- tion of ^'reiit numbers of boulders which still remain nearly in place. Granite surfaces breaking up into such boulders, were particulai'ly noted on the i.lateau between Moore Creek and the head of Clapper- ton Creek. In the neiglilH)urhood of the edges of the granite, the stratified Divilopnieut rocks, are frequently penetrated by quartz-veins, and it is highly v^i',',"'"^ '' probable that the n.etallife.rous veins of the vicinity of Stump Lake, are connected in their origin with the production or intrusion of this neighbi uring granite ma.ss. About Campbell Creek and Trapp Lake, another important granitic Camiilifll area is in part covered by the maji. The granites composing this area 'ii'i'pii Lal«'. are not dissimilar in appearance to tho.se of the last, but are somewhat jilii'iiiiiiii'iia. ■!■ 248 H BRITISH COLUMBIA. more hornblendic, being either hornblende-granites or hornblende' biotite-granites — in some cases .possibly (juartz-diorites.* The rocks generally, differ little over the whole area, but on the west side of Trapj) Lake, near their contact with the stratified materials, are repre- sented by a black-and-white diorite. The character of thft contact of these granites with the rocks of the Nicola formation is noted on another page, as well as the fact that they include, to the east of Newman's, some much altered remnants of the diabases of that series (p. 12;3b). Near DouglaB The granitic area to the north of Douglas Lake, is occupied by a nearly homogeneous mass of medium to somewhat coarse-grnined gray granite, which is in some places cnaracterized Vjy a preponderance of hornblende, in others by that of mica. It was seen in several localities to be cut by conspicuous parallel jointage planes, in such a manner that it might easily be quarried in well chosen spots. The fine am- phibolites and argiilitcs which appear to surround this nuws, are con- siderably altered and disturbed, and are traversed by numerous small quartz veins. GLACIATION AND SURFACE DEPOSITH. Iitipoitaiicc of Hurfiicc depoHits. Economic featurcK. The character and arrangement of the surface deposits whicli cover the older rocks in this district, as elsewhere in British Columbia, are to bo explained chiefly by the events of the glacial period. It is thus important, even from a strictly practical point of view, that the nature of the changes brought about during this period should bo understood. It is nevertheless the case that the history of this period, owing tf» the indeterminate character of much of the evidence relating to it, is as yet imperfectly known, and considerable diversity of opinion prevails as to the explanation of sunie portions of the evidence. While diffi- culties of this kind yet remain even in the little-diversified and closely studied eastern parts of North America, and in Europe, it is not sur- prising that they should also attend the history of the same period in British Columbia, where tlie varied and bold relief of the surface tends greatly to complicate the investigation. The i-esearches carried out in this province have, however, already resulted in the discovery of some interesting facts, which are not only important locally but bear also upon the general questions of glaciation. The most obvious effects of the period of glaciation on the district here referred to, are those connected with the transport and distri- bution of diUjris or , 'drift,' which lias gone to form the l)oulder-clay, ' Ai)i)eii(lix I., No. 87 -1 GLACIATION AND 8UHFACE DEPOSITS. 249 n has been left in .'■■ shape of moraines, or appears as the niMterial of the numerous terraces which are everywhere so cliaracteristic a feature of tlie country. "The great .accumulations of loose material formed at this time aie also responsible, though less directly, for chiiiigcs in the drainage system of the country, by the blocking uj) of pri'-glacial river- valleys, leading to the diversion of streams or the formation of lakes. From an economic point of view, the geology of tlie glacial period has some features of special interest. It has deter- niiiiwl the character of the soil, and must also be taken into account ill the investigation of the sui)erficial deposits in which gold [)lacers are worked." * In a paper published seme years since in the Transactions of the ]?oval • rpvinus I r I J V lOVlow lit ■Society of C-i.nHcla,f on the Later Phjsiographical Geologv of the Kliij liixtory Rocky Moi'jitain legicn in Canada, with special reference to Jhangt-s Cdlumliiii. in Elevation and the History of the Glacial Period, I have endeavoured to give a coniprcJiensive review of the events of the glacial peiiod in Britisli Columbia as a whole, and to connect these with those of the adjacent area of the (ireat Plains. This review was based upon the very numerous observations made by me in various parts of the whole region descril)ed, most of which are recorded in the report^ of the Geological (Survey. Tlie method of treatment a( )j.tcd in it is, however, intimately connected with certain hypotheses as to the course of events, some of which must be considered as still open to question, while all are held subject to modification in the light of new facts. In this Rc^port, it is proposed to record the principal ob- served facts within the district covered by the map to which it I'elates, with as little reference as possible to the theoretical e.xplanations which these may appear to warrant. To a certain extent, howe\er, the sequence of events during the period of glaciation is so well proven, lis to admit of the grouping of the observations under headings ap- pn).\imately in theii' order of occurrence. To provide (he reader with some scheme of events, with which the HiKtmical facts sub-seipiently grouped by kind may be comparetl, a provisional sli/rL.Ji,,,!, outline of the glacial history of the Cordillera will in the first place 1)6 presented. Though at the time it was written this appeared to accord with all the observations collected during many yeais of work ill th(! region, it may probably be already subject to modification in Sniijcct to some particulars. Care will be taken to note the fncts which appear •'■^i-i'"'- to conflict witii its tenor, althougli I am not yet in possession of a siillicient body of such facts to induce me to undertidio a general revibion of the scheme. * Kcpiirtdf I'liiKccsM, (ico). Surv. Can., 1H77 "K, p. t;t;t ii. t Vol. VIII., 18JI0. Early maxi- inuin of glaciation. C<)i'vestigation of the southorn portion of the In- terior Plateau oi the provincii. Several hypothec es at first preseiitod them.selves as likely to expla'n the existence of 'his general (as dis- tinct from the obviously local) glaciation of the region, but these were gradually eliminated or modified at latnt' dates, and the conclusion above stated was arrived at. In 1887, in the course of an exploin- tion of the Yukon district, evidence was found of the north-westward extension of the same great ice-mass, and its limits were approxi niately ascertained in that direction also. Having thus discovered the area of this great glacier, it was pro- posed to name it the Cordilleran Glacier, in order to distinguish it from the second and still larger ice-cap, by which the north-eastern part of the continent was at about the same time more or less com pletely covered. f The Cordilleran glacier, as thus defined, had, when at its niaximum development, a length of nearly 1200 miles. The main gatheriiii;- ground or nc'vd oi this ico-sheet, was contained appi-oximately between the 55th and 59th parallels of north latitude, that part of the ice wliieli flowed north-westward having a length beyond these limits of :'>-J0 miles, that which floweil in the opposite direction a length of ahoui 600 miles. When at its greatest, a portion of its ice also passed oil' laterally by gaps transverse to the Coast Ranges, and filled the v.idc valley between Vancouver Island and the mainland. The ice theio divided and flowed in opposite directions, as the subsidii.ry. but yet large, glaciers of Que ,'n Charlotte Sound and the Strait of (Jei.'i,dii. Ice from the main iiicr clc glace does not appear to have crossed iln> Rocky Mountain range proper, on the other side, although considenil.le local glaciers were at the same time developed on the north-eastward slopes of this range. That portion of the Cordilleran glacier which moved south-eastward along the Interior Plateau of British Columbia, is now known, t'lom • Septemlier, 1890. p. 163. t Geol. Miig., AujpiBt, 1888. ■] GLACIATION AND SURFACE DEPOSITS. •251 B ation, from as prepai-ed of the West •e phase of of glacier ng and stri- obtaineil at 1 of the III- b presented eral (as (lis- ; these were i conolusiiiii an exploiii- ;h-westwanl re approxi- it was pro- stinguish it orth-easteni or less com" bs niaxiimim I gatlieriiig- ,ely between he ice which imits of •TiO ;th of alioui io passed oil' led the wide he ice there i.ry. but yet of {je<."f;ia. crossed the considenil/le I'th-eastwanl uth-eastwiud known, from numerous observed instances of striation crossing high points, to liave covered the summits of isolated mountains of 7000 feet and more in height ; a circumstance which implies that the ice reached a general thickness of 2000 to 3000 feet above even the higher tracts of the plateau, while it must have attained a thickness of over 6000 feet above the main river-valleys and other principal depressions of the surface. During the maximum of the Cordilleran glacier, it appears that the Cordillera, ^ ,.,, . . • 1 1 1 1 • , • elevated. Cordillcrian region stood at a level considerably higher than it now does, while an important part at least of the Great Plains was proba- bly depressed to such an extent as to admit waters in connection with, and at the level of. those of the sea. The eventual retreat of the Cor- diiieran glacier was contemporaneous with, if not caused by, a subsi- Siilwidtucc. - dance of the mountain region. The first effect of the decay of the great glacier, may be supposed to petay of ^reiit ,., , . ,. ■- , • ■ , ice-sheet. have been the production or lakes upon its surface or within the central part of the .southern portion of its area, in the relatively dry region of the Interior Plateau. Along the borders of one or more such englacial lakes, terraces, composed of material resembling bhulder-cia}-, were formed on projecting highlands.* The best marked and highest tm-race to which this origin is attributed, has an elevation of about 5290 feet above the present sea-level, and this terrace (or others at or about this level) has now been recognized in a number of places.f Such 'englacial' lakes may have continued to increase in size, and to become lower in level, for some time, while a general subsidence also progressed. There is further some evidence to show that, after the final draining of these lakes and as the great glacier retreated from the Interior Plateau, it was followed FdllowinR- by gradually deepening water which was in communication wiih that *'" '""'Keiite- of the sea. The boulder-clay deposit of the Interior Plateau is believed to iiave been formed principallj during this retreat, at, or in water contiguous to, the retiring ice-front. The lower boulder-clay of the littoral was laid down under similar circumstances, 'but at a some- what earlier stage in the glacial decadence, and as the submergence became deeper, stratified interglacial silts were formed above it in the same region. The next change is .supposed to have been a reelevation of the Kcilmntinn Cordillera, during which most of the higher terraces of British Columbia |"|!,xim'i',','i'i"of were formed. Some further evidence of ibis rise i.s afforded by the glaeiatmn. removal at about this time of much of the previously formed bouklc.r- * These muHt at the time iiave reseielileil the iiunatalK of ( Jreenland. tSee, however, in tlii.s eoiineetioii, \i. L'4",l ii and funt note to ]). '2H'2\i. '>n2 URITISH COLUAIHIA. 'SfKIOlHl s>ib- ^siilenct! -id ixjrioc ta- bility. Whit." Silt /oniiatioii. Filial riitreat of glaciorH. clay from some of the larger river-valleys.* The laud probably stood as high as (and possibly higher than) it now does relatively to the Pacific, and in consequence of its elevation and the severe general con- ditions of the climate of the period, it became again covered to a considerable extent by glaciers, which, however, were as a rule, of a local character and in evident relation to the various mountain ranges. Following the maximum of this second period of glaciation, came apparently a second subsidence, less in amount than the first, but sufficient to depress the Cordilleran region generally, to a level about 2500 feet below that which it holds at the present day. At this stage, and while glaciers of considerable size still occupied the mountain- valleys, and the position of the nrrr of \he former Cordilleran glacier was probably held by an ice-cap of some size, the land remained nearly stationary for a long interval, and remarkable and important silt deposits, well bedded and of considerable thickness, were tranquilly laid down in different low tracts scattered along the Cordilleran region for a length of some 1200 miles. These deposits, the wiiter has in previous publications referred to as the Whiti'. Si/ts, and as observations accumuatod. ii at length became evident that these silts possess more than a local significance. They appear, in fact, to constitute a well marked formation, characterizing a definite and long maintained stage of stability in the glacial history. In the various more or less com- pletely separated basins in which they occur, their level is so nearly identical, as -lonarriitly to show that this must be referrei. to a comi.ion cause, which it is believed, in consideration of all the circumstances, and particularly in view of the vast area which the obsei;vations here referred to cover, can have been no other than the level of the sea at the time. No morainic or other accumulations have been found, such as to account for the production of lakes, in which these silts might lie supposed to have been deposited, and had they been formed in .separate lakes, held in either in the manner suggested or by glacier-dams, they would, in a region of such bold relief as the Cordillera, be expected to occur at very different levels in each basin. The evidently somewhat rapid retreat of- the already reduced glaciers of the second period, was apparently not in relation to subsidence of the Cordillera, but, on the contrary, seems to have been contemporane- ous with, or was soon followed by, a progressive movement in elevation. It is supposed that this final decay of glaciers occurred chiefly in con- nection with a general amelioration of climate, by which the close of the * Thf dato aosiinied to thi« rwnoval, deiwiids on the exigtenoe and relationg of the silt dejositu next alluded to, in the same valleyH. ] STRIATION AND SCORING OF ROCK SURKACKS. 253 H [glacial period as a whole was brought about, as to the cause of wliich no opinion is here offered.* It is worthy of note, that most of the long fiord-like lakes of the Latest move- mounti'in regions of British Columbia, can be shown to occupy portion:* of the abandoned beds of the glaciers of the stage of the White Silt formation. To the elevation which began about the time at wMch we have now arrived, the draining of the White Silt wa'er, together with the formation of all the lower-level terraces, is supposed to be due. There appears, however, to have been one well marked pause, dui-ing which the littoral, at least, was at a height about 200 feet lower than it now is, and tiiere is in addition some evidence of a succeeding movement in elevation of several hundred feet, which, if it occurred, constitutes the last important change uf the kind in the region, t STRIATION AND SCORING OP ROCK-SUUFACKS. The direction of motion and thickness of the ice-mass of the Cordil- Diititiniiof leran "lacier, have been determined chieflv on the evidence of glaciated ")"^f''\''''"ort, (ieol. Survey, vol. VII., p. in a) corresi)oud, the latter being liigh \ni, and far in towards tlie eentral iiere region. Tlie possiliility of ni'rriil jrreat oscillations in temperature is by no means excluded by the facts .-fo far ascertained. t Of. Canadian Naturalist, February, 1878. ! i 254 B BRITISH COLUMBIA. Above 3000 feet. of placing them. The directions of striation stated eie in all instances true bearings : — (1). GLACIATION NOTED AT LEVELS ABOVE 3000 FEET. Locality. Height I above seft, i Direction, ill feet. I Plateau between North Thompaon Rircr and Deadman River. South of BonaiJarte Lake (Skoatl Point) . . 2 miles E. of Young Lake ((■) miles N. K. of Deadman Lake) (3 miles westward from Tsin-tsoon'-ko Lake) Poison Hill 1 mile E. of Caribou Lake \Basult Point) Near Porcupine Ridge 3J miles south of Tranquille Lake 4t}40 S. 3,5° E 6840 S. 37^ E 4170 S. 19° E 4220 S.30°E 6220 S. 34° E 5370 S. 41° E 6810 S. 48° E 6840 S. :j5' E 5920 S, 39° E 4830 S, 40° E Plateau bettveen Thompson and Nicula Vallei/s, and Valley which coniieeta Nicola Lake and Kaiiiloops. Ci miles east of Ashcroft ]Nortli part of Mount Glossy. (Cinder Hill)... Between Pukaist and In-ki-kuh' Creeks, (Spaist Mountain) Plateau 8. W, of Spaist Mountain Choo-whels Mountain -. . . . (Plateau 14 miles S. of Kamloops) Edge of high plateau 2 miles ,S.S, W, of Separation Lake 3 miles N. W. of Head of Stump Lake Little Timbered Hills Between Clapperton and (iuiclion Creeks Douglas Plateau. 2 miles E. of Stump Lake 4 mile X.E. of (Jlimpse Lake : abt. ;«00 2 J miles east of last \ 4030 Other Localities. Meander Hills (Niooamen Plateau) Lytton Mountains (Mount Murray) Pass N.VV. of Mount Murray. Trachyte Hills. (Arrowstone Hills) (Sunnnit E. of Paul's Peak) . . 3240 mat) abt, f)20() ()S80 5480 6200 5500 3520 S. 55° E, S, 40° E, s, r>ir E, S. 13° E, S. 28° E. S, 27°E, S. 30° E. S, 28° E, S, 27° E. s, 3r> E, S. 31' E, S ()° W to S 27" W, S. 20'W, S. 15° E. S. 35° E, S, 15° W. S. 9°W. 8, 18° E, S. 12° W. S, 1.3°E. H. 2.3° W. S. 10° E. abt. S. 20°E. .S. 51"E, S, 35° E. S, 51° E. D.WJOII. ] BTRIATION AND SCORINO OF ROPK SURFACES. 255 B (2). GLACIATION NOTED AT LEVELS BELOW 3000 FEET. Below 3000 feet. Locality. Niirtli Thompson River above Indian Reservation Inner Valley, ni'ur Kdwanl.s Creek ... Ea.st side Stinnj) T>uke, north end / .\l)()ve and behind Battle Bluff, N. of Kainloops Lake Hihs smith of Seinlin Valley '.'(MKI feet above Fraser River, \V. side, 4 miles H. of Lytton Direction. 8. 2°E. X. *r w S. 30' E. abt. S. In explanation of the observations included in the above list, it may Xmiiber of be stated, in the first place, that the small number of these referring to >ij«fr^'ati<"i« ' ^ ' " above and levels below 3000 feet as compared to those at greater elevations, af- below 3U0o . . . . feet fords no true index of the relative frequency with which glaciated rock-surfaces occur above 'j,nd below this plane. If all the glaciated surfaces met with below 3000 feet had been duly entered, probably a hundred observations might have been recorded, V)ut, as a rule, glacia- tion met with at such lower levels was not specially noted, b "ing obvi- ously so much affected by the bold relief of the country, and by the tendency of the ice to follow tiie main troughs in the directions cf their lengths. At high elevations, on the contrary, glaciation was always sought for, and carefully noted when found, though the dis- integration of the rock-surfaces is frequently such that no distinct St "tion, but only the general forms of the projecting parts, still re- maui. In the examples collected in the list, however, no merely general evidence of this kind is included. In nearly all the recorded instances of glaciation at high levels, the directions have also been obtained either from approximately flat surfaces, or from .slopes at right angles to tlie general direction, as it is notable that on oblique ]„fl, „.„(.,. of slopes the direction always varies, to an indeterminate amount, local features c, I. 1 1 1 !• ■ 1 1 . . , on direction, ooiiie of the recorded directions, however, even tho-ie obtained on points of very considerable height, were still obviously influenced by the vicinity of more elevated tracts or by that of important depressions. In such cases, a study of the local condition.^ nearly always shows that the ice was affected by a tendency to veer away from the elevations and to slant down towards the hollows. To determine all the local defl -xions thus produced in a great mass of ice which moved across a broken country like this, would be an almost endless task, even if the instances of well-preserved glaciation were much more numerous than they are. In a general way, it may be i>articularlv stated that the ice ai)pears to have moved in more or less complete '^' lower levels parallelism with the larger valleys below the 3000-foot contour, follow- Diffeiviitiiil inotiun. Striatioii due to retreating edge of ice. Average direction. 256 n imiTISII COLllMltlA. Correspon- dence with main trend of Interior Pla- teau. ing their trend in the senae which agrees in each case moat closely with that of the main direction of its motion. In this respect, tliese larger valleys appear to have acted, in imposing their direction on tlit> mass, much as the rifling does on the bullet in a gun-barrel, but it is im- possible to say to how great an extent what is known as 'stripping' in the illustration cited, has occurred. In other words, it is probalile that even (and perhaps particularly) at the time at which the thirk ness of the Cordilleran Glacier was greatest, the lower parts of the mass followed the larger valleys, while the higher parts broke away from these and continued to pursue the general direction. It imist further be remembered, that when the ice-shet?t finally disappeared, its thinned and melting edge must have occupied each part of the dis- trict successively, and that at this time tongues or lobes of ice projected southward in some of the larger valleys, when the ice-covering on in- tervening areas of higher plateau had vanished or had at least broken up into detached masses, which had ceased to participate in the genera! movement. The existence of small terminal and lateral moraines, in evident connection with such tongues or lobes, is the chief apparent evidence of this, but it is mentioned here as tending still further to account for the movement of ice along the valleys, and for the purpose of introducing the remark that the striation then and in this way formed, is not clearly separable in all cases from that produced by siicli differential motion in the main mass as may be supposed to have oc- curred. The mean direction of the general glaciation of the district included by the accompanying map, obtained from all the recorded observations at heights above 5000 feet (rejecting o\\\y the observation on Lyttnn Mountains which was taken on a sloping surface and was manifestly affected by the neighbouring great valley of the Fraser) is S. 'X^ E. If, however, several ob.servations, with respect to which local eireiim- stances were observed which explains their departure from the aver- age, are discarded, a mean direction of S. 33.5° E is obtained, which is probably better, and may be accepted as an approximation as close as can be arrived at. In the paper which has already been several times referred to, the main direction of motion of the southern part of the Cordilleran glacier, is stated to have lain between S. 30° E. and S. 35° E., with wliicli it will be seen the result of the present discussion, confined to the area of the Kamloops sheet, corresponds. A line drawn from the southern part of Stuart Lake, to Osoyoos Lake, along the centre of the Interior Plateau, and as nearly as possible parallel to its main direction, with a length of 450 miles, runs S.35° E., and with this the value here loially lOst closely ipeot, tlicse tion on tlio hut it isiiii- 'strippin;^' is probable the tiiick arts of the jroke iiwiiy a. It must ppeared, its of the ills- 36 projected ring on in- east broken 1 the f^eiuTiil moraines, in ef apparent 1 further to the purpose in this \v!i\ uced by such to have oc •ict included observations n on Lytton 15 roanit'pstly lisS. 'X] i local circuni- om the a vei- led, which is in as close as terred to, the leran glacici', , with which d to the area the southern i the Interior rection, with 16 here locally X -; H % X i! J m arriv( evide south Rock luent Pai met 1 8il-wl rivers occurs ii» Laki . I'lohalile (liffcivntial inovfinciit. How oauswi. I)iri'rti()n aiTdss till' rraolivtf Hilk' other things being equal, usually oucurred to the eastward rather than to the westwarfl. From this it seems reasonable to conclude that, in this part of the Interior Plateau, tiie weight of ice superposed on the western side was greater than that on the eastern, the maxinium accumu- lation occurring here in the vicinity of the Coast Ranges. In that part of the Thompson Valley which extends nearly due east- ward fi'on. the mouth of the IJonaparte, for about fifty-eight miles, and which includes Kamloops Lake, some rather remarkable instances of glaciation nearly parallel in direction to the valley have been noted, (ilaciation of this kind is found on the vertical front of Battle Blud', near the level of the water of the lai a, and again in the upper valley immediately behind and above the bluff at a height of 1000 feet above this level. Similar glaciation was again noted, in several places, on the hills to the north of the valley, some niiles east of the Kamloops sheet. It is by no means certain in what manner this aberrant glaciation was l)roduced, but as the general direction of glaciation is souoh-oasterly and those parts of the \alley affected run some degrees to the south of east, it appears to be probable tliat a lowei' part of Jie glacier-ice was here actually for ed to follow this valley in an easterly direcfon. Tliia is supported by the fact of the general tendency of the ice to deflect eastward where interrupted, and by the circumstance that the contin- uous range of high-lands to the south of the valley, did not jiermit any very great mass of ice to discharge southward by the Guichon Creek hollow; also by the observation of the abnormally great easting of the sti'iation found on the sunnnit of the ridge near Paul's I'eak, which appe rs to be explical)le only on the hypothesis of the addition, to the nuiin flow, of an underlying mass with eastward motion, derived from the valley of Kaiidoops Lake. AVithout some such unusual I'ondition, the motion of the ice would, in fact, here be likely to show a mon- direct southerly course that usual, for the great valley running soutli- ward f rom Kamloops by Stump Lake, nnist have been one of the main discharges for this part of the plateau. The ice, in fact, followed this valley, in an almost due southerly direction, till the \ alley began to t\rn to the westward, when it gradually resumed its normal course, across the Douglas Platen u. An aiv.iogous ease is met with in tlie abnormal ninount of eastiiv.' found i'. the stria* on the summit of t'lC Traciiyte i 'ilis, where it would appei r that a thick rib of ice moving along the JMarl)le Caflon valley, e.\er'jised a directional influence on the main mass after its b harge from that valley. •] SURFACE DK POSITS Oil DRIFT. 259 B It is, at any rate, scarcely prohaljlc tliat the glaciation of tbc second Kxicnt of period was sufficiently extensive to result in the i)rotrusion el 'lacier- Kli»i'il . . . 'ii'i'i'. the area of the map-sheet, no evidence has been obtained of the existence *It may be (>x|)lninela valleys apiirai- (in tlic iHa|p ai'('oni|ianyiri)f my |ia|ii'r nn tlu; til.iciation nf lliitisli Cnliniiliia imlilislii'd in tlu' l.Jiiailcrly .loMiiiai cif till' (iciildffii'al '-'iH'ii'ty for 187H, Imt tliat tln' fiirtlicr and niuoh more drtailcd ivjiniinationof t!ii> country, now tends nit; to distrust the inilifatioim i>rt'vion»ly relied uu in placinif tlieae marks. 17 miotanmmmxm msm 260 B nurnsH Columbia. of more than a single boukler-clny, though both in the littoral of Hritish Columbia and in the Great Plains* two boulder-clays have been recog- nized, separated in each case by a well marked zone of stratified materials. ^ ]3Mdn Ixlinv houltIc;r-cliiy. (•eiii'val c'liivi- actci- 1 if liouldi'i -cliw. Fl(!. 9. HKCTION ON IIAKNES CREEK. ". StnitiK<-(l (gravels, silt^* mill siiiids. '/. lioiikliT-cla.v, iilisc\ircly stratiti<-(l. c. Silt.v (lc|ni!it places, preserve- its well known features throughout. It consists of a paste of hard sandy clay, usually containing a considerable amount of fine sandy n: siltv material, and throughout it stones and boulders are gemn'ally abundantly though irregularly distributed. In colour, it varies from light brown, buff or yellowish to bluish-gray, the last-named being usually that characteristic of fr'>sh exposures cut down to some depth from the surface, or of ♦^h, se which have been otherwise protected from weathering and sub-aiiriai agencies. Some of ^he contained stones arc * Alwi now in the Carilnio flistrict, a« In^foic niit('ll marked, rmr can they >'"cb» be so closely correlated with the varying nature of the underlying strata, as for in.^tance in some parts of the Great Plains, where tlu- strata, being softer, are more easily incorporated as a part of the bouldcrclay. Neither is the bouider-clay of this district so plastic and Jrnly clayey in character as that of the 8t. La'ivrence Valley or ma;"y '/■it, ks of the (Jreat Plains, where the disintegrscion of limestones, or of suit clayey l)eds of Cretaceous age, luive rcs])ectively supplied much of the material. The contained stones are often, perliaps u^uii!iy, 1>". vntion of chiefly those of each particular vicini'^y; but with these then is alw.iys gtoiios. a considerable and o**'''u r. large proportion of stones of varied origin. In most places, a consiuerable pari of these travelled stones is f(jund to be obviously derived froiu st^nie rock-exposures to the north-north-west- wai'd, in th's line of the genend direction of glaciation. Tliis is par- ticularly apparent when 1 r|,e surfaces of granitic rocks occur to the north-west of any particular place, as rocks of this class seem liere, as usual, to have been specially productive of boulders. A part of this effect, iloubtless depends on the generally superioi- elevation of tlie granitic regions. There is, however, cousid'irablo evidence of cross- iningling of material The results of this arc* least ol)vious in tlic liigher parts oi the plateau and most notable at somewhat lower ele- \ ations. In the case of stones which can be clearly referretl to their places of i )ishuico of origin (as for instance granitic fragments on basaltic plateaux) an ex- '''''*"''l "''''• amination of all the notes made, shows that these have seldom or nevm' been transported in large numbers for a distance greater than about ten miles, in the direction of the glaciation. In smaller numbers, however, they have in several cases been traced to a minimum distance of twenty or twenty-fi\e miles in that direction. The above remarks respecting the derivation of the stones and boulders of the drift, apply spi'cially to those includcMl iti the bouldur- (\oj 'tself or obviously deriAcd fi'om it. The stones found on the ill, points to which drift has been traced, at heights greater than that H'hich the boulder-clay is known to chiiracleri/c, often show con- sideiable diversity in ch.uacter, and their origin cannot always cer taialy l)e traced. Again, in the lower and larger valleys, the materiid .¥■■ ■ 'mm ^m' B i . wti— tw 'M irw ■RBH 262 B }tRITISH COLUMBIA. of the drift, in consequence of the carrying power of the rivers, and possibly of other causes, is much more varied. Main devtlf.])- Speakinjj; of the whole district included by the Kamloops sheet, as l"'u'M<'r (lav **■ ''*'''*"'t of the pretty complete examination of all its parts, it is very )M'tw('i"n fHHK) noticeable th.'it, while many considerable areas even of the plateau country rise above .5000 feet, the greatest development of the drift deposits is found beiow this level. It is further probable that, thou,i,'h considerable (juantiiies of drift occur in the deep and svide \alleys which traAerse the region, it is by no means so uniforndy spread in these, and its mass, area for area, is smaller than that met with on some parts of the plateau above. To tliis general statement there are numerous exceptions, and though (as subsequently noted) there is reason to l)elieve that the upper line of the heavy drift deposits is a rather definite one, it is impossible to fix any lower line for them. All that ca!ibe aflirmed with certainty, is that the greatest average thickness and most continuous and unbnjken developmimt of drift deposits, i.s met with on those parts of the plateau between 5000 and .say 3000 feet, above the level of the sea. The aggregate area of the parts of the plateau between these limits, constitutes probably half the entire area of the plateau region embraced by the map. I'urtlier Tt is further fouad, however, that the drift deposits are • tills certain hoUow.s to a considerable depth and often runs out upon rocky prouiinences within a short distance with a feather-edge. It is probably in some places at least a hundred feet thick, t)ut no single section was observed within the area of the Kainloops sheet which showed such thickness. This paucity of good .sections is readily e.\- plicable, for it is probable that its persistence over the lower parts of the pktteau is to be accounted for chielly by the circumstance that it has there not been subjected in any great degree to dtmudaticn. In the cour.se of the examination of the region, 1 found myself be- Boul'lfei-oliiy conn ng accustomed to note the occurrence 01 'ordinary plateau boiil- ),|.-,tiiuix. der-clay.' A difference was in fact observed between the boulder- clay of the plateaux and that seen in some sections in the lower valleys, which though one of degree rathei than of kind is jiretty obviuu.^ in its character. This consists principally in the somewhat more s indy and silty natui'e of the boulder-clays of the plateaux, which becomes most marked towards the upper limit f>f the deposit. I Jut tlie.se pla- teau boulder-clays are also generally paler coloured than those of the lower levels and usually present drab, fawn or yellov/ish tints. This is doubtless in part due to their greater porosity, which favours wea- thering and oxidation by surface waters, but also, probably, to the ver\- slow removal of the weathered superticial portions on these areas. The only fundamental difference is, however, that in the original texture of the materials. One of the best and most extensive exposures of boulder-cla\ , is found K\i"i.-iiii'.s of to the north of ravuion Ureek, about two mues eastward from the Pavilimi jilace at which the road begins its ascent to tlie Pavilion Mountain -^'"""ti'i"- farms, and almost directly behind Captain Martley s house. A land- slip which has occurred here on tlie upper edge of the valley, has pro- duced a large bowl-shaped hollow, the bottom of which is strewn with ^'reat broken masses, while the sides present a cliff of about forty feet ill height and several hundred feet in total length, composed almost entirely of boulder-clay. The material is here of a nearly uniform, pale yi'llowish-drab colour when diy, and so hard as to stand without mucli sign of waste in vertical faces of the whole height of the cliii'. It is well charged with boulders and smaller stones of all sizes and of some- what varied character, thou;^h granitic matprials are most abundant. A considerable proportion of the stones are strongly glaciated. The 266 B BRITISH COLUMBIA. Nortli Thiiiiip son Valley. Bdiiapivitc, iicarAslioioft. whole thickness of the boulder-clay here exposed, shows only very faint traces of any stratification or lamination, but it includes in its mass ,i few lenticular, horizontal and stratified layers of sand. Overlying the boulder-clay, is a variable thickness of stratified gravels, containing ,i, few distinctly red layers. Above the gravels, and extending to the sur face, is a thickness of a few feet of earthy material, constituting the soil. This is reddish and contains some stones and boulders. It has evidently been coloured by the decomposing Tertiary volcanic rocks of the vicinity, and may have accumulated by the washing down of the material resulting from this, together with that of the surface of the drift deposits proper, under the actual conditions. The elevation of the exposures of this place is alx)ut 3D00 feet above sea- level. Another excellent section of the boulder-clay, which may be described as typical of its general character, occurs in the Xorth Thompson valley near the extreme north-eastern corner of the Kamloops sheet, on Coal Brook, a mile or rather more to the east of the river and some 200 or 300 feet above it, or 1500 feet above sea-level. One bank affords a sec- tion of about fifty feet, and the boukler-clay is also shown in numerous smaller exposures. The following description is quoted from my Report of 1877-78 (p. 140 b) :— "The matrix is a very hard, bluish, sandy clay, through which stones of all sizes are scattered in every position. These are chietly of the rocks of the neighbourhood, but include numerous fragments of granite, not seen at this spot. Many of the stones are heavily scored and a few are very large ; one, a mass of coarse granite, was found to be eleven feet four inches long, by eleven feet wide, and six feet four inches deep, the last dimension not fully shown. Notwithstanding the rough, or even tumultuous aspect of the deposit, traces of bedding are distinctly seen here and there, and near the top of the section a bed of clean-washed gravel about ton feet thick occurs. Above this, tlie boulder-clay, with all its usual characters, resumes for a thickness of three or four feet, and is again covered by horizontally stratified and false-bedded gravels which form the upper ten feet or so of the bank." Another excellent exposure of the boulder-clay of the region is nut with at the mouth of the Bonaparte, where the river enters the Thump- son, about a mile and a half only distant from Ashcroft station on tiie Canadian Pacific i-ailwaj', and thus easily accessible. It is described in another connection on a following page (p. 273 n). These notes on individual exposures of the boulder-clay within tiie limits of the Kamloops map-sheet, may sutlice to characterize this deposit, It ap zoiital higiier llats, an action j^uch fh deposit, *Zoc "■] THE HOULDER-CLAY. 267 B 'ery faint ts mass ;i lying tlu- taining a J the sur- iting the ;. It has nic rocks washing at of the ins. The ibove sea- described son valley t, on Coal rae 200 or fords a sec- numerous from my igh which are chielly agments of vily scored is found to { feet four anding the jedding are on a bed of e this, the hicknesR of ratified and the bank.' jgion is met the Thomp- ,tion on the is described ' within the this deposit, and no further mention need be made of the almost innumerable minor exposures met witii in the district. In the paper published in the Transactions of the Uoyal Society of Coincidfneo Canada, to winch reference has already been made, the L'oneral result , '"*'''""'^ , of the investigation of many parts of the interior of Hiitish Columbia liiKl'>'«t 1 • ,, rnl I .IT ■ ni i i i. • l»Ollldnr-cIliy. IS thus given :— " Ihroughout the Interior rhiteau the upward limit of the boulder-clay is found at a height somewhat greater than 5000 feet above the present sea-level, and corresponding in this respect with the highest level of well-marked terraces ; the higher terraces in fact generally consisting of material identical in character with that of the general covering of boulder-clay, or so closely alike as to bo indistinguishable from it. Though, as previously noted, travelled stones occur on much higher points, no boulder clay, and very little tine drift material of any kind, has been found above the highest terrace-level above referred to.'* Various explanations may be offered of the general fact thus stated. It may be supposed, for example, that the boulder-clay by reason of its increasingly arenaceous character at higher levels ceases to be rec- ognisable as such above a certain line, or that the naturally greater effect of denudation on the higher points has, in process of time, re- moved such deposits of boulder-clay as may at one time have occurred on them. As it is intended here merely to present the facts them- selves, as cleai'ly as may be from the evidence aftbi-ded by the area of the Kamloops sheet, no discus.sion of these or other hypotheses will be undertaken. It may be stated, however, that the proximately ex- act coincidence of the ujiper limit of the boulder-clay with the highest of the well marked terraces of the region, is apparently such as imply a common cause. No distinct boulder-clay has been recognized above the level of these higher terraces, and the main mass of the drift depo- sits of all kinds lies below it. As we have already seen, these deposits do not increase jjrogressively in volume as we descend, -but they are found in their greatest and most connected spread at levels between about 5000 and about 3000 feet. It appears reasonable to consider the wide-spiead and nearly hori- zontal deposits of boulder-clay which freijuently occur tcnvard the higher limit of the main drift, as essentially of the character of terrace.- llats, and as probably evidencing the contemporaiiious or subse(iuent action of water, in the same manner as do the narrower terraces- Such flats are in fact often covered by a few feet of fine silty or earthy deposit, which seems to imply sedimentatifin of a comparatively tranquil *Loc. i'it., p. »i. Possihl.. cinmi'.s of tluM. 1 irracc-icvcl; (•l)Ill|i(ISI'(l of liijiilil('i'-cl:iy. 268 u UltlTISH COLUMniA. ]i::^ 'Cliaraoter (if ii|i|>('i' limit. Grwn Tim! Kir Plateau. clinracter, iih a last event. Instance.s of such liigli-level Hats uf lioulder- clay have already been cited. It now remains, to describe the essential features of some parts of the upper level of the main development of drift deposits, by way of illustration of the character of this limit, and with special reference tn the boulder-clay. It is, however, unfortunately not possible in all cases to ascertain the precise character or composition of the drift towards its upper limit, because of the infreiiuency or obscure cli.-ir acter of the natural exposures, rendering a complete knowledge i;f the facts impossible and preventing a perfectly definite c!a.ssificatioii. It is also necessary, in so doing, to forestall in part what is subsequently said on the question of terraces. The general surface of the Green Timber plateau, ranging in height from ."J^OO to 4000 feet, is thickly and very uniforndy covered liy boulder-day, this in many places forms tlie actual soil, but is elsewhere covered by a limited depth of sandy deposits and is traversed also by moraine ridges (p. 27!) it). The character of this boulder-chiy, which is quite normal, is very well shown in numerous borrow-pits along the wagon-road. The plateau rises ve.y gradually to the west, toward the ^Marble Mountains, all the higher parts of which con- sist of almost perfectly bare rock, but of which the entire ba.se, with ii length of fifteen miles, is thickly heaped with drift deposits. As viewed from any part of the plateau at a considerable distance, tin- upper line of these deposits appears to be perfectly definite and straight and is very strikingly outlined.* On approaching the southern part of the range, near the upper parts of Clinton and Sandy creeks, tlit^ boulder-clay becomes covered with sandy deposits, some miles before tln^ actual base is reache deposits increase in importance, till near the base of the mountains they appear as horizontally stratified terrace-flats, fifty feet or more in thickness as shown in the banks of Sandy Creek. Above this, aie still higher, though narrow, terraces which were distinctly traced at this place to an elevation of about uDOO feet. Morainic mounds ami ridges, showing gravelly material and some boulders on their slopl•^ but not .seen in section, are associated with these higher terraces, in such a way as to show that the terraces are of later date and have been formed in part by the levelling and redistribution of material derived from the moraines. The northern part of the same base of the Marble Mountains, wa- ()f"basi"If "^ examined to the south-we«t of Big Bar Lake. The plateau here rises jiiouiitiuns. ~ "»v, , V < rv< ', vr" ■ ~, ", — T . — ■ I oniliaro the sketch of ll-ga-chuj! Mountain, much further north, (^uart. .Inuiii. r.eol. Hoc, vol. XXXIV., p. lOi), Kig. o. S<)\ithern ] of Marlile Mountains. TlIK IlOl'I.DEH-CI.AY. 2t)0 II soiiiHwhat less ;;rafluiilly toward the luisc of the nioimtains, iiud tho conditions observed wore not absolutely identical with those in tho lirst-d(fscribed vicinity. Tho hei;,'ht of l>if,' Bar Lake is .'Ul.iO feet, and alwut its upper or southern end, moraine ridges ai'e observable to a height of about a hundred feet above it. Higher than these anil nearer to tlui mountains, a wide sandy and gravelly terraee-llat is crossed which slopes gradually up from a level of 4000 feet to one of about 1300 feet. iSeyond this, a considerable width of moraine country is again found, in which tho general direction of tho ridges is parallel to tho ba.se of tho range. Higher than these moraines and running back to tiie mountains, is a second terrrace with a hoight of 4700 feet. Other smaller terraces with narrow treads occur still higher, to an elevation in this place of about ")100 feet. The im|)ression conveyed by the con- ditions observed here is, that the several tiers of small moraines had been pi'oduced by temporary periods of advance of a glacier-mass, which, on the whole, was shrinking back to the north-westward f i om tho then submerged area of the Green Timber plateau. Near a local summit on the Tranquille plateau, due south of Tran- (|uille Lake, a terrace occurs with a height of ;j.'