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ZwatM, Dnorr Mimmi. «EOIX>6ICAL SVBVSY I MBMOIR »1 No. S6 Gmumkal Snm G^oiogfoi Franklin Mining Gamp, British Columbia n Charies W. Dcyidale OTTAWA GOViKMiiBMT Puimiio Bduad 191S No. 1383 ■'""^imr 9ii^ jKIt-'' iS:: J^^^ Brit sh Coiunn ExrtANATioN or Plate 1. Looking down Franklin valley from northiwtt corner ol map-area: Franklin mountain on left; McKinJey m«iutain o« rifht; Kettle River valley m dirtance; granite ran^e in backiround. Show. V-haped v|Uley en- trenched beneath older upUnd aurface*. trachyte lava cUffi to left. (See pufe 21.) -V'" %/>- .1 AM.fl «) iU^i 111 /flit.' isviX illi^X : irtah no fliall«iMn pocket Map (133A), Mineral claim*, Franklin mining camp in pocket I. Looking down Franklin valley from northweat comer o( map-area Frontiapiece Looking up Kettle valley towardi Tenderloin mountain at junction with Gloucester valley (on left) 187 East side o( Kettle valley; Boulder creek to riftht 189 Looking down Franklin valley towards Kettle river . . 191 Poat-Gladal gorge in Kettle River conglomerate on Franklin creek W3 Tenderloin mountain from Newby cabin 195 Caves in trachyte lava cliffs, east slope of McKinley mountain 1" Franklin mountain 1" Kettle River conglomerate "hoodoos" 201 Biecdated Jurassic homblendite with aplite filling 203 A: Pebblea from Kettle River formation 205 B: Vesfcular rhyolite in contact with Kettle River silt. . 205 Specimens of Oligocene monionite and Miocene augite syenite Spedmen of porphyritic syenite Specimen of shonkinite-pyroxenite in contact with syeniteaplite ^^^ Kettle River conglomerate at conttct with alkalic syenite 213 Specimen showing alkalic syenite in contact with Kettle River grit and conglomerate • • • 215 Stratified basaltic and trachytic tuffs intercalated with flows, on east slope of Tenderloin mountain 217 Faulted contact of Kettle River formation and overlying Midway volcanic group 219 Miocene ejectomente from Tenderloin volcanic vent ... 221 Specimen showing induMons of quartzite and eruptive rock in pulaskite syenite dyke 223 Minette dyke in contact with brecciated Kettle River IL in. IV. V. VI. VIL vin. IX. X. XI. XIL iCIII. XIV. XV. XVI. XVII. XVIII. XIX. XX. 207 209 XXI. gnt 225 i27 XXII. Volcanic agglomeiite 'trachyte) on east slope of McKin- ley mountain XXIII. Specimen of contact metamorphosed cakareoua rock showing pore spaces due to shrinkage consequent upon expulsion of COi 229 I I vti PACK Figure 1. Index ihowing location of Fnwklin map-area 2 2. Franklin intermontane trough 18 3. Diagram thowing poat-mature Pliocene upland restored 20 4. Diagram ihowing relative amounts of eroeion before and after uplift 35 5. Jointing in Juraisie granodiorite 57 6. Normal fault with small throw, below post-Oligocene erosion surface 64 7. Illustrative of character of sedimentation in portion of Kettle River formation 70 8. Character of jointing at border of early Tertiary rhyolite porphyry remnant 72 9. Faulted aplite dyke in monaonite 75 10. Endogenous inclusions of shonkinite-pyroxenite within augite syenite 79 11. Contact between alkalic syenite and Franklin group altered tuff 81 12. Crenutation in Kettle River banded chert near augite syenite contact 82 13. Restoration of Tenderloin vok»nic vent 87 14. A: Contact of late Miocene minette dyke with early Tertiary rhyolite porphyry 90 B: Contact between late Miocene pulaakite porpyhry and Jurassic granodiorite 90 C: Contact between late Miocene pulasldte porphyry and early Pliocene trachyte 90 D: Contact between Franklin group altered eruptive and granodiorite 90 15. Micro-sketches of skeletal crystals of melanite enclosing or- thoctaae 110 16. Block diagram of McKlnley mine in pocket Geology of Franklin Mining Gamp, British Golumbia. CHAPTER I. INTRODUCTION. SITUATION AND MEANS OF COMMUNICATION. The Franklin Mining camp forms a part of the Similka- meen division of the Yale district in south-central British Columbia. It is situated on the east branch of the North Fork of Kettle river, due north of Grand Forks, British Columbia, and Danville, Washington, 37 miles from the International Bou".- dary (Figure 1). The district is accessible from Grand Forks on the Canadian Pacific railway, by the Kettle Valley railway as far as its ter- minal point at Lynch creek. From here a wagon road 25 miles in length leads to Franklin. This road is an extension of the one between Grand Forks and Lynch creek — points 18 miles apart — ^and was put in excellent condition last summer. The extension from Lynch creek to Franklin, however, is in very poor repair where it crosses numerous and extensive rock slides.* FIELD WORK AND ACKNOWLEDGMENTS. The field work upon which this report is based was carried on during the summer of 1911. The topographic control for the 16 square miles of country mapped, was obtained by a series of transit and stadia traverses * This portion of the road was put in good condition during the summer of 1912. -i« . run in cloted circuito. The latitude and departures of thew drcuiu were calculated, balanced, and the ttetions plotted by total latitudes and departures from a common origin. Fign.i' 1. Index showing location of Franklin map-area. All details were mapped by means of plane-table and stadia traverses run between ';he control circuits. Elevations are referred to mean sea-level, and were taken from a bench-mark of the Kettle Valley Railway survey at Gloucester city. Messrs. C. A. Fox and F. J. Alcock rendered efficient serv- ice as field assistants. Field work was facilitated through the kindly courtesies of Mr. Frederic Keffer of the British Columbia Copper Company, Mr. Forbes M. Kerby, Sheriff H. C. Kerman. Mr. H. B. Cannon, and many others. The writer feeb greatly indebte< to Mr. O. E. LeRoy, of the Geological Survey, under whose tupervition the field work wat conducted. He particulariy wUhet to express hit sincere gratitude to Profeuors L. V. PirMon, JoMph Barrell, Isaiah Bowman, J. D. Irving, and Charles Schuchert. members of the Yale Geological Faculty, for their kind assistance, guidance, and advice during the preparation of the manuscript. PREVIOUS WORK AND LirffRATURE. Previous work of ii less detailed nature was done in Franklin by P W. Brock, Deputy Minister of the Department of Mines, who examined the area in 1900> and again in 1906«. The results of this work were published in the annual reports of the Geological Survey. The geology and topography of the region are shown on the West Kootenay sheet, mapped on the scale of 4 miles to 1 inch.* The annual reports of the British Columbia Minister of Mines for the years 1900, 1901, 1904, and 1906 make mention of the camp ind a few of the leading p.operties. T'ley contain simply a statement of the progress of development work on the several mining t lai ns, and do not discuss the geology or mode of occurrence of the ore bodies. Outside the above-mentioned publications there is no other literature on the Franklin camp. CLIMATE. Meteorological data for Franklin camp itself, are lack- ing, but the accompanying tables from the nearest stations have been kindly furnished by Mr. R. F. Stupart, Director of the Dominion Meteorological Service, and Cooper Bros, of Grand Forks. The first table is given for Needles, B.C., a small town about 25 miles northeast from Franklin, on the west shore of the Lower Arrow lake; and the other table is for Grand Forks, which is in the "Dry Belt." 'Brock (R. W.): Gcol. Surv. Canada, Ann. Kept.. XIII, 1900, p. 70 A. 'Ibid., Summary Rept., 1906, pp. 62-65. •Ibid., Map sheet No. 792. NuiUs, B.C. Temperature. • Month. Mean highetrt Mean lowett Daily Mean range Abmlute highest Absolute lowest 28-6 30-6 491 57-7 1 651 72-7 777 74-4 68-4 56-6 41-2 34-5 17-8 14-7 26- 1 340 400 44-2 46-2 46-2 40-5 35-4 301 27 23-2 10-8 22-7 1 150 37 6 1 2J 45-9 ; 23-7 43 i 400 1 640 . 700 1 830 83 (53 85 79 630 53 440 -6-0 February March -80 40 April 25 May hugut* September October November December 52-6 58-5 620 60-3 545 460 35-7 308 25- 1 285 31-5 28-2 27-9 21-2 111 7-5 320 38 37 35 300 23 70 0-9 Precipitation. Month Number of dayi of rain or anow Average rainfall Averge snowfall Total precipitation January February March April 9 7 4 3 11 6 4 6 5 4 9 5 004 000 0-60 1-85 340 2-70 1-48 2 2 1 1-2 1-9 9^8 3-9 216 2-49 0-60 1-85 May 3-40 June 2-70 July 1-48 August September .... October November December 1-40 1-48 216 2-90 0-43 1-40 1-48 216 3-88 1-82 Grand Forks, Month. Temperature. HIgheM Lowest :9io in. 1911 in. January February March April 3S 35 69 72 87 93 100 94 92 78 53 -13 - 5 22 30 37 43 42 28 15 - 7 0-82 Ml 1 03 0-29 1-21 t 45 008 0-64 082 0-75 145 215 11 80 1 49 0-89 0-54 0-83 t^y 3-43 June J. 78 luly 0-45 Auguit September October November December 0-52 0-85 0-08 2-51 2 84 17-21 The rainfall in Franklin would probably average 30 inches per annum, a large part of which falls as snow in the winter months. The summers are moderately warm and dry with cool nights, while the winters are severe with heavy snowfall, partic- ularly on the western slopes of the mountains. TIMBER. This region was once heavily wooded with the following, main species of trees: Douglas fir (Pseudotsuga Dougkuii) and other varieties, tamarack (Larix amenrana ?), spruce {Picea canadensis), hemlock {Tsuga canadensis), white cedar {T'tuya plicata), white birch {Betula papyrifera), poplar {Populus), and Cottonwood. The three last mentioned are found generally in marshy ground. Red cedar (Juniperus scopularum) is not found in Franklin, but does occur 25 miles iarther to the south, in the vicinity of Christina lake. Large areas of timbered land have been recently destroyed by forest fires and second growth brush is rapidly springing up. There is, however, considerable 1^ timber left and available for mining purposes. The southern hill elopes are as a rule open and park-like. They support in season innumerable species of wild flowers, black raspberries, and huckleberries. GAME. Black-tailed deer (Cariacus macrotis) are numerous, and beaver (Castor fiber), owing to protective game laws, have be- come very plentiful. Black and cinnamon bear {Ursus amen- canus), mountain lion or "cougars" (Felts concolor), and coyotes (Canis latrans) are less frequently seen. Porcupine (Erethiton dorsatus,) mink (Putorius vison), red squirrel or chickaree (Sciurus hudsonicus), chipmunk (Tamias striatus), gopher (Geotnys bur- sarius), and wood rat (Neostoma) are also included among the fauna. The birds include blue grouse (Dendragapus obscurus), ruffed grouse (Bonasa umbellus), partridge, prairie chicken (Pedicecetes phasianeUus columbianus), in the valleys, ducks, geese (Brant), loon (Gaoia imber), pied-billed grebe or "hell- diver" (PodUymbus podicaps), and "mud hen" or American coot (?). CHAPTER II. SUMMARY AND CONCLUSIONS. GENERAL GEOLOGY. The Franklin mining camp embraces an area of 16 square miles situated in the centre of the Columbia Mountain system — a system composed in large part of deep-seated igneous rocks. The district, which occupies a structural or tectonic de- pression enclosed by granitic mountain ranges, presents to the geologist an unusually complete record of Mesozoic, Tertiary, and Quaternary events, particularly the latter two. All phases of igneous activity are represented, from deep-seated batholithic invasion on a large scale to the more suriicial intrusions of dykes and irregular masses which have reached close to the surface and even formed volcanic vents from which ejectamenta and lavas have been derived. A close geological examination of the Franklin district, combined with detailed field work in other nearby and surround- ing regions, leads to the following summary and conclusions. Some of the conclusions stated here must be regarded as only tentative, owing to lack of extensive detailed work in this sec- tion of the Cordillera. They are largely suggestions, made in order to promote further investigation, correlation, and the ob- taining of field facts which may throw further light on the prob- lems in question and aid in their solution. For the details upon which the conclusions are based, the reader is referred to the succeeding chapters of the report. Pal/GOZoic Era. The Franklin group of metamorphic tuffs, quartzites, and argillites, the latter containing plant impressions, are the oldest rocks in the district. They are correlated with the Knobhill 8 group of Phoenix' and possibly represent the Lower C^che Creek group of the Kamloops' district. These formations may represent early marine coastal conditions of sedimentation and igneous activity prior to submergence and eastward trans- gression of a Carboniferous sea. The Gloucester formation is correlated with the Brooklyn crystalline limestone of Phoenix and Deadwood in the Bound- ary district, and with the Upper CSche Creek group in the Kam- loops district, which Dr. Dawson proved to be of Carboniferous age on palaeontological evidence. The Gloucester formation in Franklin was found to contain crinoidal remains and an obscure Fusulina-like organism. These formations probably represent the off-shore calcareous phase of an castwardly transgressing Carboniferous sea in whose waters crinoids and Fusulina flour- ished. The in-shore phase is represented by the carbonaceous limestones and argillites of the Slocan series in the Selkirk moun- tains, which contain obscure plant r.-^mains. Mountain Making at the Close of the PaliEOZoic. The main folding and regional metamorphism of the Palan)- zoic rocks took place at the close of the Palaeozoic previous to the intrusion of the Jurassic granodiorite batholith. The Palaeo- zoic rocks in the Columbia Mountain system were more highly folded and compressed than those to the west in the Interior Plateau country. The most intpnse folding took place in the mountainous regions to the eiist, as is well illustrated by the steeply inclined and compressed folds of the Slocan series in the Selkirk mountains. The Franklin district, since its emergence at the close of the Palaeozoic, has remained above the sea, although in upper Jurassic time the Logan sea may not have been far to the north.* The district has since undergone continued continental erosion and sedimentation. 'LeRoy (O. E.): Geol. Surv. Can., Map 16A, Phoenix, B.C., 1912. 'Dawson (G. M.): Ibid., Kamloops map sheet. • Chamberlin and Salisbury: Geology, Vol. Ill, p. 66. Mesozoic Era. Triassic Period. During this period, Franklin formed a part of the high- lands which were supplying sediments for the Nicola series to the west in the Interior Plateau. Jurassic Balholilhic Invasion and Formation of Contact Meta- morphic Ore Deposits. The granodiorite batholith of the Franklin district is correlated with the Nelson granodiorite and the Remmel and Osoyoos granodiorite batholiths in the Okanagan' district. The batholith was intruded under a considerable cover of super- incumbent material and did not have access to the surface. The ores of contact metamorphic origin at Franklin and probab'- throughout the Boundary district were formef' at this tinio, as well as some of the silver-lead ores of the fissure vein type in Franklin and possibly the Slocan district. Cretaceous Cycle of Erosion {First Cycle). The Cretaceous period in Franklin was one of long con- tinued denudation, which laid bare great thicknesses of Palaeo- zoic rocks. In some favourable places, erosion even exposed the underlying Jurassic granodiorite, as, for instance, on McKinley mountain, where the Eocene sediments lie directly upon it. To the west of the Columbia mountains, in the Interior Plateau of British Columbia, local peneplanation was developed. This surface, which was recognized by Dr. G. M. Dawson and assumed to be Eocene, has dominated the topography in many plac«^s. During the Cretaceous period of erosion, no doubt many contact metamorphic ore-shoots associated with the Palaeozoic calcareous beds and fissure veins were eroded off. Further study of this problem of Cretaceous erosion should lead to some inter- esting and important economic results with regard to the distri- bution and extent of certain types of ore