{40 feet. This is ])erfectly distinct and somewhat ex tousi ve, and was seen, from a distance, to 1)6 repeated on the southern slope of Porcupine Ridge, some miles to tlio northward and beyond the lake. Where examined iii. 18.^9, this tf.rrace was found to be composed of boulder clay or identical material. In 1890, about three miles to the eastward, near the head of Watching Creek, a series of narrow but distinct terraces which can be traced for a mile or more in length, was noted. These extend in height fi'om about 5300 to r>-i^)0 feet, and are composeil, so far as could bo ascer- tained, of roundetl and sub-angular gra\els mixed with eartliy material, the gr: vel being more abundant than in most true boulder-clays. The slopes to the north of and above these terraces are but thinly and irregvdarly covered with drift material. In-ki-kuh' Creek, which joins the Thompson from the eastward five miles above the Nicola, falls very rapidly in its lower part toward the great valley of tho Thompson, but at about five miles and a half from its mouth and thence to the lake at its source, occupies a wide low- grade ^alley on the surface of the plateau, at an elevation of about 4.^00 to 5000 feet above the sea-level. The lower part of this valley opens in a tlaring manner toward tho Thomp.son, and there is no proba- bility of its having been at any time locally stopped. Tho country on l)oth sides of the upper part of the stream, is thickly covered by drift, the greater part of which is of the nature of boulder-day. The surface, of this deposit rises gradually with the slope of the valley, till just 'l"niii(|iiilkv l'l;itfiui. lii-Ui-kiili' Vall.'y. ^, '"> IMAGE EVALUATION TEST TARGET (MT-3) i /. ^/ ^ 1.0 I.I 11.25 IttlM 115 ui Uii |22 ■J IJ4 "^ 6" Photographic Sciences Corporation 73 WIST MAIN STRUT WIBSTIH.N.Y. M5«0 (716) 173-4503 ^.V .^ 270 B BRITISH COLOMBIA. Cli()0-vliel!<" Mountuin. H(>avv drift unusually liif(h DM Kil- wlioi'-a-kuu I'luteuu. below the lake and practically at its level (4920 feet) it forms a flat terrace-like floor. The rocky hills to the south of the lake beyond, arc heaped with drift deposits to a height of about 200 feet above it (.'5100 feet above sea-level) and these, from a distance, show a pretty distinct upper line, which might almost be designated as a terrace-level, though it was not closely examined. The hills above this level consist of nearly perfectly bare granitic rock. From the extensive development and wide spread of deposits of boulder-clay to the south of Choo-whels' Mountain, and the gentle slopes of the mountain itself, it was hoped that some deflnite information as to the precise upper limit of the boulder-clay might there be obtained, but this hope was not realized. The mountain was ascended on the south- west side and descended on the opposite slope. The highest distinct and wide terrace was passed over in ascending at 4240 feet. This is composed of lx)ulder-clay with a silty covering, sometimes not more than two feet in thickness. True boulder-clay was noted, where the roots of trees had been overturned, for some distance above tliis, but at heights exceeding 5000 feet, a great part of the whole suifiuc consisted of solid rock, with small intervening drift-filled hollows and valleys. The stones here contained in the boulder-clay are, as usual, more or less distinctly rounded, but become increasingly angular iit higher levels. Toward the summit, where occivsional exposures are found of the superficial deposits, these consist of earthy materiiils mingled chiefly with angular stones of proximately local origin. Tiie actual south-western summit-point of this prominent elevation on tlie plateau, has a height of GOOO feet. It is partially covered with drift of the character just described, and the rock-surfaces, though much weathered, have been heavily glaciated. The faces which still showed the original striation, indicated (as previously noted) a direction of S. 35' E. The most notable exception to the general rule of the extreme jxiu city of drift deposits above a level which approximately coincides witli the 5000-foot contour, is found in the S.'i-whoi'-a-kun Phitoau. The wide elevated portion of the plateau to the west of the North Thoiii|i son so named, is more thickly covered with drift material than any other region of equal height which has been examined. The drift is moreover pretty uniformly spread upon its surface. There is, liow ever, reason to believe, from the very frequent outcmps of rock, (lie generally local character of the boulders and the hard bouldery beds df llie small streams and rivulets, that it is rather in conseulder-clay whicli must have l)een deposited in these lower valleys, was at a later period removed by de- nudation. On referring to what has been said in the introductory part of this portion of the report, (p. 251 n) it will bo seen that I am inclined to regard this epoch of denudation as cont^Muporaneous with, and as tlie result of, a considerable reelevation of the land, which is also sup- posed to have been synchronous with the second period of increase of glacier ice. It is believed that the height at that time attained by the land, was such as to enable the larger rivers not only to ret'xcavate their valleys, but also to remove great quantities of new material which would Pa\ioity of IhiuIiIi'i clay ill Idwcr vullcy.t. ' \ Its rciiKival tlpi'iicf liy ilciiU(Jiitioii mt 'nr 272 B BRITISli COLUMBIA. Obm-rvwl xectioiiH in FriiMtT and Tlu>ni|mun VallcyH. Thp (lernida- tion of iiitt^r gliwiiil date. doubtless be carried into them from the adjacent slopes by tributarv streams and by superficial agencies. ' Without, however, insisting on the accuracy of this interpretation, I may now explain the nature of the facts upon which it is based. Ot these, the most obvious, is that already referred to, viz., the evidently small importance of the deposits of boulder-clay now remaining in the lower valleys. While it is probable that traces at least of this material may exist in that part of the length of the Fraser Valley which is included by the map, I am unable to mention any single e.xposure in which it is shown, and it was in connection with the exaiuinHtion nt' this valley, in 1889, that its notable absence first became apparent. In the Thomson Valley, between Kamloops Lake and the confluenci; of that river with the Fraser, while boulder-clay is scarce, it is not altogether wanting. Near Black Cafion, three miles and a half below Ashcroft, typical boulder-clay is seen in several places in cuttinj^s along the railway, and considerable exposures are found about tlio mouth of the Bonaparte, a mile and a half above Aslicroft. These are the only occurrences actually noted, though close search along other parts of the valley would doubtless resul in the discovery of others. Granting, therefore, that the grep ter part of the mass of the boulder- clay originally deposited in those valleys has been in some way re- moved, and of this the evidence appears to be conclusive, it remains to assign a date for this removal relatively to the other phenomena ot the glacial period. It might V)e suggested that the clearing out of these valleys occurred during the period of considerable elevation of the region which there is goofl reason to believe supervened at the close of the glacial epoch, and was thus merely a part of the post glacial valley erosion which is subsequently alluded to. The occurreiut' and relations, however, of the White Silt deposits (also referretl to in greater detail on a later page) in many parts of these valleys, negatives this supposition, and shows that the removal of the greater part of tin' boulder-clay must have occurred previous to the deposition of thcM- silts, the origin of which is clearly glacial, and the period pretty di^ tinctly that of the decline of the second maxinmm of glaciation. Tins conclusion follows so obviously from the general circumstances, that it was arrived at and used as a basis of reosoning in my paper in tlic Transactions of the Royal Society ')f Canada already referred to. Since that paper was written, additional evidence of the same kirul has lieen met with, of which two instances may now be particularly notetl. •] THE BOULDER-CLAY. 273 B The first of these, is that afforded by the sections shown in bluffs on Sittiim mi the north side of the Bonaparte at its coifluence with the Thompson, Hi>"'M«""t«' . of which a diagram is here presented, TKe bluff rises to a height of Fio. 10. ITS MOUTH. Krur lettuce SO' ahore water level SECTION ON THE NOUTH SIDE OP THE BONAP.XRTE, AT 1. Boulder-clay. 2. Stratitiecl ffrave!. 3. Whitosilt. (i. Sil,y soil. 7 St'coiid oUI river-Wl, coverefl l>y stratitit'd gnvvel. 4. Old river-bed. 5. Stratitied gravels. about 200 feet above the river> its upper limit being formed by a terrace-flat of about that height. Of its lower part, about 50 feet is concealed by a late river-terrace, but most of the remaining height of 150 feet is well exposed. The greater part of the entire section here consists of boulder-clay. (1) This is of the usual character, containing some large boulders and many smaller stones, and is so hard as to stand in vertical faces. It includes, however, layers, some of which are two feet in thickness, of hard, silty material, horizontal or proximately so, and lenticular, not exceeding a few yards in extent. There are also similar traces of local horizontal bedding aflorded by occasional sandy layers separating the general mass. No. 2, the deposit capping the boulder-clay, is a stratified gravel, composed of medium-sized and small stones like those in the boulder-clay, but more perfectly rounded. The upper part of this bed is a clean gravel, but its lower part is clayey from included material " the boulder-clay paste, and it is in consequence not always easy to fix the exact line of junction of this deposit with the Iwulder-clay. No. 3 is typical White Silt,with th.' usual creamy tint of this deposit, well and regularly ., . . j stratified in thin layers and ratlmr hard, though it may l)e crumbled White Silu. easily between the fingers. Overlying this is No. 4, a coarse, gravelly and Ixjuldery river-bed deposit with well rounded and p)iish('d stones, indicating a strong current, and precisely resembling the material of the bed and beaches of the adjacent part of the Thomp.son. No. 5, consisting of finer stratified. gravels, overlies this, and gives to the surface of the terrace flat its level form. Resting on No. 5, and forming the actual surface of the terrace, is a thin layer of silty soil. At No. 7, 18 ' \ \-^ ■ . i 1 ■ 'i ;.i EventB indi- cnt*^! by ' ■/ mM|ii('iice tK)n River. • )n Fraser KivtT. that the boulder-cones were produced after the time of the main denudation of the boulder-clay in these valleys, and during the earlier stages of the following submergence which i-esulted in the accumula- tion of the White Hilts. The most instructive case of this kind noted, is that on the Thompson four miles above Hpence's Bridge, opposite the mouth of Pimainus Creek. The Thompson Valley is here e.\cavated in Tertiary volcanic rock", while the material brought down from the valley of the Pimainus is almost entirely granitic, and is thus easily recognized. The cone of dejection has here evidently spread from the mouth of the Pimainus, quite across the wide valley of the Thompson, to the bases of the mountains on the opposite or west side. In following the wagon-road on that side, the great accumulation of heavy granitic boulders, in some cases at least six feet in diameter and massed together at a height of 200 feet or more above the present river, is very nctal)lp. What still remains there of the outer part of the cone, is now, however, separated from the east side of the valley by the whole width of the later immediate valley of the Thompson, and in being cut through at this later time by the river, it has been made to a.ssunie the form of rough, bouldery terrace-Hats. On these, the thickly strewn boulders have been rounded, worn and polished, while the river flowed at their level, and before it had succeeded in re- excavating its bed to its present depth. During this process of re- excavation the river has carried granitic material derived from the old cone along its course, and in following the river down, this material is found to decrease gradually in amount and in the size of its consti- tuent fragments. At the mouths of Ni-kai-a and Kl-ow'-a creeks, below Lytton on the west side of the Fraser, similar cones of dejection ''ontaining some very large boulders were noted. The mountains in which these short streams rise, consist of granitic rocks, which break up with facility into boulder-like masses, but no flood-water ever now occurring will account for the carriage of such largo masses us those which have been brought down under former conditions. It is probable, that these and other similar cones of rlejection along the Fraser, are refer- able to the same period with that above described. Some further allusion is made to such cones and ' fans ' in connection with the history of the Fraser Valley (p. 303 b). TeiToces and Stratified Deposits newer t/uin the Boulder-clay. Interlocking Under the last heading, particular attention has been given to the *'''"""'"'"'■ boulder-clay, with the facts bearing on its limit in elevation, or ex- MWMII.] TERRACBa AND SHORE-LIKES. 277 n the main /he earlier accumula- Thoinpson Piinainus y volcanic ey of the •ecognized. (Uth of the ) the bases owing the •y granitic nd massed nt river, is if the cone, ley by the son, and in en made to the thiokly bed, while ;ded in re- •cess of re- •om the old material is its consti- Lytton on lining some these short ith facility urring will kvhich have )bable, that r, are refer- >me further n with the er-clay. ven to the ition, or ex- plaining its relative scarcity in the lower and larger valleys, in which, other things being equal, we might reasonably have anticipated that it would be found ,n its greatest development. The various phenom- ena of the glacial period are, however, so closely interlocked, that in following the sul.)ject cf the boulder-clay it has been necessary to in- troduce the consideration of some other topics, and in part to antici- pate, by allusion to them, some of the deposits which are considered in greater detail in following pages. A strict separation of the different parts of the subject, could be arrived at only by the adoption of some ruling hypothesis, which in this description of the phenomena it is my purpose to avoid as much tvs may be possible. The more important terraces observed in the area of the Kamloops Th.. list aro- The heights given below have been barometrically determined wil;hin aswr'tain^Hl. small limits of error, by comparison with a station barometer at Kam- loops, the reduction of the various olwervations having been made in the same manner with that of those upon which the contour-lines of the map depend. List of the higher Terraces obgerved within the area of the Kamloopc Sheet. Feet ftb<)v»' spa-levol. 1. East sirle Marb'p Mountains, north of Clinton Creek (p. '2(i8 It) iJ5tK) 2. Near liead of Watching Creek valley (p. 269 n) 5300 to nlK>ut 54r>() 3. Slope of Mount Murray, a small and irregular but still distinct terrace 5380 4. West side .Marble Mountains, twelve njiles north-west of Kelley I^ike, about 5300 5. iSoutli-cast side Lyttnn Mountitins, apparently a dis- tinct terrace-flat on slo|)e of Fraser Valley 5340 «. On plateau near Trancjuille Lake (p. 269 li) 5340 7. Fast side Marble Mountains, north end, near Big Bar Lake (see \o. 9) about 5I(K) 8. Head of Bigtish Lake, (ireenstonc Creek. A small terrace, which may be due to local icc-daniming or moraine-damming of the valley 5000 9. Fast 8i 4700 4450 4400 lUwtON. ] TERRACES AND SilOKE-LlNES. 279 K Feet. 13. I'luteau l)etween hea 17. Western Hlopes of Trachyte Hills, near }/at Creek. . . 4300 18. IMateau west of Trout Lake. Terrace l' it coniixiseil of boulder-i'lay 4240 10. Vlateau between heads of (iuichon and Three-mile creeks. Distinct terrace 4150 20. (ireen Timl>er Plate»u. .Sandy terraces and terrace flats Ijetween morainio ridges 31M)0 to 4150 21. Higidand Valley near watershed. Terraces several lumdred feet aliove moraines in valley 40(X) 22. (iuichon Creek valley, west side, below Witches Brook. Terraces traceable for several miles, about 4 3.5. One mile, west of Jacko Lake. Terrace-flat 2790 30. Near Newman's, Trapp Lake. Wide terrace 2580 37. Twaal Valley. Terrace composed of silty material. . . 2.")00 38. Nicola Valley, at lower end of Nicola Lake. Best marked of several terraces 2470 39. Lower part Upper Nicola Valley, near lake. Im- portant terrace of same series with No. 31 24.'i(> 40. Inner Valley, near Kaudoops. Highest terrace locally recognized 24(J0 i/f ' s r ir «Bi 280 B IIKITIMII COLUMBIA. C(iiii]>ariK)n i)f tfrructw. i I m i jr. Higheat grou|>. An inspection of the alxjve list of observed terraces or shore-lines, will show that these occur, within the area of the Kamloops sheet, at man/ different levels from a height of 5500 feet down. The list might doubtless be largely addisd to by further and more minute examina tion of the area in question, but the actually recorded observations aro sufficient to indicate the general character of the facts as they occur there. Considerations already referred to, mnder it impossible to insti- tute any very exact comparison between the heights of terraces in different parts of the field, and in order to investigate the questions which might l)e found to depend on such comparison, it would lie nee essary to sjwnd in'jfh time in following out individual terraces, in n manner not yet attemptbd. In order, however, to arrive at such gen- eral idaa' of correlation as the observations might warrant, these were graphically represented to,][ether on a single sheet. An examination of the levels of the various terraces as thus assembed, brings out a marked tendency of the observed levels to group themselves about several points, at or near which it is to be presumed that the water stood for a longer periixl than at intermediate elevations. It also shows, that no very long interval in the whole scale is altogether with- out terraces, even when the evidence considered is limited to that obt{>:ned in the area of the Kamloops map-sheet. The highest recognized terraces appear to form one such well-marked group, the olwervations regarded as belonging to which are those in eluded l»etween about 5i500 and 5300 feet (Nos. 1 to 6 of list). The observations on terraces of this highest group are scattered over a con- siderable area of the map, and are moreover supplemented and ex tended to a much wider area by some made beyond the Kamloops sheet which have been elsewhere discussed.* A few scattered observations at less considerable elevations, in- tervene between those included above and those of the next con siderable group of terraces. Of these -intervening terraces. No. 7, with a height of about 5100 feet, met with on the eastern base of the northern end of the Marble Mountains, is similarly situated to No. 1, and there is n ason to believe that it belongs to the same series of ter- races, which, running along the base of the Marble Mountains, overlooks the Green Timber plateau. No. 9, again occurs in the same locality with No. 7, and probably forms a lower member of the same descend- ing series, and one for which there is no apparent reason to suppose any different mode of origin. This and that numbered 10, it will be • Trails. Royal Soc. Can., vol. VIII., see. IV., pp. 36, 37. Soc. Am., vol. VII., p. 31. See also Bull. Ueol. TKIiDACKH AM> 8IIORK-MNE8. 281 H i.lrnf tfiTiiceii. observed, are identical in height. The terrnccH numb«>red 8 and 1 1 may possibly be due to strictly local caunes. I have referred thus in detail to these oliscrvations relatincr to i-er- N(,tnlili' Ki»p tain terraces below these which have been included in tli ' >ve "first group," as preparatory to the statement that the most noti>Ll gap in the whole series of such shore-lines is that which occurs at iiliout tliis place. The extent of this gap, or interval in which f teir -ces are known, may probably l)e approximately detiixKl as ( .irring Itetween oSOO and ' ^50 feet. In order further to illustrat nf liijflit'.it f;i(iii|i, • C}. op. I it., pp. 36-37. t See, in this connection, foot note to next iwge. «i 282 B BRITISH COLCMBIA. Various correlatiouB. lower limit, at least, must bo considered as scarcely more than arbitrary, as no marked break again occurs in the descending series. Beyond the Kamloops map-sheet, within British Columbia, I know of only two instances of terraces which are included between the limiting heights given for this group, and these are too far removed by dis- tance to be employed as any basis of argument. The succeeding terraces enumerated, from No. 18 to No. 23, both inclusive, show a general correspondence between the region of the Green Timber plateau, and that in the valley of, or on parts of the plateau adjacent to, Guichon Creek, with a marked developement of important terraces at a level of aV)out 4000 feet. Numbers 27 and 28, in the wide valleys of Hat Creek and Guichon Creek respectively, are practically identical (3360 and 3350 feet), while No«. 30 and 31 in the Nicola Valley (which is freely in communication with the Guichon Creek valley) and Hat Creek valley respectively, (3080 and 3070 feet) seem to fonn a similar but lower pair, and to in- dicate similar periods of arrest in the subsiding water-line in both these rather widely separated places. The association of some of the terraces at le'^els of 3350 and 3250 feet in che Guichon Valley (Nos. 28 and 29) with morainic ridges, is mentioned in the list, and though at some distance to the south of the Kamloops sheet, it may be added that in valleys and on low tracts of the plateau to the east of the Coldwater River, a similar association is found at closely corresponding elevations, or between 3300 and 3200 feet approximately.* * Since thiH part of tlic reiHjrt was written (18i»3i an entirely indeiiendent ret-xnni- inntion lias Ix-en niiide of the placial (le|H»it.s of the Koiith-weHtern part of AU)erta, to the east of tlie Kocky Mountains and alonnf tlie western margin of the (Jreat I'lain> : a district removed by nearly 300 miles in distance from that here particularly '.legcriliecl. ThiH has develojied ho Htriking a general parallelism t)etween the liigher *erriu?e-levcU of the two districts that it seems necessary to allude to it, although inappropriate here to enter into a discussion of the wider (juestions wliich it aii|)earH to raii-e. including the pnilialiility of a general subsidence of land much greater in amount than that |K>stulated by the provisional scheme of events given in the first piirt of the present chapter. The main coTiciusions resjiecting the terrace-levels ut south-western Alberta, may be l)est conveyed by quoting the following paragiiipli from the |>ai)er dealing witli that subject:— " All the later and lower terraces ami gravel plains may be regarded as nutrking stiures in in the subsidenc(< of this wati i level from its maximum height of !i',MH) feet. These, it lias alp'ady l)een noted, ari- usually not strongly impressed, and there is no evidena- that the s"'' "(lenco wii- arrested long, except at one stage, which is that sjKiken of in th" reinn.. . i 1882-84 ii< being at aUnit 4'20O feet. Furtlier exumination shows that the terraces referrable ti> this particular stage slope up gradually in the foot-hills, and on approaching t' '' mountains, to a maximum height of alxnil 4500 feet, from which it may be argued th:ii from the last-mentioned height the water lowereeriod of orrest, seems to be marked liy the gravel (ilrin near Macleod at about 3200 feet." (liull. Geol. Hik. Am., vol. vii, p. (13.) -] WHITE SILT FORMATION. 283 B arbitrary, Beyond |wr of only limiting ed by dis- 23, both ion of the irts of the )pement of id Guichon feet), while munication jspectively, and to in- ae in both and 3250 ic ridges, is outh of the w tracts of ssociation is and 3200 indent rei'xnni- irt of AUwrta, ^(iri'at I'lains; arlydcBcrilic'l. r t>;rrftf('-levi'ls iiiapirt'opriat' l»>ai'H t it 'ing parajo'apli ■r terraccM ami ■ of this watir ifen noted, an- <••'■ '(lence wa^ !».. I 1882.84 iH eH referrable ti > piiroachiiiK t' '■ l)e arguecl tlial to one ot alxjut rivers from tin- irre.st, seems tu Bull. Geol. H.S/. No better examples of the lower terraces of the region (excluding Examples of river-terraces) can be found than that presented by the hills near lower terraces Kamloops (1150 feet). Behind the town, particularly in an after, noon light, the grassy slopes on both sides of Peterson Creek are seen to be ruled by parallel shorelines at 8ever.il diiferent elevations. In ascending these hills by the road, the level of one of the highest terraces in this immediate vicinity, is very clearly seen on the eastern slope of the ridgo to the north, near Guerin's, where it is marked by the lower edge of the wooded growth. Its elevation is 1900 feet above sea-level, and near Guerin's house, on the road, it is found in a more or less de- nuded and hummocky condition, to be characterized by well rolled gravels and stones, with some sandy and earthy matter. This par- ticular terrace is, very probably, that representing the margin of the body of water in which the White Silts of the vicinity were deposited. Continuing southward from Guerin's, across the hills, to the neigh- bourhood of Jacko Lake, higher terraces are discovered at many dif- ferent levels, often occupying retired angles and valleys, but none of them by any possibility due to purely local causes. Near the small hour-glass-shaped lake to che south of Jacko Lake, the highest terraces actually seen in this vicinity v/ere observed, at levels of about 3000 and 3050 feet above the aea respectively. White Silt Formation. The terraces and shore-lines enumerated in the foregoing list, and to wiiite Silt some of which the explanations just given apply, are in part of the terraces. nature of accumulations built up along the edges of water, and in part have been cut < 'Ut of still earlier drift deposits by the erosive action of the margin of the water. In many cases the information is not .suffi- cient to determine the precise mode of origin of any particular terrace, and in some instances both processes have no doubt cooperated in producing a te*Tace. At levels lower than these included in the fore- going list, terraces of both kinds continue to occur, and a considerable proportion of tlie terraces of erosion are known to be true river-terraces, formed by the rivers and streams when engaged in reexcavating their beds in post-gUxcial times. The interest attaching to these i.s chiefly in nnnection with the history of the modern river-valleys. From about the level of 2500 feet downward, a notable development of pale silty deposits is found in many parts of the area of the Kamloops sheet. These deposits have originally been much more extensive than they now are. They are sometimes still found to completely floor the valleyst but in most cases remain as terrace like fringes along the sides of i 284 B BRITISH COLUMBIA. \l ■A f valleys in which the river has since cut a deep median trough, and not infrequently, but small traces of the original deposit are preserved, cling- ing to the sides of the valleys, or occupying sheltered recesses along the bases of the plateaux. Nature of the •fleposit. These White Silt deposits are very widely developed throughout British Columbia, and their character and probable meaning has been discussed at some length in the paper which has been already severnl times referred to. The following general remarks on the White Silts are quoted from this paper* : — " In the regions characterized by them, which are in almost all cases at a less elevation than 2500 feet, these White Silts very often rest directly upon the boulder-clay. They are generally fine and uniform in texture and .ire usually well bedded in perfectly horizontal layers of an inch to two or three inches each in thickness. Where occasional sandy or gravelly layers are intercalated, these are attributable to local causes, being most frequently found opposite the mouths of valleys down which streams have flowed. * * * The silts have evidently been laid down, as a rule, in tranquil water of considerable depth, and their material has as obviously been supplied by streams or rivers discharging from glaciers not far removed. In physical characters the silts resemble the deposits of the Red River valley, though usually in the Cordilleran region paler in colour, and seldom so clayey as those of some parts of the Red River. They differ from Loess chiefly in their well-bedded character. It is believed that the general correspondence in elevation of the various and more or less separated bodies of water in which this White Silt formation was formed, in itself constitutes a strong argument in favour of the hypothesis that these bodies of water were in direct communi- cation with the sea and were governed in their level by that which it held at the time. No traces of morainic or other barriers have been found in any case sufficient to account for the damming back of water at the requisite level, nor do the local circumstances admit the supposi- tion that such water was held in by glacier dams. Had the silts been formed merely in lakes proe alKiut ;"iiH) feet aUive the lake, or alnnit lOW) feet aUive sea-level. It existence , leans, that at tlie time the ire had almost or entirely left the lake-liasins, the Whitt Silt water still stood at the .iliove-mentioned h vel. t Op. cit., II. U}M>. 286 B BRITISH COLUMBIA. IM Silts ftt two l>rinci|>al levels. Wliit»»Silt forinivtion iii'jir kam- llKllJS. Hction in these main outlets of the plateau region. The silt forma- tion is entirely absent from the upper portions of the valleys occupied by Adams Lake, Shuswap Lake with its various arms, the Arrow Lakes, and the northern part at least of Kootanie Lake.* "In previous publications I have stated the maximum observed height of the main deposits of these silts of the southern part of the Interior Plateau at about 1700 feet,t but later observations show that they are developed to a notable extent at considerably greater eleva- tions. I will here only instance the valleys of Barriere River, a tribu- tary of the North Thompson, Upper Nicola River below Douglas I^ke, and Skuh'-un Creek, a tributary of the Lower Nicola, where thick de- posits of White Silt, cut into terraces, were observed at heights of about 2250, 2500, and :' ' •")0 feet respectively. It is thus probable that we may place the upper level of the silt formation in this region at about 2500 feet, though it is still apparent that the more important develop- ments of the deposit lie below 1700 feet. The silt deposits are found in this part of the Interior Plateau down to heights less than 1000 feet, but it is possible that some of the lower-level deposits have been secondarily formed from the denudation of the higher.'' In my preliminary report on the Southern Portion of the Interior of British Columbia,! some details respecting the White Silt formation in the area of the Kamloops sheet are given, together with r. discussion of the mode of origin of the deposit. From this source v> j following passage may be quoted in further explanation cf the mode of appear- ance and character of the .silts, the special reference being to one of the main developments of the formation at about the level of 1700 feet: — "In the valley of the South Thompson, the silt formation is most char- acteristically represented, forming as before statefl, broad terraces or benches along the sides of the valley, with the surfaces gently slopinj; towards its axis, where the river has formed for itself a deep subsidi ary channel. In some places — as above Kamloops on the south side of the valley — the edge of the White Silt bench has been cut up by little streams descending at times from its summit, into complicated and ragged ridges. The eroded faces are always very steep, and occasion- ally vertical, and in the sunlight have a peculiar glossy shimmer, duo to the great abundance of minute particles of mica, which, when the bank is wot, become arranged parallel to its surfaces and on drying adhere in that position. The bedding is generally almost or quite hori- •The southern jwrtion of this lake has not yet been oxatnined. fRpimrt of Progr»>Hs, (tihjI. Sur. Can., 1877-78, p. 143 n. Quart.Joum.Gool. Soc., vol. XXX VII., p. 275. JRetwrt of Progress, Geol. Surv. Can., 1877-78, pp. 142-14'1. It forma- occupied le Arrow observed rt of the show that ter eleva- a tribu- thick de- 8 of about that we 1 at about t develop- are found than 1000 have been Interior of irmation in scusaion of ! following of appear- ) one of the 700 feet:— 1 most char- terraces or tly slopinj; ep subsidi- outh side of up by little icated and id occasion - imner, due , when the on drying r quite hori- m.Geol. Sot'., "•] WHITE SILT FORMATION. 2H7 n intercalations. zontal and layers of a few inches in thickness succeed one another with great regularity. The deposit is remarkably tine thoughout, and no boulders or stones so large as to imply the action of ice were seen. A short distance below Little Sliuswap Lake, the silts apjiear in a bank about sixty feei above the river, but Ijeyond this are not again met with (to the east) nor were they recognized on any part of the shore of the Great Shuswap Lake." The occurrence of silts interbedded with gravels of local origin, in (iravdl the valley of the Tranquille, has alreiuly been referred to in another connection (p. 274 b) and so has the remarkabledisplay of interbedded silts and gravel on the Thompson some miles above Ashcroft, where such deposits form cliffs 359 feet in height (p. 274 n and Fig. 14, p. 306 B.) Similar interbedded silts and gravels are displayed near the mouth of Cherry Bluff Creek on Kandoops Lake, where cliffs, worn into columnar forms, show well stratified and rounded gravels, hard packed, for a thickness of twenty feet or more. Above these is about fifteen feet of typical White Silt, finely bedded in horizontal layers and some- times holding flattened calcareous nodules. The White Silts areagft'n well e.xpo.sed in high bluffs or cliffs on the line of the railway follow- ing the Thompson between Black Canon and Spatsum station. In illustration of the coarser character of the silt deposits and the Cliaiis'e t<> manner in which the typical development of silts dies away on the Ti"',im'",,,,."''^ lower Thompson, the following notes are given : — The silts are seen fairly well developed about the mouth of the Nicola River and Spence's Bridge, and for a few mi!'>s beyond. But further down, below the r ^ .1 of the Nicoamen Uivor and between that place and Lytton, the scarped banks in which silts might be expected to appear, show instead bedded coa se sands and gravels, with lenticular beds of pale fine sands and only occasional similar beds of silt. These finer beds are well marked and occur at a height of several hundred feet above the river a couple of miles above Lytton on the old wagon-road. They are in general horizontal or nearly so. These deposits, as a whole, appear thus gradually to replace the typical White Silts in descending the river, but it is possible that they may consist of rearranged material of somewhat later date. It is probable also, that in this narrow part of the valley, much of the material has been immediately derived ivoiv. the wash from the slopes of the adjacent hills. Thediscussionof the WhiteSilt formation naturally allies itself closely ^,, ,. ■' •' Miore-lmes or with that of the terraces and shoie-lines, for the body of water in which "ate . the silts were gradually laid down must, obviously, have left some such marginal traces. It is further, however, obvious that the littorpl de- J I- 288 B BRITISH COLUMBIA. ^■Vi Relation to terraces. Special fundi. ti(in» in Soutiiern Interior. HfightM of White Silt. posits of such a body of water would probably not be silty, but rather of the nature of sand or gravel, and that the correlative terraces, whether of erosion or accumulation, cannot be expected to show in themselves, by their character, their connection with the period of formation of the silts. In endeavouring to arrive at the height held by the water at this time, it is moreovei* plain that the highest parts of the silt deposits are alone capable of giving definite information, as the accumulation of the silts may have gone on in some places in water of considerable depth. The heights at which the silts are found, appear to render it probable that some of the lower terraces enumerated in the list already given, may actually be connected with levels held by the body of water in which the White Silts were laid down. The five last terraces of the list (Nos. 36 to 40) may particularly be suspected of standing in this relation to the White Silts, but in one cose only (No. 35) is the terrace- flat itself actually formed of silt. The relative abundance of sometimes faintly impressed but yet well preserved shore-lines, at heights below that of the higher of these ter- races (near to or below the upper limit of the White Silt formation), seems to accord with the date to which this formation must be assigned, which is that of the latest phenomena of the glacial period and attending its close. The circumstance, in the southern part of the Interior Plateau that the White Silts occur at or about the general upper level of the similar deposits found very widely throughout the northern Cordillera,* while at the same time their maximum develop- ment is locally confined to elevations below 1700 feet, though no such important development is noticed elsewhere at a well marked stage below the maximum level, requires explanation. It is bilieved to indicate a partial elevation of the corresponding portion of the Inte- rior Plat>}au, during the period of deposit of the White Silts, which was local in its character and did not affect other portions of the Cordil- lera, t The following is an enumeration of the principal observations of the height of the upper surface of the White Silt formation, obtained in the •Cf. Trans. Royal Soc., Can., vol. VIII, !>. 40. f It apiH'arH to lie (Hiite imKsilile that the HJiore-linHt) lately traced in central Waxhiiigton by Mr. I. C. RuH-ell, at a hori/.on of alioiit 1400 feet aU.vc Hea-level. may repivsent ft further extension (with less considerable depression) of tlieWliite Silt formation. Mr. Russell attributes these tu a hyjiothetical " Lake Lewis," but admits that tiiey may have tieen iiroi.. 2()-37.) o»w»oii. ] WHITE SILT FORMATION. 289 B southern part of the Interior Plateau. Several of these are contained in the Kamloops sheet, but for the purpose of making the evidence more complete, sfjme are quoted from adjacent regions. These last are named in italic letters in the list ; — Feet. 1. Upper Nicola Valltti, betwit'n Xicola Lake and Douglas Lake 2500 2. Valley of Twaal Creek. White silty material fl Twaal Valley passes. Flat terrace-level filling valley lietwe'Mi the h'lls and composed of silts 1830 11. V(ill< II of Deep Creek; i)kaiinf!;Mi Lake. Wide terraee-fiat containing much silty material, but also sometimes s.andy and occasionally stony. .Supposed to represent tlie upjK'r level of silt deposits about this place 1840 12. Valhii of Ohniiifiiin Lsits extend in some places down to the lake level (lloO feet). 1730 1.3. Flat al/out sHiiiiiiit level between .Salmon Arm and outlet of (Jreat Shuswap liake. This is crossed liy the Canadian Pacific railway, and is coin]X)sed to a considerable dejith at least of silts, which are not so pale-coloured as usual. , ; Avenvge highest level 1708 14. f leneral highest level of extensive silty deiH)sits found alMUt K.imltHjj - and eastward. The edge of the de|K)sit here apjiears to be marked by a beach at about 1!I00 feet. See II. 283 b 1700 It is of course impossible to exhibit in detail or describe completely Separation of the circumstances which have led me to regard the White Silts i!is a dis- formadon* tinctive and important member of the glacial series. The appearance ^r."'" °"""' 19 i i 290 B URITISII COLUMBIA. HiltR of HiRh- land Valley. of these depoHits in the field, and their restriction, in mass, to certain levels of the country, appear to justify this view if we. speak alone of the Kamloops sheet, and without reference to the wider developments of White Silts elsewhere found in B.itish Columbia. Deposits of a silty character, however, occur in minor development, and in conse- quence of circumstances more or less strictly local, at various higlier elevations, and thus the mere occurrence of such deposits taken with- out reference to other considerations, is not diagnostic. The only occurrence of silts in mass and forming entire, though low, terraces distinctly abovo the general mnximum level, in the area of the Kamloops sheet, is one met with in the Highland Valley. The silts developed at this place are quite local, and appear in that part of the valley which drains north-westward to the Thompson River, at a level somewhat less than 4000 feet above the sea. Small moraines are also found in this valley, of such a character as to show that a tongue of ice occupied it and pushed south-eastward in it at one stage in the decline of the general Cordilleran glacier. It is supposed that a glacier-lake was here formed between the front of the ice-tongue and the watershed in the valley, in which a certain development of silts took place liefore it was drained (p. 301 u). Silts of LoiiiH Cn-ek Valley. The upper valley of Louis Creek, a short distance beyond the Kam- loops sheet to the eastward, apparently aflFords another case similar to the last and explicable in the same way, which may be briefly referred to l^ecause of its bearing on the general question. This deep valley again slopes in a northerly direction, the stream rising only a short distance from tho north bank of the South Thompson, from which river the valley may be entered by a somewhat remarkable notch in the plateau. In the upper part of the Louis Creek valley, rather impor- tant an(i well marked silty terraces, through the material of which a certain amount of angular rock-debris is scattered, reach up to 34G0 feet. This is approximately the height of the notch above referred to, and there is every appearance to show that through this notch a large stream at one time flowed. This could only have occurred when a A glacier lake, tongue of the retreating glacier still filled the lower and northern pari of the Louis Creek valley, precluding the northward flow of the water, and producing a glacier-lake in which the silts are supposed here to have been locally deposited. Similar - chon Creek. Here the terrace numbered 12 in the list on page 278 n occurs. Rocky prominences standing above it, show long attached tails of drift pointing about S. 50° E., and the surface of the terrace itself is grooved by long hollows parallel in direction, evidently due to the same cause with the ridges, acting at the same time. The terrace mentioned here is at an elevation of 4400 feet, and as the ridges some- what exceed this, they are the highest instances of the structure in question which have been found. In this case it is pretty clear that the drumlin-like ridges and the terrace must either be contemporaneous, or that the terrace is the older. In that of the hill near Stump Lake, the terrace-markings must have been produced either at the same time with the drift tail or at a later date. In both the occurrence of water action in close re- lation to the ridges is apparent. Respecting the physical features of the ragion first described, and physical fea- that in which the main development of such drumlin-like ridges occurs, *'!"•'*.''' '^.