deposits and their age. •See p. 62, General and Structural Geology, Ch. IV. IT 10 The Laramide Uplift and Mountain Making Period. The Mesozoic era closed with the Laramide revolution, which uplifted the whole Cordillera and further folded and com- pressed the eastern mountainous belt. The Valhalla quartzose granite was probably intruded at this time. The Cretaceous surface of erosion in the Interior Plateau was uplifted fully 3,000 feet along the region of maximum up- lift to the north of the International Boundary, and decreased southward towards the Columbia lava plains. Vigorous dissec- tion by rivers was commenced, with much consequent drainage away from the area of maximum uplift. Tertiary Era. Early Tertiary Conditions— as Shovm by the Kettle River Formation (Coldwaier Croup of Dawson). The Franklin district in early Tertiary time, was it. the region of maximum uplift and formed part of a tectonic basin enclosed between lofty sedimentary mountain ranges. Great quantities of coarse alluvial gravels and some glacial origin were deposited, chiefly in alluvial cones at '' jase of the ranges. The main drainage was southward, and cne coarse heterogeneous conglomerate member of the Kettle River formation in Franklin corresponds to the river gravels o*" the same formation farther south at the International Boundary. With the regional sinking, or subsidence, following the maximum uplift, aggradation set in and the deep valleys and irregularities of the surface became filled with, chiefly, fluvial material, which includes water-laid acidic tuffs and rhyolitic arkoses. Sedimentation, with contemporaneous volcanic activity, progressed until near the close of the Oligocene. Oligocene Deformative Period — Monzonite Stocks Intruded and Erosion Cycle {Second Cycle). The early Tertiary closed with crustal disturbances which tilted the Kettle River formation in Franklin, to the north- northeast and inaugurated a new cycle of erosion. 11 Monzonite, a dark-grey, mottled, fresh-looking rock, co- magmatically' related to the younger alkalic intrusives, was intruded at this time in the form of stocks. A new cycle of erosion was commenced, which stripped off extensive records of loose Kettle River conglomerate and arkose, particularly the sediments along the main drainage courses. Miocene Igneous Activity. Porphyritic Syenite Intrusions. The first manifestation of Miocene igneous activity was the intrusion of small porphyritic syenite chonoliths* which reached the surface at least in one place to form the oldest trachyte flow on McKinley mountain. The syenite and trachyte of this period are less alkalic than those which followed later from the same parent stock. No important mineralization accompanied these intrusions. Intrusion of Shonkinite-Pyroxenite Augite and Syenites. Extrusion of Corresponding Alkalic Basalt and Trachytes, and Formation of Tertiary Ores. A short erosion interval elapsed before the main alkalic intrusions and extrusions, which were of two immiscible magmas, feldspathic pyroxenite and augite syenite, the products of a deep-seateii separation of the original magrna into unlike portions. The basic pyroxenite portion was intruded slightly in advance of the augite syenite, and formed at the surface basal lava flows. The augite syenite followed, almost simultaneously, and favoured the lower contact of the pyroxenite. Portions of the pyroxenite were included and drawn out as "schlieren" in the syenite. The magmas were extruded from a vent on Tenderloin mountain and solidifled as basaltic tufls. ' Means that both monzon^e and the younger alkalic intrusives were all derived from a common parent magma, which separated into different types through a process of diFfrentiation. 'A term defined by R. A. Daly as "an igneous body (a) injected into dis- located rock of any kind, stratified or not; (b) of shape and relations irregular in the sense that they are not those of a true dyke, vein, sheet, laccolith, bysmalith, or neck; and (c) composed of magma either passively squeezed into a subterranean orogenic chamber, or actively forcing apart the countr rocks. Word derived from x'-"'"(> a mould used in the casting of metal, and >iiio(, a ■tone." 12 ejectamenta, alkalic basalto, and trachytes. The syenite, which has a characteristic trachytic or flow structure of its feldspar laths, was found in contact with the Kettle River formation on the east side of the Kettle river, and there the conglomerate and grit show intense contact metamorphism produced by a gran- ular intrusive into an unconsolidated sedimentary formation. The magmatic segregation type of sulphide ore, chalcopy- rite, and bomite was formed at this time, as well as those deposit- ed in contact zones adjacent to the syenite. Period of Younger Pulaskite Dyke Intrusions and Local Faulting. In the last period of Miocene volcanic activity, tongues and dykes from the Rossland alkalic syenite and granite of the Granite range, penetrated the rocks of the district along certain definite systems. The rocks of this period are pinkish alkalic syenites and porphyries of the pulaskite type, and there is no evidence in Franklin to •' dicate that they reached the sur- face to form mica trachyte flows, as they did in the Boundary district. The youngest lamprophyre dykes, which are of the minette type, are genetically related to the pulaskites. The faulting of the post-Oligocene erosion surface on Tenderloin mountain is referred to this period of igneous activity. Disorganization of Pre-Miocene Drainage and Inauguration of the Present System. The extrusion of trachyte flows brought about a change of drainage, and instead of a single main stream, two streams were formed, one on each side of the trachyte flow. The easterly one went to form the new east branch of the North Fork of the Kettle river. Pliocene Cycle of Erosion (Third Cycle). Following igneous activity, a new cycle — the third cycle — of long continued erosion was commenced, which lasted through the most of Pliocene time and was of sufficient duration to trans- form former divides into valleys, and produce a coarse-textured, post-mature topography. The Franklin upland, which is present above 4,000 feet in elevation, is referred to this cycle of erosion. 13 Regional Uplift at Close of Tertiary and Incision of Antecedent Pliocene Drainage. Regional uplift, amounting in this case to about 2,500 feet, closed the Tertiary, as it did the Mesozoic and Palaeozoic eras. The Pliocene drainage was entrenched deeply below the upland surface by the invigorated rivers which formed V- shaped valleys very nearly as deep as those following the Lara- mide revolution. CORDILLERAN ICE SHEET — PLEISTOCENE. The course of the Cordilleran ice sheet, which covered all except a few of the highest peaks in the Cariboo range, was S. 30" E. First Period of Valley Glaciation. With the waning of the continental ice sheet, the first period of valley glaciation was inaugurated and considerable till and erratic boulders were left on the upper slopes above the new level of the ice surface. Second Period of Valley Glaciation. The intense glaciaiion of the valleys is referred to a period of valley glaciation at the time of the maximum extension of the Keewatin ice sheet. With the advance of the ice during this period, while the main valley heads were the scenes of vigorous denudation, extensive moraines were deposited. The streams draining the ice front carried down and deposited large quantities of land waste in the form of outwash gravels. In the waning stages of the Glacial period, glacial conditions gave place to high water conditions. The streams continued to be burdened with land waste and allu- viation was prolonged into the high water stage. Formation of Terrace-steps. Upon the complete with- drawal of the ice or its restriction to headwater cirques, those regions which had already been the scene of vigorous glaciation did not supply much waste to the streams. With the conse- quent reduction, then, in waste supply and but a slight reduction in volume, the streams degraded their earlier accumulations. Periodic cu»..^es of climate in post-Glacial time brought about minor stages of alluviation and degradation with the pro- duction of the present terrace-steps, gorges, and ravines. 14 ORE DEPOSITS. Up to the present, no ore has been shipped from 'i^nklin and the camp may still be said to be in the prospect stage.' Owing to lack of extensive development work on the various properties, very little underground data could be obtained, so that any conclusions regarding the ore deposits must necessarily be based upon the areal and structural geology of the camp. The Tertiary sulphide ores of the magmatic segregation type ("Black Lead" ores) should have great persistence in depth. They are, however, of no present economic value because of their low grade character snA the fact that they cannot be treated by any known process of ore dressing. Until some suitable method of treatment is found, and the camp made more accessible to a smelter through railway connexion, such ores are of little value. The most important ores in the district are those of the con- tact metamorphic and fissure vein types of Mesozoic age, although the former are of too low grade a character and limited an extent to be of much value at present. The fissure vein type yields the highest values. The ore shoots developed at the McKinley mine are very small and low grade. The quantity and distribution of such ore depends (1) on the depth to which the calcareous rocks extend, and (2) upon the extent of the Cretaceous and subse- quent cycles of erosion which have removed favourable ground for ore deposition. The fact that the Franklin valley exposes lenses of Gloucester marble as wide at its bottom as where they outcrop in its lower slopes, would point towards a depth of at least 1,000 feet of favourable ground for the formation of contact metamorphic ores similar to those developed at the McKinley. There is no reason why the ores, if present, should not extend to the parent granodiorite itself, provided the calcareous beds persist to that depth. 'During the summers of 1913 and 1914, 1,767 tons of ore wei« shipped from the Uuion group of claims. 15 CHAPTER III. PHYSIOGRAPHY. GENERAL ACCOUNT. Regional. The Columbia Mountain system of the North American Cordillera, in which the Franklin district lies, extends northward from the Columbia lava plain in Washington, to the great bend in the Columbia river about 80 miles north of Revelstoke, B.C. At the great bend, according to Daly's' delineation of the oro- graphic boundaries (which is followed :n this report), ..le Rocky Mountain trench truncates on the northeast both the Selkirk and the Columbia systems. The Columbia system is bounded, in British Columbia, on the west by the rolling country of the Interior Plateau, into which it grades imperceptibly, dropping from elevations of 7,000 feet and more in the system itself, to elevations seldom reaching 6,000 feet above sea-level in the plateau country. The boundary line is placed by Daly along the Thompson river, Adams lake, and the west fork of Keitle river in British Columbia, while in Washington it is determined by the lower Okanagan valley. On the east the Columbia Mountain system is bounded by the Selkirk mountains and separated from them by the great Sel- kirk valley, within which lie the Arrow lakes. The Columbia system comprises many ranges which trend in a general north and south direction. They are in many places separated by deep longitudinal valleys, here and there occupied by lakes. Suess in the last edition of his "Das Antlitz der Erde"' ' Daly (R. A.) : The Nomenclature of the North American Cordillera, Geog. Jour., Vol. XXVII. 1906, p. 588. 'Suess (E.): Das Antlitz der Erde, III, Pt. 2, 1909. Joerg (W.): Bull. Amer. Geos. Soc., XLII, No. 3, Mch. 1910. Combines translation and review. 16 follows structural and geologic principles for delineating the different ranges of the northern Cordillera, though in his text the mountain boundaries, owing to lack of sufficiently detailed information, are delimited only in a tentative way. His guid- ing principles are embodied in the two terms, syntaxis (or coal- escence) and linking, which describe the manner in which moun- tain ranges or arcs encounter each other.' The term syntaxis or coalescence designates the union of convergent arcs at a ter- minal point, while Hnkini is applied to cases where one arc cuts across the trend of the other and terminates it. He points out that as the coalescence or syntaxis of two mountain ranges shows the result of two opposing dynamic influences, it should be considered a boundary and that the name of a mountain range should never be extended beyond it. He includes in his "Zwishchengebirge" or Inter-Mountains, corresponding broadly to Dawson's "Interior Plateau," the western half of Daly's Columbia system. This shifts the boun- dary line eastward to the western base of Dawson's Gold range, a unit of the Columbia system, and places it, possibly, along the North Fork of the Kettle river and Christina lake (118 V W.). He states that this important tectonic boundary between the Rocky Mountain system (using this term to include the Selkirk, Purcell, and Rocky Mountain systems of Daly) and the Inter-Mountains, is marked by no structural feature of note; no fault line separates the two divisions. Which is the more advisable to adopt, a genetic classifi- cation or nomenclature based on underiying principles of geo- loijic structure and origin following Suess, or one based on purely geographic principles as suggested by Daly? The genetic classification, which would take into consideration both deformational and erosional processes, however impracticable it may be at present, would certainly be the more logical. It would remove to a large extent those wrong impressions of sharp and well-defined boundaries between the different units, which * For example: the arcs formed in the caae of a consolidating asphalt pavement, an analogy which Sue** uses, present concave surfaces towards the areas of subsidence. The tension produced by the subsidence is resolved nto arcs, not of identical, but often of equivalent magnitude. 17 the geographic classification is likely to give. One would pic- ture, instead, natural transitions between the various tectonic lines and their significantly curved and causally related trends. Furthermore, one would be forced to discontinue the bad prac- tice of extending range names past important points of coales- cence: such a classification would materially aid in the solution of certain problems in geologic history and in finding what re- lations there are, if any, between orogenic movement and igneous activity, a broad problem not only of scienti . but also of great economic interest, bearing as it does on the aistribution of ore deposits and their exploitation. The need of such a comprehensive classification, in which every local range and subrange can be tied up definitely to its broader system and that in turn to the Cordillera as a whole, is felt now in certain mining districts of British Columbia and will be felt more and more as the vei7 extensive British Columbia Cordillera becomes better known and more thickly settled. However, such a genetic classification for mountain ranges and systems must necessarily evolve with the progress of detailed geo- logic and physiographic work. For the present, then, it scenes most advisable to adopt Daly's clear and concise geographic nomenclature, which is adequate for all immediate practical purposes, and to determine as far as possible the plan of the trend lines for this section of the Cordillera. Local. The Franklin district lies within 8 miles of the eastern boundary of the Columbia Mountain system and about 40 miles due north of the International Boundary (Figure I). It embraces three lava-capped mountains separated by deeply entrenched valleys. The valleys unite to the southrast with the main East Branch of the North Fork of Kettle valley, which extends through the