^p^^ , , <> drift luljjes it may be explained that, apart from the narrow valley of the Fraser, it forms one of the principal southern outlets of the Interior Plateau of the province. From this it may be argued, that the circumstances attending the flow of the Coi-diileran glacier along this wide depres- sion, were those which gave rise to the ridges, in the manner ordinarily assumed for the formation of drumlins. But the Okanagan Valley, to the esistward, formed a second and at least equally important avenue for the escape of the glacier-ice from the plateau, and in this vicinity, although the circumstances appear to be equally favourable to their producth)n, no similar well-marked ridges are found, and if they occur at all (of which I could not satisfy myself,) they are inconspicuous and insignificant. Drift-ridges of this character are therefore not a geunral normal re- Such ridges suit of glaciation in the region, but are due to some exceptional and '^'"*'' '""'' • relatively local cause, and the fact that they characterize chiefly a wide depressed area in the plateau country, through which the ice is known to have passed in their direction, is not in itself suflicient to show that they have been produced by the passage of such ice; for the vsame physical features would equally have given a similar direction to " \ I u 294 B imtTIHn COLOMBIA. I unipii. any Ixxly of water seeking an outlet, and the existence of high terraces throughout the country, shows that it wivs deeply flooded during a pint or parts of the glacial period, PnibabU- (late Although not in a position to arrive at any definite conclusions v of iiiniiatKiii J <...,., , 1. iM /. of ridKiK. garding the mode or date of origin of these drunilin-like forms, it may b« useful to enumerate the main points which bear upon these ques tions, before leaving the subject. They almost certainly antedate the White Silt formation, which is attributed to the latter part of the second epoch of jjlmiation. Theif is no reason to believe that either ice or water r hed such hi;.'li levels at or after that time, and, moreover, the Whii ilts themselves could scarcely have remained under the stress of ciicumstances such as to account for the production of the drift-ridges. Tlicir iiukIh of This being admitted, it must be supposed that they originated either as a direct result of the passage over the country of the main Cor dilleran glacier, or in consequence of circumstances immediately suc- ceeding that event. They may thus have been formed : — (1) Heiicatli the mass of the great glacier in the manner usually attributed to drumlins. (2) Along the margin of the retreating ice either sub- aerially or below water. (3) By some exceptional and sudden move ment of a great volume of water about the close of the time of maximum glaciation. Against the first hypothesis is the exceptional character of the drift-ridges relatively to the whole area examined, and the freshness of their forms. Had their date been so early, they could scarcely haM; escaped much denudation and extensive b'.'rial during the si'bmergence evidenced by the numerous high-level terraces. They must have been exposed successively at every level to the waves of the declining edge of the water, having already been subjected to the denuding action ui the wat«r flowing from the edge of the retreating glacier itself. whether on land or in a body of water. Under the second hypothesis, it is easy to imagine that tunnel-like cavities may have been produced from time to time by the protrusion of the edge of the glacier over masses of rock, in which deposits resembling the drift-ridges might have been formed. But such cavities should be flaring outward, a form not followed by the depo.sits in question, and the eifects of issuing waters, already alluded to, should be equally manifest in this case. The third hypothesis, assumes that the ridges were produced partly by denudation and partly by accumulation, along the path of some ■ : f «i^ -] MOKAINEH. 29") 11 ;h terraces inng a pun lusiona re ns, it may hese ques 1, which is in. Thi'ii' such hii.'li themselvi's ances such ated either main Cf In the wide though rather high depression which.running from north terriKes, (iui- ^ south, forms the valley of Guichon Creek, there is a remarkable chon Creek, association of moraines and terraces ».-bich must be assigned a proximately contemporaneous origin. Moraines art everywhere abun- dant on the upper part of (juichon Creek to the west of Toon- kwa Lake, as well as to the east and south-east of that lake. In the last-named locality they tend to run north-and-south, and appear to be lateral moraines of a tongue or lobe. All these are at levels approximating to 4000 feet ai.d saow only occasionally some traces of water action. Further down in the Guichon Creek valley to the north of Wit-hes Brook, at a level of about 3500 feet, Hat-topperl moraine-ridges abound, botli parallel to the sides of the valley and more or less directly transverse to it. Some of these have held in ponds, wliicli have now for the most part been drained. On the west side of the valley, below \Vitches Brook, similar closely connected moraines and terraces occur at nearly the same height as liefore, and lateral moraines are very well marked in places on the opposite sido of tlie valley. Again, on the west side of this valley and extendini,' from a point about two miles below Mamit Lake soutiiward for several miles, a remarkable display of rough, irregular moraine-ridges is found. Some of these are nearly transver.se to tlie valley, others, particularly those nearest the preseTit stream, in tlie bottom of the valley, run nearly parallel with it, but little general regularity in trend is apparent. The moraine-ridges are here full of granite blocks and boulders,and are .so closely crowded together that they areofteii sepai-ated only by narrow V-sha' >ed valleys. As noted elsewhere, (p. 279 h) terraces appear on the slopes of this part of the valley high above these moraines, which may be slated to occur at levels of 3300 to 3200 feet. Anions; the moraines, terraces formed of their material aLso appear, and in fol- lowing the valley for a couple of miles further, the terraces become the more prominent feature, but still show, by the occasional pot-holes •1 MORAINES. 299 B found to- i890 feet, show any )tice some jsitions of T the con- ry shortly 3r marked e noted as rom north eniarkabhi issigned a here abun- of Toon- e. In the appear to lit levels e traces of ley to the Hat-topped valley and ve held in II the west connected before, and ipositp side I extei\din.i,' for several le-ridjies is ,ey, otliers, tuni of tlie ity in trenil blocks and ^n separated 9 b) terraces se moraines, ^t. Anionj; , and in fol- become the al pot-holes which indent them, their superposition on moraine material. On the summit of the plateau, some miles to the west of this part of Guichon Creek, about the watershed between it and the main Nicola River, at heights of 4300 to 4400 feet, moraines and terraces are again found so closely associated as to suggest contemporaneity, but those belong to a different and probably earlier sta ,'e, and are possibly due to different conditions from those which have just been described. Reverting to the moraines and terraces of the lower part of Guichon other iu- Creek, it is interesting to note (though in doing so reference nmst be ■■'t'"ic!'« 'jf , 1 /■ 11 11 11^1 iii'iraiiif's iiiui made to a tract of country somewhat beyond the south edge of the tt'rrac''s. map) how frequent the association of moi-aines and terraces is at a level approximately identical. In different places along the Coldwater Valley and following the Voght Valley to the sources of Otter River, extending thus about thirty-five miles southward from the locality particularly referred to as Guichon Creek, terraces were noted, in as- cending, to be replaced by moraines at levels of 3310, 3l'20, 3230, 32G0 and 3290 feet approximately. Taking into account the somewhat indeterminate character of the phenomenon and possible errors of obsr/vation in height, the facts seem to prove tliat water stood for some little time in this region at about the elevation indicated. A comparison of the circumstances here, with the generally higher levels of similar instances to the northward, suggests that an increa.s- ing depth of water followed the retreating edge of the Cordilleran glacier.* The following are a few additional instances of places in which I'm-tlu'i- fx- moraines were noted to have a considerable development, but in which ni"nJne». tiiey did not show any distinct relation to terraces. Some of these moraines may bo due to ice moving from the higher parts of the region at dates subsequent to that of the main glaciation, while others are pretty certainly the result of the Cordilleran glacier itself in its waning stages. l^j)per part of Afooro Ci'oek, to south-ea.st of Trout Lake, numerous moraine-iidges, often parallel to the valley. Elevation about 3r)U0 feet. Meadow Creek valley —This contains numerous hillocks and trans- verse ridges, evidently representing moraines, but partly i)uried in horizontal deposits which have formed in ponds and marshes betw(!en them. Elevation aiwnt 4000 feet. Murray Creek valley— Numerous moraine-ridges occur in liie wide part of the valley, where a tributary stream enters, at an tlevation of about 3790 feet. Terraces are found about fifty feet lower. Cf. TiaiiH. Ro Soo. Ciiii., vol. VIII., Hect. IV , \k 42. < ! 300 B BRITISH COLUMBIA. Moraines (inniiniiig lukes. IiiHtaucBs. Blue-earth Creek, a tributary of Hat Creek — In the lower part of the valley of this stream, transverse, gravelly, moraiue-ridges occur at a level of about 4550 feet and somewhat lower. These appear to have been formed by an oflFshoot of the tongue of glacier-ice which at one time pushed southward along the upper valley of Hat Creek. Medicine Creek, also a tributary of Hat Creek— Moraines occur in the lower part of this valley between about 3500 and 4000 feet. They have probably been produced in the same way with those last noted. Vicinity of McLean Lake, between Ashcroft and Hat Creek — Very distinct moraine-ridges occur to the south of this lake, on the slopes of the hill, with easterly and westerly trends and deep narrow interven- ing valleys. Elevation about 4000 feet. Cattle Valley, running north from McLean Lake, is aiso in its southe"n part encumbered and often ridged across by moraines. All these moraines seem to have been formed by a tongue of ice pushing southward along the Cattle Valley. Upper valley of Pavilion Creek, where it runs through the higiier parts of the Pavilion Mountains — Much earthy drift in this part of the valley, apparently arranged in the form of moraines formed by an oflFshoot of ice pushing eastward. Valley connecting Copper Creek with Criss Creek. Near the lakes in its northern part, at heights somewhat greater than 3000 feet, numerous small moraines, both longitudinal and transverse. Moraines directly concsrned in the formation of lakes have not been enumerated in the foregoing pages. They do not of course diS'er in any essential respect from many of the others, but it has been tiiought best to note a few conspicuous instances of these together. Already several cases have been alluded to of ponds and lakelets held in b)- moraines but since emptied by the cutting down of their issuing streams. There are also almost innumerable cases of small ponds which lie in pot-holes in morainic country, or between moraine- ridges, which have not been considered to be worthy of separate note. Trout Lake, at the head of Meadow Greek, (4100 feet) is evident!)' held in by more or less degraded moraines. Fish Lake and Big Fish Lake on Greenstone Creek are similarly moraine-dammed at eleva- tions of 4840 to 4100 feet. The moraines closing the first ai-e more or les-^ degraded by weathering or water action, but in the second case they arc well preserved. These moraines are in part transverse to the valley but also in part parallel to it, and it is not possible to state whether they were produced by a tongue of the Cordilleran glacier or by local glaciera moving down from the adjacent plateaux. A small lake or '■] MORAINES. 301 B m In- (■eiural n ■ marks cm uioraiiK's. pond south of the middle part of Meadow Creek, not named on the map, is surrounded by moraine ridges. It here seems probable that a local glacier, descending from the eastward, may account for tiie mor- aines and for the preservation of the basin of this little lake. The lakes of the Highland Valley, with heights of about 3900 feet, are also mor- aine-dammed. As previously stated (p. 290 h) it appears that the ice forming these /noraines came from the westward. The lakes in the northern part of Glen Hart valley, again lie between moraines wiiich have been thrown down in the valley. Though not certain, it ap- peared to be probable that the ice forming tiiese was a local tongue which for a time moved northward in the valley, towards Clinton. The small lakes in the southern part of this valley seem to be caused by fans which have locally interrupted the drainage. On the Green Timber plateau it has already been noted that lakes inclosed between moraines are common. The numerous lakes about Skoatl Point, are not evidently due to moraines, but appear rather to owe their exist- ence to material of the character of boulder-clay, irregularly distributed over a previously uneven rocky floor. The foregoing notes on moraines in general are not entirely satisfac- tory, because it is impossible to discuss individual cases at such length as to render manifest tiie bearing of the local topography on their existence or position. They may suriice, however, to show how commonly mor- aines are met with in the region covered by tiie Kamloops sheet, which may be taken as a specimen of much of the Interior Plateau of British Columbia. One fact is so striking as to deserve special mention, i. e. that no very large moraines liave been found. The moraiiie-ridges i-eldom attain a height of one hundred feet above their liases and are often not fifty fett in he'fht. It is furtlier notable, that large boulders occur only exceptioh.illy and locally in them, wiiile much of their material appears essentially to resemble that of the boulder-clay, or, wht .e •' shows points of difference, these tend to evidence greater water action and more rounding of the contained atony material. All the circumstances seem to show tiiat, though tlie ice occasionally ceased its retreat and even advanced again for a certain distance, the main movement in retreat was rather rapid, and most of the material thrown into the form of moraines when a halt occurred, or a temporary re- advance happened, was tliat which otherwise would have gone to form ordinary boulder-ciay, or which had already been deposited in tliat form and was subsequently ploughed up. It is further remarkable, that no moraines have been recognized in this Nomp at low area below a level of about 3000 feet above the sea, or in other ''^''"' None large. 302 B BRITISH COLUMBIA. Absent fi-om vicinit^V of drift-ridges. words, that none of the lower and hirger valleys are characterized by moraines. Various explanations may be suggested to account for this circumstance. It may be supposed, for instance, tliat such moraines as were produced in these lower valleys weresub.sequently destroyed during the period of denudation which appears to have followed the main glaciation. (See pp. 251 n, 271 b). It may again be suggested, that the considerable depth of subaqueous deposits which occurred in these lower valleys covered and masked the moraines, or such remnants as were left of them. It is believed that both these causes may have cooperated, but in the present state of our knowlbv^^jj it is not deemed advisable to discuss the matter further. In conclusion, still another point may be remarked on. This is the relative, or possibly nearly complete, absence of recognizable moraines in the belt of country which is principally characterized by the occur- rence of the peculiar drift-ridges which have been described in a preceding part of this portion of the report (p. 291 b). This statement applies principally to the notable valley which runs southward from Kamloops. As no satisfactory reason can be given to explain the original absence or paucity of moraines in this particular valley, it becomes reasonable to suggest that the special conditions which have produced the ridges have removed, or have so changed as to obsciire, the older moraines. If it be admitted that the ridges resulted from a rush of flood-water at one particular stage of the glacial period, it is easily conceivable that such moraines as m.ay have remained, resulting from the antecedent retreat of the Cordilleran glacier, may have lost their identity at this time and in the area so affected. Glacial and Post -Glacial Histoky of tiik Fkasek and Thompson \''allkvs. VhIu'vs cxca- The excavation of the great valleys now occupied by the Eraser and the rii'ocoiiT Thompson rivers, is believed to have been accomplished wholly or almost wholly in the interval between the close of the JNIiorene Tertiary and the Vjeginning of the glacial period. Many observed facts show tlie post-Miocene age of these valleys, but perhaps the most striking is the occurrence near Leon and Pavilion creeks and again about Big Bar Creek (the last-named situated a short distance beyond the edge of the Kamloops sheet) of horizontal basalts and sandstones referable to the Miocene, on both sides of the valley but now cut through and fringing, far up, the edges of the plateau. Such excavation as may have occurred in these valleys during or after the glacial period, is, in fact, quite insignificant, compared to the pre-glacial erosion. It H.] HISTORY OK FRASER AND THOMPSON VALLEYS. 303 n terized by nt for this oraines as red (luring the main i, that the 1 in these mnants as may have ot deemed This is the e moraines the occur- ribed in a statement ward from 3xpUiin the r valley, it which have to obsctire, Ited from a period, it is [], resulting r have lost Thompson Fraser and wholly or jne Tertiary facts show t striking is about Big lid the edge les referable through and cavation as acial period, erosion. It is nevertheless a matter of some interest, particularly in its intimate connection with the problems offered by tiie occurrence of alluvial gold along these rivers. As already noted, there can be little doubt that both tliese great Siiiiiinaiy of valleys were throughout more or less deeply filled with boulder- Z\y. clay, or analogous drift deposits, at the close of the first maximum of glaciation. This epoch is sup})Osed to ha\ e been followed by a sub- sidence, during which, not only these valleys but much of the adjacent plateau country was deeply Hooded, and this again is believed to have been succeeded by a ret'levation, that was either a forerunner of or coincided with the earlier stages of a second less severe and more local glaciation. The evidence relied on to show tliat the Fraser and Thompson valleys were during this time of elevation practically cleared of the boulder-clay deposits which had previously encumbered them, is referred to on page 271 n. On another page of this Report (p. 275 n) certain remarkable cones of dejection, composed chieily of boulders and formed opposite the mouths of some streams which enter the Fraser and Thompson valleys, are described, and it is explained that these prol)ably had their origin after the removal of the greater part of the boulder-clay, and during the earlier portion of a still later period of flooding of the valleys, before the close of which the White Silt for- mation was produced. It is difficult, in the presence oft so many interlocking phenomena, to arrive at certainty as to the precise nature of the train of events, but that here sketched now ippears to me to be the most probable one, and is referred to, with reserve, as a basis of arrangement for our ideas in respect to the later history of these great valleys. In addition to the rough cones of dejection above alluded to, which X;\t>ii-i> (if were evidently formed only where there was an adequate supply '^"''' of large boulders and occasional heavy local floods sufficient to transport these, many " fans " occur along these valleys opposite the mouths of streams. These are with probability assigned to the same period. In my Preliminary lleport on the Southei'n Portion of the Interior of British Columbia (1877) I h^ve named tlie accumula- tions here referred to "fans " (p. 10 n) following Drew* and no better descriptive name can probably be suggested for them. Fans may be formed at the opening of a narrow valley upon a plain or How pro- wider valley either bidow water, as of a lake, or sub-aerially. In the former ''"'^'^'''• case, their slope from the mouth of tiie tributary valley, is generally low, *liuart. Journ. Geol. Soc, vol. XXIX., p. 441. ' \ 304 B BRITISH COLUMBIA. 3 m- Ss Fan« older than river- terraces. Later aiidi- tiuiis tu fans. their material is usually pretty well stratified, and under certain circum- stances they become nearly flat-topped and pass into ordii delta- plain.**. When formed sub-aerially, they are built up somewhat more irregularly, by the lateral deposition of debris by the stream itself, which continually changes its course to those parts of the fan whicli are lowest or least blocked by previously deposited matter. Fans are thus, in another direction, connected with cones of dejection, from which they differ essentially only in the greater fineness of their mateiial. Fans of both kinds described above, are very common throughout the southern interior of British Columbia, but those to which particular attention is here drawn, in the Fraser and Thompson valleys, have evidently been produced at a time when these valleys were flooded. This is shown, first by the nature and arrangement of their materials, second by the fact that some of them have been able to spread completely across the valleys, which tliey could never have done while a large and rapid river occupied the valley. The larger fans, of which there are many along the Fraser and Thorap.son valleys, have evidently been produced at a time previous to that of the formation of the river-terraces, which took place durini,' the post-glacial period, for these terraces are cut out in the material with which the valleys were partially refilled after the removal of the boulder-clay and previous to and during the time of the White Silt formation. As instances of these older and more important fans, those of La-loo- wissin Creek, another stre:iin two miles above thi!=, and Cinquefoil Creek may be referred to. There is also a wide fan of this character at the mouth of Deadman River, to which the damming' back of the water of Kainloops Lake is evidently largely due. Even the fan at the mouth of Hoey Creek, at Lillooet, though a small one, i.s cut away into terraces below and only its upper part remains intact. There are of course many smaller fans of later date than the terraces and of sub-at'rial origin. These are often spread out upon the surfaces of some of the terraces, and doubtless the construction of fans has never entirely ceased since the beginning of the older ones and is .still to some extent in progress. Many of the older fans Imve also, at later dates, received superficial additions sub-aerially. A g .od instance of this is seen at Eleven-mile Creek, two miles above Fountain Creek, where the stratified gravels and sands of an old and evidently sub-aqueous fan, are irregularly covered by a rough wash much resembling boulder- clay, but distinctly a deposit brought down by the stream. At a still later date, and in consequence of the lowering of the river-bed into which the stream discharges, the stream has cut a ravine through both vallr foui whic out few foi'i Tl of th whic entir whic sandf but I area, silts very ■J HISTORY OF FKASER AND THOMPSON VALLEYS. 305 B a circum- delta- hat more am itself, an which Fans are ;ion, from of their common t those to rhompson we valleys ^ement of been able lever have ("raser and jrevious to tee durinj,' e material removal of the White rtant fans, 6 thi?, and fan of this :inuni.' back Even the lall one, is lins intact. the terraces ihe surfaces )f fans has and is still ,lso, at later instance of Ireek, where sub-aqueous ing boulder- At a still ver-bed into hrough both deposits. This subsequent trenching of the old fans is another feature common to most, or all of them. Fig. 12. — sectional diagram of a fan projected across the wide river valley, during a period of suhmergence. a. Position oi ri;riner river-bed. m,r~— 1 Fig. 1.3. — sectional diatiram, showing new conditions on REiJLEVATION. a. Positiim of foniier rivt'r-lx>cl. h. Ntw river-l)i'(l, fcjrced against tlio rocky wall of the vallt^y, and cutting terraces in the old tan. Where the larger old fans have been projected quite across the river- Ktrioton valley, the river, on resuminj,' its course when the flooded state of the courseof river, valley ceased, has selected the lowest point, and is therefore usually found to be pressed close to the side of the valley opposite to that on which the stream j)roduciiig the fan rnters. Here it has very often cut out part of its new bed in the rocks of the side of the valley , and in a few cases has cut a new channel largely in the rock and has thus formed a little cafion. These old fans are of course only special cases in the general process Connection of the filling of theFraser and Thompson valleys with drift materials, ",',':'' ^""'"y- , , . . fiUnig gener- whicli ensued on tiieir flooding and ctmtinued doubtless during thi^ ally. entire period of the formation of the White Silts. The materials with which the valleys were thus partially filled, consist of stratified gravels, sands and silts, evidencing no doubt, more or less cuirent action, but such as may have effected a body of water with a large sectional area, and very different from any deposits of the present rivers. The silts are in certain places largely developed, and in some instances are very closely connected with, if they do not actually form a part of the fans. The principal localities in which the silty deposits are shown have already been referred to (p. 283 b). 20 ' \ M ggBg 306 B BRITISH COLUMBIA. t Valleys at cloeo of sub- mergence. Depth ofJiH>st- glacial excaviv tioD. During the subsidence of the waters in which the White Silts were laid down so widely in this part of the province, it is probable that a certain amount of erosion of a genei-al character occurred, in these main val- leys of outflow, before the water became actually concentrated into true river-channels. In any case, as a result of this period, the valleys were left, about the time that true river conditions resumed, deeply floored with drift deposits, in which duriug the post-glacial and mod- ern period, with the country standing at or about its present elevation relatively to the sea, the Fraser and 'i ;iompson have reexcavated their comparatively narrow actual channels, producing series of ri's-er- terraces as they cut down. The depth of this post-glacial erosion varies considerably in differ- ent places, but can generally be approximately determined, by produc- ing the light slopes of the remaining portions of the old floor, which can often be recognized, till these meet in the axis of the valley. Notes made in this manner, show that the Fraser Valley, near the mouth of Cinquefoil Creek and thence to Lillooet, was filled to a depth of 350 to 550 feet above the present water-level. From Lillooet to Pavilion Creek, the depth of filling appears to have averaged about 400 feet, while above Pavilion Creek it becomes rather deeper, and near the place at which the Fraser enters the Kamloops sheet, it appears to have been as much as 600 to 800 feet. On the Thompson River near Ashcroft, the surface of the drift deposits tilling the valley stood at least 300 feet, and possibly m much as 500 feet, above the present river-level. Fig. 14. — section of east side of Thompson river, above the bonaparte. Illustrating the post-glar'al reexcavation of the Thompson Valley in later-glacial or interglftcial deposits of the White Silt i)eriod. (See p. 325 b). a. Stratified sands and gravels, often false-bedded, about 30 feet. b. Wliite Silts, in vertical bluffs, aliout 35 feet. c. Stratified gravels, alxiut 30 feet. d. Re-de[K)sited silts and gravels, filling post-glacial river-bed, 15 to 20 feet. The lower line of the section is at the railway track, about 40 feet above the river_ The bank below the railway appeai-s to consist chiefly of stratified gravels, but is imperfectly exixjsed. ra ''• 5 y. ^ M i ■r. H fW -^ Tl of th but I lifter sidpH ail e> inclu wlier very beyoi botto twecr old b« sides, tiincej where liave Uridg. l)y ro( accoiu done 8 miles heightl and ca old, th rocky Foi- to ha\ tity an belief lower rocky course in so Rev Creel be sue, which rocks flats of above tliroug 2( ■] HISTORY or FRA8ER A\D THOMPSON VALLETS. 307 H The figures just given afford an approximate measure of the depth Hilation of of the post-ghicial erosion accomplislied by the Fraser and Thompson, ,,, MHd-rnck.' but this cutting-down was probably carried on pretty rapidly at lirst,and afterwards more slowly, as the river began to transgress on thc^ locky sides of the valley, or to reach its old rocky bed. The general result of an examination of the Fraser and Thompson rivers, so far as these are included in the map, from this latter point of view, seems to prove, that where the old rocky bed has been deepened at all, this has been to a very inconsiderable amount. Near the southern edge of the map and beyond it, the Fraser appears to have cut somewhat deeper than the |.'r_^^,.r ninth bottom of the prc-glacial valley. Further up, above Lytton and be. '" Fouutain. tween Cinquefoil Creek and Lillooet, it can scarcely have reached its old bed, for though in some places boidered by solid rock on both sides, the gravelly material of the terraces, often for considerable dis- tances, descends to and apparently below the level of the water. Thus, where rock shows on both banks, the river must be supposed to have cut its new channel across projecting points. From Lillooet Bridge to Fountain Creek, however, the river is very generally bordered by rocks on both si' , in such a way as to show that it has probably accomplished some . ,e erosion in the rock itself. It has certainly done so in the east-and-west portion of this part of its course, for some miles below Fountain Creek, where very steep rocky walls rise to a height of 100 to 300 feet above the water. The valley is here narrow and cafion-like and the new course of the river must coincide with the old, the former channel having been again cleared out between the same rocky walls. For some distance above Fountain Creek, the river seems scarcely Above Foun- to have yec regained its old level, but aVjove Pavilion Cref;k, the quan- tity and manner of appearing of the rock along its margins, leads to the belief that it has reached its old level or has even cut down somewhat lower than it. There are also in this part of the river, several little rocky canons, which evidently show where the river has taken a new course in the wide trough-like valley and has cut across points of rock in so doing (p. 327 b). Reverting to the east-and-west part of the river below Fountain Peo'liar con- /-i 1 . 1 !• • -11 (litiiins iH-ar Creek, it may be added that the conditions met with there, appear to Kuuiitain. be such as to indicate a slight differential uplift of this part of its bed, which may have taken place along the axis of the ridge of Cretaceous rocks which crosses the river. It is, moreover, notable that no low river- flats of considerable size occur along the river for a considerable distance above this place, the new trench now occupied by the river, being cut through nearly the whole depth of the glacial filling. This may indi- 20i mm TlioiiiiMou River. af .«;* Depth of Kainloiips Lake. 308 B BHITISH COLUMBIA. cate that it required a long time for the river to completely clear out the filling of the canon-like portion below Fountain Creek. It can- not be supposed that any possible differential uplift was sufficient in amount to account for this particular feature. It certainly seems, however, that this canon-like part of the river has been one of the latest to be fully excavated in pre-glacial times, and that a waterfall may have long existed here. That part of the Thompson above Lyt- ton which lies in an east-and-west bearing, has a like, new, narro\v and raw character, and appears to require a similar explanation. For the Thompson River generally, above the part just referred to, the evidence is not perfectly conclusive, but appears to point to the fact that it now flows little if at all below its pre-glacial level. It is certain, on the other hand, that the North Thompson, for at least twenty-fivo miles above Kamloops, and the South Thompson throughout its length, or to the point at which it issues from the Shus- wap lakes, have not rnywhere cut down to the level of tlieir p-e- glacial beds ; nor is the fall on the.se lengths of river, governed by Uie level of Kamloops Lake, at present sufhcient to enable them to accom- plish any appreciable amount of excavation. KAMLOOPS, NICOLA AND BONAPARTE lAkES. A cer'.ain part cl' the valley of the Thompson is occupied by Kan? loops Lake, eighteen miles in length, and if the history of the later Tertiary erosion is correctly given on page 318 B, the trough now occupied by the lake mu;,t have originated in tlie Liter Pliocene. Some soundings \ven> made in this lake by myself in 1877, but in 189-i Mr. McEvoy carried out a number of soundings in all parts of its e.vtent. The greatest depth found was 498 feet, between the eastern part of Battle and Cherry Bluffs, and the middle of the lake was found to bo continuously greater than 400 feet in depth from this place to aV>o:it opposite Six- mile Point, a length of nine miles. Tlie part of the basin below 400 feet, is both deepest and widest toward the upper end of the lake. Tin' lake is almost certainly in part a rock basin, for althougii the fan from Deadman River is partly accountable for the height of its water-sur- face, the character of the valley beluw, is such as to show that it could at no time have afforded free drainage to the deeper basin of the laki' at the present relative levels. Peculiar con- The lake has therefore the general character of a fiord or fiord-lake, hike!"" "^ ""* but differs completely from the.se in not being related in the usu.il way to a mountain range. It lias, it is true, in a hilly country, but one which is still essentially a part of the Interior Plateau, where the main clear out It can- ufficient in nly seems, one of the a waterfall above Lyt 3W, narro\v Ltion. For ■red to, the to the fact pson, for at 1 Thompson m the Shus- )f tlieir p-e- med by the n to accom- ly Kamloops ter Tertiary upied by the mdiiigs were 3voy carrietl i'he greatest Battle anfl continuously ipposite Six- i below too le lake. The the fiin from ts water-sur- that it could 1 of the lake 9r fiord lake, in the usual ntry, but one liere the main mmm K AM LOOPS r.AKK 309 II % ti ti! ^ i hJ — a i o o Ji i, kp^ < o s i I ^} J! !-■ i« ■H ' 3i0 B BRITISn COLUMBIA. Mode of for- mation doubt- ful. Nicola Lako. Bonaparte Lake. direction of glaciation is nearly transverse to it ; and although the ice of the glacial period may have had something to do with clearing the debris from its hollow (see p. 258 b) it does not appear possible, under any circumstances, to consider it as the result of glacial erosion. The question of the mode of origin of this lake is one deserving fur- ther inquiry, and requiring comparison with fiord-lakes such as the Shuswap Lakes. I will here only add, that it seems most easily "^ plicable on the hypothesis of local changes in elevation of the 8u:'{;v by which this part of the Thompson Valley, after its excavation, be- came relatively depressed. Such a movement may have been accom- panied by faulting, evidences of which at a date posterior to the Mio- cene are found near both ends of the lake. Tt will be noted, how- ever, that this supposition does not accord with the permanence of re- lative level of the surface assumed in connection with the origin of the early Pliocene valleys. The matter is still an open question. A few sound- A part of Nicola Lake is also included by the map. ings made in this lake, near the south line of the raaj), showed the bottom to be almost perfectly flat, with a depth of 130 to 150 feet. In Bonaparte Lake, no soundings were made, but the shelving character of its shores indicate that it is probably not very deep. In (lonnection with the theory of a relative depres^^ion of a portion of the surface of the Interior Plattsau, it is worth notintr that the three large lakes of this district lie nearly in line, north-and- south, though each of them is transverse to this general direction. MINERALS OF ECONOMIC VALUE. Object of this chapter. In the following pages, the conclusions respecting the distribution and mode of occurrence of placer gold which result from the geological study of the region here reportctl upon, nre given in summarized form. Tliis is followed by notes on the various deposits of ores and other useful minerals, including details not given in the foregoing sections of the report, and referring, wherever necessary, to these pages. AUIHPKROUS PLACER DEPOSITS OF DIFKKRENT PERIOnS. Investigation for Hource.i of gold. One of the more important (|uestions of an ecouoinio knn! connected with the particular region here described, but ni'^ which 's oommon also to the greater part of British Columbia, is ti.atof th' v.. i . s of the gold contained in the jilaccr de[)osits of the nvers p \d streams. In investigating this, it is desirable not only that ',uartz-veins traversing the older rocks should be examined, but also, from the generally close }$ / -] PLACKR DEPOSITS OF DIFFERENT PERIODS. 311 B ;h the ice aring the ble, under on. rving fur- leh as the easily ■■'- e su-'frv ation, be- en accom- the Mio- )te(l, how- nce of re- igin of the ew sound- liowed the 50 feet. In character connection bhe surface 26 lakes of o of them is hstribution B geological irized form, and other ng sections ages. )ns. 1 connected I :s common '. 1. .sof the breams. In s traversing lerally close associations of gold with pyrites, that any considerable masses of rock which have become charged with pyrites should be tested, and that attention should further be given to the conglomerates found to occur in the several formations, representing as these do, the river wash or shore work of former periods of denudation and concentration. With this object in view, specimens were collected from a number of localities, Assays made. during the progress ( t' the geological work, and of thc.-.e, those which appeared to be the more important, by reason of their mass or because of other circumstances, have been subjected to a'^jsay in the laboratory of the Survey. In most cases, specimens of this kind naturally prove to contain Pyritous rocks nothing, but where they are found to hold traces of gold, this may be g,'icif' "'"^ "" taken as an incentive to further examination of the deposits. The following is a list of specinioas examined of pyritizod rocks, very often in a decomposed and rusty state, which yielded traces of gold : — 1. Decomposed syenitic rock with pvriles. !Near the little lake shown on the map to the south of Edwards Creek. 2. Decomposed rocks (quartzites ?) of the Cache Creek formation. Red Hill, 4A miles south of Cornwall Creek and ^ mile east of the \F\i!on-road. ' 3. Rusty quartzite, 1^ miles west of northern part of Stump Lake, i; i ai ruginous deposit with basalt. Clinton Creek, above the lOWi. . r Hoddish quartzite, 7| miles north of Clinton, at east base of Mail, J .\Iountains. 6. Rusty, shattered and altered rock. Near north edge of Granite. Greit Rock-slide, Thompson River. Gold trace. Silver 01 75 oz. to th'j ton. 7. A considerably metamorphosed greenish-gray rock, "apparently, clastic, with grains of iron- and wipper-pyrites. In-kai kuh' Creek,v I'hompson River. A mile east of the railway. N. .Shattered and dolomitized rock. Near the wagon-road between ■V auvloops Ferry and Tranquille. 9. Decomposed anu rusty diabase rock. East side of Nicola Lake, half a mile from the head of the lake. 10. Shattered, rusty Cretaceous rocks, near mouth of Texas Creek, Eraser i^iver. The following specimens afforded no trace of gold : — 11. Df^'omposed schists, 4+ miles south of Cornwall Creek and IJ mile west of the wagon-road. Trace of silver. I'vritouH rtK'ks witliout nu\d. 312 B BRITISH COLUMBIA. 12. Rusty decomposed volcanic rock. Cairn Mountain, Clear Mountain Range. 13. Rusty decomposed rock. Hills south of Nicola Lake, IJ mile east of i 1 et, 14. Dcc d and rusty schists. East side Napier Lake. 15. Rust) ^aceous rocks, forming wide zones in the formation. West side of Fraser River, three miles above Fountain Creek. 16. Shattered and pyritized rock of the Cache Creek formation. Wagon-road 2^ miles north of Hat Creek. 17. Quartz and wad. Clinton Creek, above the town. 18. Red and purple quartz or quartzite. In drift at Clinton. 19. Silicified and rusty quartzite. Cretaceous. One mile east of Fountain Creek, near the wagon-road. 20. Rusty, shattered, and altered rock showing some copper carbon- ates. Near north edge of granite, (ireat Rock-slide, Thompson River. Referring to the foregoing assays, the following notes may be added respecting a few of the localities represented which appear to me to warrant further investigation as possible sources of gold in paying quantities. No. 1. The syenitic rock met with near Edwards Creek, is peculiar in its character and appearance and is evidently a true intrusive mass (see p. 246 b). It contains a considerable proportion of pyrites, which is evidently auriferous, and it is quite possible that some portion of this mass may prove to contain a workable quantity of gold, constituting a deposit of low grade, but obtainable in large quantity at an almost nominal cost. Gold was not only found in this rock on assay, but also observed in a thin slice, microscopically examined. The .syenite intru- sion extends for a considerable distance in a south-eastward direction, beyond the limits of the Kamloops sheet.* Cnislied pyiitl- No. 2. The shattered and reddened rocks of some parts of the Cftche rv recently been drawn to the auriferoiiK (f rttiiitoK of tlie Tinibarra p)l(l-fielmatite, in the gravel deposits near Clinton, has been noticed in a previous report.* Inquiries made on the spot, show that such specimens, consisting of jaspei-y hiematite with quartz, have been found in three separate places near the west end of the tov.ii of Clinton, and one of these, subjected to assay, is reported as yielding gold to the value of S300 to the ton. The source from which these fragments have been derived has not yet been ascertained, but the gravelly mounds in or near wiiicli they occur', are evidently of the character of moraines, due either to the period of recession of the main Cordilleran glacier, or to that of local glaciers of somewhat later date. In the first cases, the origin of the loose materiiil should be ^'^ i/i"l'iiljle ' ^ origin. sought for to the north-north-westward, somewhere along the eastern watershed of the Marble Mountains ; in the second, probably more to the north-westward, but in either case in some part of the Marble Mountain range or in its vicinity. In the same gra. elly deposits, spe- cimens of red (juartzites or silicified argillites occur. Tiiese are not very abundant, but their occurrence is rather unusual in this region. Tims, when in travelling northward from Clinton specimens of similar red rocks were found from time to time, till rocks of the same character were found in place at the east base of the Marble JMountains between Clinton Creak and Sandy Creek, it appeared to be probai)le that the source of the associates of the auriferous specimens, at least, had been discovered. No. 5 of the foregoing list, represents the rock found at this place and it proved to contain, as will be observed, traces of gold. It would thus appear, that the ea^^tern edge and tlie eastward slopes of the Mai'ble Mountains, well deserve to be closely examined and searched tor the possil)le place of origin of the richly gold-bearing specimens first alluded to, the clue being in the first instance afforded by the f(eneral study of the character and direction of the glaciation by which the country has been affected. Passing now to the second class of possibly auriferous materials roiiglnnii>r- above alluded to, the conglomerates of various ages, it may be gu'hl. ' * Annnal Rejtort, (tool. Hurv. Can., vol. HI. (N.S.) pp. 5-1 h, 144 u. 314 B BRITISH COLUMBIA. Specimens examined. Gold in Oli- gocene con- glomeraten. explained, in the first place, that to test these thoroughly, a con- siderable mass of rock in each case should be pulverised and sampled in order to obtain a specimen entirely suited for assay. This arises from the fact that such conglomerates may be ex- pected to contain visible grains or pellets of gold, like those met with in the more recent placers, that these may be but sparingly distri- buted and that large masses of intervening rock may be practically barren. The means were not at hand to subject the conglomerates met with to treatment of this kind, and the specimens actually assayed have been merely hand specimens, so that the investigation of the pos- sibly auriferous character of the conglomerates must be regarded as be- ing as yet very incomplete. The assays actually made have, moreover, been confined to a small number of conglomerates, all of Tertiary age but two, which are Cretaceous. The following is a list of such assays : 1. Rusty Cretaceous conglomerate. Cliff to the east of the Fraser opposite Lillooet Bridge (p. 152 n). No gold. 2. Rust_y cretaceoc conglomerate. East side of mouth of Botanie Creek (p. 153 b). No gold. 3. Cherty conglomerate (Oligocene). Near Copper Creek (p. 162 b). Traces of gold. 4. Cherty conglomerates (Oligocene) one mile south of Lac a la Fourche (p. 69 n). Traces of gold. (This locality is situated some miles beyond the edge of the present map — about 12 miles south of Nicola Lake, in the valley of McDonald River or Quilchenna Creek.) 