eastern half of the district. The broad open valley of the North Fork has a gentle grade and affords easy access to Grand Forks, 45 miles southward b;> wagon road. In a summit view the mountains appear to occupy a broad, gentle depression between the Cariboo range (local terminology) on the west and northwest, and the Granite range to the east and northeast. The Cariboo range exhibito alpine crest lines; the Granite range has a broad, domenihaped summit with oc- casional rugged, outaUnding peaks and ridges, and forms a great barrier between Franklin and the Lower Arrow lake, only 8 miles distant, upon whose waters there is considerable through traffic. " The Cariboo and Granite ranges coalesce 16 miles due north of Franlr'in, enclosing between them a broad longitudinal depression within which an oWer drainage system appears to have been deeply incised (Figure 2). The steep slopes, resulting from vigorous erosion and subsequent glaciation, give the whole district a decidedly mountainous aspect. The intermont depression has been a tectonic trough or basin ever since it was formed, very probably in the great Uramide Revolution. Within it there is sealed, by protective lava cappings, a fairly complete record of Tertiary continental sedimentation, interrupted at intervals by epeirogenic move- ments, great erosion cycles, and igneous activity on a grand scale. DETAILED ACCOUNT. In order to give the reader a clear view of the many and diversified physiographic features of the Franklin district, the subject will be discussed under two main divisions: (1) Regional -erosion cycles and related forms; (2) Local— forms related primarily to rock structure. Regional— Erosion Cycles and Related Forms. Post-mature Upland Topography. From the summits above 4,000 feet, may be observed the presence of a post-mature upland topography with gently rounded outlines except near the borders of the dissected lava remnants. The upland can be traced in every direction. To the west it may be followed to the base of the residual granite ridge of « Geological Sorvy, Canada Fig. 2 Franklin Intermontane Trough and coalescence of bounding mountain ranges Miles 4 i a To aeoompuMy Memoir kgi CMDrrodale^ in' 1 -Ji 3 19 the Cariboo mountains, which show a somewhat alpine topog- raphy, modified by post-Glacial erosion, with gently curved cols' and peaks on the crest line. It exhibits glacial cirques with post- Glacial talus accumulations along the bases of the bounding walls and aretes or ridges between the glacial amphitheatres. The ridge due west of Franklin mountain clearly shows the effects of insolation upon cirp c recession as seen on alpine sum- mits.' The southern sir .k>s, wiiicti receive the more direct rays of the sun and were, the; ' foro unable in i - acial times to support n€v6 accumulations as 'ait^c as th» lurthern slopes, present gentle declivities in strciij cntrtist to the steep northern ex- posures. Basal sapping has naturally taken place more vigor- ously on the latter slopes, causing the cirques to retreat in a southward direction, producing steeper bounding walls on their southern sides. Northward along the Cariboo range these alpine features are not so pronounced, but the range as a unit becomes more massive and resembles the Granite range to the east, though it exceeds it in altitude. Looking southward on both sides of the broad North Fork valley, one still sees the typical undulating upland topography. In the vicinity of Newby camp, north end of Franklin mountain, the upland or old erosion surface is seen to decline eastward towards the wide Gloucester Creek drainage course. This is shown by the flat- topped, gently sloping spurs, leading out from the main ridges, which are cut off sharply to the east by steep valley slopes. It is interesting to note that the best preserved remnants of the old erosion surface occur where the underlying formation is the resistant granodiorite. The spurs elsewhere underlciin by the less resistant conglomerate and Palaeo- zoic rocks have been greatly eroded and modified. In many other places the summit slopes on the old upland were found 'A term used to designate a common form of crest line seen on alpine summits. It is a concave curve (theoretically a hyperbola) formed by ad- jacent cirque glaciers cutting down a crest line from opposite sides and lowering it at their points of tangency. 'Gilbert (G. K.): Systematic Asymmetry of Crest Lines in the High Sierra of Cal., Jour, of Geol., XH, 1904, pp. S79-S8& f'l 20 to decline gently towards the axis of the larger entrenched valleys. This fact signifies that the present drainage occupies antecedent valleys (discussed later under drainage). The restoration of the old upland in the Franklin district has been attempted by filling in the deeply entrenched and glaciated valleys between the remnants. The result is shown in Figure 3. Diagram showing post-mature Pliocene upland restored Figure 3. This gives an approximate idea of the character of the old upland topography before it was uplifted and dissected, except that continental glaciation has slightly modified it. No doubt a much thicker mantle of soil existed on it before glada- 'ii ■it I 1 leys, dent trict and n in / > / -J :he id. Sfo ia- 21 tion, and rock exposures would be comparatively rare except on the steepest slopes. It was found in Franklin that the mature upland bevelled both lavas and i trusive rocks of Miocene age. Thus the main erosion was accumplished during a long period of denudation in the Pliocene. The local irregularities of the upland indicate that this denudation stopped far short of a beise level, for there are variations in relief amounting to hundreds of feet. The question of age and correlation will be discussed at the end of the chapter. Younger Valley Topography. On descending the upland slopes, younger valleys may be noted deeply entrenched below the upland surface (1,000 feet or more). The incised valleys with steep walls afford splendid rock exposures; on them conditions in certain localities are fav- ourable for rock slides. The present shape of the valleys may be attributed to the work of rejuvenated rivers following the late Tertiary differ- ential uplift. The pre-Glacial valleys were characterized by having V-shaped sides with slopes of about 30 degrees, in strong contrast with the 10 degrees upland ones. The two slopes at their junction made rock shoulders about 1,000 feet above the valley floor which is now partially filled in many places by out- wash material of glacial origin (to be discussed in a later section). The pre-GIacial valley slooes had relatively little soil compared with those of the u The pre-Glacial V-shaped courses, however, were modifi - '■■ unded to their present configuration by Pleistocene glacier. .,e least modification of pre-Glacial valley-form is to be seen in the case of the present Franklin creek, and to a less extent in that of Gloucester creek, where the antecedent streams cut across an early Tertiary course before joining the main Kettle River valley (Fl^te I). Here the valleys are decidedly V-shaped and narrow, but towards their sources become typically U-shaped, leading up to broad glacial amphi- theatres. The significance of this feature will be discussed in the section on glaciation. 