5. Rough basal conglomerate (Oligocene). Plateau 2 miles south of Thompson, opposite mouth of Deadman. Traces of gold (p. 100 b). 6. Outlier of dolomitic conglomerate (Oligocene). Garde Laft'erty, north of Kamloops (p. 163 b). No gold. 7. Cherty conglomerate (Oligocene). Hat Creek (p. 212 b). No gold. 8. Cherty conglomerate (Oligocene). Near McLean Lake (p. 213 li). No gold. It thus appears, that in three localities of the occurrence of the peculiar cherty conglomerates of the lower Tertiary, traces of gold have been found. In three other Tertiary conglomerate specimens, and in the two only specimens of Cretaceous conglomerates examined, no gold has been found. It may, I think, be assumed that wherevei traces of gold can be detected in a hand specimen of a conglomerate, it is worth while to further examine the deposit, to investigate particularly its lower layer upon the old bed-rock if this can be reached, to test in succession each of the superposed beds wnich shows points of difi"erence, and to seek for any layers in which notable •1 PLACER DEPOSITS OF DIFFERENT PERIODS. 315 B ', > y, a con- rised and for assay. y be ex- met with gly distri- practically glomerates lly assayed of the pos- rded as be- , moreover, artiary age iich assays : the Fraser . of Botanie (p. 162 b). )f Lac a lit 1 some miles th of Nicohi ek.) iles south of (p. 100 b). de Laft'erty, b). No gold. te(p. 213 b). rence of the aces of gold e specimens. es examined, hat wherever gloraei-ate, it ) investigate this can hi- w.iich shows hich notable quantities of pyrites, magnetite or other heavy minerals liave ac- cumulated. Magnetite is perhaps the most constant associate of gold in placer deposits of all kinds, and a ready mode of ascertaining ii presence in conglomerates is found in pulverising these and apply- ing the magnet to the powder. It ia not neces.sary to enter at greater length into this general sub- ComiJosition ject. Some remarks upon it will be found in luy previously published iri,,nierutes" Mineral Wealth of British Columbia.* It need here only be added that the coincidence of the belt of Cretaceous rocks, holding much conglomerate, with the line of the Fraser River, which in its recent placers has proved to be richly auriferous, suggests the possibility that the gold found may in part have been derived secondaril}' from these conglomerates. The proximity of the conglomerates to the schistose and slaty rocks of the same region, frum veins in which most of the gold has probably been originally derived, in itself affords some reason to assume the existence of gold in these conglomerates. On the other hand, the great abundance of diabase and diahase-like fragments in the conglomeratt;s, may show that the distinctively gold-bearing rocks were not at the time supplying much material towards the formation of the conglomerates. The composition of the early Tertiary (Oligocene) conglomerates is in geueml very different. Their material i has been very larg(?ly derived from the outcrops of the lower parts of the Caclxe. (JxfisJi J:ocks» to the east of the main limestone belt. Xllfise rocks are traversed by very numerous, though generally small, (juartz- veins and the occurrence of more or less gold in their debris, wherever this has been properly concentrated by natural agencies, may be looked for with considerable confifleiice, It appeal's to be proljable, for example, that gold found in Criss Creek has been derived from these conglomerates, which are cut through by it. None of the older conglomerates of the Cache Creek formation, found in limited beds on and near the North Thompson, have been examined for gold. Since the above notes on the jiossible occurrence of workable auri- Kxiieiitnce lerous conglomerates in British Coiuml)ia were written, adclitional encouragement to investigation in this direction has been given by development elsewhere. The continued and vast importance of beds of this character in the Transvaal may be alluded to. In California, Mr. R. L. Dunn has lately describetl Cretaceous conglomerates which have proved to contain payable gold and have been the .source nf lo(;al placers ;f and in Central Otago, New Zealand, Mr. A. JIcKay tabu- * Annual Kcport, (ieul. Surv. Can. vol. TTI. (X.S.) p. 47u, et tci/. t California State Mining Bumi\i, iL'tli Hipoit (l.S!)4), p. 45!!. 'ij^^^H "v.^tJ^^^I^H JH 1; ^^^^^^^^^^m f^^^^^m ^^i , 316 B I're-Miocene •erosion. BRITISH COLUMBIA. Diflferf nt sys- tems of Ter- tiary rivers. Uriunajfe wys- tein buried. lates seven or eight " auriferous wash-drifts " of which four are of Cretaceous or Tertiary age.* The older Tertiary or Oligoceiie conglomerates above referred to, represent remaining portions of the products of the earliest great period of Tertiary denudation. It is elsewhere explained (p. 69 h) that these beds subsequently suffered some disturbance, at least locally, and that during a succeeding period of considerable duration, denudation again progressed actively. A new or considerably modified system of drainage must at this time have been produced. This period of waste was brought to a close by he great volcanic eruptions of the Miocene, and these must undoubtedly have covered up many stream- and river- beds of the time. The quantity of volcanic products due to this period in the area of the present map, must have been such as to entirely obliterate the previously existing drainage system, the evidence being that all, or nearly all, the valleys of the present rivers and streams, have since been excavated along new lines, largely determined in the first instance by the distribution and local mass of the volcanic accu- mulations which gave form to the surface.f Whenever these later erosions, whether confined to the valleys of streams or extending more widely from these, have cut down to the old pre-Miocene surface, any gold which may have been contained in the old stream-courses of this surface has of course been redistributed and has gone toward the enrichment of the niotlern gravels. But where the volcanic rocks remain, the old drainage-channels prob- ably still exist beneath them intact. In districts based upon the older rocks referred to the Cache Creek formation, these channels may rea- sonably be expected to contain more or less gold. This is, however, less pi'obable, where the underlying rocks are those of the Nicola for mation. Very few instances are found in the Kamloops sheet, in which basaltic or other volcanic rocks still actually floor valleys antedating the Miocene volcanic period. The valley between the Marble IMoun- tains and Edge Hills is, however, probably a case of this kind, and it is possible that parts of an old chanjiel may exist here beneath the ba.salts. In most cases, there is im existing indication of the position of such old drainage-channels, and as a matter of fact none such had yet been exploited. It is quite clear, however, that large * (ieol. RejKirts on Older Auriferous Drifts of Central Otagfo (1804), pp. 3S, 34. t On the general subject of the physical features at different periods and the epochs of denudation and deiKwition. reference may lie made to a paiH'r by tiie WTitei- on the Later Pliysiotfraphical (ieologv of tlie Rocky Mountaii Uepfion in Canada. Trans. Royal Soc. Can., vol. VIII., sect. IV., 18!K).' tlio the whi( •] Pi-.xJ'ilK DEPOSITS OF DIFFERENT PEIUODS. relatively-level tracts now covered by basaltic or other volcanic rocks, such as those of the Green Timber, Bonaparte, and Arrowstone Hills plateaux, must have been provided witli well developed systems of drainage before the time at which they became covered with volcanic products, and it can scarcely be doubted that some at least of tliese will yet be discovered, and followed up if they should be found to yield gold in payable quantity. Some of the occurrences of gold in the gravels of existing rivprs and ''"ssit'lc i"')b- streams, very possibly depend on the robbing by tiiese rivers of pre- iilufcrs. Miocene placers. Thus, the local occurrence of coarse gold on the Thompson, near Nicoamen, is difficult of explanation except on this hypothesis. Tlie Tertiary rocks, including sedimentary materials bt>low, and consisting entirely of volcanic rocks above, here overlap the steeply-sloping edge of the granitic rocks of the Scarped i\Ii)untains. It is almost certain that this margin of the old rock-surface conti- nues to slope down beneath the Tertiary strata below the present river-level, and tliat if followed, it would terminate in the bottoin of a pre-Miocene valley, now covered ; though whether this may have NiciKiim-u. drained to the northward or to the southward idong the base of the granitic hills cannut be determined. The border of the Tertiary rocks in contact with the granitic materials, is considerably broken up and distributed, so that it may easily have happened that portions of the old valley-doposits have been brought up and have yielded their contained gold to the denudation of the present river. The cxplana. tion suggested in this case is of course merely a conjectural one, but it is instanced as an example of the manner in which a study of the geological conditions and history may assist in detcrii.ining the most probable places in which to seek for the older auriferous deposits. (See p. 107 b.) It is to be noted, that in the case of any auriferous gravels beneath ();<1 piavcls the volcanic rocks of the Tertiary, these will have been exempt from i',f jut'i'irm^'' the scouring and transporting action of ice during the glacial period, ''""■ which has undoubtedly resulted, in the case of the more modern de- posits, in obscuring and complicating the question of the origin of the gold, as well as in breaking the continuity of the deposits, and in some instances, probably, in dispersing concentrations of gold naturally brought about before that period. Another and still later system of old valleys occurs in the district, i.;,i,.iy pn,,. to which a few words of description may be given, for though no at- '^^''"'' ^■'''ll''ys- tempt is made. in the present Report to repeat in detail the study of the -trssp" ffli 318 B BKITI8H COM'MBIA. Later Plio- ceue erosion. IB 0. successive physiographical events of the Tertiary, on which the paper last referred to may be consulted, it is desirable from an economic point of view to point out the various directions in which search for the older gold placers may be made. This system of valleys is referred to the Pliocene, or latest Tertiary period, the close of which is marked by the onset of the conditions of the glacial period.* When the great period of accumulation of Miocene volcanic materials upon the surface of the Interior Plateau came to an end, there is reason to believe that the country stood at p iovel consider- ably lower than the present, relatively to the sea. The streams of the new drainage system which outlined itself, appear to have possessed rather low gradients, but their action was long continued, and resulted in considerable denudation. The streams themselves, in many cases appear to have excavated nearly to the maximum depth which the height of the country admitted, and to have produced somewhat wide, but usually not very deep, trough-like valleys, which may still be recognized in many places and which are generally still occupied by existing streams, though in some cases now interrupted or abandoned in consequence of later changes. After this action had been in progress for a long interval, a very considerable and general ele ration of this part of the Cordilleran region must have occurred, by which the gradients and powers of erosion of the rivers became greatly increased. A comparison of the average levels of the old valleys with that of the present levels of the Fraser and Thompson in their vicinity, leads to the belief that this elevation must have amounted to about 3200 feet. Great changes effected at this . time. The results of this great increase in the elevation of the land were important. Such rivers as the Fraser and Thompson, fed by the perennial snows of extensive mountainous districts about their sources, were then enabled, by the increased gradients given to them, tc cut down so rapidly as compared to other streams less copiously supplied, that they become the main drainage-channels of the country. From the low levels thus soon achieved by these main streams, their lateral branches cut back rapidly in some cases trenching the bottoms of the valleys of the earlier Pliocene erosions with deep newly cut ravines, in others crossing them and diverting their waters to new and more direct courses. Thus great changes were worked on the drainage system of the region as a whole, and the system of water- 'Ibid. p. 16, et scq. \ he paper seonomic h search /alleys is which is volcanic o an end, consider- ms of the possessed i resulted lany cases which the rhat wide, y still be icupied by ibandoned ml, a very ^ordilleran powers of son of the els of the : that this land were ed by the bout their n to them, s copiously le country, earns, their he bottoms ) newly cut bers to new :ed on the m of water- ••WMM.] PLACKH DEPOSITS OF DIFFEBENT PERIODS. 319 B courses as it now exists, was, in respect to all its main features, completed.* In the following list, the best marked examples of the early I'liocene Hfi^jlits of valleys of low gradient met with in the Kamloops sheet, are enumer- v"ii;\„ '"*^*'"'' ated. The elevations set opposite the names of the several streams, are those ascertained for the lower remaining parts of ^,he old valleys, below which, in each case, the existing stream falls into a steep gorge- like valley, which it descends to one or other of the main river-valleys, or to some deeply cut tributary of these : Feet. Meadow Creek (upper valley) 3,350 Piikaist-Cieek ( " ) 3,7r>0 Witches Brook ( " ) .S,0-)0 Three- lake Valley (south part) '2,~iH) Kelley Creek (lower part) aud Junction Valley 3,3tH) Cache Creek (upper valley) 2,050 La-loo-wissin Creek(upper valley) 3,4.50 Pavilion Creek 2,.S(X) A careful inspection of the map, with its contour-lines and the ele- Possibly anri- vations otherwise noted upon it, will afford more information on this ''^'■'°"'*- subject than any further general description could give. From what has already been stated, it will be evident that wherever the early Plio- cene valleys have been excavated on or near to areas of the older rocks, and particularly those of the Cache Creek formation, placer deposits of gold referable to the time of erosion of these valleys may be looked for, It must be borne it mind, however, that these valleys lay open to the work of the ice of the glacial period, and that it is probably in the main, if not alone, in such of them as lie transverse to the general direction of motion of this ice, that placer deposits may be expected ptill to remain intact. Where the direction of the old and wide valley nearly coincided with that of the motion of the Cor- dilleran glacier, it is probable that in most cases the original deposits may have been swept out to the bottom by this agent. * It may be ajipropriate to note hei-e, that much remains to be ascertained i»i detail, respecting the progress and various arrests of the i)Ost-Miocene jirriod of t-osion. Many interesting details are yet to be exjilainod. A subsidiary feature of this kind, and one of some iniiHirtance, occurs in the vicinity of Kaml(K)ps lake, where the roek.v l)c)ttoms of wide trough-like valleys, into which the modern streams of the lower parts of the Tranquille and of Copi>ev Creek liave cut, have an elevation of about 800 feet above tlie present lake (1900 to 2000 feet above sea-level. ) The terrace-like main bottom- level of the Thompson valley near Eight-mile Creek, is nearly the same, aud the evidence ap|>ear8 to show an ep<,ch of stability of some duration, Ixjtween tliat of the low eleva- tion of the early Pliocene a;u! that of the high elevation of the- later I'HcK'ene. The notably low and wide valley or rhe lower Deadnian, unless it maybe assumed to l)e due to faulting at the time nieui'ioned in pages 175 n, 310 b, likewise awaits explaniv- tion, lieing otneri*'ise apparently inconsistent with the course traced out for the for- mation of the Old cache Creek valley (p. 320 b.) i kmlm 320 B UUITI8H COLUMBIA. [iiNtancnM. Old Cilclie Creek. Pans Lake Valley. Thrfelake Valley. Evente of gla- cial periinl af- fecting gold deposits. By reason of the character of the rocks through which they are in part excavated, and becar.se of tlieir direction relatively to that of the general glaciutio.' the Kelley Cr»-ek and Junction Valley, together with the higher or early Pliocene valleys of Pavilion Creek and C/iiclie Creek, appear to be, amongst those ibo 'e enrmerated, the most likely to contiiin old gold place. s beneath their more recent filling of drift deposits. The upper valley, of Cache Creek has been particularly in- stanced in the pp per already referred to, (p. Id et seq.) and is there shown on a special map. It may be traced upon the Kamloops sheet, following the Pa.ss Valley eastvvard, crossing the Deadman lliver, con- tinuing by the Red Lakes to the Tranquille lliver, nearly following,' this river for some miles, then crossing the Middle Fork and Wu* ing Creek above their mouths and reaching the Carde LaflFerty by Lake. In thi.s instance, the water which originally flowed thiv^^^ the old valley appears to have been intercepted at several points by Eight-mile Creek, Deadman River and the Tran((uille Oliver, all dis charging at right angles toward the great later valley of the Thompson. The only portion of this particular early Pliocene valley which was excavated in possibly gold-bearing rocks, is its eastern part, toward the (larde Lafterty. This part may not only have obtained some gold directly from veins in the schistose argillites of that vicinity, but is also known to have been engaged in carrying the denuded material of the older Tertiary conglomerates, of which remnants are still found there. It would thus appear, that the valley in which Pass Lake lies, may still contain some of the old auriferous gravels of the early Pliocene, in the lower deposits tilling it, and that it is very po.s.sibly to the sub- sequent robbing of such old placer.^;, that the auriferous character of the lower part of the present Tranquille Valley is due. The Three-lake V^alley, enumerated in the list just given, appears to be B ipeci;;! case. There is some reason to suppose that tlie Fr.tser River, before it cut through the Cretaceous ridge near Fountain, flowed for a time througli this valley. That the valley is deeply tilled with drift deposits, is shown by tiie disappearance of streams which flow into it and the subsequent reappearance of their waters in springs in its southern part. The trend of this valley i.s, however, such that the ice of the Cordilleran glacier must have flowed almost directly along it, and this circumstance renders it doubtful to what extent any auriferous gravels which may be supposed to have been depositetl in it, still remain there undisturbed, beneath the modern co"er. In outlining the history of the recent denudation of the country, we have now arrived at a time in which the deep valleys of the Fraserand its main tributary the Thompson were foi med. The next event was the -] GOLD IN FRA8KR AND THOMPSON VALLEYS. 321 II are in t of the ler witli 1 Cache st likely of drift larly in is there ips sheet, ver, con- Eollowin!^ I Wat thiv.. , points by r, all dis- hompson. vhich WHS •t, toward some {;<)ld ity, but is Qaterial <>t^ itill found Lake lies, yr Pliocene, ,o the Rul> laracter of appears to tlie Fraser Fountain, 3eply tilled ams which in sprinj;s such that ist directly liat extent |i deposited ;ountry, we Fraser and ent was the spread of the ice of the Cordilleran glacier over the whole region. The conditions thus brought about and the changes produced, it has been endeavoured, as far as possible, to follow in foregoing pages. Tiie resulting effects on the occurrence and distribution of gold in the Fraser and Thompson valleys, may now be alluded to, in the endeavour to follow the story of their gold accunudations, in the light of tlie geological investigation of the region. The succeeding notes on this subject, must be read in connection with what has already been stated respecting the glacial and post-glacial Instory of these great valleys. Conditions afferting the Occnm'enci' and Dixtribution of (Jold P/timr.'i In the Valleys of the Fraser and Thompson. The concentration of gold in certain layersof limited thickness, such as Original am- to form rich auriferous placer deposits, has without doubt occurred onh- 'i,.'!.'""'!'."'i During Tliomiisuu valleys. during the periods of erosion or cutting out of the valleys, the long period of erosion in which the great troughdike valleys of the Fraser and Thompson were originally produced, in the later part of the Tertiary era, analogy with other well-known cases leads us to be- lieve that rich gold-bearing deposits must have been formed along tlus rivers. Where the river itself cut its way through auriferous rocks, as was doubtloss the case along many parts of the Fraser and some parts at least of the Thompson, or where rapid tributaries which were engaged in excavating such rocks entered the main stream, deposits of ' coarse ' gold must have been produced. The rapid current which un- doubtedly characterized these rivers at this time, would naturally lead to the trailing of the finer particles of gold along their entire lengths. Had the miner been on hand to exploit the j)rehistoric placers, as they existed at the close of this long period of denudation, he would in all probability have found them to be richer and more regular in char- acter than any of those discovered by the pioneers of 1838 and 1859. Tn Cariboo, it is believed that the richest old channels, such as those of Williams and Lightning creeks, met with beneath the boulderclay, actu.ally date from this period. A thick rib of the Cordilleran glacier must, however, have followed the north-and-south valley of the Fraser, and it is possible that, as a result, the pre-glacial river-gravels were either entirely removed or much displaced and disturbed. It is not known that any pre-glacial placers have been found or worked on Pre-giacial either the Fraser or Thompson. What has already been said as to'''""'"'"''*,""* . . 1-11 • '^'^^ tested. the reaches of the Fraser in which its postglacial channel is still" higher than the level of the old pre-glacial rock-floor (p. 307b), shows 21 ■ 322 B BRITIsa COLUMBIA. Gold dissemi- nated ill boulder-clay. Later glacial concentration and tilling of vailoys. Poet-glacial concent iT.tion, (f.-i 1 deiHwit- ed in various old (jhannelH it is to be possible, that if spared by the great glacier, portions of this old channel may yet remain, though below the water-level, and there- fore very didicult of access. Much of the material which must have filled the old channel, to- gether with debris fioin a distance, may doubtless have been incor- porated in the boulder-clay, but the mass of this deposit is so thor- oughly commingled, that whatever gold may occur in it must now be sparingly and irregularly disseminated. It is likely that the next im- j)ortant concentration of gold, occurred during the later time at whicli the boulder-clay itself became subject to denudation, and sorae placei deposits may yet be discovered in the gravels due to thii period of waste, such as those found overlying remnants of boulder-clay near Ashcroft (p. 273 it). In the succeeding period, during which the large valleys were again being filled with detf itus while they were in o flooded state, a certain amount of gold was no doubt also brought into them, whether from the transport of material from the boulder-days of the adjacent slopes, or that derived directly from the waste of rocks then in progress. Such gold must, however, have been irregularly distrib- uted through the entiie mass of the d iposits which went toward fill- ing the large valley.s, and only in certain places, where streams brought their material from richly auriferous localities, can it be sup- posed that these deposits as a whole — whether horizor.tally arranged or in the form of fans — may contain enough gold to enable them to be worked at a profit. When, however, the post-glacial L.T08ion of the Fraser and Thomp- son val'eys began, >.he conditions were changed. The rivers in gradu- ally cutting down through the drift,-filling, swung from side to side of the often widt^ valleys, so that the surface of every river-terrace may be considered as more or less exactly representing part of the bed of th.) river at a certain stage in its descent. In e:ich of these old river-beds, a certain proportion of the gold, V hicli iiad been disseminated in the material cut away and removed by water, becume concentrated ; and when the river cut down to a still lower stage, this was left in the gravelly and bouldery wash of the old bod. In most cases, however, these beds were in turn cut away by the river when operating at a still lower stage, and thus instead of contin- uous river-channels at various elevations, we find only the bouldery and gravelly materials of parts of old river-beds, capping more or less irrc<2;ular and limited terrace-flats. It will further be obvious, that whenever a lower and newer channel of the river, in the course of this UWOON. ~j GOLD IN FRA8EB AND THOMPSON VALI.KYS. 323 B ons of this and theic- bannel, to- )een incor- i is so thor- ist now be he next ini- le at 'vhicli some placei' ii period of r-r-clay near ih the large y were in i> jfought into Ider-clays of jf rocks then arly distrib- toward fill- ere streams an it be sup- \y arranged e them to be and Thorn p- ers in gradu- do to side of terrace may if the bed of of the gohl, \nd removed iwn to a still sli of the old away by the ■ad of conti li- the bouldeiy more or less obvious, that course of this period of denudation, either coincided with or cut across any portion of an older bed, this would be robbed of its accumulated gold and the later river-bed would be correspondingly enriched locally. This, with tb;i o.'igina! differences in richness which must have existed as between tlifferent places, goes far to explain the varying character of the placers met with on the several terraces, or benches along the valley and in the bars of the modern river. It will also be apparent that, other things being equal, the lowest and latest river channel should be the I-Atest chmi- richest, for though in the progres.s of those cha.iges a considerable part of the gold must have become so highly comminuted as to be car_ ried away by the stream and altogether lost, and though other por. tions of it were left on the rearranged surfaces of the river-terraces, a considerable proportion of the whole amount originally contained in the drift-filling of the valley, must in the end have been concentrated > in the bed of the present river. The foregoing considerations may appear to be of a somewhat the- Actual imxli- oretical character, but most of them scarcely admit of doubt, and the ",f mid" " "'^' conclusions arrived at agree with the facts as observer] by the miners. It is thus of importance to clearly picture to the mind the way in which the placer deposits were formed, in order to recognize the places and conditions under which they should besought for. Miners who have worked upon the ' benches ' of the Fraser and the Thomp- son, affirm that the payable gold (which except in certain limited local- ities is usually fine) is invariably, or almost invariably, found in a yellow layer a few inches to a foot or more in thickness, jiot far be- low the surface of each bench, and very generally in association with a coarse bouldery or gravelly wash. The appearance of neai i , all the old claims, most of the richest of which were worked out i.umy years ago, tallies with these statements and with the explanti'ion of them CuHmiiI to above given. It is not merely that the mining ceased to be ^'i'''"" li'-yt'''' profitable when a certain depth of cover was exceeded, for in many cases a. good head of water was available, and if recurrent pay-streaks had existed throughout the thickness of the benches, tliese could in such instances easily have been sluiced away and the whole of the gold " ■ obtained. The general mass of the material composing the terraces or benches along these rivers has not been proved to be payable when worked by ordinary rough d'» thods. When such work is enteTed into, \ the miner is called upon to concentrate disseminated deposits, like those which hiive elsewhere been concentrated naturally for him by the river itself. 21i ."^S'lS-lU'lll-J 324 u BRITISH COLUMBIA. Deix)sit8 suit- The question is often asked — In a valley which has proved to eel for hy- |jg g^ richly auriferous as that of the Fraser, may not the terraces draulic work. •' . ' i i i everywhere be profitably worked by the hydraulic method on the large scale ? So far as a limited experience of the method goes, this does not seem to be the case, but it may be considered as demonstrated that some portions at least of the great mass of terraced deposits which still remain in the valley, are susceptible of profitable treatment by this method. One or two trials will not test this important matter completely, and in further endeavour towards its solution, it is necessary to bear in mind the general principles governing the formation of the placer deposits as a whole. The most favourable places for such fur- ther trials, are doubtless those ir. which rapid tributaries from known auriferous districts have piled their debris into the old valley of the « Fraser. Of the.se Cayoosh Creek is probably the best known at the pre- sent time, and it may be considered as quite within the bounds of pro- bability, thai, the terrace materials in the vicinity of the mouth of tiiis stream, at least, will prove to justify operations on a large scale. Van Winkle Hydraulic Mine. Since the foregoing pages were written, hydraulic work carried out at Van Winkle Flat, about two miles above Lytton, has sujiplied new information on the character of the gravels of the Fras(U' Valley, which goes far to bear out the views previously expressed. A good hydraulic plant has been established at this place, with the object of working the whole mass of the higher terraces or benches, which rise from the river in successive steps towards the base of the moun- tains on the west. In 1894, an excellent section was found in the hydraulic pit, running backfrom the river for alx)ut 1200 feet. The character of the work is described in the summary report for 1894 (p. 17 a). The river-flat, originally worked by hand, as well as some parts of the edges, of an older river-channel now about 100 feet above the stream, proved to be rich in gold ; but the yield from the hydraulii- workings had not, at the time of my visit, fully realized the anticipn tions of the owners. It is here proposed, with the aid of the annexed diagram, and as a type of the structure of the drift materials found in this part of the Fraser Valley, to briefly explain the characU'r of the deposits exposed, Sertion Hoen The river-tlat (d), a few feet only above high-water, is not actually '" ''• cut across by the lino of sluices, where the first principal terrace (cj rises steeply from the river to a height of about 100 feet. The next terrace (h) is about sixty feet higher, and there are other ii-rogular terraces at still greater heights. the III- on has mail the N. ] GOLD IN VRASER AND THOMPSON VALLEYS. 325 B Fig. 16. — section at van winkle hydraulic mine, fraser river.* a. Deposit foniicd in yalley dmiiig time of floocliiig (Wliite Silt |)erio('t). 6. Material filling an early river-cliannel nf the succeeding jw^ricHl of erosion. c. Material filling a later rivei-cliannel of the same period, with (r') marginal flol. Surv. Can., vol. III. (N.S.), i.i>. 24 u 2'.l n, 115 u - 11!1 h. •] GOLD IN PHASER AN» THOMPSON VALLEYS. 327 R inds, con- esenb the id by the cetch was )f the de- id nearly nticipated ,t no auri- irt of its le gravels unerative. i, but the ntly been it river, local ori- below the i,nd crowd- 11 manifest • from the 3 probably btless alsi) !nt of the > have had Fniser and le Mineral and much work, has ilong these ,0 yield for derived al t" the Fraser ig was coii- uicing, and has never uture alonii d hydraulic the Fraser, the publica. ) II - 119 H. tion just referred to.* Upon an examination of this admittedly in- complete list, the following observations bearing on the part of the river included in the present map, are based. — " From a point on the river a few miles below Boston Bar (about sixteen miles above Yale) to Sisco Flat, (a short way below Lytton) a distance in all of about twenty-five miles, rich deposits of ' heavy ' gold wei'e worked. Further up the river is a second run of 'heavy ' gold, the limits of which can not now be so well defined, but which appears to have extended from a point about half-way between Lytton and Foster's Bar, to some little distance above Fountain. Here nuggets of some size were occasion- ally unearthed, and there were some exceptionally rich diggings. On the Thompson, the vicinity of Nicoamen, where the original gold dis- covery occurred, has always been noted for its ' coarse ' gold." Where upon these large streams the river-bars only have been mined, Auiifcron.- all signs of such mining disappear each year, in consequence of the jl!\'s siumu hv descent of the flood-water of summer, but wherever the mining has "•'' work. extended to the terraces or benches, its traces remain. Thus, apart from our knowledge of the fact that almost every bar in the length of the Fraser included by the map has at one time or other been worked over, the evidences of bench mining are alone sufficient to show that this whole length has been more or le.ss richly auriferous. Such traces are less conspicuous in the case of the Thompson River, and tiie evidence is that it was found to be much less continuously gold-bearing. Had we a complete plan of the Fraser, upon a sufficiently large scale, Hhmtration nl on which all the benches, with the areas occupied by solid rock and j,'|!."^'*p" ""* "" the patches upon which mining lias been conducted were laid down, it would enable us to gain a pretty clear idea of the probable relations of the present stream to the pre-glacial one, both in regard to the elevation of the latter relatively to the former and to the manner in which the older concentrations have enriched some parts of the present I'iver. No such general plan has yet been attempted, but a small part of the river which has been sketched with these points in view, is here presented as an example. It may be added, however, that to any one examining the river, with a just appreciation of the facts of its history as here outlined, the relations spoken of are quite apparent on the ground, and that these will doubtless be studied on tiie spot by the miner and all promising places prospected at the same time. It may, however, be stated, that several places were seen along that Drift-filled part of the river above Fountain, in which the existence of an old drift- J,,' " "(i'*^^ " tilled channel, with rocky sides, appeared to be very probable. One of these occurs on the east side of the river opposite Black Hill Creek ; * ()/). eit, p. 115 H. ct Mq. J;i: M 328 B BRITISH COLUMBIA. another, though in this case a very short length of old channel, may occur about half a mile below Kelley Creek, on the west side of the present river ; a third, where the channel is probably three-quarters of a mile in length, is two miles below the point at which the Fraser enters the map-sheet, also on the west side of the river. #N Fig. 17.— .sketch-plan of part of fraser river, near texas and cinquefoil cheek.h. TlIiiHtrating tlu' iflatimis of the pre-glacial aiul iiiiKleni cliannels of the river and the ]K)8ition of alluvial gold deiK>8itH. Tlie ])rul)able course of tlie pre-glacial chan- nel, shown l\v dot-and-dash line. Rocky hlutfH, shown in heavy iiachures ; bluffs or banks of ij^ravel, in lighter Iiachures. Parts of low ' benches ' worked over for gold, stippled. Trails and loutes shown by dotted lines. (Ap])ro.\imate scale, KtH cliain8=l incli). Recapitula- In recapitulation of the foregoing discussion, it would appear that deposits "" ^'^® conglomerates and gravels of the district included in the subjoining list, are either known to be auriferous or may bo regarded as probable or possible sources of gold. The list begins with the older deposits, but does not inckde the still older conglomerates of the Cache Creek and '^:.,mbrian, less regularly developed and of wiiicli no tests have been made : — 1. Cretaceous Conglomen-tes. — No gtld yet found. J KECAPITUIATION OF PLACER DEPOSITS. 329 B 2. Oligocene Tertiary Conglomerates. — Traces of gold found. 3. Miocene Conglomerates or buried river gravels. — Not yet dis- covered in this district, though sand.stones and water-bedded tufl'aceous rocks are known in some places, 4. Early Pliocene Gravels : a. In high-level valleys. — Buried under drift deposits wherever remaining ; not prospected. b. Along main river-valleys. — Excavated and redistributed in suc- ceeding period. 5. Later Pliocene Gravels. — Possibly in part still remaining along Eraser, Thompson and other deep valleys, and if so, probably in some places above, in others below the present river-level. These would undoubtedly be richly auriferous, but no such deposits appear yet to have been discovered or worked by miners. 6. Boulder-clay.— In this the gold is probably everywhere too much disseminated for profitable working. 7. Intorgbicial gravels, silts, etc. — These have constituted most of the drift-filling of the Eraser and Thompson at one period, and still form the mass of the river-terraces — probably containing payable gold in places. 8. Gravels and bouldery deposits capping river-terraces. — These, with the gravels of the next class, have been those chiefly worked on the Eraser and Thompson. Nearly everywhei'e auriferous along these rivers, and often elsewhere. 9. Modern river gravels. — Nearly everywhere auriferous along the Eraser, frequently so on the Thompson, and often elsewhere. Other Placer Deposits Woiked. The following brief notes refer to other livers and streams in the <'"lil '»' "t''^''' district, upon wh'.ch gold working has been carried on. They are de- rived in part from the general list given in m) Mineral Wealth of British Columbia. Vnyoosh Creek. — This is again referred to in connection with auri- p"'' ferous quartz (p. JSS u). It was not discovered to contain valuable placers till 188G, but has since been continuously worked by Chinese. In the first year it yielded 725 ounces of gold. I^p to 1890, inclu- sive, it is estimated that gold to the value of $160,000 had been ob- tained.* *Re|)ort of Mininter of Mines of British Columbia, 1800, p. 'A7(S. )sli Bridge River Honapnrtc River. 330 B BRITISH COLUMBIA. The part of this creek which has been worked, is about five miles in length, extending from the flat land where it meets the stream from Seton Lake, as far up as the Bonanza mine. Throughout this part of its length, the valley is bordered on both sides by high mountains, and is never wide. The greater part of the gold has been obtained below the " ca3on," in a length of about two miles ; but the richest claims of all occurred in a distance of about 1000 feet above the "canon," where the old rock-bottom of the stream was reached. Else- where it has not been "bottomed," for though still rapid, the stream has been blocked by rock-slides from the mountains, in such a manner as to lead to the accumulation of great quantities of gravelly deposits in it. A.ll the gold obtained is coarse. The Enterprise Company of Vancouver, has been engaged for some years in endeavouring to open the lower part of the creek, just above the flat, for hydraulic working, by providing a channel deep enough to drain the old rock- bottom. In 1892 :\ tunnel was completed for this purpose at a cost of §25,000, and wd. ,vas continued in 1893 and 1894, although with only moderate returns, much difficulty being experienced in dealing with large boulders. Bridge Eirei: — Discovered in 1858, and soon prospected nearly to its sources, some mining being done throughout. The coarsest gold is reported to be found along the first ten miles from the mouth, further on, for about fifteen miles, more or less scale gold was obtained. Still further up, the river becomes rather slack and little gold has been got, though seme gold occurs in all the tributary streams. A good deal of mining has been done of late years in the vicinity of the South Fork, which is reached by a journey of three or four days from Lillooet, via Seton Lake and across the mountains. It is reported that one nugget weighing 32 ounces was found five miles up Bridge River, and that in 1866 twelve Chinese miners obtained gold to the value of $66,000 by wing-damming. The part of Bridge River included by the map, flows swiftly in a deep, mountain-bordereil valley not of great width, in the bottom of which the stream itself has cut a nearly vertical-sided trench, averag- ing about fifty feet in depth, with rocky walls. The rocks belong to the Cretaceous formation. Patches of terrace-deposits occur at various elevations up to 300 or 400 feet above the water, those at lower levels being flat, while the higher ones slope toward the axis of the valley. Bonaparte River. — More or less placer mining has occurred along the lower part of this stream, below Cache Creek. On its tributaries, Hat Creek and Scottie Creek, gold has also been found, but in small ■] VARIOUS PLACER DEPOSITS. 331 H quantities. The lower deposits of an old valley, which leaves the Bonaparte three mijes above its mouth and is followed southward by the wagon- road, may be worthy of examination. TranquiUe liicrr. — Gold was discovered here in 1858, and appears Traiumille to have been worked with little interruption ever since, chiefly by '^^'' Chinese. For many years, twenty to thirty Chinese have been con- tinuously employed here, but latterly the number has decreased and the earnings are now supposed to be small. The gravels worked are those of the bed and banks of the streams, with narrow Hats adjacent to it, but in 1893 the miners began to pay attention to the benches on the west side of the creek. Arrangements have also been made by a company to begin hydraulic work on the gravels along the east side of the valley. Gold is said to have been found for a distance of eight miles in all up the stream, but the working has been practically confined to a length of three or four miles of the lower, narrow and canon-like part of the valley. The gold is scaly and a little platinum is associated with it. Even the narrow lower part of the valley still holds considerable masses of gravels interstratified with silts, with which it has at one time been filled. These belong to No. 7 of the classification given on page 329 n, and may be found to contain suffi cient gold for hydraulic working. The origin of the gold in this valley is somewhat obscure. Thjmain Source of trokl.. stream apparently flows throughout upon Tertiary volcanic rocks which can scarcely be supposed to be auriferous. Its branch, Watching Creek, drains a considerable area of argillites, etc., holding some quartz-veins, but the gold has not been traced up to this branch. It is possible, however, that in some places the lower part of the river may reach older Tertiary gravels, like those of which remnants are found on the Garde LafFerty. It is also possible, that gold has been carried into the valley from the slaty rocks or conglomerates of the (rarde Laiferty by means of the cross valley from Lac le Bois or that of Pass Lake, while the last-mentioned old valley maj itself still con- tain gravelly deposits of later Pliocene age. (p. 320 b.) Xirola River. — Scale gold may be found along all that part of the Nicola River., i^ower Nicola included in the map, but no work of importance has ever been done and the quantity of gold is probably small. Upper Nicola River. — Gold was found and worked to a limited ex- tent on this stream in 188V, just above Douglas Lako The gold was course and was found upon bed-rock, but only on sloping surfaces, as no attempt was made to reach the bottom of the old valhn'. Some gold has also been found along the river between Douglas and Nicola 332 B BRITISH COLUMBIA. North Thomp- son. TribiuarieH of North Thomp- son. Deadmaii River. Ray Creek. lakes, but it was probably unremunerative, as very little work was done. It is noteworthy, however, that all this part of the country has been very little prospected, though the abundance of slaty rocks with quartz-veins and their proximity to the granites, would seem to render it promising. North Thompson. — No part of this river within the limits of the pre- sent map, appears to have been found to yield much gold. Some of the river-bars at one time paid to work, particularly along the lower part of the river. The following tributaries of the North Thompson are knownto have yielded more or less gold. Jamieaon Creek. — Some mining was formerly done on the lower parts of this stream. The gold is probably locally derived from veins like those elsewhere described (p. 336 b.) Louis Creek. — It is reported that gold to the value of $8 to §10 a day to the hand was obtained here in 1861. Chinese and other miners have occasionally worked here since, chiefly in and just below the canon, near the mouth of the treek. Higher tributaries to the south- eastward considered promising. Barriere River. — Mining is reported to have occurred on this stream on a limited scale in 1861, but no particulars can be obtained. Running across between the Barriere River and Louis Creek, about two miles to the east of the North Thompson, is a well marked high valley. This is continued also to the north of the Barriere for some miles, when it runs out obliquely on the edge of the North Thompson valley. It reaches Lewis Creek above the head of the little caSon re- ferred to on that stream. This valley is partly filled with drift depos- its, but its rocky bed is probably about 300 feet above adjacent parts of the main river. It appears at one time to have been occupied by n pre-glacial representative of Louis Creek and possibly by the North Thompson, at a still earlier period. I was informed, that coarse gold has been obtained in the small stream which now runs northward out of this valley to the Barriere. If auriferous gravels should be found to remain in the bottom of tliis old valley, these might be worked by drifting, with free drainage. Deadman River. — A Chinese company worked for a season about the mouth of Criss Creek, but as the operations were not continued, the ground may be assumed to have proved poor. Ray Creek. — * Prospects ' of fine gold are stated to have been ob- tained on the lower part of this stream, near its confluence with Gui- •] GOLD- AND SILVER-BEARING VEINS. 333 n chon Creek. There is a notable development of gravelly terraces here, with a good head of water, but it is doubtful whether the gravels are rich enough to pay for work. Clirrry Bhiff Creok. — Gold has also been found here and some work Cherry Rluff was at one time attempted, but without important result. Creek, GOLD- AND SILVER-BEARING VEINS. Notes respecting a number of massive deposits, found to contain more or less gold, have already been given (p. 311 u); what follows re- lates to auriferous and argentiferous veins. Stump Lake and Vicinity — The metalliferous deposits found in the neighbourhood of Stump "Nicola" Lake, upjn some of which a good deal of work of a preliminary ^^"""'' character has been accomplished, are generally spoken of as the "Nicola mines." The geological character of the district, v;ith the nature of the country-rock, the general course of the \eins and the area within which the actual discoveries are comprised, have already been noted (see p. 130 b). The metalliferous veins already known in this somewhat limited distiict are numerous, and while it is perhaps probable, from their very number, that no individual lode will be found to possess great continu- ity, the work done is sufficient to show that a considerable permanent output of ore may be obtained. The recognized veins vary in width from about 10 inches up to about 5 or 6 feet, and some of them have been traced for lengths of several hundred feet and to depths of 100 to 400 feet. The mines and prospects in this district were visited by me in 1888, 1889 and 1890, and some account of them hfis been given in the sum- mary reports for 1888 and 1890, as well as in the Mineral Wealth of British Columbia.* The vein-matter generally consists of white quartz, containing iron- Vein-inatter. pyrites, copper-pyrites, galena, blende and tetrahedrite, with a vary- ing, but on the whole very satisfactory content of silver and gold. The following are assays of these ores made in the laboratory of the Survey. It is not always possible to attach these to the particular claims from which they were derived, the specimens having been obtained for the •Annual Report, Geol. Surv. Can., vol. III. (N.S.). p. («) h. Assays. 334 B UUITISH COLUMBIA. most part during the early stages of the prospecting and before my visit to the loci.lity.* Locality. One of the Hepburn claimn. . . , Niculii Mining and Milling Co Near Stump Lake Gold. Silver. Ounces. Ounoes. 0-75!) 4(K;'r)74 0-729 104-7LM distinct trace. 20-;«!) (iODO no •().-){) 0-7it2 I.")0il4 1 •!)(>!> 17-003 Ounces to the ton of 2,000 lbs. Though scarcely any w ork has been done upon these deposits since 1890, partly in conse'ry little oxidized at a short distance below the surface. In 1888, this shaft had a depth slightly exceeding 100 feet, Imt was closed down in 1889 when the small crushing and concentrat- ing mill which had been erected was burnt. Planet Shaft. — Ti)is was Plaiu't Shaft. about 40 feet in depth only in 1888, and was closed at the same time with the last. The lode runs about N. 10' E., with an easterly dip, at an angle of about 70". It has a width of T feet or more near the surface, but varied in this respect when followed down. The character of the ore here met with, differs somewhat from that seen in any other deposit of this vicinity. It has origi..all3' consisted of ijuartz with iron- and copper-pyrites and some galena, but the vein has subsequently been re-opened, and brecciated, and a cement of brown-spar and chalcedony has been introduced. The sulphides have at the same time become much oxidized, and considerable quantities of blue and green copper c irbonates have been formed. This subse- quent action may probably be attributed to the period of Tertiary volcanic activity. Mary Rnynoldit. — (J. Hepburn & Co.) — This is one of the " Hepburn ^r.arv Hpv Claims," and probably that to which the assay previously (juoted "ol'l^- refers. It is situated about two miles up the valley of. Scott's Ci-eek, on the north side. The lode is about 4 feet wide and very well de- lined, nearly vertical, and running N. 15° E. through a country-rock of porphyritic green diabase. It has been traced on the surface for 300 feet or more. According to the British Columbian Mining Report, *Ibid., p. 200. \Tbid., p. 2!)1. 336 B Bn(TISH COLUMBIA. Dunginuir. Various smal- U'l' openings. LikU'm on Jainifson Creek. there were at the end of 1889 three shafts on this vein, 100, 75 and 35 feet deep respectively, with 90 feet of drifts. Dunsmuir. — Sicuated about 500 feet west of the last, on a lode running about N. 5° W. and two feet or more in width, nearlj' vertical. Considerably decomposed where opened, but otherwise resembling the ore of the Mary Reynolds. The following prospects are situated some distance to the south of the last two. They have been developed to a limited extent by sink- ing and costeaning upon the outcrops. British Empire. — A well defined lode about 5 feet wide, running N. 15 W., with a dip at angles of 70' to 80 to the eastward. Pyrites and galena are rather sparingly disseminated through the quartz. Zeila. — This lode runs about N. 15' E., with a dip to the eastward of 45' at the surface, but becoming more nearly vertical at the bottom of a shaft 27 feet deep. Iron-pyrites is the most abundant visible metallic mineral, but galena and blende also occur. The wall-rock is a porphyritic green diabase with rather abundant pyrites crystals scattered through it. Ardmorp. — This claim adjoins the north end of the last. The lode runs here N. 38° W., and is called a ' cross lode.' It is about 15 inches wide anii shows some pyrites and galena in openings about 200 feet apart. Jftinie Long. — Situated about half a mile south-east of liookford post-office. This runs about N. 85" E., and had been opened to a depth of 66 feet at the time of my vi^it in 1888. The greatest width seen in the shaft was about 20 inches. It is somewhat irregular in dip, but not far from vertical. A certain amount of prospecting work has been done on many other claims, but some of these it was not possible to visit in the time at my disposal, while in the case of others, no well-defined lodes had been developed by the work done. Jamieson Creek. — The metalliferous veins found in this vicinity, fifteen miles up the North Thompson on the west side of the river, occur in a muss of greyish granite which here breaks through the Paltvo/oic argillites (see p. 245 n). A number of claims have been taken up and a little surface work has been done on some (jf them, but I am unable to add much o the notes already given on these deposits in the Summary Report "oi 1 888, as the locality was visited by me only in that year and no fui tht i work of any importance seems to have bet*n done on any of th'^ C \ivas since. gene: II.I.IK SilviM K tiiiloi Th: ] HOLD- AND SILVER-BEAniNfi VEINS. 3:)7 11 , 75 and Situated ■ W. and oni posed j^nolds. south of by sink- running Pyrites irtz. eastward le bottom it visible dl-rock is s crystals The lode about li) about 200 Kockford peiK'd to a test width •egular in lany other tne at my had been miles up ccur in a Palii'ozoit: taken up but I am deposits in me only in have bc^'n Tlie granite is considerably decomposed and in the vicinity oi the veins is highly siliceous. The veins themselves are composed of quartz, sometimes holding fragments of granite and sliowing pyrites, with a litthi galena, blende, and tetrahedrite. It is probable that the date of origin of the veins is contemporaneous, (»r ns;i 07o« O'OO Silver. .'ill! 13 •2 :yS> L's ;i;i2 1.'.") U'(H) OimcoB to the ton of 2000 inmiifls. The deposits met with in tills locality certainly apjiear to ileserve ■ onie further examination. It seems not improbable, that by o'lerations partaking, in the first instance at least, more of the nature of quarrying tlian mining and not strictly confined to the wider veins, large quantities of ore of medium grade might here be obtained. *Aiiiuial Koiiort, Gool. Hurv. Can., vol. \\. (X.S.). p. liii h. 22 I ■■:;:^ 338 B imiTISII COLUMBIA. Lodeh (111 oo.sli Ci'oi TViiiiin/a cliiiiiis. Cayoosh Creok. — Cay- The source of the placer gold of this stream is evirlentlj' quite local, for coarse rough gold containing quartz has frequently been found in it. Mr. A. W. Smith, M.P.P., showed nie, in 1889, several pieces of such gold mixed with quartz, one of which was estimated to contain several ounces of gold. The gangue in this case was about half ((uartz and half white calcite, through botii of which the gold penetrated indiffer- ently. Discoveries made subsequently to that of the placer mines, leave no room for doubt that the gold has originated from quartz-veins travers- ing the argillite-schisis of the adjacent mountains, and a number of claims have been staked out on these. Specimens from several of them show visible gold, and many others yield gold in tine particles when roasted', crushed and washed. The best known and first discov- ered (1887) of the quartz properties upon this creek, is that named the Bonanza, in which several claims have been consolidated. Some \i)v\ rich specimens of auriferous quartz have been obtained fi'oiii this place, though the gold is moi-e usually minutely and uniforndy distributed through the quartz. A considerable amount of prospecting work has been done, but so far without leading to the establishment of any regular mining. The quartz-veins occur in the si;hi-itose series of rocks whicli forms considerable tongues and infolds in the granite of this part of the Coast Ranges and is referred to in greater detail elsewhere. (See p. 99 n.) The Bonanza claims are situated about seven miles up Cayoosli Creek from its mouth, on the steep mountain side on its right, or south bank. Numerous small quartz-veins here run with the strike of the black argillite-scliists, generally about south-east by north-west, and usuidly following the dip of the rocks to the south-westward, but sometimes cutting across it. Few of these veins individually exceed a foot in thickness and some are much less. At the time of my visit. in 1889, the lowest work done, at about 390 feet above the creek, showed a face of say 30 feet in width, charged with broken and irreg ular small veins separated by crushed and displaced schists. Several tons of quartz had been tnken out and piled here. Further uj) the very steep slope, (about 910 feet above the creek) a tunnel was being run in to intersect several (juartz stringers seen at a greater elevation, from which rich specimens containing gold had been obtained. The length of the tunnel was then 100fe(!t, but was subse(]uently increased. Still further up (about 1110 feet above the creek) a shaft some i>ii feet in depth had been sunk on a rather irregular vein, which in places showed 2 feet 5 inches of quartz. It would appear, tliat the best method of fairly testing this OoUl. Silwi I'liinanza . . . . (Jiowii Point (,'rown Point Oim 0«!)2 0-722 0r)8 None. Noni'. Onuces to the ton of 20(X) ix)un(ls. Bi;/ Slide Mine. — The Big Slide mine, is situated on the bank of the I'rftsor, at tlio mouth of Kelley Stream. This stream falls very rapidly to the Fraser in a steep and rough gorge, and a good deal of labour was spent in constructing a tramway down this gurge to the mine. The mining operations were cl.iefly carried on in 1880, when a nuudjer of tunnels and drifts wore made and a ten-stami> mill, with cuncentiutor and chlorinating furnace was (erected. All work was, however, sus- l«nded in 1887 and it has not since been resumed. The rocks f)bserved in this locality have already been noticed (p. 93 u). The vein upon which the work was done, is several feet in thickness and can be seen in the cliffs for a height of 3(J0 or 400 feet at least. It runs with considerable regularity on a bearing of S. 45" !•]. with a north-eastward dip at an angle of about 70°. The material is quartz, containing iron-pyntes and a little copper-pyrites, and there appears to be no dou))t that the ore can be obtained in considerable •Annual Keiiort, Opol. Hurv. Can., vol IV. (N.S.), pp. 58 r, o!) h, 22J Mine. 340 B BRITISH COLUMBIA. 11^ quantity. I was informed that difficulty had been found in saving the more valuable parts of the ore by the process of coneentratictn em- ployed, but whether or not this arose from unskilful work in the niill is not known. A specimen of the concentrates remaining in the liiill at the time of my visit, in 1889, was subjected to assay in the laboratory of the Survey, with the following result : — AsKaya of con- Gold 0-41)8 oz. to tho ton of L'lHXt ll)s. centrales. Sjlvei \m " The occurrence of the metalliferouf vein at this place is prettv evidently in connection with the granitic massiif the vicinity (pp. 78 n, 242 «) havirig probably residted from the hydrothernial action set up at tiie time of its intrusion. Further deposits of a similar kind may occur elsewhere along tlie same line. OTHER MIXERAI..S AND ORES. Cinnabm- on MercHiy. — What may prove to be an important deposit of cinnal)ar. opper lei •. jjas lately been found in the vicinity of CopperCreek, Kamloops Lake, ami several contiguous claims have been taken upon this, on the west side of the valley of tlie creek, near its mouth. The claims have, I believe, been combined in a single property, but the Ix'st looking deposit of ore occurs on the E a second shaft, thirty-five feet deep, on the Yelloir Jacket claim. about a cjuarter of a mile northward of the Rosebush. The cinnabar occurs in irregular sparry veins, consisting chictly of calcite and quartz, with some dolomite, traversing zones of a gray t'el- spathic and doJomitic rock which readily weathers to a yellowish colour. [?otli these zones and the contained veins, as a i'ul(>, run nearly magnet ii north and-south througii the main rock of the hiil,;, which is a dark greenish-blacif. Tertiary eruptive, containing pyroxere a.'.d olivine but much deconipo.sed. A considerable cjuantity of rich ore has been taken from the wider portions of the main vein opened on the llose- oush. Although the slopes of the hills are abrupt, they are almo.st everywhere covered with drift deposits, and much more work is neces- sarv in order that the true value of the deposit may be ascertained. Exploratory trenching in an east-anrk ia neces- ascortaini'd. be tlie nui-l )ny sulpliidi' Another claim, upon wliich very little work has been done, is the Last Chance, Xo. J, situated on the east side of Copper Creek, near ilie junction of the Tertiary volcanic rocks with a small area of decom- posed granite. Small quantities of cinnabar are found here, and .some narrow seams of molybdenite al.so occur. In the adjacent granitic mass (p. 174 u), minute bright-red specks of cinnabar may also be detected, and it would appear that the exten.sive decomposition of the basic volcanic rocks of this region, by heated waters or steam, has led to the diffusion of a certain quantity nf cinnabar through some parts of both classes of rocks, and to its concentration in some of the veins. Decomposition of a similar character, has aff'ected the rocks seen on possible fx- tlie opposite side of Kandoops Lake, along the railway, to the east of 'i',.'.' J ,!;'■; the nwuth of Cherry Bluff' creek. No cinnab:ir has been observed here, but distinct traces of cinnabar are found in seams cutting some of the rocks at Six-mile Point, also on the south shore, but further to the west. I have a'so been informed that grains of ciniuxbar have been iibserved in washing for gold on Criss Creek, to the north. The.se occurrences, taken together, indicate that search for cinnabar may be made with some pi-ospect of success over a considerable area in tills vicinity.* I'htfiiniDi.' -The occurrence of minute scales of platinum, with gold on I'latimii.i. the Tranquille, has already been alluded to. It is also stated to have been found in the same manner on the Fraser, particularly at a place ten miles below Lillooet, but there are no indications of its existence in quantities of economic importance in this district. Xatire tSih'fi: — This metal is also occasionally found in the native x.uivo silver, state in gold-wiishings, jiarti( ularly near Nicoamen on the Thompson, whore pellets of considerable size are reported to have been discovered , ill 1S58 and ISHO. /roil. — The occurrence of considerable quantities of magnetic iron-ore, r.ragmtiti at iuid the general conditions underwhicli it is found, inthe rocks couiposing "'"-^ " • Ciierry anfl Battle Bluffs on Kamloops Lake, are elsewhere mentioned (p. 15711). The largest of these deposits which have been discovered, lie near the west end of Cherry Bluff. These were noted in my Report of 1877, and an assay by Dr. B. J. Harrington is there quoted which shows the ore to contain 6G-83 per cent of nmtallic iron, with very little phosphorus or sulphur.f *Siiici' till' iiliovi' \v;iM written, furtlier wnrk liiis lieen i- naiing masses of ore, do not iippear to be of the nature of a segregation from the enclosing eruptive rocks. The walls are often distinct, ami the ore contains in so.^ie places brecciated fragments of the surround- ing rocks, as well as imperfectly developed crystals of white felspar, and occasionally is associated with much epidote. It is evident that a large quantity of good ore may easily bo obtained at this place. A spi'- cimen of impure ore, consisting chiefiy of a mi.Kture of magnetite and *(^u()t»' Hummary Rojiort, (ifol. Snrv. Can., 1892. 'J MINERALS AND OHICS. 343 hornblende, was examined for silver and gold in the laboratory of the Survey, but proved to contain only a trace of gold with O'lUl ounce of silver to the ton of 2000 lbs.* Magnetic iron-ore is also known to occur near Watkinson's, about twenty-three miles above Lytton, on the Fraser ]liver, where the vein is reported to be 20 feet in thickness. Magnetite and iron pyrites are found, apparently in considerable Other dccnr- mass, in a ravine upon which a saw mill was at one time situated, about ^„.j. half a mile below JNicoamen. The ore contains too much pyrites to be of value and on assay it proved to hold no gold or silver. Copper. — The vicinity of Copper Creek, Kair.loops Lake, has been Xative cop- known to the Indians from time immemoiial as a place of occurrence of native copper, but the precise locality had been lost.f Specimens litive, however, since been obtained from the Painted Bluft's, to tiie east of the creek, in which small grains and thin plates of copper appear. This occurs both in the mass of the rotten serpeii- tinized rocks, and in dykes of now serpentinoua trap cutting it. It is scarcely probable that deposits of a workable character will be found, but it was doubtless from nieh occurrences th;it the Indians derived their supply. In 1888, a couple of claims which had been staked out on the east IkiniiU'. side of the creek about lialf a mile back from the lake, were visited. A small opening had l)een made which .showed a shattered zone in the brown porphyritic trap of the vicinity, holding small (luanti- ties of copper-ores, largely decomposed. A specimen subjected to as.say proved to contain no gold, and only 1-158 ounce of silver to the ton.:{: Since then, another claim nametl the J'ciidi'r/oof, has ijcen taken up at the same place, and some prospecting work has been done, resulting in the discovery of a vein from twelve to fifteen inches thick, holding some quantity of bornite, in a gangui^ of dolomite, with some; white felspar. The vein, so far as exposed, is a very irregular one, but the amount of work done upon it w.is (|uite inconsiderable. Near Watkinson's, Fraser Jliver, about ^2'^ miles above JjVtton, gray Otlici- occur- copper (tctrahedrite) is reported to occur in considerable mass. A ''■"'• specimen assayed in the laboratory of the Survey, contained a trace only of gold and r)-83.'{ ounces of silver to the ton of "JOOO lbs. In association with magnetic iron-ore at the wes end of Cherry Blutf, copper-pyrites occurs, but probably in small ([uantity. 'Aumial Report, lii-Cf)l(l- of the Cold water, lie beyond the edge of the present map, but inasmuch as the extensions of the same basin enter the southern part of tiie map, some references to the known localities to the south are included in that part of the Report which deals with the Tertiary rocks of the Nicola Valley. Further particulars, with a section, may be found in the Report for 1877-78 (pp. 12.3 n, 127 ii). Borings recently made in this vicinity, ha\e allbrded further evidence of the value of this coal-basin, and it is hoped that with the aid of these, and the better knowledge now gained of the Tertiaiy rocks as a whole, it may soon be possible to work out the structure of this Ijasin in greater detail. It is tlie only locality in ornearthe Kamloops sheet in wiiich a true coal of actually known workable thickness has yet been found. The following list of localities in which coals or lignites are known to Kfftifiuis to ■ 1 (.111 i-i liK-'iilities. occur, will serve as an index to the pages ot the Report upon which a description of these occurrences may be found : — North Thompson, near the Indian Reservation. Coul, p. 229 u. Near Kaudoops. Coal, p. 168 n. Nicola Valley. Coal and lignite, p. 190 u. Uuichon Creek. Ligniti', p. 192 ii. Hat Creek. Ligniti', p. 207 u. Bonaparte River, between Cache Creek and Ashcroft. Lignite, p. 21:? B. Thompson River, near Nicoamen. Lignite, p. 11^4 n. Fraser River, below Lytton. Lignite, p. 188 it. Red Point, Kamloops Lake. lAgnite, p. lG7i!. Asbestiis. — Small veins of chrysotile or serpentine asbestus, have been AsbestiiH. observed in or near some of the deposits of serpentine contained in the Cache Creek rocks, especially in the vicinity of the Fraser River, be- tween Texas Creek and Bridge River, and in the southern base of Mount Soues, near Junction Valley. It is possible that workable deposits of asbestus may yet be found in these rocks, but the specimens so far obtained are too small and too short in the fibre to be of any economic value. Building and Orname.nfal Stones. — Nearly all the rocks met with Stiiutuiiil ii • 1 c ■ 1 1 ■ •' 1 1 • 11 iiiiiti'iial>. in the region, are so much fractured and jointed as to be incajiabli' Brick clays. Limp. 346 B k ■^ W: P Js !■ Cliinastoiip iR'arSpatsuni BRITISH rOUTMBIA. of yielding good stone for masonry. There are no easily di'essed free-stones, and the limestones are invariably greatly sliattered. The granites, and some of the basaltic and other volcanic rocks of the Tertiary, are alone capable of affording good blocks of any con- siderable size, and of these only tho.se which occur in the vicinity of the railway, or near to navigable waters, can be con- sidered as possessing any great importance. Tho granites of the Coast Ranges are those best suited for purposes of construction, but these can be obtained most easilj' to the south of the present sheet. The marbles, in which form the limestones are not seldom found, are too much shattered to be considered of value for polishing, and the same remark applies to the serpentines. Brick C/ay.i. — Clays or silty deposits suitable for the manufacture of ordinary brick of fair quality, may be obtained from the alluvial dc- positsor lower benches of many of the larger valleys. The White Silts (p. 283 h) afford an unlimited supply of material from which fine, cream-coloured or fawn-coloured, haul bricks may be made, but the scarcity of fuel for burning bricks near the line of railway, detracts from the value of these silts for this purpose. Lime. — Limestones suitable for burning, are, as will be gathered from the map and from the foregoing descriptions of the rocks, extremely abundant, but to be readily utilized they must be situated on navigable waters or on the line of railway. The limestones most easily accessible from Kamloops and suitable for this purpose, are found near Venn's, seventeen miles up the North Thompson, on the west side ; opposite the mouth of Campbell Creek, ten or eleven miles up the South Thompson from Kamloops, on tho north side of the river, and near the iJiouth of Three-mile Creek, to the south of the railway. These and other lo- calities nearest to the various settlements are indicated upon one of the maps accompanying this report. Opposite Spatsum station, on the west side of the Thompson, a mass of remarkably decomposed rocks occurs. So far as could beobserved, the areaof great decomposition is about half a mile long by quarter of a mile in width. The state of the rocks at this place is only a special case of the alteration which has affected €a great belt of strata along this part of the river, as elsewhere noticed (pp. 79n, llSn). It is evidently related to the marginof the great granite mass on the east and to the faulting which has occurred here. The rocks have, in the first place, Vieen thoroughly decomposed and pyritized, probably by the action of heated waters oi' steam, and su'.jsequently more or less completely leached out by acid waters resulting from the oxidation of the p3'rites. The soft resulting •] MINERALS AND OUKS. 3n di-essecl d. The 1 of the tny con- in the be oon- i of the tion, but .sheet. iin found, liing, iind faeturc of luvial do- hite Silts lidi fine. , but the , detracts lered from extremely navigable accessible ir Venn's, jposite the Thompson mouth of d other lo- pon one of son, a mass )served,tli(' >r of a mile cial case of this part of y related tv 1 ting which thoroughly [1 waters or )ut by acid ft resulting mateiial has been cut out in several steep gullies, where it appears as crumbling banks of rod, yellow or white tints, upon which scaice!\ any vegetation grows. Some parts of these are almost purely siliceous, others consist of mixtures of cjuartz and kaolinite in varying proportions, often with a perceptible efflorescence of .soluble salts of a styptic taste. The white and thoroughly leached rocks are those which have attracted attention as china-stone, and in these, kernels and veins of i)ure white gypsum sometimes occur. Tt is doubtful, however, whether any con- siderable ([uantity of china-stone could easily be ((uarried free from iron stains, while the china-clay or kaolinite could only be obtained in a pure state by the crushing and washing of the mas'!. I It is probable that parts of this deposit miglit advantageously bo P(.>sil,ly use- employed in the manufacture of fire-bricks. Specimens of the higlily i„.i,.J^'. pyritous rock w(M-e assayed, but proved not to contain any gold. A(ji nations of conditions which are always more or less local. Ili/alite ]\y!i]\u'i\m\ or ]\Iuller's glass, occurs in basaltic rocks near Hi-hium' Lake (p. "'''' ' 220n) and it is quite within the bounds of possibility that precious opal may be found in some of the volcanic rocks of (h- district (p. l.'3;> it). Jade or Xfphrite formerly much prized by the Indians for the .l:i[assigo Gesteine," but classification based on the age of the rocks has not iiecn strictly adhered to. Owing to the extreme alteration of some of the specimens submitted to me foi- examination, it has onh' been possible to refer these altered rocks to the general grouji in which they belong, without assigning them to t!ieir exact position in that group. My acknowledgments are due to Dr V. D. Adams of McGill Uni- versity for valualilo suggestions and assistance received from him at various times during the progress of :lie work. 1. Felspathic Actinolite Schist. — Louis Creek, north sitle, two Achims Laki miles up. 167 (1888). ^ c'aml'.'lian Tliis, in the hand specimen, is a fine-grained, greenish-gray, schistose rock, stained with iron oxide. Under the microscope it is seen to consist principidl}- of felspar ; a little (juartz ; a green mineral in long needle-like crystals possess- ing inclined extinction, which is probably actinolite; epidote ; and chlorite. The felspar, like the(|uartz, occurs in aggregates of small clear grains and is only to be distinguished from it by the axial figure. Several of these were obtained, and showed clearly the revolving bar of a biaxial figure. The felspar and quartu grain.i often form, together with epidote, little clear lenticular areas in the section. 350 B BRITISH COLUMBIA. AdaniH Luke ifriesi- Otiit. The epidote is chiefly in irre<;uhir gniins, occasionally in minute crystals showing sharply defined rhombic sections which are parallel to 00 Poo and bounded by the faces oP and P5b. 2. Gaiibro(?) — North Thompson River, east side, opposite mouth of Skull Creek. 1!):5 (1890). This rock, examined under the microscope, is seen to be much altered. The augite orif(inaiiy present in it, is now almost entirely changed to hornblende, which, in its turn, is very largely altered to dilorite. The felspar is all decomposed, and can now be traced only hy out- lines filled with various alterafion products. Tiie whole section is so 'illed with chlorite, epiiiote, and sericite, that hut little trace of the original structure of the rock can be seen, but it appears to have been of the nature of a gabbro, or possibly a diabase. Dr. Dawson staces that in tlu^ mass the rock is slightly schistose. 5.* DiAUASK PoiiPiivuiTK. — Two miles east of PoLson Hill. 22G (1890). cache Cri'ck A ratiier coarse-grained rock, in which plagioclase and augite crystals, CarlHiniferouH ttkfe'-ther with iron ore, occur porphyritically developed in a fine-f, rained groundmass. The rock is nmch altered, and the augite i.« nearly all converted into a fibrous, pale green hornblende, which, in its turn, is largely altered to chlorite. The latter mineral, together with other decomposition products and fine needle-shaped individuals of liorn- blent'p, is trnekly scattered through the sei;tion. The plagioclase is well twinned, often possesses good form, and is much decomposed, being filled with little granules of zoisile, epidote, etc. The groundmass of tho rock, where visible, apparently possesses a holocrystalline diabasic structure. 6. Diabase pori'HVRITE (?). — Pass between Hat Creek and Orego.. Jack's Creek, one mile east of Hat Creek. 239 (1889). The section submitted to me was so thick that a satisfactory deter- mination was imp(jssible. The rock is much altered and filled with cidorite, oxides of iron, etc. Both felspar and augite are exceedingly decomposed. The former occvirs in lath-shaped Individuals which show the twinning characteristic o'.' plagiocla.se. There is apparently considerable fine-grained "i-ound- mass present, in which minute plagioclase erystals can be distinguished . but, owing to the thickness of the sectimi and the extreme alteration of th,!>owiiig imbedded enstutite with its characteristic pearh- lustre. ^,--— .«_ Tlie only minerals observed in the sectiouffliamined were 9oli\ inc in an advanc(i(l staj^e of scrpentinization, an altered ortiiDriioinbic pvinNcnc (en.statite), and iron oxides. For sucli rocks, composed essentially of olivine and enstatite, Wads- worth pro]>oscd tiie name Su.i-oni/i'.* roseid)usch has used the name H( rrMiirgile for the same group, and iliara(.'terizes them as felspai-freo olivine-norites.t The section was compared with sections of 1 lar/burgite from Haste in the Harz and found to closely reseml)le them. Dr. Dawson states tliat the specimen submitted to me was fi-om one of many liardei- " cores '' occurring in soft scT-peniinous scliist ;it tlie locality. It will readily be understocd that as the serpentinization of tlie principal constituent, the olivine, proceeds, the olivine substance will cventuall}' entirely disappear, giving rise to the soft serpentine rock in wiiich, macroscopically, no trace of the original character of the rock would be perceivable. The olivine occurs in '"v juiar masses and shows in jiej-fection its characteristic net-like alteration to serpentine, the strings of seriieiitine forming the net-'vork inclosing the yet unaltered portions of olivine Hydrous iron oxides aud magnetite have separated out during the process of alteration. The unaltered poi'tic-n of thi; olivine is trans- parent, with marked relief, almost colourless, non-pleochroic, and exhibits brilliant interference colours. The enstatite, like the olivine, occurs in broad, colourless, irregular uiasses, with )-.:vrallel extinction, .vhich are occasioii Jly bent and twisted, and possess little or no pler)chroism. It is l.irgely altei-ed to schiller-spar or bastite, the \arious stages of alteration being well shown in the sections. Home inili\iduals exhibit merely a ihie stria tion parallel tf) the vertical axis of the prism and at right angles to th(! partings. Others again show an alteration into a green serptn- tinous matei'ial, commencing in the cracks, especially those parallel to i>P. and extending fn^m them as threads and fibres ))arallel to ihe principal axis. The columnar structure often .seen in enstatite was also observed, one individual in paiticular showing the long cylindrical hollows, sometimes filled with secondary ores, whicii are described by Uosenbusch;!; as occurring in enstatite. As he has pointed out, it is " TjitlKplogical StiKliew, Cnmbridsfc, Ma»»., 18H4. t MassiKiMlHsteiiie, 2n(l VA., 1SH7, i.ji. L'C.'.i-'JTl. + Pic iictnigniiiliixch wiclitiffcn .Mincralii'ii, i-'nil fvl., ISS.j, pp. IV.HlSil". ('."iclle CliiK fiMiiiatiim - CoiU. 352 B liUITISIl COLUMHIA. Cdchc Cict'k f jriiiation- Cont. somewhat difficult at tiiiu's ttected in tilt section. Similar schists have been siujwn by many observers to result from the shearing of cUorites and diaba.ses*, and it is (juite likely that the rock now under consideration may have Ii.mI such an origin. Teall • Si'o LcliniiUiii, iitirM\icliiMiKi'ii ulitr '!■ ■ Kiitstclini!!^ der Altkijf*fiilliiii.'«, Miinicli, 1H7I. 1). '.». (i. H. Williams, Hiill. V. S. (i<>el. Siirv.. No. 112. 1K!)0. Tfi.ll. i}-1M.>'., \Ii.. iWI3, 1>- K<;t: \W'\\'\»\\ PctreKiapliy, 1S.'<8, pe. 1!IK tui.! •_'lt. Hatcli, .\l<'iii. Uiiil, Survey, K.yi.lu'iiitiiiii c){ .SlifntH, 11(8, tail, li.'lmiil. !■ V.i. :';;>tr-""- «•] PRETOGRAPHICAL CIIAKACTEnS OF ROCKS. :J53 H ■oin solid •111 which roughout and cha- eristatite is strung •e. pxamina- 10 portion e referred Shumway tially of a ell shown mgatod in 11 acicular rough the Ifochroisni lan in ihf ndividuiils striation, the horn- net tliat it a little is .■-ection, scales I if a )t detected csult from ihat the ;iii. 'i'eall iilliiiisclici) l\muli, 1K"I. t'l, points out that quartz appears to be rare in those schists which can be C-XcUe Creek definitely proved to have originated in consequence of the metanior- Cnnt. " ~ phosis of igneous rocks. (Compare Nos. 9, 10, 1, and 16). 9 Ami'IIIUOLIte. — Campbell Creek, one half mile below Shuniway Lake. Ill (1889). This section is almost identical in its gei\eral features with No. 8. The iron ore, however, is nearly all altered to leueoxene, whicli occurs in great abundance in translucent irreguhu* tornis, sometimes rudely ; norabic in outline, having a granular structure and a grayish colour. The individual granules, examined with a high power, .-.how a liigh index of refraction and brilliant interference coliurs. The section was compared with those describefl by Dr. Adams from the Mastern Townships O- ...uebec as containing a similar mineral,* and it was at once seen that the two mini'rals are the siune, and undoubtedly leueoxene, a forn of ti*^anite or sphene derived from the alteration of titanic iron ore. Finely divided plagioclase was recognized in the groi'ndmass. This is another of those altered rocks which in all probalulity have been derived from basic igneous rocks by contact and dynamic meta- morphism. The hornblende, as in No. 8, possesses a fibrous structure and has c\ery a;)pearance of secondary ori{;in. Phillips has well described i.he j assage from tlie original eruptive to similar schistose rocks, entirely devoid of the chai.icteristics of the original rock, in occurrences at various localities in the west of Eng- land, t Teall also dc'scribes in detail the \ariations in structure and composition in "greenstones'" from England,;;; stating that the i\iost important secondary structural characteristics are these which depend on the development of foliation, and that th.e most important second- ary characters in comjiositior. depend upon the deviilpment of chlorite, wr some form of hcu-nblenile, at the expense of the original augite ; of leueoxene, and ultimately granular sphene, or rntile, at the expense of the titaniferous iron ore ; and of water-clear socDnd.iiy felspar (albite ?) and other substances, at the exjjeti.se of the original ()lagioclas(\ From a pern lal of the alrove remarks it will be ^een how closely ~!ose rf)cks descri ley api)ly by ly * Rtport. iif PrognwH, (Jcol. Hmv. Ciui., lWO-81-82. Ap'*inlix to Dr. SuhvytiK i|K)rt, p. UlA. + q .rO.S., v„I. XXXII., mo, V- 1.56: vol. .\X.\IV.. 1,S7H, p. 171. ; HAtiAi ^.•t^l^'^Mllly. 188H, pp. 2.t0, :.:t4, 'J'tn. CAche Cr(-i forniatidn Cont. 354 H IIRITISII COLUMIUA. / k referred to (see p. 353 of the present report, foot-note), and to the ones from British Columbia now under consideration. 10. Ami'HIBOLITE. — Campbell Creek, one mile Ijelow Shuniway Lake. 110 (1889). Tlii.s .specimen is of a rather finer grain than No.s. 8 and 9, and the section .shows it to contain a larjje ([uantity of a brown mica in addi- tion to the hornblende, but its general features are tlie same as in those two rocks. The groundmass, as before, consists of a fine mosaic of water-clear grains of felspar, pi'obaljly albitc, embedded in which are numerous little needles of actinolite, proving its secondary character. 8ome of the fel.spar grains are striated. Tiie hornblende occurs in irregidar fibrous individuals, and also in the form of fine needle-like cryytals of actinolite. tt commonly shows an alteration to chlorite. Leucoxene, in ii-regular bunches of fine granules with a very high index of refraction, is aljundant. Quartz was not determined with certainty, a.s satisfactory axial figures could not be obtained. The brown mica is very abv^ndant in the section, being nearly equal in quantity to the hornblende with which it is intimately associated. Tt is reddi.sh-brown in colour, and occurs in small irregular folia, which, in sections at right angles to the basal plane, are strongly dichroic. Its interference colours are the .same as in biotite, to which species it is undoubtedly closely related, if not identical with it. The rock is without douht of the same oi'igin as the similar ones already described. 11. AMi'mnof.iTE.— Moore Creek, west side, four miles above Nicola Lake. '2U (1890). This rook, whilst presenting the general features of those of the .same class alread}' described, ditl'ers from them in some respects. It is apparently less foliated, and its matrix, whilst siiowing the usual dear felsjiar mosaic, also cont-'ins numerous larger fragments of plagioelase, in some instances with crystalline foim. Quartz is also present, and epidote is exceedingly abundant, in irregulai-, strongly pleochroic grains, exhibiting brilliant interference colours. Irregular bunches of finely granular leucoxen(>, accompanied by some ilmenitc are thickly scattered through the section, Tiiere are also nunierou.-; crystals of pyrite. of m good size, a,nd showing alteration to limunitc The hornblende isdecideilly uralitic in appearance and largely altercu Dawson. 1 to chlorite, ] Only a very fe Jl-- -Vm I'll 1 1 N^icola Lake, li The i-ock is pri.bably result 13. TuFi.'?.- (1877). A dark-gray, great ly ci-uslie( lamination bein specimen is big chloric acid, an •^■rystallino calcii The microscoj consists of an e: locking grain.s, lenticular patchc also exhibit a nu Numerous lit biotite are scatte in irregular patcl ings. ,>-!cales of A large (juan lenticular p.itch arrangement, wh rock in the thin .i embedded fragnie .iltered tufl^oras' 't is hard to arri 11. Turr? -Ij A black, rust which, in Ihin sj) irlassy slag, but contains carlidii, in spots. The remarks n •miy that it is n, i^tituents, and is also more ubund 38^ m 111 "■] HKTRO(iUAI»HirAL CHARACTEHS OK HOCKS. 355 R to chlorite. Id some iii'^tanoes forms ••esembling augite were seen, ('.icln' f 'reek Only a very few small scales of brown ai'e present. r!m/"'^""' 1'2. AMi'iiiKOr.riK. — Moore Creek, west side, four miles aiiove Nicola Lake. -Jtio (1890). The rock is the same as No. 11 in its fjeneral oharaeters, aiul has probably resulted from the alteration of some basic ei'uiUive. 1.5. Tuff?. — Half a mile north-west of Shumway I^iike. 2a (1877). A dark-gray, fine-grained, compact rock, which has evideiitly been art- ings. .'-'cales of sericite are also abundant. A large (|uantity of a l)lack nondescript material is present, in lenticular patches and irregular strings with a general parallel arrangement, which marks out clearly the lann'nalod structure of the mck in the thin section. Some irregular, angular patches, resembling embedded fragments, suggest that this rock may possibly hv'ii highly altered tuff or ash-rock, but, owing to its very bad state of ])reservation. it is bard to arrive at any definite conclusinn as to its origin. 1 1. Tuff? -Half a mile north-west of Jr^humway Lake. 2ii (1877). A black, rusty weathering, finegrained, thinly laminated r(jck, which, in thin splinters before the blowpipe, fu.ses readily to a brctwnish, gliijsy slag, but does not alter greatly in Cf)loin' befoi-e fusion. Jt contains carbonat«s, effervescing slightly with iiilute acid, but only in spots. The remarks made regarding No. 13 apply in general to this ?ock, only that it is not nearlj' so calcareous, contains more mit aceous con- stituents, and is more evenly laminati'd. T\, angular fragments are also more abundant and much more distinct. Large angular fragments 23J Ofiche Cr(,'ck formation— Cunt. 356 B BRITISH f'Gl,UMBIA. of felspar were observed lying across the planes of lamination, around which the other constituents bend in such a manner as to mimic " flow-structure." Scales of a brownish micaceous mineral occur, which are frequently- aggregated into rosettes throughout the rock. As in the case of No. 13 numerous little granulated areas of quartz were oBnerved. I'). Clastic Rock (Tuff?). — North of Douglas Lake granite mass. 342 (1877). A fine-grained, thinly laminated, dark-gray, almost black, rusty weathering rock, in which tlie planes of bedding, indicated by layers of different coloured materials, are inclined at an angle of about 65' to the planes of lamination. The microscope shows it to be made up of layers of light and dark material, very finely granular, and mainly fel.ipathic, showing evidcncesof partial re-crystallization, and containing many small angular fragments of felspar and quartz, scales of stjricite, grains of calcite, and a large quantity of a strongly pleochroic brown mica, probably secondary, the folia of which have a general parallel arrangement corresponding to the plane, of lamination in the rock. The whole .section is much stained by hydrous oxides of iron, often aggregated into patches of considerable size. The light-coloured layers in the rock contain what appear to bo compo>:te fragments of some foliated clastic rock, the foliation of these being often at a considerable anijle to that of the main mass of the rock. 16. Chloritic and Epipotic Schist. — Cayoosh Creek, near Bonanza Mine. 278 (1889) The matrix is very fine-grained, consisting of quartz and felsp^ir. through V. liich the chlorite and seticite ruji in long, continuous, irregular folia. Epidote is very abundant in irregular {granules, possessing marked pleochroism, yellow to colourless, and brilliant interference colours. Numerous little lenticular patches and I ands occur through out the section, which are chiefly composed of a hydro-niica (serieite?), with irregular cru.shed f ragmen"' of quartz and felspar, showing very uneven extinction, embedded in it. These fragments are larger than those in the main mass of the section. The micaceous constituents of the rock show a well-defined parallelism. 17. PoRPiivROiD (sciiLSTOSF.). — Between Seton Lake and Cayoosh Creek. 