22 Glaciation and Glacial Forms. After this brief examination of the upland and younger valley topography, some of the more detailed features, due chiefly to glacial erosion, will now be considered. Evidences of the Cordilleran ice cap were found on rem- nants of the upland within the Franklin map area. They con- sist chiefly of glacial striae with an average strike about S. 30° E. Further evidence of past continental glaciation may be seen, on the upland slopes, in the piasence of scattered glacial erratics, till, glacially scoured and smoothed rock surfaces, and rounded hillocks with intervening depressions, in many places, occupied by stagnant pools of water locally known as "sloughs." The scouring effects of glaciation and ice motion, however, are not so pronounced on the summits as they are in the valleys, and it is probable that some of the highest peaks of the Cariboo range (those over 7,500 feet present altitude) stood as nunataks above the ice surface. It is known* from glacial stri» on the Cariboo range that the ice cap reached as high as 7,400 feet above sea- level. Evidence obtained by Daly in regions to the south and west, fixes the upper limit of the ice cap at about 7,500 feet, and this coincides with the results of investigations on the sou en side of the boundary line.' Turning now to the valley features, it is to be noted that the Gloucester Creek valley unites with that of the main North Fork just be'ow Tenderioin mountain, forming a broad U-shaped basin whose . \i are well scoured and steepened (Plate II). Glaciation has only slightly modified the upland as compared with the valleys, which show signs of intense ice motion. Fresh, sharp glacial striae on valley floors and sides strike with the val- leys, as do also the well scoured rock ridges (Plate III). Glacial still extends along the lower slopes of the valley walls and con- sists of a heterogeneous mixture of boulders, pebbles, and angular fragments of different kinds of rock. ' West Kootenay Map Sheet. Topographic Sheet No. 791, G.S.C. •Camsell (Charles): Hedley Mining District, G.S.C, Memoir 2, 1910, p. 126. Smith (G. O.) and Calkins: U.S.G.S. Bull. 32S, 1904. 23 The Franklin valley joins that of the main river at almost a right angle and does not show the broadening feature, as in the case of Gloucester valley, but, on the other hand, it does show the best preserved terrace-remnants composed of fluvio- glacial material, which, as will be shown later, has been laid down as valley trains contemporaneous with the retreat of the valley glaciers. Both valleys have their heads in the Cariboo range; the Gloucester, with a larger drainage basin, rises at the base of one of the highest peaks (altitude, 7,325 feet) ; and the Franki'.j, about 2 miles farther south. The Cariboo mountains, as already noted, exhibit alpine topographic features modified by post-Glacial erosion. Glacial cirques, some of which are occupied by lakes, aidtes, cols, and rugged crest lines, were developed. From the preceding facts it may be inferred that during the Pleistocene period the whole region, with the possible ex- ception of a few peaks on the Cariboo range, was buried beneath an ice sheet — the Cordilleran glacier. Farther south, however, in the State of Washington, the ice sheet was not general, but gave place to valley glaciers forced southwest from the main ice sheet to the north.' The progressively younger age of the maximum extensions of the continental ice sheets as they occur in order eastward has been pointed out by Mr. J. B. Tyrrell* and Dr. G. M. D wson,* who found that the Cordilleran glacier reached its greatest extent and retired before the bouldci-clay that generally underlies the western plains was deposited. This boulder-clay Mr. Tyrrell takes to be the true till or ground moraine of the Kce- watin glacier, when the glacier had reached its greatest south- westerly extent.* 'Willis (Bailey): U.S.G.S.. Bull. 40. 1887. •Tyrrell (J. B.): The Genesis of Lake Agassiz. Jour, of Geol. Vol. IV, 1896, pp. 811-815. •Glacial Deposits of Southwestern Alberta, in the Vicinity of the Rocky Mountains, by George M. Dawson, Bull. Geol. Soc. Am., Vol. VII, pp. 31-66, Nov. 1895. •Calhoun (F.H.H.): The Montana Lobe of the Keewatin Ice Sheet. P. P. No. 50, U.S.G.S., 1906, p. 56. 24 It might be inferred, then, that if there was a second period of valley glaciation in the Franklin district the first period was associated with the retreat of the Cordilleran ice cap and this second period at the time of the maximum extension of the Keewatin ice sheet. There is evidence to support the idea of more than one period of glaciation throughout the Canadian Cordillera, but, in the Franklin district, the amount of direct evidence supporting this view is quite meagre. The field evidence present in the Franklin district to support the inference of a second period of valley glaciation is as follows:— (1) The glacial striae in the valley bottoms were found to be much sharper and fresher than those on the upland, and both were cut in the same rock formation (granodiorite). (2) A divergence of 50 degrees was found between the strike of the main continental ice sheet stria and that of the valley glacier (See geological map sheet 97 A). (3) Fresh striae were found 500 feet up on the valley side below the Little jiioperty. The younger valleys below the upland surface were, no doubt, hnes of maximum movement of the ice during Cordilleran glacia- tion, but the glaciation of the valleys appears to be much more intense than any single ice sheet would be capable of accom- plishing. Furthermore, the valley glaciers associated with the retreat of the Cordilleran ice cap would be loaded with waste, enfeebled, and less capable of accomplishing vigorous valley erosion than the advancing valley glaciers of the second period. The work done in the valleys is fully as great as any accomplished by alpme glaciation. With the retreat of the Cordilleran ice cap, glaciers became confined to the higher depressions of the ridges and in the mtermont valleys where they were fed by extensive n6v6 fields. At this time considerable supergiacial and englacial material must have been left from the waning ice sheet on the upper slopes above the new level of the ice surface, as indicated by the present distribution of erratics and till. Then, with the advance of the ice dunng the second period of valley glaciation, while the main valley heads were the scenes of vigorous denudation, extensive moraines both lateral and terminal were deposited. In addition 25 the streams draining the ice-front carried down and deposited large quantities of land waste in the form of a deep alluvial fill. In Twin Creek gully, with its small fan-shaped drainage basin, there are preserved remnants, in a series of terraced spurs, of what was, possibly, a lateral moraine laid down subsequent to the maximum advance of this youngest valley glacier. The iroraine may have been formed in a similar way to certain lateral moraines described by Penck', where the main ice sheet has forced tongues of ice up tributary valleys. No evidence of ice- shove, however, was noted in the case of these terraced spurs. It is of interest t" note here that valley glaciers, like riveis, erode more readily when flowing in longitudinal courses with the grain of the country than in transverse courses across the grain. This is well illustrated in the case of Franklin Creek val- ley, with its V-shaped transverse course below its West Fork and U-shaped longitudinal course above it (Plate I). In its longitudinal course the valley follows not only the regional strike of the master joint and bedding planes of the rock for- mations, but also a contact for some distance. In the valley's transverse course, on the other hand, it cuts through the more resisUnt greenstones and across the strike of many porphyry dykes (page 28) as well as the regional strike of the Gloucester formation. In the case of Gloucester Creek valley, this feature is not so marked because (1) the transverse course of the valley joins that of the main North Fork at a smaller angle, and (2) the Gloucester Valley glacier must have been larger than that in Franklin creek on account of its greater catchment basin and more strongly glaciated valley characters. In the waning stages of the Glacial period, glacial condi- tions gave place to high-water conditions, for to the normal precipitation of the time was added the accumulated precipita- tion liberated from its previous condition as snow and ice. With the melting and recession of the ice, vast amounts of englacial land waste would be set free. The streams would con- tinue to be burdened and the period of alluviation would be pro- longed into the high water stage. Upon the complete with- drawal of the ice or its restriction to headwater cirques, the de- 'Penck (A.): Die Alpen im Eiszeitalter. 