276 (1889). This consists of an exceedingly fine-grained felsite-like groundmas-^ with a schistose structure, composed of quartz, orthoclase, and plagioolase. fs,. Xlikr,, in, around to niiinic frequently i of quartz ;e granite ack, rusty 1 Vjy layers 30ut 65" to nade up of ,nd mainly containing of sericite, roic brown ral parallel he rock. iron, often pear to be ton of these jf the rock. ar Bonanza nd felspnr. IS, irregular possessing ntf'rferoncc ur through I (sericite?), lowing very larger than well-dcfineil id Cayoosh groundnuiss plagioolaso. ■] PETRO(iRAPIIICAL ClIAHACTEHS OK UOCKS. 357 n much sericitic and uhloritic material, and also large quantities of fViclic Crook a black, opatjue, decomposition product, which maiks out clearly the Con't'^ '"" lines of wavy foliation in the rock. Much hydrous oxide of iron is also present, giving a rusty stain to the rock. Occasional larger "grains of (piartz and felspar are to be seen, and the section is traversed by numerous little v(;ins of quartz. The planes of schistosity are very wavy and contorted, and tlu' specimen resembles the class of rocks to which the name porphyroid has been given, and wliich weie first dcsi'rilied from Thuringia, the Harz, the Taunus, and the Ardennes, where tlu^y occur associated with Pahvozoic strata. They may be characterized as rocks com- posed of a felaite-like gioundmass which has assumed a more or less schistose structure from the de\ elopracnt of micaceous (sericitic) scales, and which contain porjihyritically scattered crystals of felsj)ar and quartz. As pointed out by Teall,* many of them are distinguished from the porphyries merely by the presence of wavy planes occupied by sericite or some other micaceous mineral, and that by an i' erea.se in the number of these planes, and a corre.sponding increase \n the micaceous mineral, they pass into sdiistose porphyroid^, and finally into sericite schists. They shade into h lletlinta-like rocks by thedis- appearance of the porphyriticcoiistJtuents and of the schistose structure. He points out that the typical porphyroids of the Ai'dennes bear the same relation to quartz porphyries that the " schistose greenstones " do to dolerites, and are for the most part acid rocks that have been affected by dynamic metamorphism. 18. Saussukitic Rock. — Cayoosh Creek, near Bonanza Mine. 277 (1889). The hand specimen is a light-green, tough, comjiact, and somewhat schistose rock. Under the microscope the section presents the apjiear- ance of a confused felted aggregate of chk)rite, zoisite, epidote, calcite, a pale green mineral in needle-like crystals resembling ai.'tinolite, and occasional patches of more or less alteied felspar. Little bands filled with epidote and zoisite grains, and scales of sericite, run through the main mass. It is probably the result of metamorphism of the basic felspar of a gabbro or diabase, a change common in rocks aS'ected by regional metamorphism. t The name saitaKitritu was (Originally applied by De Saussure to a similar aggregate occurring in the rock named i njJiotide by Haiiy. De Saussure • BritiRh Petrography, 188«, pp. 21)4, 337, ;m. I See HoHoiihiiKcli, MiisHigo (ieBteine, 2ml Ed., 1SS7, pp. l()3-](i4: also Hagge, ^bkr(>skopiKcllo UntersiicliuiiKoii iilior (!al>bro, etc., Kiel, 1S"1, p. ."il. 358 n BRITISH C0L17MDIA. CAclif Cri'ok believed the substance to be a definit'^ mineral, but subsequent inves- foriiiatioii- ,. ,. , . . , jt r>i 1 • 1 11- C'onr. tij»ation pi'oveu its composite character.* Cathrein thorouj^hly inves- tigated tlu; substance chemically and microscopically, and Ids conclu- sions, summed up by Teall, are : — that it is not a uiineial, but a mixture, as above ; thiit in its chemical composition it, in general, resembles the soda lime felspars ; that it is produced by the inetam()r]ihisin of tin; felsjiar through interchange of silica and alkalies, with lime, iron, and water; and that epidote is produced in a similar manner to the zoisite, only that more iron is taken up.t In the specimen examined the zoisite occurs in irregular grains and crystals, exhibiting its characteristic pale blut^ interfei-ence colours. Calcite is abundant. The few fragments of felspar observed, though much altered, show indistinctly the twinning of plagioclase. The section being thick, but little of the matrix could be made out, but here and there a tine-grained glassy mo.saic was ol)served, which is pi'obably composed of felspar (albite ?). 19. DiAHAsK Tuff. — Ridge east of Paul's Peak, near Kamloops. 102 (1889). A rather fine-grained fraginental rock, made up of fragments of augite, plagioclase, titanic iron ore accompanied by leucoxene, hydrous iron oxiiles, chlorite, and fragments of what is apparently diabase porphyrite. One of these rock fragments, though much altered, shows large' well crystalli/.ed plagiocLises, a large augite crystal, and a grain of ilmcnite accompanied by leucoxene, embedded in a fine-grainetl ground- mass. Other fragments are of a much finer grain. The augite, as a rule, is quite fresh, and often posse.sses sharp crystal form. Occasionally it shows alteration to a chloritic substance. It is yellowish in colour, clear, and exhibits the usual cleavages and other physical characters of the species. A few crystals were observed poly.synthetically twinned according to ocPx. The extinction angle on the clinopinacoid in one instance was found to be H'. The plagioclases, like the augites, often have shari)ly defined crystallographic IwDundaries. They are greatly decomposed, and pre- sent a very cloudy ajipearance, the twinning structure l)eing almost obliterated. Zonal structure was noticed in a few of them. *Sf-p Oatlu-i-in, UflitT Suussiu-it, 7..K., Hiiud VII, 188."?, ),. 2.S4 : also T.'iill, Hiitisli Petnigrai)hy, 1SS8, pji. 14«-ir).'>. + Sinr(' the al)i)Vi' was written Mr. A. E. IWlow Iuih pnlilinlicd a iiajK'r, in wliiili the striKturc of Saussiiriti' is niiiuiti'ly describcfl. Sre On toiut' Dykes coutainiii^f Hurunite, Ottawa Naturalist, vol. IX., |i|i. L'.")-47. lient invos- ;,'lily iiives- liis conclu- a inixturo, lenibles the isiii of the ', iron, and the zoisite, iilar grains lee colours, ed, thouj,'h 1 ni-ide out, d, wliich is Kamloops. ignients of ne, liyih'oiis tly diabase lows large' a grain of led ground- esses sharp ; substance. 3avages and re observed ction angle )ly deiined kI, and pre- eing almost 1. Teall, Uritisli iptr, ill which :e8 coutaiiiiu^f -] PKTROfiRAPniCAI, CHARACTERS OK ROCKS. ;?r)9 n 20. DiABASK TuKP. — Lower part of Cayoosh Creek. 28") (1889). (Valir ('iv.k A tine-grained, greenish-gray, somewhat schistose rook, whose elastic ^'""f- structure is at once seen undc^r the microscope. Tt is made uji of irregular fragments of plagioclase, ijuartz, augite, ilmenite with leucoxene, and numerous rock fragments, embedded in a line-grained matrix filled with chlorite and epitlote. ^[ost of the gi'ains are plagi-iclase, generally much altered to caleite, kaolin, and otiier })roducts of decomposition. Some of the rock fragments referred to above, consist of broad crystals of plagioclase, with tibrous much altered hornblende, probably derived from pyroxene, and resemble gabbros ; others are tine to medium-grained, with diabasic structure ; whilst otlun-s again are very finegrained and felsitic, resembling de vitrified glassy eruptives. They are idl nmch decomposed. 21. Chert, or Cherty Quartzite. — Hills north of Medicine Creek, near Hat Creek. 259 (1889). This is a very fine-grained, compact, siliceous rock, which, in the section examined, is cut by numerous little veins of (piarlz. The texture of the I'ock is too fine to atlinit of a satisfactory determination of the optical cliaracter of the separate grains or eoiicretiotis of silica, but the spherulitic interfei'ence cross given by the concretions, and their general appearance, indicate that they are probably composed of chalcedonic (juartz. Dr. Dawson has pointed out *that these cherts, or cherty quartzites, have probably been produced by tlie action of thermal waters which silicified the accompanying rocks, and suggests that some of tiiem may have originally been argillites. The section examined shows many nondescript imimritias, including considerable quantities of a blackish carbonaceous-looking material, and hydrous oxides of iron. 22. Diabase Poupmvrite. — North of Kandoops Lake, one mile and Xiiclii fuimii- a half east of Red Point. 104 (1890). T.i.'.ssic. Under the microscope this rock is seen to cfinsist essentially of large, well defined ti'ystals of [ilagioclasc;, augite, and iron ore, embedded in a tine-grained holocrystallino groundmass of the same materials. Epidote, caleite, pyrite, a little chlorite, and hydi'ous oxides of iron are also present. • Report of Propi-css, Geo]. Surv. Can., lS"7-78, ]>. 92 n. 360 n HRITISH COLUMBIA. Nioiln forma- tion — Cont. The rock is considerably altered. The plagioclase is cloudy and filled with decomposition products. It occurs in larj^e, sharply-detined, well striated individuals, and also in smaller lath-shaped crystals in the groundniass. The augite exhibits large, sharp, crystal forms, which are generally octagonal in outline and often beautifully symmetrical, both pinacoids being well developed. It is much altered to epidote, calcite, etc. The iron ore (ilmenite) is abundant and accompanied by its alteration product, leucoxene. Epidote occurs throughout the section in large (juantity as the result of the decomposition of the felspar and augite. It is in the form of coarse and tine granules, anil also in nidiating bunches of small prisms which sometimes exhibit aggregate polarization, with a well-defined interference cross. Its pleochroism is marked, yellow to colourless. The rock is a typical diabase porphyrite. 23. DiAHASE PoiiPiivRiTK. -Hills south of Nicola Lake. 1 40 (188!)). The section submitted for examination was very thick, but the rock appears to be a diabase porphyrite of the ordinary type. It is in an advanced stage of alteration, and consi'ijuently its structure, in the thin section, is much obscured by the products of decomposition. The augite occurs in large, well defined, eight-sided sections, many of which show most beautifully its uralitization (the alteration from augite to hornblende), the central cores of the crystals consisting of unaltered augite with its characteristic cleavage, and the margins of a pale green fibrous hornblende. Numerous radiating bundles of needle-like crystals of some zeolitic mineral occur throughout the section, probably derived fi'om the altercation of the felspar. Several little clear areas were noticed, which, between crossed nichols, are seen to be male up of grains of some mineral having a finely fibrous, radiated structure, and showing an interference cross. These are probably composed of chalcedonic (juartz. 24. DiABASK PoniniYiUTE (amvodaloidal). — One mile south of Meadow Creek, '2h miles above Greenstone Creek. 18 (1890). A rather fine-grained, distinctly amygdaloidal, chocolate-brown rock, spotted with white, due to the calcite filling of the amygdules. It consists essentially of porpln'i'itic crystals of augite and plagio- clase felspar, embedded in a tine-grained groundmass of the same materials. This groundmass is so impregnated with products of decomposition, such as hydrous iron oxides, epidote, calcite, and chlorite, as to render it impossible to determine with certainty whether glassy 1 PKTIlOORAPHirAL rilARACTKHH OF HOCKS. 361 H matter is present or not, hut the tlow-strui'turc, observable in portions Nicola fortiin of the section, would leid one to believe tluit it is. t\im-i oni. Large aniygdules now tilled with calcite, yellow, strongly pleocliroic epidote, and zeolites, are thickly distributed through the rock. Some of these amygdules, filletl as they are with radiated bundles of bril liantly polarizing epidote, are most beautiful objects under the microscope. The portions of the rock immediately surrounding the amygdules are stained a very deep brown, presumably by hydrous oxides of iron. Alteration of the porphyritic crystals of plagioclase has proceeded to sucli an extent as to almost entirely obliten te their twinned struc- ture. The porphyritic augites are also nmch altered to chlorite, epidote and calcite. As seen in the .section, the groundmass of the rock is made up of slender, lath-shaped sections of plagioclase, and irregular grains of augite, and possesses an apparently hypocrystalline structure, although, as above mentioned, the pr<'spnce of glassy matter cannot be positively proved. A little secondary (juartz was observed, and the .specimen examined is traversed by numerous little cracks lilled with crystalline calcite. 25. DiAHASK PoRPHYRiTE. — Soutli sliore of Kamloops Lake, opposite Copper Creek. 320 (1877). A very poor section. The rock presents no unusual features. It contains a few included fragments. 2G. PoRPiiYRiTE. — J o.shua Mine, Stump Lake. 102(1888). This is a soft, exceedingly decompo.sed, highly calcareous rock, which exhibits, in sections, a confused mass of chloritic and sericitic or talcose material, with <•>. large quantity of carbonates. More or less indistinct outlines of the original porphyritic fcls])ar crystals are still visible, but now tilled with calcite and other alteration products. The large amount of carbonates in the rock renders it probable that the predominating felspar was a plagioclase. Some of these carbonates present good crystal form, showing sharply defined rhombic sections, and may be dolomite. The absorption in these crystals is marked, with O > E. 27. Melapiivrk (amycdaloidal). — One quarter mile south of Mea- dow Creek, '21 miles below (Jreenstone Creek. 22 (1890). This rock, whilst resembling in a general way No. 24, is coarse- grained, and the phenocrysts of augite are larger, as are also the amygdules. Olivine is also one of its constituent minerals. IMAGE EVALUATION TEST TARGET (MT-3) 1.0 I.I no ^^ mm m m u ■25 ■ 22 2.0 ■IWu L25 114 11.6 1^1 6" Photographic Sciences Corporation 23 WEST MAIN STRECT WEBSTIR.N.Y. HS80 (716)872-4503 362 D BRITISH COLOMBIA. Nicula furma- tion — Ctmt. The amygdules, mostly rudely spherical in form, occasionally measure fths of an inch in diameter and are filled with zeolites, calcite, sericite, chlorite, and epidote. The colour of the matrix is about the same as in No. 24, namely a dark chocolate-brown. The plagioclase phenocrysts are comparatively few in numl)er and greatly decomposed. Those of augite on the other hand are remarkably fresh, and occur chiefly in sharply defined, octagonal sections, which are approximately at right angles to the c-axie, frequently nhow polysynthetic twinning, a zonal structure, and contain grains of magnetite. Numerous porphyritic skeleton crystal forms, filled with hydrous iron oxides, etc., which accompany the augites, in all probability represent a highly ferruginous olivine originally present in the rock. These ferruginous olivines (hyaloaiderite, fayalite, etc.) are vei'v charac- teristic of the porphyritic eruptive rocks. 28. Melapiiyre. (?) — Hills south of Nicola Lake, near McDonald or Quilchenna Creek. 139 (188y). A fine-grained, compact, dark-green rock, much fissured, and con- taining porphyritic crystals of augite. The section is filled with epidote, calcite, chlorite, serpentine, and other decomposition products. Blotches of serpentine, calcite, and iron ore, representing what was probably originally olivine, occur side by side with comparatively un altered augite. The plagioclase is almost entirely decomposed. Well-twinned, comparatively fresh, crystals of augite are abundant. The different states of preservation of these two minerals may be due to the com- position of water acting as the decomposing agent, permitting it tu act more powerfully on the plagioclasb than on the augite. A small fissure, filled with epidote, passes through the section and traverses a large augite crystal, h.^lf of which is faulted considerably to one side. 29. Gauhro, with ihabasic structure. North of Kamloops Lake, one mile and a half east of Red Point. 163 (1890). This is a considerably altered eruptive, which owes its red colour to iron oxides derived from the pyrite which is plentifully scattered through the section. The rock is composed chiefly of plagioclase, augite, epidote, and pyrite, and has somewhat the structure of a gabbro, that is, thste are considerable areas of plagiochvse comparatively free from •] PKTKOfiRAPniCAL CHARACTERS OP ROCKS. 363 H y measure e, aericite, , namely a aml)or and and occur roximately twinning, ,h hydrous probability n the rock, ei y charac- cDonald or 1, and con entine, and g what was i-atively uii ell-twinned, ie different o thf com n^ it to act section and ionwiderably loops Lake, ed colour to y scattered lase, augit)', ^abbro, that ly free from bisilicates, so that it does not possess the typical ophitic structure Xicok fomm characteristic of a diabase. The habit of tlie plagiocluse is also more that of gabbi'O plagioclases than of those occurring in diaba.'se. A few j>orphyritic crystals of the plagioclase and augite are scattered tiu'ough the section. No <|uartz was detected. In a few instances what appear to be fragments of .some eruptise are embedded in tiie mass of the rock. 30. Protkrouase ok Epidiorite. Road north of Trapp Lake. 120 (1889). In the hand specimen this is a mottled green and whitish, rather coarse-grained, gneissic rock, wiiose foliation is not of the even type seen in a typical schist, but is more like " fla.ser " structure, the min- erals occurring in more or less elongated streaks. In the thin section the rock is seen to be composed chielly of plagio- clase, hornblende, augite, biotite, and a little KoHenbiifich, Mamige Gustcine 2nd ed., 1887, pp. 20<(-210. t See Alliiort On the Metaniorphic Rocks Surrounding the Land'is Knd Mans of Granite, ti..I.G.S., 1870, XXXTI., p. 407. I^iOHHen in SitR. d. (iea. nutur. treunde, Berlin, 1885, p, 32. Liehe, lTl)er»icht tlber der Schichten-aufbau Ostthuringena. Abhand. Z. geo. .Specialkarte v. Preussnn u. d. ThUring. Htaaten. Bd. V., Hft. 4. Dd similar ,1 diabases imic.t t in only ti between idual, and lass. The ;ro8Copical the tield. oy contact base from al of that an Pacific fragments in ore, to- abase por- iillographic ize. Both > than the ;s. crystals of developed nnces filled shows in a exhibiting ing similar ne in the it fiUing-in iccount for 874, p. 9. Knd Mass of »nd. Z. gw). J PETROORAPHICAL CHARACTERS OF ROCKS. 365 B this structure.* Zonal structure also is seen in many of the augites Nicola forma- in the section, the zones sometimes not being parallel to the boundaries ""n""^""'- of the crystal. 32. Diabase Tuff. — North of Kamloops Lake, two miles and three- quarters east of Red Point, and behind Battle Bluff. 165(1890). This rock, under the microscope, is seen to be clastic in its origin It is composed of fragments of plagioclase felspar, augite, pyrite, zircons, etc., cemented together by a highly calcareous and ferruginous matrix which is proportionately small in quantity. Numerous fragments of tuffaceous rock are also present along with the fragments of simple minerals. In its constituent minerals it bears a close resemblance to No. 29 and is just such a tuff as one might expect to find accompany- ing a rock of that character. The pyrite is very abundant, and by its oxidation has stained the rock a deep reddish-brown. 33. Diabase Tuff.— Hills south of Nicola Lake. 138 (1889). A dark-green, fine-grained rock, showing vaiious irregular mineral fragments embedded in it. The section shows this to be a typical diabase tuff", holding fragments of diabase porphyrite. This clastic rock is made up of irregular fragments of plagioclase, augite, iron ore, and the rock fragments referred to above. Both plagioclase and augite are much decomposed, and the section has much epidote and chlorite scattered through it. The included rock fragments possess a very fine-grained matrix, in which well defined crystals of plagioclase, augite, and iron ore are porphyritically developed. The augite occurs in octagonal sections, is often well twinned, and in many of the fragments quite fresh, in marked contrast with the plagioclose, which is nearly always greatlv decomposed. 34. DiAB.'VSE Tuff.— Peterson Creek, south of Coal Hill. 1 (1890). A fine-grained, compact, dark-green, clastic rock, composed chiefly of irregular grains and crystals of plagioclase felspar, augite, and iron ore, together with fragments of a greatly decomposed porphyritic rock, all cemented together by finer grained material of the same kind. The specimen is much decomposetl and highly calcareous. Both plagioclase and augite are considerably altered, the former to calcite, kaolin, etc., the latter to chlorite, epidote and magnetite. • See L. Van Werveke in Neue« Jahrbucli fiir Mineralogie, Geologie, und Palaoiitologie, Stuttgart, 1879, pp. 482 and 822. 366 B BRITISH COLUMBIA. Nicfila forma- tion — Cont. Cretaceous Mcks. 35. Volcanic Breccia or Ash Rock. — One mile east of Penny's Station, Canadian Pacific Railway. A(18S8). This is a clastic rock composed of irregular fragments of felspar, augite, and iron ore, together with various more or less rounded rock fragments. The whole rock is in an advanced stage of alteration, the section being filled with the products of decomposition, such as epidote, chlorite, kaolin and hydrous iron oxides. The calcite occurs in great abundance, and the hand specimen effervesces very freely when treated with cold dilute hydrochloric acid. The rock owes its red coloration to the abundance of iron oxides distributed through it. The majority of the plagioclase fragments, though greatly decom- posed, still show the characteristic twinning. Although the included rock fragments show tolerably fresh, lath, shaped crystals of plagioclase, their matrix is so filled with rusty de- composition products that it is well-nigh impossible to tletermine what bisilicates, if any, are present. The iron ore is mainly ilmenite, which is accompanied by its alteration product leucoxene. 36. Tuffaceous Rock. — Greenstone Creek, one mile and a half below Big Fish Lake. 14 (1890). A very fine-grained rock, tiark-gray to almost block in colour. The section examined is very thick, and the rock much decomposed, rendering it almost impossible to determine its true nature. My im- pression is that it is a badly decomposed, siliceous, clastic rock, pro- bably a tuff connected with some of tlie eruptives of the neighbour, hood. Irregular, badly shattered fragments of quartz, augite, and felspar, are embedded in a very fine-grained granular matrix of apparently the same materials, but the section is so filled with a con- fused mass of chloritic and sericitic material, together with calcite and iron oxides, that it is difficult to make out any traces of structure in it. 37. Diabasic Tuff.— Near Cornwall's. 247 (1889). A dark coloured, highly calcareous rock, the clastic character of which is well seen in the hand spi'cimen. Under the microscope it presents the appearance of a loose volcanic tuff made up of fragmen^^s of an exceedingly fine-grained, amygdaloidal, porphyritic rock, cementtv together by alteration products, of which the chief is calcite. The individual fragments resemble somewhat a pumice-stone, and l)€fore the rock was consolidated and the cavities filled up, it nmst have been of the nature of a very loosely coherent volcanic tuff. 38. Diabase Tuff. — East side of Fraser River, about eight miles below Lillooet. 295 (1889), )£ Penny's of felspar, inded rock ration, the us epidote, rs in great len treated ron oxides tly decom- fresh, lath- 1 rusty de- ■mine what f ilinenite, md a half )lour. ecomposed, ). My im- ! rock, pro- neighbour. lugite, and matrix of vith a con- calcite nnd icture in it. ;harncter of icroscope it f fragments {, cementfc. stone, and ip, it must tufiF. eight miles •] PETROUnAPlIICAL CIIAKArTF.RS OF ROCKS. 3G7 It /i A rather fine-grained, much decomposed, but distinctly clastic rock, Cmtaccous composed of irregular grains of plagiocliise, quartz, augite, ilmenite, '^"*' """ "" ' and titanite, together with fragments of some porphyritic basic eruptivo. The thin section examined is full of chlorite, epidote, secondary biotite, and hydrous iron oxides, resulting from the alteration of the constituent minerals, of which plagioclase, greatly decomposed, pre- dominates. The augite is mainly altered to chlorite, although a few tolerably fresh grains were observed. Ilmenite is tolerably abundant and is accompanied by leucoxene. The grains of quartz are sometimes angular and sometimes rounded in outline. Fragments of some basic eruptive containing well-developed phero- crysts of plagioclase, and bisilicates too decomposed for satisfactory identification, are scattered through the section. It is not always possible to determine with certainty whether a tuffaceous rock Ins been built up of ejected volcanic material, or has been derived from the disintegration of pre-existing eruptive masses.* Dr. Daw.son informs me that this rock and the two following' (Nos. 39 and 40), from the field evidence, have apparently been formed in the latter way from older diabasic rocks. 39. DiAnASE TUFF. — Near Fountain. 316 (1889). In appearance this rock greatly resembles No. 38, but is slightly darker in colour, and under the microscope their structure and com- position is seen to be practically identical, No. 38, as ri'presentod by the section examined, holding perhaps a somewhat larger (juantity of bisilicates than No. 39. 40 DiAHASE TUFF. — Road from Ashcroft to Cache Creek, two and a half miles from Ashcroft. 120 (1890). This is a very fine-grained, compact, dark-green, somewliat calcareous rock, which the mien (scope shows to be distinctly clastic in origin. Irregular angular grains and crystals of felspar, quartz, augite, and iron ore, together with fragments of some fine-grained porphyritic rock, are cemented together by a paste of finer-grained material of the same kind, filled with calcite, chlorite, epidote, and other decomposition products. Plagioclase is the most abundant mineral prerent and is much altered. A few untwinned grains of felspar were also observed. The grains of quartz are much fractured as the result of pressure. * See K. Rpyer, TTel)er Tuff« and Tu(fo;;en« Sediniente. Jalirb. K.K. Geo Rvichanst, XXXI., 1881, p. 57. WPrTf Cretaceous rooks — C'ont. Tertiary rooks. 368 B BRITI6H COLUMBIA. The augite, although in a few instances fresh and exhibiting crystal form, is usually largely changed to chlorite, with separation of secondary magnetite in little granules. The iron ore, chiefly titaniferous, is generally accompanied by its alteration product, leucoxene. Some fragments of a badly decomposed basic porphyritic rock were noted in the section examined, which is also traversed by several little veins of calcite. 41. See page 389 b 42. Gabbro.— Arthur's Seat. 53 (1890). A medium<-grained, altered, greenish rock, composed principally of plagioclase felspar, augite, quartz, diallage (now almost entirely decom- posed), iron ore, epidote, chlorite, serpentine, and apatite. The rock is greatly decomposed, and in places has a coarse ophitic structure, causing it to approach the diabases. The plagioclaise is almost completely saussuritized. Sharply defined crystals of augite occur as phenocrysts, also some forms which were perhaps once olivine. The augites are fresh, often polysynthetically twinned, and hold numerous inclusions. The diallage is in broad laminae, which are almost entirely altered to fibrous aggregates of pale brownish-green serpentine and chlorite, trogether with granules of brilliantly polarizing yellow epidote. Titanic iron ore, in some instances accompanied by leucoxene, is abundant. A little quartz is also present. 43. QuARTZLEss PoRPHYRY (Ortiiophyre). One mile and a half north of Spence's Bridge, west side of Thompson River. 51 (1890). A light yellowish, decomposed rock, with marked spherulitic struc- ture, in fact nearly the whole mass of the rock is made up of spher- ulites averaging three-eighths of an inch in diameter. The ground- mass of the rock is a holocrystalline fine-grained mosaic of unstriated felspar and quartz, both possessing very uneven extinction. In this groundmass are embedded broad, irregular, kaolinized, felspar individuals. Most of the felspar in the rock occurs, however, in the form of exceedingly slender microlitic crystals, radially grouped, and forming complete star-like spherulites of felspar, which are often outlined by borders of limonite or some similar hydrous oxide of iron. Pyrite cubes largely altered to limonite, and irregular blotches of the latter mineral, are plentiful, and the whole rock is stained a yellowish- brown from this cause. "•] PETROOKAPHICAL CHARACTERS OF HOCKS. I 3G9 I! aolinized, however, grouped, are often e of iron, chesof the yellowish- Carbonates also occur, and there are several little cracks, filled with Ttrtiurv rocks chalcedoais quartz, running through the section. —Cont. 44. MicaPorpuyuite.* Twomiles south-east of Ashcroft. 249(1889). A light greenish, medium-grained, porphyritic rock, in whicii large glassy phenocrysts of plagioclase felspar, with a most beautiful zonal structure, o.cur, together with a dark-brown strongly pleochroic biotite and numerous grains and crystals of magnetite, embedded in a very fine-grained groundmass composed of plagioclase, little scales of biotite, and granules of iron ore, together with, apparently, a little glassy matter. The plagioclase phenocrysts are often in the form of two polysyii- thetically twinned individuals united according to the Carlsbad law. The biotite individuals bear evidence of magmatic resorption in their corroded outline^', and frecjuently hold inclusions of the magnetite. A little apatite is present, but no quartz was detected in the section examined. 45. Mica Pori'Iivhitk. — Nicola River, three miles below Spioos River. 152 (1889). This is essentially the same rock as No. 46, but the section, under the microscope, shows the porpiiyritic constituents to be more al)und- ant, and also that a considerable quantity of a dark green hornblende is present amongst them. The groundmass, too, presents a different appearance, the felspar individuals being stouter and the " tluw- structure " not nearly so marked a feature of the rock. Zonal struc- ture is beautifully e.xliibited in many of the plagioclase individuids. Evidences of magmatic resorption are numerous, especially in the ease of the hornblende, the individuals of whicli have often more than half disappeared, the remaining portion being surrounded by a rim of little granules of magnetite. The hornblende occurs in prismatic individual.s, which occasionally, where resorption has not proceeded too far, show good termination.*. It possesses strong pleochroism in brownish-green to yellow tints. The biotite fre>ly defined hexp-gonal fonns of an opa(|ue black substance resembling iron ore were observed in this section. These have been seen and described, in the case of porphyrites from various foreign localities, as being due to the magmatic resorption of the original biotite, which has been entirely replaced by magnetite.* 47. Diabase Porpuyrite. — Arthur's Seat. 184 (1889). A light green, fine-grained, porphyritic rock, in which the microscope reveals a diabasic crystalline groundmass, made up of lath-shaped sections of plagioclase and irregular grains of augite. Through this groundmass are scattered numerous phenocrysts of augite and plagio- clase. Irregular granules of iron ore are sprinkled through the section, which also contains much epidote, and chloritic material exhibiting spherulitic structure with the usual revolving black crosces when viewed between crossed nichols. The felspar phenocrysts are much altered, and in many cases show no twinning striation. Occasionally several irregular shaped individuals are bunched together, forming " eyes." The augite is remarkably fresh, usually exhibits good crystal out- lines, and occurs sometimes in isolated individuals, sometimes in polyso- matic groups resembling those described by Lawson in dykes from *Cf. Koeenbusuh, Massige GeBteine, 2nd edition, 1887, p. 452. •] PETROGRAPIIICAL CHARACTERS OF ROCKS. 371 H ed, appar- 1, slender, tine scales \ ore, and ark brown ■ell-marked al parallel •ystals like ;ckm1 crystal binary and ved, is not i tilUd with ) kaolin and urn coloured 388888 sharp e, a bending Btinies show sions, princi- ipaque black tion. Those from various ption of the letite.* lie microscope lath-shaped Through this and plagio- the section, al exhibiting crosses when cases show no id individuals d crystal out- mes in polyso- n dykes from Rainy Lake, Ontario.* In colour it varies from pale-yellow to almost Xtrtiury rockH colourless, is frequently polysynthetically twinned, and posscisses little ~ ^""'• or no pleochroisni. 48. Diabase Porpiiyritb? — Overlying the massive rocks of Battle Bluff, near Tranquille. 204 (1888). In the hand specimen this is a gsed, and were descrilK-d without reference to their geological ijosition. They differ from the fresh glassy rocks of the U|>|)er Volcanic Series, and I prefer in the meantime, to retain this term for them. Roseubusch confines the name to pre-Tertiary rocks. -] PETKOOKAPUICAL CHARACTKB8 OF HOCKS. .173 U nta and is the weak outer rim le sections and some- oundmass, I the rock, polarizing ro present, ic'h decom- Icite to be vith dilute e structure, ite porphy- the general or diahasic port, but is the actual d, owing to [jre present, ite fresh and lath-shaped, ten, by their lure." sb, although hloritic and rnetite, were ish-green to seen ; poly- n occurrence. as of apatite, )undma88. ly (IpcoihikjhjhI, hey differ from lie meantime, to iary rocks. Some quartz occurs in the section, whicli, as the whole rock is greatly Tertiary n>cki altered, is probably secondary in its origin. —Cont. 62. Ai'OiTE PoupiiYUiTE. Murray Mountain (svuiiniit). 224 (1889). A rather flne-grained, dark yellowish-green, pdrpu) litic rock. In thin sections it appears to be tolerably fresh, consist' ng of large ))hcno- crysts of pliigioclnse and augite in a llne-graincj groun '-iiass whii li is appartntly composed of the same materials, together with umerous 'rnn les of iron ore and a little glassy biisa. Some crystalr of what appears to l)0 an oithorl- ..:ibio pyroxene, now largely altered to serpentine, also occur in elongateci narrow fuiins, as w^ll as in smaller, stouter ones. It possesses marked pkochroism. The plagioclase phenocrysts are tolerably fresh, full of inclusiona, well striated, and possess good zonal structure. A determination of the angle of extinction in one instance showed the crystal to be labia- dorite. Penetration twins are common. The augite phenocrysts have well-defined crystal form, .ire quite fresh, often twinned, and occur frequently in groups. Their colour is a pale yellowish-green ; they show brilliant polarization colours and hold numerous inclusions. A little apatite was observed in the rock- 53. AucJiTE PoRPHYHJTE? — Calm Mountain. 231(1889). A rather fine-grained, brownish-green, rusty weathering, porphyri- tic rock, the hand specimen of which somewhat resembles No. r)2. Plagioclase phenocrysts are abundant and tolerably fiesli, but the bi- silicates have been almost entirely decomposed. The quantity of iron oxides separated out in the decomposed material in the section gives one the impression that the principal bisilicate present was augite, and the rock might therefore be classed with the augite porphyrites. 54, Augite PoRPnYRiTK. — Za-kwaski Mountain. 160 (1889) A fine-grained, brownish-gray, .nsty weathering rock, with very small porphyritic crystals of plagioclase, and augite. Under the microscope the augite individuals in iriany instances show polysynthetic twinning according to ooPoo. Most of the ss^ctions are parallel to the principal axis ; a few at right angles to it. Some of the crystals have an outer shell which does not extinguish with the inner portion of the crystal, this zonal structure being sometimes very • marked. Flow-structure is beautifully developed in the thin section exariined. Iron ore, probably magnetite, is very abundant in small grains, and a brown decomposition product is spread throughout the mass of the \ 374 B BRITISH COLUMBIA. Tertiary rocks rock, giving a brownish tinge to the hand specimen on a freshly —Cent. fractured surface. Numerous " nests " of granular augite, epidote, magnetite, etc., occur, some of which, by their form, seem to indicate a replacement of some porphyritic bisilicate constituent. The plagioclase phenocrysts are not nearly so abundant as those of augite. A very little quartz is present. 55. AuoiTE PoRPiiYRiTE. — Nicola River, south side, two miles above Skuh'-un Creek. 168(1889). A fine-grained groundraass, apparently largely made up of slender little plagioclase crystals, with abundant brownish oxides of iron and chloritic materia!. Throughout this groundmass are scattered numer- ous porphyritic crystals and grains of felspar, augite, and iron ore. The felspar is chiefly plagioclase, but some untwinned grains occur which may possibly be orthocla.se, in which case the rock would ap- proach tiie syenite porphyries in composition. Some of the felspar individuals exhibit only binary twinning and all show good crystal form. The striated felspar frequently exhibits an alteration to calcite. The augite is light green to almost colourless, very faintly pleochroici polarizes in brilliant tints, and often exhibits more or less complete alteration to a light green chloritic material. 56. Augite Porphyrite? — Three miles up Pimainus Creek. 183 (1889). A very dark green, compact, finegrained, porphyritic rock ; the phenocrysts of felspar being of a yellowish-white colour and showing up in marked contrast with the dark groundmass of the rock. The thin section shows this rock to be exceedingly decomposed and sheared, many of the shearing planes being marked by a deposition of felspathic \ and quartzose material. The groundmass consists of a confused aggregate of decomposition products, chiefly chlorite, carbonates, iron oxides, and pyrite. The felspar phenocrysts, though in an advanced stage of alteration to saussurite. calcite, etc., still show the characteri '": twinning of plagioclase in many instances. Numerous skeleton forms, some of them octagonal in outline and now filled with chlorite, secondary quartz, and other materials, probably represent the augite originally present in the rock. Pyrite is very abundant in the section, and numerous small prisms of apatite were also observed. 1 a freshly netite, etc., lacenient of as those of miles above p of slender of iron and ered numer- iron ore. grains occur k would ap- f the felspar good crystal Iteration to y pleochroic) less complete reek. 183 c rock ; the i showing up . The thin and sheared, of felspathic ecomposition rite. of alteration twinning of n outline and ials, probably Pyrite is very apatite were ■] PETROGRAPIIICAL CHARACTERS OF ttOCKS. .'$75 B Whi,t little structure can still be made out leads me to refer the Tertiary rocks rock, somewhat doubtfully, to the augite porphyrites. 57. Augite Pohpiiyrite. — Copper Creek Valley, east side, ^ mile back from Kamloops Lake. 199 (1888). A greenish, much decomposed, highly calcareous, medium-grained, porphyritic rock, the matrix of which is of a darker shade of green than the porphyritic crystals. In a thin section, under the microscope, the rock is seen to have suf- fered extreme alteration to saussuritic, chloritic, and other decomposi- tion products. It is full of pyrite, and stained throughout with hydrous oxides of iron. Its alteration, however, has but little aflected the sharpness of outline of its porphyritic constituents, which, although their original substance has now almost entirely disappeared, were clearly plagioc'ase and augite. Iron ore was also abundant. Small lath-shaped sections of plagioclase can still be seen in the matrix, but whether glassy matter is present or not could not be satis- factorily determined. The I'ock can, without doubt, be referred to the group of augite porpiiyrites, but it is hardly possible to refer it with certainty to its exact place in that group, owing to its extreme alteration. 58. PoKPHYRiTE? — Hill near Murray Mountain. 218(1889). The rock, in the hand specimen, is much decomposed, of a light-gray colour, mottled with whitish crystals of altered felspar. It is fine- grained and porous in texture. On examination it proved to be so completely decomposed that a determination of its true character would be a matter of much difficulty, unless fresh material could be obtained. Porphyritic crystals of plagioclase, almost entirely replaced by saus- suritic iK.iterial, and carlwnaies, occur in a groundmass equally decom- posed, and apparently made up of slender little plagioclase laths with epidote, chlorite, iron ore, and patches of crystalline carbonates. Portions of the rock show an indistinct "flow-structure." The O-'iginal bisilicates have now entirely disappeared, their places being taken by the chlorite, epidote and other products of decomposition already mentioned. 59. PoRPiiYRiTii;. — Mi mem'ooh, Nicoamen Plateau. 164 (1889). A light greenish-gray, fine-grained, porphyritic rock, exceedingly decomposed. Porphyritic crystals of plagioclase with well-marked zonal structure, twinned according to both albite and pericline laws, and showing alteration to calcite, are plentifully distributed through an apparently holocrystalline groundmass consisting chiefly of plagioclase. 376 B BRITISH COLUMBIA. Tertiary rocks I" addition to tlie porphyritic plagioclases, many elongated forms —Cont. occur which represent the original bisilicates of the rock. They are row chiefly filled with magnetite and chlorite, and, from their general appearance, woro probably hornblende, although biotite may also have originally been present. They bear every evidence of having been subjected to magmatic resorption. Iron ore is quite plentiful in the section. 60. PoRPHYRiTE. — North side of Nicola River, four miles and three- quarters above Skuh'-un Creek. 171 (1889). ' A fine-grained, greenish and deep red, compact rock. Alteration is .seen, by an examination of the section, to have proceeded to such an extent as to almost entirely nm.sk the original otructure of the rock. , A few scattered porphyritic crystals of felspar, apparently plagioclase, occur in the fine-grained groundmass, and numerous patches of reddisli- brown to black decomposition products, some of which have cores of bright light-green serpentinous material, probably represent the original bisilicates of the rock. The serpentine exhibits a fibrous spherulitic structure with aggregate polarization. 61. PonPHYHiTK. — Nicola River, four miles above Skuh'-un Creek south side. 170 (1889). A fine-grained, dark brownish rock, with numei'ous small, yellowish, white, porphyritic felspar crystals. It is exceedingly decomposed, and consists of a very tine-grained groundmass, full of carbonates, clilorite, and other decomposition pro- ducts, through which are distributed numerous porphyritic individuals of felspar, most of which, when not too much altered, sliow tbe poly- synthetic twinning of plagioclase. The majority of ihe individuals, however, show more or less complete alteration to a grayish paussuritic material. In addition to the felspar, a number of forms occur, now filled almost entirely with decomposition products, which were originally either augite or hornblende. Magnetite and brown or reddish oxides of iron are abundant. A few of the highly altered forms above referred to, show small comparatively unaltered cores, whicli possess tlie cleavage of augite, and the rock may possibly be a much altered augite porphyrite. 62 PoRi'iiVRiTE (AUfiiTE PORPHYRITE?). — South side Nicola River, one mile and a half above Skuh'-un Creek. 176 (1889). A much altered, light greenish, medium-grained, porphyritic rock. H.] PETROOBAPHICAL CUARACTERS OF ROCKS. 377 B ited forms They aie ?ir general (T also have aving been biful in the and three- Iteration is to such an the rock. plagioclasp, I of reddish- ive cores of the original 3 spherulitic ih'-un Creek 11, yellowish, tine-grained position pro- individuals o\v t\\e poly- individuals, h paussuritic filled almost [inally either )xidf8 of iron show small ge of augite, lyrite. Nicola River, yritic rock. Numerous phenocrysts of plagioclase and augite, both much decom- TtitiiirynKkK posed, are embedded in a very fine-grainod diabasic groundmass com- posed of sections of plagioclase, grains of augit«, and granules of magnetite. The augite shows very uneven extinction. The whole section is so tilled with the products of decomposition that it is difficult to say whellier glassy matter is present or not. 63. Olivine Basalt.— East end of Porcupine Ridge. 234 (1890). A dark-gray, almost black, fine-grained, porphyritic rock, in which plagioclase, olivine, and biotite are porphyritically developed in a fine- grained groundmass of the same materials, thickly sprinkled with granules of iron ore, and containing some augite, together with a cer- tain amount of glassy matter. The plagioclase phenocrysts are clear and glassy, polysynthetically twinned, usually in long lath-shaped sections, but occasionally in stouter forms. They frequently show corrotled outlines, and hold in- clusions of the general groundmass o^' the lock. Plagioclase is also abundant in fine microlitic crystals in the groundmass. The olivine is mostly in irregular individuals, rarely showing crystal outlines, and exhibits its characteristic alteration to a browni.ih ser- pentine, although many of the grains are remarkably fresh, and polarize brilliantly. The biotite is in irregular scales, which are strongly pleochroic, from deep reddish-brown to pale yellow. The augite is not very abundant, and occurs as small, irregular, pale yellowish or greenish grains. 64. Hornblende Andesite. — Porcupine Ridge, slope north of Tran- quillo Lake. 236 (1890). A dark greenish-gray laminated rock, with a vitreous lustre, holding large phenocrysts of plagiocla.se. The groundmass i i composed of long, slender plagioclases, with a marked parallel arrangement, .so thickly crowded together that but little interstitial glassy matter can be seen. In fact, the structure is almost entirely holocrystalline, but the parallel arrangement of the plagioclases, and the manner in which t'ley bend around the porphy- ritic constituents, give a most typical " ilow-structure " to the rock. Distributed through this groundmass are numerous'phenocrysts of plagioclase, hornblende, and augite, with magnetite, and a little apatite. Olivine and titanite occur as accessory constituents. The plagioclase phenocrysts are mostly broadly tabular in habit, and frequently over J inch long. They frequently form complicatetl groups of int /Ciietrating crystals, which sometimes form Carlsbad twins, in 378 B BRITISH COLUMBIA. Tertiary rocks addition to the ordinary polysynthetic twinning. They are much —Cont. altered, and hold numerous inclusions of hornblende, augite, mag netite, etc. It is possible that a few clear non-striated Carlsbad twins observed, may be sanidine. Evidences of pressure are seen in the uneven extinction and breaking of felspars, hornblende, and augite. The hornblende forms sometimes idiomorphic, sometimes irregular, strongly pleochroic individuals of a green colour, containing many inclusions, and frequently showing alteration to chlorite. Augite of pale greenish or yellowish tints, sometimes with crystal outlines, more often without, is not so common as the hornblende. A few individuals of what may be an orthorhombic pyroxene, much altered, were also observed. Olivine occurs in irregular grains with characteristi< double refraction and alteration to serpentine. The magnetite frequently forms large individuals with good crystal outlines, around some of which the little felspar laths of the ground- mass bend in a most remarkable manner. A few small crystals of titanite and apatite were observed. 65. PiCRiTE PoRPHYRiTE. — Bames Creek Valley, north side, four miles east of Barnes Lake. 47 (1889). A very dark green, fine-grained, compact, porphyritic rock. Phenocrysts of olivine, and a few of augite, occu • in a groundmass made up of plagioclase, augite, and glassy material. A section of the rock was etched with hydrochloric acid and stained with fuchsine, and it was found that at least nine-tenths of the pheno- crysts are olivine. A very few of augite also occur which greatly resemble the olivines. The rock is exceedingly basic in composition and, consequently, there are no plagioclase phenocrysts, all of that mineral being in the grtjund- maas. 66. PiCBiTK PoRPiivRiTE. — Near Watching Creek, north of Pass Lake. 245(1890). A dark greenish-gray rock, thickly mottled with dark brown spots representing some altered porphyritic constituent. On examining thin sections of the rock it proves to be in a very advanced stage of decom- position. Numerous skeleton forms, sometimes pos.sessing rude crystal outlines, but often of very irregular shape and surrounded by dark rims of iron ore, are scattered thickly through the groundmass. They apparently represent phenocrysts of olivine originally present, but now replaced by serpentine, and in nonie instances by a colourless substance H-l PETROORAPHICAL CHARACTERS OP ROCKS. 379 B with weak double-refraction, which appears to correspond in character Tertiary rocks, with pseudophite.* Occasionally the filling consists of an isotropic sub- stance which is probably glass. These forms are numerous, of large size, up to one-eighth inch or more, and are much fractured, the broken pieces being sometimes quite widely separated. The groundmass is a confused aggregate of glassy matter, holding numerous granules and little crystals of augite, a little quartz and , felspar, and iron ore in small granules. The glass is full of trichites, globulites, and other inclusions. A few forms, which may have been plagioclase, were observed, and it is probable that a little basic plagio- cLase was originally present, from which the pseudophitic alteration product might be derived. Clear, rounded areas, with spherulitic structure, containing chlorite, etc., which are probably partly devitrified glass, occur in the groundmass. This rock, in spite of its poor state of preservation, is a most inter- esting one and should well repay further study. 67. Au(;iTE PiCKiTE PoRPHYRiTE. — West side of Copper Creek Valley, one mile and a half back from Kamloops Lake. 197 (1888). A dark-green, medium-grained rock ; pitted on weathered surfaces, and showing clearly the reddish, weathered-out, olivine. An examination of the section shows that the porphyritic constituents make up fully two-thirds of the mass of the rock. Olivine, augite, iron ore, serpentine, chlorite, epidote, and leucoxene, are the principal minerals present in the .section. It is so filled with serpentinous and chljritic material, derived from the alteration of the olivine, as to make it very difficult to determine whether glassy matter exists or not ; but it is probably present in the rock. The olivine is the most abundant constituent, and occui-s in large rounded, phenocrysts which show in a most beautiful and remarkable manner the usual alteration to serpentine. The centres of the crystals are in most cases composed of quite fresh, colourless, olivine, possessing the usual high index of refraction, brilliant polarization colours, and other characters pertaining to that mineral. Granules of iron ore, separated out during the process of alteration, are plentifully sprinkled throughout the crystals. The augite occurs in well-defined yellowish crystals, occasionally twinned, with characteristic cleavage and well-marked zonal structure. They are, as a rule, much fresher than the olivines, and often occur in groups of sharp crystals. / "Cf. Kenngott, Hit. Ak. Wien, 10, 1885. 380 B BRITISH COLUMBIA. -Cont. Tertiary rocks Iron ore, probably mostly magnetite, although ilmenite also occurs, is very abundant in irregular grains and crystals. The groundmass of the rock consists of a confused mass of serpen- tinous and chloritic material, \»ith numerous little granules and minute crystals of augite and epidote. often collected in the form of rims around the olivine and augite phenocrysts. Glassy matter is appa- rently present, but, as stated above, it is diflicult to identify it with certainty. 68. Mica Tkachytk. — Savona Mountain. 147(1890). A pale grayish, compact, fine-grained, cellular rock ; in which occur numerous minute porphyritic crystals of a glassy felspar and a dark- coloured mica. It possesses a well marked " flow-structure." In the thin section the rock is seen to consist of a tine-grained, hypocr}'8tiil- line groundmass, through which are distributed numerous porphyritic crystals of sanidinCj plagioclase, biotite, and acmite or ivgirine. Apatite is also present. The rock is therefore to be regarded as an intermediate form between the mica trachytes and the andesites, but is more closely related to tjie former. The sanidine is in quite fresh, tabular, glassy, well formed, much cracked, idiomorphic crystals, inclosing microlites, some of which at least may be refei-red to augite. The srnidines possess good cleavage as a rule, and occasionally hold, in addition to the microlites, larger inclusions of the biotite, augite, and other constituents of the rock. On the whole, however, the crystals are tolerably free from foreign matter. The sections are sometimes broad and tabular, sonietimes narrow and columnar. Tliose parallel to ooPx, bounded by oP, ooPi otPoo are common. In one example the angle oPAocPoo was mea- 8u>'ed, and gave 105°. Rectangular sections at right angles to oP. ocPx, also occur. The outlines are occasionally rounded or irregular owing to magniatic resorption, and the crystals frequently show little bays running into them, filled with the material of the groundmass. Sometimes several individuals of irregular shape are clustered together, forming the so-called " sanidine eyes." The crystals are often bent and broken, and twinning according to the Carlsbad law, with very irregular boundaries between the two halves of the crystal, is common. Zonal structure is beautifully developed in some cases, the extinction varying in the different layers of the crystal. A few felspar crystals possessing a fine microcline-like structure and undulatory extinction were observed, which may possibly be anorthoclase. ?r ] PETROGRAPHICAIi CHARACTERS OF ROCKS. 381 n lo occurs, of serpen- lid minute a of rims r is appa- ify it witli liich occur ,nd a dark- ;." In the ypocr5'8tal- porphyritic or ivgirine. rm between f related to irmed, much jf which at Mjd cleavage jlites, larger of the rock, torn foreign sometimes by oP, ocP. oc was mea- igles to oP. or irregular y show little sjroundmass. red together, •e often bent w, with very 1, is common, he extinction ike structure possibly be 69. Dacite. — Twaal Creek, five miles and a half above its mouth. Tertiary rocks 41 (1890). ~^""'- This is a coarse-grained, light yellowish-gray rock, with numerous large porphyriticcrystals of quartz and plagioclase distributed throughit. It is remarkably free from coloured bisilicatcs ; a few little patches of chlorite and epidotc, stained with iron ore, probably representing those originally present. Large, much fractured, phenocrysts of quartz and plagioclase occur in a fine-grained granular groundnuiss, composed of quartz and felspar, with numerous little patches of calcite. A little unstriated glassy felspar is present, which may be sanidine. Pyrite crystals are thickly scattered through the section, and apatite, in rather large, well-developed crystals, is also plentiful. The plagioclase phenocrysts are tabular in form and lave the niicro- iine habit, that is, are glas.sj' and colourless, resembling sanidine. They are much altered to calcite, epidote, and a greenish pseudophitic sub- stance, similar to that which has been noted by llosenbuseh as a de- composition produci I plagioclase in anilesites from Kapnik and Stenzelberg in the Siebengebirge.* The average of six determinations of the extinction angle on M gave 22' 30', which brings it in the labradoritc series of the plagioclase felspars. The felspar of the groundmass is maiiily allotriomorphic in habit, and, like the phenocrysts, is much decomposed. The quartz phenocrysts are rounded in outline, and occasionally measure as much as half an inch in length. A close examination of the specin:en reveals the fact that many of them are really doubly terminated prisms, whose edges and angles have been greatly rounded owing to magraatic resorption. They are much cracked, bi'okeii, and displaced, and are full of inclusions, such as minute colourless micro- lites and inclosures of the groundmass, also confused aggregates of chloritic and epidotic material, with some pyrite. Little bays run into the quartz, filled with the groundmass material. The quartz of the groundmass has the .same appearance as that usually seen in the microgranitic quartz porphyries. 70. Da .TE, PASSixo into a Liparite. — Upper Tranquille River. 353 (1889). A very light pinkish-gray, tine-grained, compact, fresh looking, por- phyritic rock, composed .chiefly of plagioclase, an unstriated felspar •Massige Qesteine, 2nd Ed., Stuttpart, 1887, p. 650. 1.1 i" 382 n BRIT18U COLUMBIA. I > Tertiary rocks (sanidine ?), quartz, and biotite individuals, porphyritically developed —Cont. jjj j^ microcrystalline groundmass. The occurrence of a considerable quantity of unstriated felspar along with the plagioclase shows that the rock is to be regarded as a transition form between the dacites and liparitea. The quartz occurs in much cracked, rounded individuals, frequently inclosing portions of the groundmass. Both the plagioclase and sanidine are fresh and glassy, the former well-striated, and the latter frequently occurring in large binary twins. Their outlines are much rounded, as in the case of the quartz. The biotite, of a deep brown colour, occurj in well-formed six-sided crystals and irregular plates, which exhibit strong pleochroism and polarize in brilliant tints. Inclusions of iron ore and apatite arc frequent. Little microlites of augite occur in the groundmass of the rock, through which granules of iron ore are also plentifully scattered. 71. Mica Andksite.— Trachyte Hills. 260 (1889). A chalky, fine-grained, light cream-coloured, porphyritic, rusty weathering rock, which, examined under the microscope, exhibits porphyritic crystals of plagioclase and biotite, developed in a fine- grained groundmass composed chiefly of plagioclase, with a little iron ore. The plagioclase phenocrysts are comparatively few in number, have a glassy and colourless habit, and well developed fine zonal structure. In form they are mostly tabular, the sections being rectangular or short oblong, occasionally prismatic. Binary twinning according to the Carlsbad law is common. The twinning lamalltv are not numerous in the individuals, and in one instance apparently entirely absent. In such a case it is hardly possible, without a chemical test, to assert that the individual is a plagioclase and not sanidine. A determi- nation of the angles of extinction seems to show that most of the felspar is to be referred to the oligoclase and albite divisions. The crystals often have an uneven extinction, are cracked, and hold numer- ous inclusions of glassy material, prisms of apatite, granules of iron ore, and little scales of biotite. Evidences of corrosion are numerous, the sections having the angles much rounded, and numerous little bays, filled with the materials of the groundmass, running into them from all sides. A pseudophitic alteration product is developed in some instances along the cracks which traverse the crystals. The felspar of the groundmass consists of small lath-shaped sections of plagioclase of greatly varying dimensions, mostly in the form of binary twins, though occasionally in simple individuals. Multiple PETHOORAPHICAL CHARACTERS OF ROCKS. 383 H striation is very infrequent. In addition to tliese lath-shaped sections Tertiary rockx of felspar, other rude rectangular sections occur, some striated, but the majority not. A little .sanidine might be present amongst tlio unstri- ated individuals, and, without a separation of the felspars, its deter- mination would be a matter of extreme difficulty. The mica, which occurs in porphyritio individuals sparsely distributed through the rock, is quite fresh, of a deep brown colour, strongly pleochroic from light straw-yellow to deep b'-own, holds numerous in- clusions of iron ore, and occasionally exhibits evidence of mfigmatic resorption. Little scales of this mineral are also scattered through the mass of the rock. Slender little prisms of zircon, well terminated, are not infrequent in the section ; also apatite crystals, and iron ore. The whole section is stained with yellowish-brown decomposition products. As regards the groundmass of this rock, its felspathic constituents have already been described, but in addition to these there appears to be a certain amount of glassy interstitial matter, and the small plagio- clase crystals are arranged in such a manner as to give a " flow-struc- ture " to the rock. Owing to the fact that the rock, as seen in the hand specimen, bears a striking resemblance to a typical trachyte, and also that the majority of the felspar individuals e.Khibit binary twinning only, it was thought advisable to make a separation of the felspars in order to be certain that plagioclase, and not orthoclase, is the predominating constituent. The rock was finely powdered in an iion n\ortar, and the powder passed through, first, a sieve having 43 meshes to the square inch, and, finally, through one of 160 meshes to the square inch. The powder, after having a powerful magnet passed through it in order to remove any particles of iron which might have become detached from the mortar, was carefully washed and placed in a Harada apparatus filled with Thoulet's solution of specific gravity 2-670, as determined by a float of anorthite. It was found that all the powder, with the excep- tion of a very little dark-coloured material, which was mostly mica, floated at this specific gravity. It also floated readily at 2'62. The solution was further diluted until a float of perthite (cp. gr. 2-592) just rose. At this specific gravity all the constituents sank very slowly to the bottom. The exact density of the fluid was then deter- mined, and found to l)e 2-598 ; so that the powder must have a specific gravity of slightly over 2-60. This is the specific gravity of a felspar having the composition of albite, or of the heaviest anorthoclase.* (/ •See Rosenbusch, Mik, Phys. d. iiet. wclit. Min., 2nd Ed., 1885, pp. 542 and 550. / f^l^m^^fi 384 n BRITISH COLUMUIA. Tertiary rotkB It hiw frequently been observed that in the andesites the felspars of —Cant. j.jjg groundmass are more acid than those which occur porphyritically developed. Fouque has shown that in a pyroxene andesite from San torin the former are albite and the latter labradorite. 72. HoKNiiLENDE Andesitk. — North side Maiden Creek. 327 (1889). A lij^lit brownish-j^ray, rusty weathering rock ; consisting of a fine- grained matrix in which are eml>edded ratlier large prismatic cry.stals of hornblt-nde. Cavities filled with carbonates are numerous in the specimen, and on the outer surfaces of the rock the removal of the carbonates by weathering gives it a cavernous appearance. Phenocrysts of hornblende and plagioclase occur in a microcrystalline groundmass composed of the same materials, in which, if any glass be present, it must exist in extremely small proportions as minute liluis between the grains. The hornblende phenocrysts are brownish-green in colour, and possess rather strong pleochroism, the axis of least elasticity bisecting the acute angle. The maximum extinction angle observed was about 25°. Inclusions of the other minerals pre.sent in the section are nu- merous, and alteration to chlorite was observed. Twinning according to ooP5b (100) is common. One individual is cut in a direction at right angles to the principal axis by a crystal of plagioclase, .so that the section resembles a cross, the shorter cross-piece being formed by the plagioclase. 73. Basalt. — Hills between Loon Lake and Hi-hium Lake. 23 (1889). A dark-gray, compact, fine-grained rock, which is quite fresh, and consists essentially of minute lath-shaped crystals of plagioclase, small grains and crystals of augite, and numerous granules of iron ore, embedded in a very fine-grained microfelsitic and gl.issy groundmass. Patches and streaks of the groundmass, almost entirely free from plagioclase and augite individuals, occur throughout the section. The plagioclases vary considerably in size, the smallest being mere microlites. The augite individuals are usually very small, but, when examined with a high-power objective, are frequently seen to have good crystal forms, sometimes polysynthetically twinned. A very few individuals of plagiocla.se and augite of a comparatively large size are present, and around these the smaller plagioclases bend in a manner which gives a typical "tlow-structure " to the rock. ■] PETROOIUPIIICAL CIIARAC'TEHS OF K0CK8. 385 B The aection is somewhat stained with hydrous iron oxides. The rock is one which, according to Rosenbusch's system of classifi- cation, would l>e referred to tlie basalts, althouf^h, disrej^ardinj^ ajji-, it is often well-nigh impossible to draw the line between the auyite porphyritesi and the basalts. Taking into consideration the freshness and glassy character of the rock, together with its Tei-tiary age, the writer prefers lo refer it to the basalts, 74. Basalt. — Arrowstone Hills, 2 miles south of Scoltio Creek. 20 (1SS9). An exceedingly fine-graineil, compact, light-gray rock, having a strong argillaceous odour. Owing to the extreme fineness of grain, a satisfactory microscopic examination of the section is a matter of sotne dilUculty. It appears to consist chiefly of minute luth-shaped crystals of plagioolase, togethei- with little irregular grains, and occiieionally eight-sided sections, of a pale yellowish-green bisilicato (usually considerably altered) having a highly inclined extinction angle, wliiuh is undoubtedly aui;ite. The plagiocla.ses have a general parallel arrangement and bend around the larger augites, (Jlassy matter is apparently present in the groundmas;5, lying between the plagioclases, but this could not be definitely proved in the section examined. 75. Olivink hasalt. — Plateau, near Middle Branch of Tranquille River, north of Kamloops Lake. 355 (1889). This is a very dark-coloured, somewhat porous, compact, fine-grained, porphyritic rock, with a decidedly resinous lustre, and exhibiting dis- tinct flow-structure in the hand specimen. A microscopic examination shows it to be a most typical and quite fresh basalt. Plagioclase, hornblende, augite, olivine, and iron ore, occur porphy- ritically developed in a fine-grained groundraass made up of brownish glassy matter with embedded minute crystals and granules of plagio- clase and augite ; the whole possessing a well-marked flow-structure. The porphyritic plagioclases often include portions of the glassy groundmass. The hornblendes are brown in colour, and almost always have a dark rim surrounding them, composed of opaque iron ore and grains of augite. These rims are due to magmatic resorption of the hornblende.* Tertiary rockii —Coiit. *Cf. Iddiiiirs's translation of Rosenbusch's Microscopical Physiojjraphy of the Rockmaking Minerals, 1893, p. 2(18. 25 "'SI, ' ' "f 386 B IIRITISII COLl'MBIA. I T.trtiary rockH The olivine is almost entirely decomposed, and is now representeii —Cone. largely by rounded irregular patches of serpentinous material. The augites are of a light yellowish colour and quite fresh. 76. Olivine Basalt.— Upper Tramjuille Hivor. .IS.'} (1889). A very dark-coloured, rather fine grained, Hoiiiewhat p(erhaps, resulting from the decomposition of a glassy base. It pro- bably originates from both sources, as it is also frequently seen sur- rounding cores of unaltered pale-green olivine and augite. Owing to their extreme alteration, it is somewhat difficult to dis- tinguish at tirst between the augite and olivine, but some elongated crystals with parallel extinction and, when fresh, brilliant polarization colours, were unhesitatingly referred to the latter mineral. Microlites of augite are exceedingly abundant, and granules and crystals of iron ore are evenly and plentifully distributed through the section. 77. Olivine Basalt. — Plateau west of North Thompson River, east and north of Caribou Lake. 193 (1888). A medium-grained, rather light gray, crystalline, micro-porpliyritic and amygdaloidal rock, which weathers to a rusty-brown colour. The amygdaloidal cavities are frequently lined with some zeolitic mineral. The rock is composed chiefly of plagioclase, augite, olivine and iron ore. The plagioclase occurs in broad porphyritically developed forms, as well as in lath-shaped sections in the groundmass of the rock, these latter forms freijuently penetrating the augite. The phenocrysts aie fresh, glass}', well-striated, and hold numerous inclusions of augite, iron ore, and other minerals, often arranged in lines around the periphery of the crystal. Determinations of the angle of extinction, measured on P, appear to show that the felspar is to be referred to bytownite. The crystals have very irregular boundaries, due to niagma*ic absorption, and the smaller plagioclases of the groundmass bend around them in the usual manner observed in those rockswhich exhibit "flow-structure." ' representeil rial. ish. ;1889). porphyritic, ly fresh and ire. M'phyiitically ough the sec- te form, as it ite or olivine, in such cases, )a8e. It pro- itly seen sur- rticult to dis- inie elongated t poliiiization I. Microlites 1 crystals of the section. m River, east ro- porphyritic colour. The itic mineral. vine and iron ped forms, as k, these latter fsis are fresh, gite, iron ore, liphery of the asured on P, ownite. The ic absorption, ound them in 3w-structure." ] PE llOCiKAPIIICAL CHAUACTEH8 OF ROCKS. .18 I II The groundina.ss plagiodase is frequently intergrown with the augite, Tiitiuty rucks often in such a way as to make it probable that they crystallized "" ' simultaneously. The augito is of a violet-brown colour, (jtiite fresh, rather strongly pleochroic, and exhibits brilliant interfen-nec colours. It docs not occur with tegular crystal outlines, but intergrown with, lyiig between, and sometimes almost completely surrounding, the plngiodases. The olivine is very abundant in irregular pale olivo-grcen grains, which are usually (juite fresh, altliougii many examples of alteiation to brown serpentine, accompanied by .separation of magnetite, may be seen in the section. It possesses the usual high index of refrac- tion, brilliant polarization colours, and other features characteristic of lie mineral. I 'on ore, probably magnetite, is extremely abundant, mostly in irregular grains and rods. The structure of the rock is apparently a holocrystalline one, and if glassy matter be present it must exist in very small (juantity. 78. Olivine Basalt.— Skoatl Point. 194 (1888). In the hand specimen this is a dark greenish-gray, rather tine grained, porphyritic rock. Dr. Dawson states that it forms the " neck " of an old volcano from which basalt has flowed out, and is probably of Tertiary age. Phenocrysts of plagiodase, olivine, and augite, are embedded in a fine-grained groundmasa composed of lath-shaped sections of plagiodase and granules of augite, olivine, and magnetite, together with some glassy interstitial matter. " Flow-structure " is sometimes well brought out by the arrangement of the small plagiodase crystals in the rock. Olivine is very abundant and remarkably fresh, exhibiting only the first stages of alteration to serpentine. It occurs in little grains in the groundmass, as well as in porphyritically developed individuals. Its outlines are often rounded, a phenomenon Yfhich is no doubt due to magmatic resorption. It is frequently included in the felspar, thus showing that it is the older of the two, and itself holds numerous in- clusions. In colour it is yellowish to almost colourless, and possesses ' good cleavage. 79. TuFFACEOUS Rock. ^-Thompson River, opposite Drynoch. 188 <1889). 25^ ,/ -*T^T^^W " : 388 B BRITISH COLUMBIA. I Tfirtiary rocks ^ coarse-grained, light greenish, apparently clastic rock, consisting —O.ni. very largely of fragments of plagioclase felspar, which are greatly decomposed. The fragments representing bisilicates originally present, are now so entirely altered as to he unrecognizahle. The section contains some quartz, also much calcite, chlorite, and other decomposition products. The rock is probably made up of material derived from basic eruptives. [The following description is by Dr. F. D. Adams, of McGill University, who e.xaiiiined a. thin section of the rock in question.] 7"«. Alnoite-ltke Rock. — Road between Ashcroft and Savona, three miles east of Eight-mile Creek. 441 (1877). A rock consisting of a vpry fine-grained groundmass in which are embedded large phenocrysts of biotite, augite, and olivine. In the hand specimens the large plates of biotite are especially noticeable, giving the rock the appearance of an alnoite. The olivine is now all decomposed to serpentine, or a mixture of serpentine and a rhomboiiedral carbonate ; the biotite is also much aii.ered. The augite is nearly colourless and possesses a barely per- ceptible pleochroism, these large augites are often surrounded by a darker border of a different variety of augite with a somewhat diffei'ent extinction, — as in the alnoite from Ste. Anne de Hellevue,*^ — the small augites of the groundmass are identical in character with the outer zone. The groundmass is composed largely of augite in little crystals. Associated with this are biotite and olivine, now for the most part altered to serpentine, together with a colourless mineral having a very lo»v double refraction, little grains of iron ore, and little needles of apatite. The colourless mineral above referred to has never been observed twinned and is certainly not plagioclase. It is for the most part decomposed to calcite, this fact and its optical properties so far us they can be studied, point to nepheline or possibly mellilite. None of the distinctive characters of the latter mineral, however, could be observed, but so little of the undecomposed mineral still remains that its exact nature cannot be detonnined. The rock, therefore, is one belonging to the group which includes tlie alnoiti^ ".ionchi(iuites, and fourchites, but it is now .so decom- posed that its exact position in this group cannot be determined. ♦ See Adams, Am. Jour. Sci., vol. XLIII., 1892, p. 20fl. k, consisting are greatly t, are now so ontains some on products, lie erupt! ves. rniversity, who md Savona, in which are I. re especially a mixture of is also much a barely per- rounded by a diat diiTerent *- — the small 'ith the outer ttle crystals, be most part laving a very tie needles of 3 never been I for the most rties so far us ite. None of ver, could be remains that hich includes )w so decom- rmined. "•] PETROGRAPHICAL CHARACTERS OF ROCKS, 389 B Dr. Dawson states that the rock is probably a dyke of Tertiary age, but that the rocks at the locality are much broken auJ confused. 41. Quartz Augite Diorite, with some Biotite. — Forge Mountain. Plutonic 32 (1890). '"''k"- A medium-grained granitic rock, showir^' m the hand specimen light grayish felspar, dark green hornblende, r.nd magnetite. The microscope shows it to consist essentially of quart/, plagioclase, orthoclase, hornblende, augite, and biotice, together with magnetite apatite, chlorite, epidote, titanite and zircon. The quartz is the ordinary granitic variety, fiUing-in the spaces between the felspars. Plagioclase is the predominating felspar, and occurs in broad, well striated, much alttred, ofien nearly opaque, individuals, with a decided tendency to idiomorphic development. Some non-striated irregular, shaped grains, also much altered, are probably orthoclase. The hornblende occurs in brownish green individuals, sometimes possessing a somewhat fibrous structure, and often interspersed wil'i augite. Twins are not uncommon, and the mineral usually exhibits mor ; or less alteration to chlorite, and is sprinkled with granules of magnetite and other inclusions. Augite, besides occurring as described, associated with the hornblende, is also present in isolated individuals, generally much altered to chlorite, blight yellow epidote, and calcite, the brown colour being changed to green.. Lenticula" patches of calcite filleil with minute needles and granules of epidote, causing the whole to polarize most brilliantly, have separated out between the folia of the hornblende. 80. QuARTX Mica Diorite. — Near Pukaist Creek, three miles east of Thompson River. 35 (1890). A medium-grained, holocrystalline rock, in which the felspar, of a light greenish colour owing to_aiteration, is mottled with dark-coloured hornblende and biotite. It is composed of plagioclase, orthoclase, quartz, biotite, hornblende, pyroxene, magnetite, apatite, and ej)idote. The plagioclase, which predominates largely over the orthoclase, possesses uneven extinction, shows a marked tendency towards idiomorphic development, and is, together with the orthoclase, much decomposed. Quartz is tolerably abundant, extingui.'-hes very unevenly, and occurs in little granulated areas throughout the section. wmma ^nf«f 7 Plutonic rocks — C'ont, 390 B BRITISH COLUMBIA. Biotite is plentiful, largely altered to chlorite and epidote; the hornblende also is much decomposed and occurs intimately associated and intergrown with the biotite and pyroxene. The monoclinic pyroxene is quite abundant in the section, is of a pale green colour, and considerably altered to epidote and a light-green chlorite. Little granules of secondary magnetite are plentifully scattered through the altered crystais of this mineral. Frequently a core of comparatively fresh pyroxene may be seen surrounded by fibrous hornblende, which no doubt has resulted from its alteration. The bisilicates are all much stained by bro'.vn hydrous oxides of iron. 81. QuAKTZ Mica Dioriti', — Six miles up In-ki-kuh' Creek. 36 (1890). A rather coarse-grained hoiocrystalline rock, consisting of a light- coloured quartz and felspar matrix, in wuich numerous flakes of dark- brown mica of good size, and smaller individuals of hornblende and iron ore are embedded. The minerals composing it are plagioclase, orthoclase, quartz, biotite, hornblende, magnetite, titanite, apatite, epidote, chlorite, and zircon. The plagioclase felsf ir is the more abundant, is well-striated, and considerably altered tc saussuritic material. It possesses, in conmion with the orthoclase and quartz, a very uneven extinction, due to pres- sure. The biotite shows decompositions and alteration to chlorite,and, con- .sequently, often pre jnts a srmewhat fibrous appearance. The lior i- blende, also considerably p/itered, presents no unusual features. It is strongly pleochroic in green and yoUowish-hrown tints. Titanite and magnetite are abundant, often occurring in large grains. A few sho.'t, stout, crystals of zircon were observed, some- times embedded in the biotite. 82. Crushed Granite.— Guichon Creek, west side, one mile south of Witches Brook. 20(1 890). This is a fine-grained, light greenish, somewhat rusty, granitic rock, possessing in the ht.nd specimen a distinct finely-laminated structure. It is stated by Dr. Dawson to occur near the contact of a mass of granite with rocks of Triassic age. Under the microscope it is seen to consist of a fine-grained inter- looking mosaic of quartz and felspar, in which larger grains of the same materials are embedded. pidote ; the ly associated tion, is of a i light-green ! plentifully i'requently a •rounded by ilteration. tides of iron. ik. 36(1890). ig of a light- ,kes of dark- •nblende and lartz, biotite, and zircon. striated, and , in common due to pres- rite,and, con- The hori- turea. It is la erved, some- ! mile south ranitio rock, ed structure. of a mass of grained inter- grains of the ■] PETROGRAPIUCAL CHARACTERS OF ROCKS. 301 B Little scales and a fow larger dakes of biotite, sometimes altered to Plutonic chlorite, are scattered plentifully throughout the rock, and grains of ^^ '* "" ' magnetite are also abundant. Small quantities of apatite and titanite are also present. Orthoclase and plagioclase both occur in a greatly decomposed con- dition and exhibit, together with the quartz, very uneven extinctions, having evidently been subject«d to intense dynamic action. The larger grains are much cracked, and reduced to a fino mosaic of crushed material around their edges. A rude laminated structure is givpn to the rock in the thin section by the parallel arrangement of the flakes of luotite. It is most prob- ably a granite which has been subjected to great crushing action. 83. Gramte porphyry. — Ea.st side of Barnes Lake. 48(1889). A medium -grained, light greenish-gray, granitic rock ; blotched with porphyritic, olive-green, decomposed felspar. It is composed essentially of orthoclase, plagioclase, quartz, and very small quantities of some muiih altered bisilicates, together with iron ore, chlorite, epidote, apatite, sphene, and hydrous oxides of iron. Many portions of the section examined show a distinct coarse grano- phyric intergrowth of the (juartz and felspar. The latter occurs sometimes in large, porphyritically developed, crystals ; and the whole structure of the rock suggests the first transition stage of a granite passing into a quartz porphyry. The rock, as far as one can judge from the single section, is liolo- crystalline, no glass or interstitial matter being detected. The felspars are so exceedingly altered that the irregular grains of the quartz stand out in bold relief, giving at a first glance an almost clastic appearance to the section. ' Bisilicates occur in very insignificant (juantities, and are mostly represented by brownish chloritic and epidotic material, associated with granules of iron ore. In a few instances the original mineral was judgetl to have been biotite. Iron ore, probably magnetite, is (juite abundant, and several small grains of sphene were also observed. 84. Porphyritic Diauase.- Road between Ashcroft and Savona, six miles from Ashcroft. 129 (1890). This is a medium-grained, dark-green and yellowisii-brown mottled VitcU, in which the microscope shows a fine-grained portion, having the ophitic structure of a diabase, and holding porphyritically developed crystals of plagioclase and augite. 392 B BRITISH COLUMBIA. Plutdnic rocks— Coat. The plagioclase phenocrysts sho# an extreme stage of alteration to saussuritic material. The whole rock is much decomposed, and consists chiefly of plagio- clase, pyroxene, biotite, a little quartz, iron ore, apatite, and pyrite. Both augite and diallage are present in the rock and are greatly altered to chloritic, serpentinous, and epidotic material, with deposition of granules of secondary magnetite. The augite is light-green in colour and polarizes in brilliant tints. The phenocrysts of this mineral are greatly decomposed. Two sections of this rock were examined, one of which contains much more biotite than the other. The biotite is of a curious deep reddish-brown colour, and strongly pleochroic. It is apparently secondary in origin, and occurs int^imately associated with the confused tufted and fibrous aggregates of serpentinous and chloritic material resulting from the decomposition ^ the bisilicates. The iron ore is chiefly iimenite, accompanied by leucoxene. This rock. No. 96, and No. 99, resemble each other in the hand specimens and have the same general mineral composition, but the rock now under consideration is porphyritic, and exhibits a phase of structure more closely approach- ing that of a coarse-grained porphyritic diabase. The difference in structure would readily be produced by a difference in the rate of solidification of the magma. 85. Biotite Hornblende Gkanite, or Hornblende Granitite. — Summit of Chl'-pooin Mountain. 266 (1889). In the hand specimen the rock presents the same general appearance as No. 92. It is thoroughly holocrystalline, consisting principally of orthoclase, plagioclase, quartz, biotite, and hornblende ; with titanite, iron ore, apatite, zircon, chlorite, and epidote, as accessory constituents. The felspars, as a rule, are not greatly altered, although some in- dividuals show more or less complete saussuritization. Zonal structure is common ; they also possess very uneven extinction, and are filled wilh various inclusions, amongst which are little blood-red transparent scales of hematite. The plagioclase felspar is quite abundant and fre- quently exhibits excellent examples of pressure-twinning. The quartz is the usual granitic variety and forms a rather fine- grained mosaic between the felspars. Biotite is abundant, quite fresh, strongly pleochroic, and often inter grown with hornblende, which presents no unusual features and is frequently altered to chlorite. Iteration to y of plagio- d pyrite. are greatly 1 deposition Kt-green in his mineral ch contains jrious deep apparently he confused tic material iron ore is No. 96, and ve the same lideration is y apj)roach- lifference in the rate of BANITITE. — appearance ncipally of th titanite, onstituents. y\\ some in- al structure d are filled transparent mt and fre- rather tine- I often inter- ;urea and is •] PETROGRAPHICAL CHARACTERS OF ROCKS. 393 B ^ / Titanite is abundant, occurring mostly in large irregular grains : I'lutonic apatite is also present in small, rather stout, crystals. Several stout '"'' "^ "" ' crystals of zircon, showing a zonal structure, were observed. Chlorite, epidote, and iron ore are abundant, the latter sometimes accompanied by a substance which is apparently leucoxene, indicating that soiiie titanie iron is present ; but a test of the powdered rock showeu that magnetite is very abundant. As regards the nomenclature of this rock and No. 92, much plagio- clase is undoubtedly present, and a separation of the felspars in each case would be necessary in order to determine whether the rocks might not perhaps be more properly termed quartz diorites. In the akseiiee of such determinations, and from a close examination of the sections submitted to me, I prefer at present to refer them to the granites. 86. Hornblende Granite. — Three-lake Valley. 3S6 (1S77). A medium-grained, light pinkish, decomposed granitic rock, which, judging from the hand specimen, has a "miarolitic" stiucture ; that is, it possesses small cavities into wh, i the corners :uid edges of the crystallized mineral components project.* It consists of a holocrystalline aggregate of orthochaso, pligiocluse, hornblende, a[)ntite, and iron ore ; with epidote, chlorite, kaolin, and hydrous iron oxides, as decomposition products. Little areas of gran- ophyre are numerous in the section. The quartz is the ordinary granitic kind and holds numerous nclusions The felspars, especiiUy the plagioclase, arc greatly de- composed to a dull whitish opaque substance. The bisilicates origin- ally present are now almost entirely altered to clilofito, epidote, etc. Some comparatively -unaltered fragments, which were examined care- fully, proved to be hornblende. Aggregates of brilliantly polarizing '■p?dote granules are abundant. »th magnetite and ilmenite appear to be present, the latter fre- quently accompanied by leucoxene resulting from its alteration. 87. Hornblende Biotite Granite. — Between Campbell Creek and Kamloops. 108 (1889). A medium-grained, holocrystalline rock, exhibiting in the hand specimen a light-coloured groundmass, blotched with dark hornl)lende and mica, and somewhat stained with hydrous iron oxides. It ap- proaches in composition to the quartz thorites, in that plagioclase felspar is very abundant, equalling in quantity, if indeed it does not exceed, the orthoclase. C/. RosenlniHch, Mik. Pliys. der iim««. (Jesteine, \>. 3'J, 1HS7 I 394 B BRITISH COLUMBIA. Plutonie rocks — Cvni. The minerals present are quartz, orthoclase, plagioclase, hornblende^ biotite, ilmenite, titanite, apatite, zircon, and pyrite. The quartz is the ordinary granitic variety, is much cracked, and possesses very uneven extinction in common with the felspars. Both orthoclase and plagioclase are considerably decomposed ; the latter is well striated and often possesses a marked zonal structure. It also exhibits a tendency to idiomorphic development, and the same crystal, in addi- tion to the ordinary fine twinning striation, will frequently show twinning on the Carlsbad plan. The hornblende, which is tolerably unaltoied, occurs in irregular individuals, and also in well defined crystals which are strongly pleochroic in light yellowish-brown to dark green tints. The crystals are frequently twinned parallel to the orthopinacoid. The biotite presents a fibrous frayed-out appearance and is altering to chlorite. Zircon and apatite are among its included minerals. Titanite and iron ore are not very abundant in the section. The rock in its general characte'"' somewhat resembles a granite from the Stikine River, described by Dr. Adams.* 88. Crushed Granite. — North side of Kamloops Lake, near Copper Creek. 161 (1890). A rather coarse-grained, much decomposed, light grayish, granitic- looking rock, holding numerous patches of rather bright yellow altered felspar ; the whole spotted with small rusty dolomite and calcite crystals and little spangles of silver-v/hite mica, the former giving a general pinkish hue to the specimen. It effervesces freely with dilute hydro- chloric acid. A microscopical examination shows it to be made up chiefly of frag- ments of quartz and felspar cemented together by a fine mosaic of the same materials, aflfording a good illustration of Tornebohm's " mortar- .structure" (Ger. mortelstrucfur.'f) Numerous irregular patches and small crystals of very rusty car- bonates are scattered throughout the section, together with scales of pale green chlorite and a colourless hydro-mica. A few small zircon crystals were also observed. Patches of granophyre are not uncommon, sometimes surrounding felspar i.idividuals. Both orthoclase and plagioclase are present, generally in a much altered condition, the larger grains, together with the quartz, being cracked, bent, and granulated on their edges. * Annual Reiwrt, Geol. Surv., Can., vol. III. (N.S.), Parti., 1887-88, p. 238b. t Geol. Fijren. Forhandl, 1881, V, i).233. ■P ■] PETROGRAPHICAL CHAKACTERS OF R0CK8. 395 B ' 4 The (|uartz sliowa uneven extinction in a less degree than does the Plutonic felspar, but is much broken. The rock is probably a granite which ^"^ ^~ "" ' has been subjected to great crushing action. 