26 nrt?rL"f*? °1 ^°""" ^'«°''°"' glaciation would supply but iiDoIv anH I ' "'"'T- '^''"^ "•*'' ^^«* reduction h. waste Zw e^Thl"" '' ' '"'^"™'" '"'""'°" '" ^°'""*' the streams would either cease cutting and accept the established gradients the! dJi T." '''""i'^ ^^^^ ^''^ ^^''-'^^ accumuladons. as wft., w 'T °^f'•*"•^'" "^k and the main Kettle ri^er. 2^rl? .^^f^«t'°n ^"d no terraces except those due to the Tthe F ' W-'^r'"^"? °^ *''*^ ^*'^^'"'- This is not the case GlUl^ u "T'' ^°' P*"°^'*^ ^''^"«^ °^ ^^"'"ate in post- ed i T " c °".^''' ^'~"' '"•"°' "^8^ o^ alluviadon account of the presence on both sides of the Franklin valley, near its junction with the main Kettle valley, of a series of ter f^'ulT T '"'t ':'"'"'^'''"« •" -^^- b"' be^mSg moTe Eiv^ r'' ''°^'^ '"^"^ °" *^^"* t° the river below Tw th ^" '"''* *?' ^ °^ ^''^ «*'«•" the terraces usually show the coarsest gravels. ' th^n^hv °"^-K°^ '''u "T *^"^^^ '" this district are explained. d^'Jlf '^ **•"" ^^^ *° ^ "^^"^ ^tage of alluviation and degradation contemporaneous with and dependent upon alpine valley glaciation; and (2) to later minor stages of JSuviaSon and degradation dependent upon climatic oscillation. Ihese terrace features are most strikingly illustrated near the mouth of the Franklin Ci^k valley. This nar«.w id st^L walled portion of the valley trench, with its transverse c^u^ Xh rt'L ' "u- '^ ^°' '^' accumulation of outwash materials.' which reached a thickness of some 100 feet. The strong develop^ SlTir'""'^ • *'""^" "* '^' '"°"th of FranWin valJe^ might be further explained by the possible impounding of drain^ Smoutt "^ "" ''' KetUe Valley glacier whi,^ block^ thP Ji' TT °' V^^^^^ ^^^"^' '^ necessarily dependent upon t^ Z A ^I^hment basin, as well as upon precipitation and cold. A small tributary glacier may flow iluo a main trunC gkcier dunng the climax of the glacial period, but with an ^el^ oration of climate its small catchment basin may not supply enough snow to enable it to reach the main glacier The resuk .s the separation of the two and their gradu^ up-valley re rea i,iJL. 27 Thus it is conceivable that the small Franklin glacier, ^d by a relatively small catchment basin, may have shrunk back from a main Kettle Valley glacier. The latter would have then acted as a dam against which the stream from the former could have readily heaped up gravel deposits. Post-Glacial Gorge Cutting. The youngest set of topographic forms are the post-Glacial gorges, deep ravines, and hanging tributary draws, still in a very youthful stage of development. These forms are most markedly developed along the course of Franklin creek, whos«. present channel is a steep-sided tortuous gorge cut in the bottom of a wider valley. Its tributary creeks are left high above the water level of the main stream and join it in a series of wattr falls (about 35 feet high). The hanging relationships of some of the smaller iributary streams to the main Franklin creek is due to the excess of cutting of the latter with respect to the for- mer, and must be distinguished from somewhat similar relation- ships due to glaciation. The Franklin ^orge is cut not only in the readily eroded alluvium, but also well into the resistant bed-rock in places. The accompanying photograph (Plate V) was taken on Franklin creek below the main valley to show the amount (approximately 100 feet) of post-Glacial gorge cutting. The rock formation seen is the Kettle River conglomerate. LXKAL — FOKMS RELATI > PRIMARILY TO RoCK Structure. Under the second main division, namely, the discussion of those land forms which are dependent or consequent upon rock structure, may be included : — (1). Those forms assumed by the early Tertiary conglom- erate and grit formation through ordinary erosional processes. (2). The strike ridges and structural troughs occupied often by "sloughs," chiefly along fault or contact zones. 28 (3). The mid-Tertiary lava cliffs skirted by coarse talus ■lopes showing progress in cliff recession as observed on all three mountains (Plate VI). (4). Caves formed in lava cliffs along prominent systems of parting in the rock, which correspond as a rule to their lower contacts with the underlying grits (Plate VII). (5). Recent rock slides causing prominent scars on the mountain slopes (Plate VIII). (6). Mounds of monzonite, on both sides of Tenderloin volcanic vent which occupies the intervening depression. (7). Crystalline limestone rock-shoulders best developed on the west slope of Franklin mountain, but also on the Dane property opposite Gloucester City. The most singular topographic forms are possibly those developed upon the Tertiary conglomerate and grit. The unique forms of the conglomerate hillocks and mounds with prominent pmnacles or "hoodoos" are typical of those tracts which were m early Tertiary time areas of maximum deposition (Plate IX). The conglomerate ridges so conspicuous in places are a conse- quence of under • r-r structure and differential glacial erosion. Their strikes doi.. .:antly coincide with that of the valley, having steep escarpments on one side and relatively gentle slopes on the other. An interesting case of stream deflection was noted about half a mile south of the junction of the West Fork with the main Franklin creek. A syenite-aplite dyke here strikes diagonally across the stream and has deflected it to the west, causing it to make a sharp bend in its course (See geological map 97 A). All three mountains in the district have protective cap- pings of lava lying upon a poroui conglomerate and grit forma- tion. The conglomerate formation in its turn lies upon imper- vious basal rocks. It is quite to be expected, then, that when such a section is well exposed on the steep eastern slopes of the mountains, in a humid climate subject to great tempera- ture changes, rock slides will take place from time to time. The breaking away of large blocks might be assisted greatly by seepage developed through breaks in the lava cap as well as by frost action. 1 i^i ; m 29 le talu§ on all terns of r lower on the derloin pedon Dane those Jnique ninent 1 were bIX). conse- osion. laving es on i about i main 1 mally | ing it A). cap- '^ irma- nper- 3 when ES of 1 pera- J The 1 ^^ by J * by M Rock slides are cauited chiefly by the undermining effects of seepage water issuing along the contact of pervious and im- pervious layers. Their development is hastened where the con- tact of the formations corresponds in gradient with the slope of the hill. Below the Maple Leaf property on Franklin moun- tain an alkalic syenite intrusion has bowed up its conglomerate - grit cov^ r and makes the contact approximate in gradient that of the hill, thus facilitating rock slides in this vicinity. It is of interest to note here that with few exceptions all the striking topographic forms dependent upon structure are to be found below the old upland. Drainage. The relations of the prominent drainage characteristics will be made clear by a few words concerning the geologic his- tory of the region. The full evidence upon which the Tertiary history of this district is based is discussed in later chapters. One persistent trait of the drainage ever since its begin- ning in the Laramide Revolution is its southward discharge. Drainage conditions in early Tertiary time were naturally quite different in Franklin from what they are to-day. The dis- trict was then probably lower than it is now, but it still occupied the same intermont depression. The surrounding mountains were then composed chiefly of sedimentary rocks highly folded ani " 'ten during the great Laramide Revolution. No doubt the -wj. -graphic relief was then much greater than it is now, and alpine conditions probably prevailed. It was found that the course of the early drainage was directed south westwardly, as shown by current-markings in the grit formation on Franklin mountain. In this broad basin-like valley both streams and lakes were subject to great variations in size and position, due (1) to crustal disturbances and (2) chiefly to the ponding effect of contemporaneous lavas (rhyolites). Marshes and lakes were formed and about them vegetation flourished at intervals. Volcanic tuff was washed down into the shallow lakes and flood- plains. Much volcanic ash became mixed up and deposited with coarser arkosic (rhyolitic) grits in the rivers. Coarse JO gravd. were .wept down from the highland, to form .ubaeri, ^ra" nat' i: T" P '""*' '""""'^^ ^ ^'' °^ »»'« -^'^i- ^ril„ K "^ "^ '^r'y •**«*• °^ »''« Tertiary mu.t neces «nly have been .n a decidedly diwrganized .uTe. In a^Z aui!rSr;>-""'' *'*'"^"'^ ^"' '«"~"- ""'«•» gave pla e" qu«t oond. .on.: mature .lope, were produced and the draina,. he«me well orgamxed with re,pect to one main river-JJ S^e^ite'of fh * """-««*'"« *»-"» 25 degree. we.t of K,uth o Z.ZZ °f the pre«mt mountain summit.. The old valley wa- probaWy broader and flatter toward, it. head and narrow^ M^^z liir - ''' '-' -' °^ *^« »>-- ^'- " volumJ^" /''' °"^'*'' °' '^'°""* •8"~"» ««'vity. great t«chv!