89. Sye:«te (poRPiiYRiTic). — Edwards Creek. 81(1889). A rather coarse-grained, holocrystalline, light pinkish or yellowish- gray rock, with large porphyritic felspar crj otais thickly scattered through it. Its texture varies considerably in difT'erent portions of the mass. That it has been considerably squeezed is shown by the crush- ing and undulatory extinction of the component minerals. The minerals composing it are orthoclase, plagioclase, niicrocline, biotite, some hornblende largely altered to chlorite, titaiiite, ilraenite, apatite, zircon, calcite, epidote, sericite, and pyrite. Very little, if any, quartz is present. It was searched for amongst the crushed mosaic of felspar grains lying between the phenocrysts, but could not be identified with certainty. The felspars are much deconr posed and often exhibit a zonal structure. Titanite is very abundant in large irregular single grains and aggregates, and is frequently as- sociated with ilmenite. An exceedingly minute yellow metallic particle was thought to be gold, and Dr. Dawson has since informe:l me that an assay has been made which showed that appreciable traces of that metal exist in the rock. . 90. AuGiTE Syenite. North Branch Bonaparte River, near the mouth. 33G (1889). A. ratlier coarse-grained holocrystalline rock, which in its structure diflFers somewhat from a typical syenite. The principal mineral constituents are orthoclase, microcline, augite, biotite, apatite, magnetite, and zircon. Quartz was not detected in the section examined. The orthoclase presents the usual characteristics of the variety com- monly occurring in granites. A curious micro-perthitic intergrowth of the felspars is of very common occurrence. A felspar resembling anorthoclase is rather abundant in the section in very finely striated grains. In sections at right angles to P and M this felspar exhibits a very fine microcline-like twinning striation.* The augite is of a clear light-green colour, occurring in irregular grains and sometimes in rude octagonal sections. It is often intiui- ately associated wiiih the biotite, which is of a deep brown colour and strongly pleochroic. * RoHenbusch, Mik. Phyg. d. pet. wicht. Miu., 3rd Ed., 1892, pp. 679-(}80. 396 B BRITISH COLUMBIA. Plutonic Apatite in large stout crystals and irregular gmins i*^ very abundant Magnetite is also plentiful, and a few zircons were . rved. The rock shows considerable saussuritization of the felspars, and the Section is stained throughout with brownish decomposition products resulting probably from the alteration of bisilicates. 91. Hornblende Granite. — East aide Fraser River, seven miles north from mouth of Cincjuefoil Creek. 274 (1889). This is a medium-grained, dark-green and white rock, which, exam- ined , microscopically, is seen to be composed chiefly of orthoolase, quartz, hornblende, and a little plagioclase felspar ; also titanite, epidote, chlorite, and iron ore. Cataclastic structure is remarkably well-developed, the very uneven extinction and crushing of both quartz and fei.^par being evidence of the intense dynamic action to which the rock has been subjected. The felspar, as usual, is not so badly shattered as the quartz, but, like it, possesses very uneven extinction. Th( quartz shows every gradation from slightly uneven extinction to complete shattering of the grains. The hornblende is intensely pleochroic in yellowish- brown to deep green tints, and is altering to chlorite and epidote. Much titanite and epidote are present, the former often in rude crystals as well as in irregular grains. 92. BioTiTE Hornblende Granite, or Hornblende Guanitite. — East side of Fraser River, four and a half miles above Cinquefoil Creek. 273 (1889). This rock, whilst resembling No. 91 in the hand specimen, does not exhibit such marked cataclastic structure when microscopically examined. Biotite is also present, and plagioclase is much more abun- dant. Its component minerals are orthoclase, plagioclase, quartz, biotite, hornblende, iron ore, chlorite, apatite, zircon, epidote, and titanite. The felspar is considerably altered, and frequently exhibits a beauti- ful zonal structure. Biotite is abundant in quite large individuals, •often bleached and altered to chlorite. The hornblende, also showing alteration to chlorite, occurs intimately associated and intergrown with the biotite. Iron ore in irregular grains is very abundant, and some- times accompanied by a grayish substance resembling leucoxene ; so that the iron ore in these instances is no doubt ilmenite. 93. Quartz Mica Porpiiyrite. — Kl-ow-a Mountain. 76 (1890). In the hand specimen this is a grayish-white, fine-grained, compact, ielsitic-looking rock, through which are distributed numerous porphy- •] PETROGHAPHICAI. CHARACTERa OP KOCKS. 397 n ritic individuals of quartz, felspar, and a dark-coloured, almost black, Plutonic mica. rociiu- Cont. Seen under the microscope the groundmass of the rock consists of a very fine-grained mosaic of quartz and felspar, in which tiie phenocrysts of quartz, felspar, and biotite, are embedded together with garnet, epidote, chlorite and apatite. Very few phenocrysts are pre- sent in the section examined, but the.se appear to consist chielly of'i plagioclase. An examination of quite a number of sections would be necessary to determine the question as to whether the rock should be referred to the porpliyrites, in which plagioclase predominates, or to the porphy- ries, in which orthoclase is the prevailing felspar. Dr. Dawson states that the rock forms a dyke cutting granite of the Coast Range. 94. (Quartz Porphyry, passinc; into Quartz Porphyrite. — North side of 8eton I^ake. 297 (1889). A very light coloured, grayish-white, medium-grained, gi'anitic- looking rook, occurring, according to Dr. Dawson, in the form of a large dyke. Under the microscope it is seen to possess some remarkable features. Porphyrilic crystals of quartz which are sometimes sharply idionior- phic, together with idiomorphic plagioclases, are embedded in a micro- granitic groundmass which is appai'ently chietly composed of grains of unstriated felspar, and perhaps a little ipiartz, although the latter mineral was not determined with certainty. The porphyritic plagioclases show well-developed zonal structure, and often occur in interpenetrating twins with the usual sti-iation. A determination of the extinction angles shows that they are inter- mediate in composition between oligoclase and labradorite, with the centre more basic than the outer portion. Small quantities of biotite and hornblende, much altered to chlorite, are present. The rock is altogether a remarkable one ; the plagioclase is unusually basic to be associated with so much quartz, and there is an unusually small quantity of coloured bisilicates for a porphyrite. Sections were submitted to Dr. F. D. Adams and Prof. A. P. Coleman, and the writer is much indeljted to these gentlemen for their views regarding the rock. They agree with him in regarding it as a quartz porphyry, which, from the large amount of plagioclase present, is passing into a quartz porphyrite. / i I 398 » BRITISH COLUMBIA. Pliitoiiio rooks — Cont. 95. Amphibolite. — Stein Mountain. 83 (1890). A tine-grained, dark-green, somewhat schistose rock, in which the microscope reveals the fact that it has been subjected to intense dynamic action, and so sheared and crushed as to almost entirely obliterate its original structure. Finely granulated plagioclase, tlie individual grains of which exhibit very uneven extinction, is mingled with confused aggregates of horn- blende, chlorite, muscovite, and a lark-brown mica, these minerals also occurring in isolated scales and minute crystals scattered through the felspar. Many forms occur almost entirely altered to chlorite or some other substance, an alteration accompanied by the separating out of magnetite in small granules, which are now thickly sprinkled through the ma^s. These forms, by their general appearance, suggest that the original mineral may have been pyroxene. Zircon, apatite, and little cubes of pyrite mostly altered to limonite, were observed, and the whole section is permeated by hydrous oxides of iron, to which its brown coloration is due. The hornblende is largely in the form of slender needle-like crystals which are probably actinolite. The constituent minerals as seen in the section have a distinct paral- lel arrangement, and the rock, which Dr. Dawson informs me occurs as a dyke cutting granite, is doubtless a much squeezed and altered basic eruptive.* 96. Gabhuo.— North end of Coal Hill Ridge, near the road. 1 (1888) A medium-grained, dark-green rock, mottled with whitish felspar. It has a granitic structure, and is composed of plagioclase felspar, augite, ilmenite usually accompanied by leucoxene, chlorite, and epidote. The specimen is in an advanced stage of alteration, the felspar being changed almost entirely to a confused mass of saussuritic material. The augite, though less altered than the felspar, is changing in many instances to pale green chloritic and serpentinous substances. Twin- ned grains are not infrequent. Iron ore is quite abundant. 97. Gahhro, approaching diabase in structure. — Behind Battle Bluff. 202 (1888). This is a mottled, pink and dark-green, rather coarse-grained and much decomposed rock, consisting chiefly of plagioclase, augite, a little quartz, and ilmenite, together with epidote, chlorite and apatite. * See notes on Nos. 8 and 9, pp. 3.52-353 b. ■J PETROORAPniCAL CIIARACTEKS OF HOCKS. 399 M The plagioclaiae is almost completely sivussuritized, iind the augite, Plutonic which is much cracked, is largely altered to chlorite and epidote. '"^ " ' '" Ilmenite, accompanied by its alteration pnxluct leucoxene, is abun- dant. Epidote is also plentiful and is intensely pleochroic, from deep yellow to almost colourless. Apatite in irregular grains and crystals is of frequent occurrence. The plagioclase individuals are broad, and the structure of the rock is intermediate between that of a gabl)ro and that of a diabase, .some portions of the sections showing an approach to the granitic structure of the former, whilst others again have a coarse ophitic structure. On the whole, the writer is inclined to refer the rock to the gabbros rather than to the diabases. 98. Gabhro, APPROACHiNn diaba.se in structurk. — Near Edith Lake. 249 (1890). A fine-grained, pale green, dbcomposed rock, consisting of plagio- clase, augite, iron ore, chlorite, epidote, and apatite. As seen in the thin section the rock is greatly altered, the plagioclase felspar being partly converted into saussurite. A curious regular " lattice-structure " is often to be seen in the arrangement of the scales of sericite derived from the alteration of the plagioclase. The rock does not possess a strictly typical gabbro structure, por- tions of it showing a very coarse ophitic structure, which tends to ally it with the diabases. The augite is very pale green to colourless when fresh, but is gene- rally much altered to chlorite and epidote. It exhibits a tendency to idiomorphic development. Iron ore, probably magnetite, is abundant. This specimen must be classed with No. 97 as regards its structure. 99. PoRPHYRiTic Diabase.— Cherry Bluff. A (1888). This rock in the hand specimen is fine-grained, of a dark olive-green colour, with porphyritic crystals of plagioclase felspar, which, in com- parison with the main mass of the rock, are of large size. Augite also occurs porphyriticaliy developed, in exceedingly decomposed crystals. The structure of the specimen is that of a typical diabase, its ophitic character being marked, and it possesses but very little groundmass. The plagioclase felspar, though not extremely altered, is much cracked, full of inclusions, extinguishes very une\ enly, and is stained with brown decomposition products derived from the augite. It often forms binary twins, and possesses a most beautiful zonal structure. A number of determinations of the angle of extinction, measured between / 400 II BRITISH COLUMIIIA. IMutonic rock*— (''t-place. ? Circling or ddtour. Big Trout. •> Long Lake. Trout Lake. Diver Lake. Young Fish Lake. Slaty. Cold Spring. Dry. Sometimes dry. Red. Deei>. Overhung Mountain. Drift pile. Medicine. Green. Gravelly River. S|)ear-head Lake? Green Mountain. Ojwn or clear. Skull hill. Whitefish. Projecting |)oint. Bearberry (Arctosta- phi/Ion. Deep. Ridge lake. Going-over .stream. Tro\it. Porcuoiue place. Chief-liare. BIue-lMittle fly. Poison-weed ( Vera- truin) place. Sucker. Whitp. Deep, with shallow margin. g (iiven for n Name. iintain. [il ropt-place. or datour. ut. ? ike. ivke. ake. Fish Lake. )ring. nes dry. ing Mountain. )ile. ,ne. ly River. head Laku? Mountain. ir dear. Iiill. fish. ting jwint. erry {Arctosta- ilos. lake. ■over strpani. I niui' place, liare. Ixittle fly. uwfed ( Vera- nm) 1.1 ace. T. with shallow argin. -] 8HUSWAP NAMES OP PLACES. 403 « / Indian Name. Name Adopted or De.soription of Place on the Map. Pnt-hil-i-hil Shaw-ow-itlan She-kOk'-ilwh. Shit »hoo^s'-tl . Shloot. Shooi)em-liiU'-kwa. Silwhoi'-akun... . Sin-|)o-ut'-kwa . . . . Si-o-kani Sitz-kwok'-aum. . . . Sl-whe' Skem-a-kaini' Ski'-hist Ski-klot)sha 8koon-ko' Skoo-talis Skoo-wat'-kum Sko-whautl Skuh'-un Skuk'-o-uke. . . Skup kak-wa Hku-Hkul-a-hilt'- kwa Skutl-hi"-h;'-tl .Skwil-a'-tin. Hkwil-kwa'-kwil . Spa-.Hist Spiip-sil kwa .... Hpa-tnin' SlM!I)'-HUni 8pi-al-li\v Si)ilim-.^t'-lG-la . , Spil-mii-nioos.. . . Spil-i>rir-uiii Spit'-poo-thnii . . . Bpit-ti-k wous' . . . yta-ai'in or Ste-in. S'.lim'-what-kwa . S'tl-jio'-nuni Swuz-uk-ain' Tai-a-ka Ta-tlh Meaning Given for Indian name. Three-lake valley Mouth of Jaiiiieson Creek Lower part of Sandy Creek Allen Creek Fraser River near Leon Creek South Thompson Sil-whoi'-a-kun North Thompson Trapp Lake lA mile below Leon Creek sl-whe' Creek Lower end of Seton Lake Ski'-liiat Mountain Face Lake Skoon-ko' C.^ek Hills between Thompson, Bonaparte and cache Creek Skull Creek Skoatl Point Skuh'-un Creek .... Mountain H miles north-north-east of Za- kwas'-ki Sandy Creek River Lake I (inawed Mountain Kelley Creek, lower liart . . . Skwil-kwi'-kwil Mountain. . 8))aist Mountain (ilen Hart Spu-tsin Lake .Spatzi'iii Ki •!.> Hill Near mouth of Cilche Creek. Maiden Creek Clinton Creek Marble Cafion Ti-H.aniia Tik-i-niilx' Til-kwo-k we'-ki-la , Til-kwa-si-shoo. . . Titl'-whiloom Tlirt-li-put-flui'. . . . Toon -kwa Ton-il-ta-kai Tshi-it'-lin-stum. . , Tshil-tshitr-nuts., Tsliiui mt Him. . . Tshi-|i()0-in Tshi-wo'-us Tsio-hanidus. ... Till (H1-1(K1!'' Tsh(M)-whels' Tehntshn 26i Pass from Hat Creek to .Lack's Creek . . . Stein Oeek Fraser River near Lillooet ITppcr part of Hat Creek valley Rotanie Movuitain Tai-a-kn Liike .Small stream 1 mile north of Fourteen- mile Creek Stump Lake Trnntpiille River Tran(piine River, near mouth.. One of the Re,i'-iu Nef i-kip Kan-lax Hull-ill)' Skwai'-luh . . KwC-kwe-a-kwet' . Pil-te'-uk. E-kuh-kah'-sha-tin Ski-shis-tiii 8h-ha-ha-uih N'-kah-li-niil-uh... Spa'-ha-min Tsuk-tsuk-kwalk' . Kamloojw Comvall's. 4 miles alx)ve CAclic Creek li mile above Pukaist Creek SjMmce'a Bridge Lytton . . . OpiKisite Lytton Stein Creek Op|M)8ite Poster Bar Bridge River Foinitain Pavilion Creek 11 miles above Kelley Creek Clinton Pass Valli'V near Deadman River. Deainian River Skuh'-uii Creek Moutli of Up|)er Nicola River. . . . Douglas Lake Nortli Thompson Meaning Given for Indian Name. Point between the rivers. White. The iK)int. On the edge. Hi lar- frost. Blue. White earth. Drying place. Serai«'.d. Red place. th w iit 'V Ciiven for Name. ocks. ;e. ivO I-' '•■: ■^• (ta««). nd. leel. Hi von for u Name. Btween the t. Ige. it. rth. lace Dawson. ] UPPER AND LOWER LIMITS OP TREES. APPENDIX III, 405 B Notes on the Upper and Lower Limits of Growth op some Trees AND OTHER PlANTS, IN DIFFERENT PLACES WITHIN THE ArEA OF thf Kamloops Map-sheet. The subjoined observations are p'incipally of interest in their bearing.s on the climatic features of the region to which they relate. In this connection reference may be made to pages U b, 15 b of the foregoing report. PsEUDOTsuGA DouGLASii (Douglas fir). (Greatest heights at which this tree has been observed in various parts of the Kamloops sheet. * Feet. East slope Cairn Mountain 5 ^.-jq South-east slope Mount Afurray 5 750 Vans, Pavilion Ci-eek to Maiden Creek g'soo North (jf Za-k\vaski 5 45Q As-koui Mountain 5 ^3^ ■ East side Forge Mountain g 350.1- West slope Clioo-whels r, 200 Head of Hat Creek (south slojie) 6'22()f Arrowstone Hills r; ^qq Cinder Hill (Highland Valley) o^OTOf South-west slope Lytton Mountains 4 8([o ^'™''h '........ 4,'840 Piniainus Creek 4 yj^O Plateau, cast of Deadnian Lake (abundant) 4 5()0 East slope Botanic Mountains. 4 220 Plateau east of Young Lake (abundant) 4,200 Though not abundant in the lower and drier valleys of the region the Douglas fir may be described as jxtending uninterruptedly down ward from the levels above giveo to the sea-level. PiNus PoNDEROSA (Yellow pine).— Greatest heights at which this tree has been observed in various parts of theKamloops sheet. Feet. North of Za-kwaski 5 300 Head of Hat Creek (south »lo|)e) 5 200 East sIi))M' Marble Moiuitaiiis, north of Clinton Creek 5,100 Head of Maiden Creek 4 g(jo East slo|«) Cairn Mountain 4 j^oo Clinton Creek 4 (jjo •Where nuirked f, it is not (juite certain that tlie actually higliest limit was observed. 406 B BRITISH COLUMBIA. Feet. North slope, Lytton Mountains 4,340 West of Clapperton Creek (east slope) 4,300 ■^ ■:'"' 1U8 Creek 4,190 >f Skuh'-un Creek (south slope) 4,170 b vest slope of Lytton Mountains 4,000 Hife.-.und Valley 4,000+ Hills above Leon Creek 3,930 La-loo-wissin Creek 3,830 Trail, Niooamen to Nicola River 3,770 Hart Ridgo (north slope) 3,530 Above Younjf Lake ,S,500 Criss Creek 3,370 This pine is particularly characteristic of the lower and drier valleys and their slopes. It extends down the Fraser Valley about as far as North Bend Station (487 feet) and there ceases only because of the increasing moisture of the climate on approaching the coast. PiNUS Albicaulis, (White-barked pine). Least elevations at which this tree has been observed in the Kamloops sheet. — Feet. East side Clear Mountains 5,750 East side Chi-ixx)in Mountain 5,610 Pass between La-loo-wissin and Hat Creeks . 6,480 As-kom Mountain 5,400 Botanie 5,400 Lytto.i Mountains (north slojie) 5,340 North slope Nicoamen Plateau 5,300 .East end Niooamen Plateau 5,1'0 Stein Monntani 5,000 Ascending Coivst Range towards Kl-ow'a Mountain 4,900 Prospect Creek (south {)art of Xicoanien Plateau) 4,450 From such heights as those above stated, this tree e.xtend.s upward to the timber-line, but it is most abundant and characteristic between about 5500 and 6000 feet, in the region lying immediately to the eastward of the Coast Ranges, and characterized at such elevations by an alpine, but relatively dry climate. Within the limits of the Kam- loops sheet, its geographical area may be thus defined : — To the west, bounded by a line following the higher summits of the Coast Ranges, to the east, by a lino including Pavilion Mountains, following Hat Creek southward, including Mount Murray and thence following the Nicola Valley to the southern edge of the map. A very few specimens were, however, seen oft the summits of Cornwall Hills to the east of this line. AiUES SuBALPiNA, (Mountain fir). Lfast elevations at which this tree has been observed in the Kamloops sheet. . I 0AW8ON. ] UPPER AND LOWER LIMITS OF TREES. 407 B Feet. Pass between La-loo-wissin iind Hat Creeks 5,480 Plateau above Jamieson Creek (abundant) 3,800 Botanie .S,()60 Ascending Coast Ranges toward Kl-ow'-a Movintain 3,500 From such heights as those above stated, this tree extends upward to the timber-line, at about 7000 feet. Rhododfndron albiflorum. Least elevations at which this shrub has been observed in the Kamloops sheet. — Feet. East end Nicoamen Plateau 5,170 Lytton Mountains (north slope) .'>,140 Plateau, head of Jiuuieson Creek 4.800 Plateau, head of Skull Creek (in shade) 4,500 Ascending Coast Range towards Kl-ow'-a (in shade) 4,300 From 3uch heights, this form extends upward nearly to the timber- line. PiNUS MuRRAYAXA (Black pine) — This tree occurs in greater or less abundance in all parts of the Kamloups sheet, and at all elevations up to the timber-line. It is, however, most characteristic of the plateaux at heights of 4000 or 5000 feet, where it frequently forms extensive forests. In the lower dry valleys it is scarce. PiCEA Enoelmanni (Engelmann's spruce) — This tree is found nearly everywhere in the area of the Kamloops sheet, extending up- wards to the timber-line, but is most characteristic of the higher plateaux and i* seldom seen in the lower valleys. TsuciA Mertensiana (Western hemlock) — This tree is very seldom found within the limits of the Kamloops sheet, where the climate appears not to be sufficiently humid for its healthy existence. It was observed at a height of 4000 feet in ascending the Coast Ranges, toward Poo-ytl Mountain, and is probably not uncommon at or above this height in the part of the Coast Ranges included by tiie map. PiNUS MoNTicoLA (Western white-pine) — This tree also occurs very sparingly within the limits of the Kamloops sheet. It was observed at a height of 4200 feet in ascending the Coast Ranges towards Poo-ytl ^[auntain. Thuya Gigantea (Western cedar) — This tree was observed in a few places within the limits of the map, but never attaining a large size It is confined usually to narrow and shaded valleys, where consider able moisture is to bo found. It was noted on the North Thompson 408 B BRITISH COLUMBIA. above the Fish-trap Rapid, on Edwards Creek, near the eastern limit of the map, at Botanie and near the oast end of the Nicoamen Plateau a little beyond the south edge of the map. Ledum Glandulosum. — Found on the plateau near the head of Skull Creek, at an elevation of 4500 feet, on the plateau near the Middle Fork of Tranquille River, at a similar elevation, and on the plateau near Spaist Mountain, between 4500 and 5000 feet. Pachystema MvHSiNrrEs was observed to be abundant on Botanie Mountain, on the Lytton Mountains, and on the eastern part of the Nicoamen Plateau, but not elsewhere within the limits of the sheet. EvERNiA VuLPiNA. — This bright yellow lichen, growing upon trees, is generally abundant at heights exceeding 3000 feet, but it was observed in abundance at exceptionally low elevations in the Twaal Valley (2740 feet) and in the Venable Valley (2230 feet). 'I TEMPERATURES AT DIFFERENT ALTITUDES. 409 B / APPENDIX IV, Comparative Observations of Temperatures at different Alti- tudes IN OR near the Region embraced by the Ivamloops Sheet, SouTirERN Interior op British Columbia, during parts op the Years 1888, 1889 and 1890. Table I. — A summary of minimum temperatures grouped according to altitudes and compared with the minima observed during the same nights at Kamloops. Table II. — Temperatures obser\'ed at 9 p.m. at various altitudes, compared with simultaneous observation at Kamloops. Note. — In the colunm headed " Difference '' + means hij'her and — lower than at Kamloops. Tlie height of Kamloops above the sea is 1150 feet. In the pages following the tables, the observations are given in detail, with the actual elevation and locality of each. The observations miide at 9 p.m., appear to show that, soon after sunset, the effect of nocturna» radiation in lowering the temperature increases almost uniformly to the greatest heights represented. The minimum temperatures likewise show a nearly icgular decrease with increased height, up to between 4000 and 5000 feet, beyond which, for 2000 feet or more (to the greatest heights represented) this ceases, and the difference as compared with Kamloops remains nearly constant. As compared with the normal vertical temperature g^'adient of the atmosphere (V ¥. to 300 feet) the minima are some 5' too low at about 4500 feet and nearly 3° too high at 6500 feet. This anomaly may be explained by the existence of consideraljle aroa.s of plateau country up to nearly 5000 feet, while the areas standing above 5000 feet are relatively email. It may also be connected with the general inflow of air from the west, across the Coast Ranges, maintaining a nearly cf)nstant temperature when little in contact with radiating land surfaces. Mr. R. F. Stupart, Director of the Meteorological Service, informs me that such an inflow, during the summer months, is indicated by the mean barometric gradients and that the years 1889 and 1890 were nearly normal in this respect. ,,, 410 B BRITISH COLUMBIA. TAB Temperature in rela Minimum Temperatures observed at various altitudes, compared with Altitudes underlOOO'. Altitudes 1000'-2000'. Altitudes 2000'-3000'. Altitud Month § g i s 1 1 P % and "i ici ^ II 8§ « H^i s Year. > •S ? f > Pi t -0 J is i 1 o S 1 o i 1 1 1 1 s ■3 6 i is ^ fi 1 a 1888. » ' o o - O o «» July 1880. 49 52-2 -3-2 4 38-2 56-5 -18-3 12 35 C Jijy 4 55-6 61-77 - 0-27 13 474 57-4 -10 4 43 1 Aug 9. 30-7 521 -12-4 <5 47 56-7 - 9-7 545-5 Sept 41-8 3!) -9 + 1-9 7 48-8 47 '+ 1-8 1 43 43-9 - 0-9 735 Oct .. . 1 4!) 41<» + 7-1 2 40 6 43 4 - 2-9 3 30-7 39 - 8-3 16 32 7 1890. i 1 2 43-5 45 50-3 56-85 - 0-8 -11 85 438 1 July 2 52-6 51-95 +0-56 1 50 54 - 4 136 1 4 413 53 --11-7 9 48-5 59 -65 -11 15 Sept 7 6 39-8 41-2 42-5 ;- 2-7 40-7 i+ 0-5 5 1 35 1 42 42-84 45-2 - 7-74 - 3-2 1 830 Oct 10 ! 45-38 38-54 + 6-84 32 44-49 47-87:- 3-38 38 43 02 53-08 j -10-06 J7': 6-35 TAB J IN RELA ared with W. A Jtitud X I* i I i ; <: > '. * 3 ! 9 a 5 2 i 1 ■. 12 35 C. 443 1 6 45-5 735 10 32 7 4 38 1 136 < <4| 3-2 LOOG 8 36 j7:635 otwaoN. 1 LE 1. TioN TO Altitude. TEMPERATURES AT DIFFERENT ALTITUDES. 411 B the minima observed during the same nights at Kamloops, B.C. eB30OO'-4O00' •^1 aj 54 4 55-1 j 54-25 45-7 44 2 56 '7 54-8 s i Altitudes 4(XH)'-5000'. -Is 8 -12 - 8 -75 -10-7 -11-5 -18-0 -18-8 s CD OJ a ^i S 3 s.« a £« S ^15 S o Altitudes 5000' -0000'. k. e j3 d ■ri ? a s M)S rt tc* ^f > i ■^8 8i li ?« i. 'n s s« i s 1^ (5 « i s I 50-15 -14- 15 5008 -13 73 22j 3377 31 34 41 33 1 286 48 39-3 29 !)0 64-4 50-0 501 49 '5 62 55-2 41-2 51-85 -24 -20 4 - 9-6 -17 -20-9 -14 -15-9 - 12-2 -1808 35-6 43 31 34 1 31 5- 37-5 2; 34 5 1 28 51-4 51 49 51-5 Altitudes 6000'-7000'. IB 3 -15-8 - 8 -18 -17-51 48-5 52 7 52-9 46 -17-51 -15-2 -18-4 -18 • I- 39 49 -10 33-5 ,52 -1 I 34 -18-6 -13 .30-5 49 7 -13-2 15 360 51 -r> 1-15-2 35-2 50 2 i-15-0 / iivi 412 B BItlTIBB COLUMBIA. TAB Temperature in hela Temperatures observed e.t 9 p.m. at various altitudes, compared AltitudesunderlOOO'. Altitudes 1000'-2000'. Altitudes 2000' -.3000'. .• .vitud Month .• ^ 1 1 s T* s o s s § and *3 u.i i tcS 11 bcX 5 a Year. I •-5S a> 1 tl i i l| n 1 1^ ^ t c a d a s i s 1^ 6 z; s s 1' 6 1' £ S 6 A 188!t. o o ° O o » o " July 8 9 f)9 Ii7'5 791 08-8 -10 1 - 13 14 R C2-8 ■")9 80-5 707 -177 -111 4 5 56-2 54 2 Sept 6 50-8 49-5 + 1-3 7 (iO (K)-3 - 0-3 1 oT) 61-9 - (I- 9 6 40 4 Oct .... 1 53 59-2 -4-2 2 48-5 51-6 - 3 3 .38 42-4 - 4 4 14 40-5 1890. .June 1 (>4 73 - 9 4 50 6 July 1 59 58 9 + 01 1 68 791 -111 5 9 3 59-4 51 3 48 06-4 56-5 47 5 - 7 - 4 + Ou 1 5 1 50 49-8 46 5 04 707 59 7 49-3 69-9 -147 - 9-9 - 2'8 Sept 7 44 1 Oct i 8 6a 36 51 9 + 0-45 32 571 61 - 3-9 SI - 5 9 1 40 45 4 TAB [IE IN RELA >, compared «)00'. / „itud ti B S •p cS t n i ^ c i 6 t Q A % o ' ■17-7 4 5(i-2 -ll-l 5 54 2 - 0!) 6 40 4 ■ 44 14 40 5 4 50 li -111 -14-7 - ilil 7 44 1 - o-S _. -59 40 45 4 itewaOH. ] TEMPERATURB8 AT DIFFERENT ALTITUDES. LE ir. TioN TO Altitude. with the observations made at the same time at Kamloops, B.C. 413 B eM300O'-400O'. Altitudes 4000 '-5000'. Altitudes 5000' 0000'. Altitudes OOOO' 7000'. a c g s g i s 1 3 i 5 ■•3 5 a a is 1 > 1 a; s c 1 o II i 1 i *M !> tM s 2:2 2 ts jj £« t ■?! d ?^ t C!ori at (5 ^, s 1'' 5 d s 3 s s Ss O " = o o o o 05 •« ■iy.(! - 9.5 . . -18-3 3 37'8 60'9 67-3 7 4(i3 06-5 -20-2 1 45 03-3 -231 51-3 -10-9 1 49 5«-5 - 9-5 1 44 59 -15 2 41-5 00-3 -18-8 40- 4 - 5-9 -17-2 3 5 1 43-3 42 I 46 540 00 9 72 -11 3 -18-8 -20 078 ♦ i 1 ^ 39-2 587 -19-5 2 43-5 02-5 -19 -151 3 2 40-7 40-5 62 3 531 -15-6 -12'6 2 1 42 45 08 1 58-8 -20 1 -13-8 69-2 1 5(i-57 -1117 22 44 57 01 7 -1713 9 410 01 3 -19-7 7 40-5 61 -•JO u- r \. 414 B I- Date. 1888. July 4 5 6 7 8 9 10 11 14. ... 15 16 10 22 23 .... 24 25 ?(>..... 27..:. 2{> 31. Aug. 1. BRITISH COLUMBIA. TEMPERATURE OB.SERVATIONS.' Ft. 3920 3920 3300 3300 3470 3470 3870 900 2«!)0 3150 a 5 I" 41 40 31 33 5 33-5 40 30 49 35 30 3150 i 37-5 ;i500 3100 3100 25 3U 2440 2530 52 28-5 31 39 39 40 5400 I 35-5 5200 ; 40 i 5200 ' 31-5 r.200 28(!0 39, 51 u .si 50 51 47-4 49-3 52-5 50 3 56 52 2 52 52 59'6 59 58-5 62 58-9 57 1 58 2 47 59-8 47-5 49 ^ - 9 -11 -10 4 -15-8 -19 -16 3 -20 - 3-2 -17 -22*6 -22 1 - 7 -30 -31 -19-9 -181 -182 -11-5 -19'8 -16 -10 Max., Wr5 Max., 75 Max., 92-5 Locality. Head of (luiclioii CrtH''<. M Mainit Lake, W iclii'H Br0UtU.»j)i(j •H(I(Ml[Ul'8;j{ ^w njn:>i!JijB lO OS S lo «5 S5 s? g g 2 ^ S 55 S (N tH -14 -tt O 1-. I- i5 C-. c: '2 *- CO ift 88 1-1 »q « "3 - - •-5 lO » I- oc « > _^ be .— 1; «Tr -4-> rt ■^ Ih i X3 'J tD s ;* X ■c B C a; X j= i s R a 3 k fi t ^ i> e3 s > tH s * ;3 tc •^ s £ H > 1 0) a> U£ « i-c isi 416 B BRITISH COLUMBIA. m "A O CS O •8 .11 !» if I 1 o Its ^ I £ -J ^3 .-*» i "rt •oonsjajjiQ »2 la 3 M O *5 o -a a a "A i a i H .a 3 u a o C5 2 S5 •SlIo<)lUIB>J JBtupuodsajjoQ •ui'rl (5 "ya I M —1 t-l T-t I + 9 {:: g •90U9aaj[ji(j •ItlUll SutpiIfKlBOjaOQ '9J(UU.I3-< r1 • ;. •»• rt IS m « I— -f t- I*) -^ -^ tfi Ti M lO I- •-; — o -t> v5 "f 1^ i i i Cl o o C w ^ r* t^ 1-1 »5 ,-1 .— c^ i?i n ?) W M C^l f-^ CO iS '^ :^ -' ?i Vj S P, 8 53 -^ . = = = r = g- 27 13 s c ^ « o "T IS 0- • IM IM -f cr n c- X ■* M ■T t 1 CO 1 \ 1 1 c *— 1 ■ : 1 + 1 1 1 JS ■ : 1 1 1 1 o 1—1 1 C5 •J C-. m li- ■ IN oc C" M c- X .^ « T' X s o cc ce I- H 3 •f z t; : '"^ ■? 1-- CO I* ? tn CO I- X cj o 1-1 c 7 M "^M^Mimixifii^mmsmmmm 418 B BRITISH COLUMBIA. I "3 -A o H > n o 14 U H •fli 03 W H •T3 11 ^ to ^ to C5 3 .14 o X *r1 ri^ s o 113 'dOuaiajgiQ Sui p u () i; H Hi •a J< 5 3 O a. o i c 9 V be 03 'Ml OS CO '»' o 1-1 I S 12 CQ -r IN OS lO + O rH S5 M » 5 —i.-J ^ O ip « o If. « ^i' ? Q »-< » T -^ . ?o ^- oi o lO -r ic o II I o C5 1-1 1-1 M w iri •(- I I cs t- -^ l>. 'ji i". I- ») + + I I iH iH »-( r-l CO s s s s s 1- •>I< (M e O -1" -r t- I- -r. r-. ^ t K-j io X lis M — m 1-1 IN + + I li in in m t- r-* iH" (?: -f c 1-1 c; o c-i -r X ci cc m CO CO CO CO 71 -^ -p o'i -i< Tj o 55 N ■-; Q cc 1-1 .n S 2 '0 1.0 I- i>. 1- I- x ir; 00 in lO CI CO O lb I + + 4- in 01 in 5§ S ff P S5 »> 25 S5 *i *^ IN O-l 1-1 »H <0 ^ CO C^ © 3 S S S $ § I- t- l~ C! t- 01 CO -f in '.e i» X c. © --^ 01 CO -t I* '.c I'- X ^ ■HH 420 B BRITISH COLUMBIA. s » 'if, O h- 1 H < > O H Ph H T3", I' .se B M 11 a, , . d be a A o &, to flj x 1 :3 •a P5 ^ 1 0) u ^ s o .3 1 s 3 o o (2 t ' m 5 5 u o m I a s S * S g o i-i b 1-H Cl U) Ph o I c B 0; B t^ 3: •eonaaagifi ^UipUodSBJ JOQ in © lo i-H ^ rH •lU'd (J ^B TJ 'i'^.SP^. !s ^ ih '^ »^ -^ ^ -^ O C! t J rH — « ^ aout)a)jui(j ■H(I^)Oll^nl^{ 5« umui ■luira Sn!'i)U(3ils.).i.i03 Tuntuiuij\[ •9p»?l»[V •i 1- t'5 I 1 + C-. -o O Cl « O I- IN p r^ »-t C^l CO 1" CO C! -i lO C-. c! ,^ S S 8 I- P»( t~ t-- I- o JJ S? S STi S V^ ■a a i : : r « s s ro 53 f? s s s s t- :5 cc t^ r-^ '; ^ cc n< M t< -^ r, I, I- I- I, cc X x 1-1 (M ffO c3 it 3 ~ e ui :? i C! Th CO 1 1 s s TEMPIJKATUUES AT UIFFKKENT ALTITUDES. 421 B o Ji« 1 a; J O |- = 1 a U O It t» Camp opposite r... 1 1 1 1 1 1' 1 o TT § 1 a 1 1-:! 1 6 a 1 5 1 1 c a C .3 1 °« 1 w QC e O 1 ; 1 1- 1 IM 1 I--. 1 ^ « -f 1 {ii!uinm »^ (M 53 c. t; .s o IC ■* -unui ijiupiKMlKAuog g §? ? s !? •* 3^ s a a s »* n m \n IC uimtnutiY o S; ?? H CO s M S ^ s s 3 s? ■epinjiiv i i « s 1 1 5 i i I 1 CO (.' s C B C^ ?^ s ^ s s S3 1 ■ -■ : ^1 » in o .n -r ^ 3 1 00 i lO -r 2? s s s 3 ^ 2 s^ ss s s s s TEMPEBATUHES AT DIFFERENT ALTITUDES. 423 li I § I i I ^ I g 1^ if. s ^ O I- » --< 5-1 i5 J i! 424 n BRITISH COLUMBIA. I 6 I cc O H > n o H 1 il •si 11 1 ^ ^ O .S CO B O P9 C8 PS > -g n 1 S M -^ E a -3 I O ll •eouaj.igiQ iuipnodsaaaoQ •aouaiajtjifj I ■luiin SuipuiKlHoajog ■am^'Bjadma:} •apini^lV ^ in + s lO 3 2 6 8 l~ M O 5 ?? in o o i I S ?3 S ~ ^ ftx m be < ^ a TT S M 0; ^ to 5 C3 o w «0 Oawson. ] TEMPER ATI' RE8 AT Dll'FEItENT AI,TITri)K8. 42-) B is 02 .2 ^ X. a o 1-1 be « .3 a 3 b &4 o n ^ 3 - I 0) o ^ I bo o » 153 e ««-■ S o b ■s ' 1 ^ ^^ 0^ 01 S -3 1> 5. e<3 I- i^ ? I I S g 3C to t-l r-l *J ? ^ ^ la 3 y. o a CO o I us 3 S lb J3 o 0-. 1(3 O M i I (3 I 13 £ P X ^. O m ,y -<■ o o in b C5 c; to iH CO N W '■'ml i i 6j"in(nSs5nS- 28 3 S IN C! I I lo in is S! CO CO ?? « §' S CJ S S 55 OT M 5* tH (N CO a. mmmmmmm m lilii n Pa 426 B BRITISH COLUMBIA. O (—1 H < O H -< » I § S IS § o b s o c ^ to •aOU3J3^!(J I- H5 IN + + I •fklooitimjf 1 B ajlUDJOlilUrJJ ^UtpilOliRUJJOQ 1-H r-l CO ^^ O CO ^ fS ^ lO cs c: 03 5 S S •it" io e*5 CO •ni'd 6 *« a.in^iu.'KlHwx s .-s ? O t" . ''T a; TT _^__ 00 -3aU3Ji)JJI(J •srfoo|uiB^ IB laum -luiui auipucxisaj.Tog •aamuiatliaai uiniuiuij\[ ! ^ 03 35 O o o iU 00 ^ s ■* ¥i ig •so^jn^piy ^■^35 i IN IN CJ t-f 11 rH rl »-1 00 ^ N 9 53 8 S S N S I J3 9 ;3 ■» -;'l i I'l. I 60 a ■* CO C5 CO lo in r-l ■^ N CO 1-1 1 1 ^ w -* 5 ^ n 3 S ?5 S TEMPBBATUBEfl AT UIFFEBENT ALTITUDK8. 427 B I 13 a 2 f ^ 6 ^ PS c o S Px « c <9 ;3 B O > to 0_.>5^. 3 S « ci. a. c. do o- • 00 CO CO 9C se g S S t^ t~ 00 I CO in •»' X X rH IM '»■ S OJ rH r-l N r-l + 1111 g '.* fi S S fc g g? to (M OS ^ 00 OS O IN I + + I 1 to 00 35 5: S5 S? ^ 3: IN s i ij (3 S S S S rH e^ CO -»■ "O !C N\ / /\ PPI m m' 1!^ Ill I ^^ TABLE OF CONTENTS. I / (B) FAOK. Phymral Geography 3 Till! Map iml Methods of Survey 17 Arraiigenieiit of (ienlogicul matter 21 The table of Formations 23 Oeneral Geology 27 Camliriaii 27 Newer Paliuo/.oio rouka — Chiolly Carboniferous 37 Triassic 49 Conditions of MetaniorphiHin affecting the Older Volcanic Rooks. . . 58 Cretaceous 02 Tertiary (16 Plutonic Rocks 77 Descriplire. Geology 79 PnJieo~oit Roeks 79 Thompson Valley — In-ki-kuh' Creek to Cliche Creek 79 Twaal and Blue-earth Creeks , 81 Medicine C'reek, McLean Lake, Cornwall Creek 82 Caclie Cieek to M iindorf "s 83 Biinaparte Valley above Mundorfs, and (Jlen H ,rt 85 MarVde Canon and vicinity 87 ^— Mount Martley and Chi-pooin Mountain 91 Pavilion Mountains 91 Junction Valley 92 Fraser Valley, north of Kelley Creek 93 Valley between Edge Hills and Marble Mountains 94 Marble Mountains 95 Outlying areas to the Southward , . . . . 96 PaLx'ozoic Rocks of the Coast Ranges 96 Palajozrtic Rocks on and near North Thompson River 103 Cambrian Rocks near Fish-trap Rapid 107 Rocks assigned to the Cambrian Soutli of Fish-trap Rapid 109 Rocks of the Plateau to the North of Whitewood Creek 109 Triassic Rockn and Sections iUuslrating the Nicola Formation 112 Section south of the Ashcroft Cretaceous area 112 Section along the Thompson Valley from Bonaparte River to Copper Creek 115 Section on Campbell Creek 122 Stump Lake, Moore Creek and Upper Nicola 125 General section near Nicohi Lake and Eastward 131 Nicola Formation to the south of Kamloops Lake antl between the Moore Creek Granite-mass and Guichon (Veek 137 Rocks of the Nicola Formation on and near the Upper Dea" ".-''/>'* i NlJA ■•/■oir ■ ■ ^ i^ ysSi-">j > V N.ll Sc (ill' I1^ Siiiiiii.. Mill' .a r-". ^n I ._ ,- 1 lii'iii|rH|iliii III Mili'i r^< — rrf — --.Tgg¥i=a- ;_" =HV'^ _feai:r^J f'lu/itiis imi I'rri vi'iiiiiil inlrmil Hi iIisI. I nluMiln,. KAMLOOPS SHi To accompany mport tv Geor^fl M DawsDn 1i "■- f-'v /■:#^"*^* v„/»,,i),fi .■ A ^ S' ^ — cnp- — r— - jr. a; ■•*> 12l"n., iHF.F_T tt C I A r I A ( ',11' cin CMG LL: m^M JVP». ■* \. 'm^: X . ^— " ' ~-t — • \\ x'^Ki;^^ ^^i^l^ :;.^t^v^ i ■■'!**,; ma ''* ^ ^t:-> tS '€'T"' 'I'll) »\i -,HH Ml r 1.; M.'if* i; t ( from ^ IMAGE EVALUATION TEST TARGET (MT-3) // 1.0 1.1 11.25 14 12.8 ■so m U^ 12.2 40 12.0 I' i ■yuu M 1.4 11.6 Photographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. M580 (716) 872-4503 %0 o^ I \ t < I.IOiiKN'O. LZ. cz: r ■ IMiocp Miocono Olif^occni' Queen t'hatlolte ixttiittt.s ., I' t . .^ ' rotrnTouH rormtinntt irK'e*ht Xtnffa f'hrmatuHi 'fhvth MtrHr t'nAnn l.i mrxtoneft f \ TrinHsif ( ll'liniuti'rnu! Sheet r — " BarF. 'janic rocks appear to have been supplied from numerous local vents of which Skoatl Point, Porcu- pine KldKC, the vicinity of Kamloops Lake and pro- bably the Arrowstone Hills, are believed to afford ex.impleg. Chalcedony, atfates and various ueolltea arc abundant In some parts of these rocks, and hyalite occurs. The Tranqullle beds, although almost entirely composed of fine Kf&liied tuffs and other volcanlo materials, have been laid down in water and are often well l>edded. They pass In some places Into tuffaceouB aifKlomerates and are KOnerally pale in colour. Fossil plants are found In a few places, and near Kamloops, thin beds of Kood coal. The Tran- qullle beds proper and some other similar beds, both newer and older, are indicated on the map by the ■ame colour. Where very thin layers of stratified material outcrop, they are Indicated on the map by blue dots. The Lower Volcanic group consists mainly of auulte-pnrphyrites, of grey, tfreeuish and purplish colours Some of these have been lava flows, white others are fragmental, either agglomerates or tuffs. Mira-porphyrltes, pfcrlte porphyrltes and numerous other species are also mon; sparingly represented. The chief region of eruption at this time Is marked by the Clear Mountain Kange and its southward continuing high lands, along which a line of active volcanoes undoubtedly existed in the early Miocene. Previous to this great period of vulcauism, and perhaps also during stages In Its progress, some water -bedded deposits of a local character were formed. Cinnabar, copper ores and small quantities of native copper are found in association with the rocki of the Lower Volcanic group near Copper Creek. COLDWATBB OROITP. These rocks antedate the period of volcanlo erup- tions and consist entirely of ordinary water-formed deposits, conglomerates, sandstones and shales, In some places holding coal and lignite. They appear to hvve been locally upturned and denuded before the Miocene period, and are attributed, althcugh with ■omo doubt, to the ttUgoceue. None of the beds are marine. The characteristic conglomerates are chiefly coiniioteil of quartstle pRbbles d«rived from roaks of the Cache Creek formation, and are often very thick. They are largely represented near the lower part of HatCreek and near Copper Creek. Lignltu-coal occurs on the upper part of Hat Creek, on Oulchon Creek near the edge of the map, and coal on the North Thompson, near the north-east corner of the map. In these places the beds are chiefly shales and sand- stones. Important deposits of coal and lignite-coal occur oil the Nicola four miles beyond the south edge of the map, and the associated rocks here Include conglomerates. It Is not quite certain that all these now Isolated occurrences represent the same geologi- cal horizon. Traces of gold have been found In a few of the conglomerates, and It Is possible that some of them may prove to contain workable quantities of gold. QUBBN OHARLOTTB IflliANDS FORMATION. These rocks belong to the earlier part of the Cretaceous period. Theyconsistchlefly of hard sand- stones and conglomerates, often greenish, and hard riBrlr itrull1||f>» Tlio K«H« urf> mitxli f1U»Mr»,nf4 mntt (uently nearly on edge. They contain a few fn-nlls Pnme bed* newer Ibnii tbo»e of the Mi l;a.ii lili/ii /rir/, /'iinntilmtl Ftimmtioit Cnrh«nifor irj OksrnTft nuUrop ft/' /.imrxtime hrtt-S'. Compi/ed and drawn by James McEvoy B.ASc. Hoadss. J^rrA- - frtith-. A\rp/onttor%' routes. /ndiftfi UHagrs Sites tt/'oM htHian / 'iifttfles f hreAwifer Aaitsvx ■' Sltdutp MilrN (MHiilrH[itn(-ii| Ntilc!i (tmffturs MM fret \frhnd ini 121*'oo l,fMIJ*Mu(li' W'rsi Iroiii ( iii'iitwirli Nrtt Scnlr im.T4o SiHhitc MtloH (MM>ftrH{ilni 111 Mili-H /'fifi/fif/s .700 f'trt vrrtinil utlrirul Itritisli Cnliiiiiliin KAMLOOPS SHEET GEOLOOIC Al.LV COLOURED by George M Dawson C M.G., Ll.D„ FRS IS!)') ThI CANADA CNb h LlTHQ CQ l.I MQNTIItAL •' GEOGRAPHICAL AND TOPOGRAPHICAL DATA. 7H«(fiim«nrnny 5Hr(t«(/f(( /mi;» aA/nllnwa: —Line nf Viintitiian l*a''ifi(^ Ruilwuy, as mensured for Bii^tf, ftj/ nr>fnmj'}n Landit Surveya. Trial Inralvm linen of ll I' Ity. Surieyafrom f/l//ii')e( rid MarMe donon ami up Hnnaparte Valley, il no along north aifle of KiitnloopH Lake antt rtp ,V. Tltomimon Valley- Lincfi I'll ll'oninion Latidtt Surveys within the Rai'way Relt, chiefly near Kamlinijis, .SuroNri antt Anhrro/t Ihitiah f'olutnbia (ioverumtnf Land Surveys alioat iVjco/a and Stump Lakea. St}me i^ared .iurr*t/H (1H77) }le of ttie tapographgt depend upon triangulationf track- aurveya and sketches by J. iScKwy, ■tones and conylomeratri, often tfrecnlHh, liiid hard llnrlr aroMlilAa Th** t «a« ar** mwoh (ll-».i.-l>»H and 7 are frequently nearly on edge. They contain a few marine for'lli. Some bed« newer than ttaoie of the Qoeon Chai.otte Islands formation are probablyj J^ clud e rt undg j v ^\m iHilnn r. VIOOIiA rOBMATIOK. These rocks are referred, as a whole, to the Triessic period, althongh It Is by no means certain that their lower limit corresponds exactly with the base of that formsiloii. The colour on the map Includes also some limited areas believed to be Lower Jurassic (marked J, In red), but the rocks of which cannot be definitely separated from those known by their contained fossils to be Triasslo. The rocks are for the most part of volcanic orlKini and the tract occupied by thfem on the map may be described In KenersI terms as a irrsat area of •* irreenstone." There are, however, some Inter- calated beds of marine limestones and arfflllltes. The volcanic rocks are In general distinctly separable from those of the Miocene because of the amount of alteration they have undergone. DIabase-porphyrltes are abundant, and these are occasionally still amyg- daloidal. Agglomerates composed of similar mate- rials are common, and pass into diabase-tuffs which are often finely water-heddod and are sometimes altered Into felslte- or petrosllex-llke rocks. The colours are generally greenish, grey or occasionally purplish. Some of the limestones of this formation are suit- able for making lime. The ores o'. the vicinity of Stump Lake, containing gold, stiver ivnd copper, also occur In this formation. CACHE CBXEK FOBMATION. Fossils of Carboniferous age are sparingly found In the rocks of this formation, but some of its lower members may possibly be of considerably greater age. The upper part of the formation consists ex- clusively of limestone, which often becomes marble. It is separately denoted on the map as the Marble Calion limestcme The lower part contains thin beds of limestone, hut Isprcponderantlycomposedof dark arglllites, cherty quartzitos and contemporaneous volcanic products. The latter comprise both effusive rocks, agglomerates and tuffs, with some beds of nearly pure serpentine. The volcanic rocks most niual are extremely decomposed diabase-porphyritos and these, together with the arglllites, frequently become schistose. An Important belt of such schistose rocks, largely arglllites, follows the lower part of the Praser Valley, and veins In these rocks have evidently contributed largely to the supply of placer gold along this part of the river. In the vicinity of Stump Lake and Campbell Creek, the rocks coloured as cicbe Creek are dark slaty amphlbolites and irgiilltes. They are referred to this formation with somb doubt. On both sides of the North Thompson, the Caohe Creek rocks are chiefly represented by arglllites, vrauwackes, and diabases with some limestone. The rocks or this formation are almost 1 tvarlably shattered and dislocated in an extreme J'>gree. Quarts veins are abundant In many places anu have been proved to be auriferous on Cayoosh Creek and at the Big Slide mine, Kelly Creek. BOOKS CLASSED AS CAMBBIAN. No direct evidence of the age of these rocks Is obtained on this sheet, but they have been traced eastward to Adams Lake and Shuswap Lake whore their relations arc better known. The upper or Adams Lake series is chiefly composed of green chiorltic or felspathic schists, derived by dynamic raetaraorphism from ancient volcanic rocks. These, near the North Thompson, arc found in some places still massive, as much decomposed diabase. The underlying Niscon- llth series is characterised by dark arglllite schlsta or phyllltes, passing into micaceous schists. CBTSTALLINK SCHISTS, BTO. Some rocks of this class, which occur in associ- ation with the granites, in the vicinity of the Fraser River, are indicated by u separate colour. They are probably in part highly altered Palseosoic rocks, la part foliated granitic materials, and include mica- ceous and taornblendic schists, and gnelsslc ma- terials. PLUTONIC BOCKS. These are coloured pink upon the map, and though in all cases Intrusive in their relations to bhe other rocks, vary considerably in character. The argor areas are, however, almost exciusively occu- pied by gray granitic rocks of different types, but between which no distinct lines can generally be drawn. Syenite occurs In some places, and on Kam- loops Lake and westward along the Thompson valley, considerable areas of gabbro, closely asso- olated with the granites, are included under the same colour. The chief granitic Intrusions have occurred about the close of the Triassic period, but ■ome later granites are found cutting through Cre- taceous rocks. Quarts veins holding gold occur In a granltio mass at .lamleson Creek, and distinct traces of gold are found in the mass of syenite on Bdwanl's Creek, east of the North Thompson. :).■»(;