^.fnHZ°'"'''r''""'' '~'"^' ei«=tamenta. and Si- ^ '"= '"'''• ^^''^ '""'«' ^°'th ^ro-" a vent on Tenderlom mountain. This wa. followed up by trachyte and phonohte lava flow, which poured forth into thi. Cd vJlcy A- . ^J "^ °^ **•* '*^* ^°^«' t''* drainage was once more d^^turbed: new cour.e. had to be taken which naturally ^iffTr^ considerably from the older ones. Instead of a single S «™.m two .tn^ams were formed, one on each .ide of the II The easterly one went to form the new Kettle river • that V„^ '*'"'?* of denudation then took place, similar to Aat m progress throughout many actions of the Cordillera in late Tertiary time, and the whole district w . reduced to a «.r^ce of low rel ef with residual ridge, and ..ak, along °he Strict. ~'" °"" '°'*^ '"°""*"'" '^^^ -^-"« the late ™5Ln?'">^"'''" °'8^'^«1' ^"d with progre«, towards .^ . ^, ^ " '^'"^ simplified; the topography was coarse- st thrl^h'""'* °- ^'V'*^'^'^^ thatTe land form hTd paeed through a previous (pre-trachyte) cycle of erosion; (2) the char acter of the country rock, which was resistant to the rJ\T^'^"j^V- '^\^'^ ^'* °f ^•" «'"« Mounuins. 0«.: 22„d Ann Kept. U.S. Gcol. Surv., pt. 2. OD. 574 S82 W7 wa mi .• "= • '*nu nnn. ofdn.i„.gecha„ge.pr;^uce;i'bVUv;flo;. •'''•'''"'"" ""'^"•'^ 'JohnKinCD.W.): Relationiof Geology to TouoeraDhv Pr.V.J„i Ptactice of Surveying. Vol. II, Ch. 7. p. 24^^ '°P<«raphy, Prmciples and ■H - 31 subaerial material. i»t ncces- In cuune place to drainage iver— the south on illey was larrowed It site of y, great ta, and vent on yte and 'alley, ce more differed le main he flow. nilar to illera in d to a )ng the ing the owards coarse- tn had n: (2) to the id Ann. uunces lies and formation of numerous small drainage channeU by smaller branch streams; (3) the character of the climate, which cannot l>c in- ferred for this district on account of the absence of Pliocene sediments; (4) age of land form, which had reached a post- mature development. The courses of the present streams correspond closely to those of the preceding cycle of erosion. For instance, the course of McKintey creek at that time must have been about 500 feet above its present course, or, to state it more concisely, the McKinley mine was then buried beneath 500 feet of rock as well as a thick surface mantle of soil. At the end of this cycle of erosion in late Pliocene or early Pleistocene time, a great regional uplift of a differential character occurred, which inaugurated a new erosion cycle with invigorated drainage which incised itself below the older surface of erosion. Certain rock benches high up on the mountain slopes, especially in the Franklin valley, may represent stream erosion duiing stable periods in the course of the uplift. The results of this uplift have already been considered. There is no evidence of any crustal warping at this time, although it may possibly have been a minor factor controlling the position of the drainage courses. Thus the composite character of the present drainage has been briefly traced through all stages of its physiographic de- velopment from its beginning in the Laramide Revolution to the present. The drainage is typically antecedent in character, although there are a few places where underlying rock structure heis domi- nated the course ' the streams, resulting in subsequent drainage. For example, the dome-shaped granodiorite batholith east of the East Branch of the North Fork of Kettle river has forced the stream to follow closely its western border, where it is in con- tact with the less resistant conglomerate formation. The river follows this contact for some miles south of a bend 800 feet down- stream from the mouth of Boulder creek. All of the main streams are perennial, while many of the draws or gullies with small catchment basins are intermittent, flowing only in wet weather or in time of melting snow. Boulder 32 sample Twm creek, on crossing die Carboniterous limeslo, Gradient. The gradient of the North Fork of Kettle river between Gloucester Oty in Franklin and Grand Forks is Xuf h!^^ one per cent or 25 feet per mile. The tributao: ir^fa FrtnUin and Gloucester, have much steeper gradients^ri^ ^ mu ^ as 150 feet per m.Ie wthin the Franklin map-area itself „,«;n .. "^^ ."^^P^" ^^^" gradients before entering the -rhiglTirgSed^h^r^^^^^^^ °" — °^ ^^ valleys GENERAL CONSIDERATIONS. A few topics of broad general interest, bearing on certain Corchleran problems, upon which the Franklin districr^^ b« able to throw some light or at least contribute its harH data for correlation purposes, will here be discussed i shets carry •od seasons o raise the ek, as for limestone n channels he surface ow, where iterrupted e brought apped by re found, the west between t half of Franklin as much ring the s true to valley's >rdinary ell as m certain ct may hare of 33 Age of Frankun Post-Mature Topography. In order to refer the Franklin upland topography to any definite erosional period in the geologic history of the region, it will be necessary to atUck the problem in a quantitative way. The relative amounts of erosion accomplished both before and after uplift will first be considered. To determine the amount of erosion accomplished before uplift, the pre-trachyte topography must necessarily be re- stored. This is a difficult task on account of the erratic nature of the conglomerate and grit structure in so many localities, for following deposition, the early Tertiary sediments had been subjected to local erogenic movement, which uplifted them and gave them a regional dip in a direction slightly north of east. The grit was found, however, to dip under the trachyte in every case— a condition which points to the following facts: (1) an erosion interval intervened between the two formations; (2) hills and valleys existed on this surface of erosion; and (3) the valleys were subsequently filled by lava flows (Figure 4). As the present lava cappings represent basal portions of former extensive flows which filled at least one depression in the old pre-trachyte land surface, it is certain that the bounding, or possibly intervening, areas and valley sides occupied higher ground at the time the flows took place. The higher ground between the lava flows was worn down into valleys, leaving the former valley flows on the present divides. The production of such broad valleys and mature slopes as we see to-day on the upland surface is necessarily the result of a long period of denudation— a period which began after the trachyte extrusions and which culminated with regional uplift. The trachyte extrusions can safely be referred to the Miocene, for the following reasons: (1) the Franklin eariy Tertiary grits and tuffs resemble closely in their lithological characters those of the Coldwater group in the Interior Plateau of British Columbia, which have been proved through palaeobotanical evidence to be of Oligocene age; (2) the crustal disturbance and erosion interval between the sedimentaries and the volcanics I 1 3i ii; ^ZT. ~"*'tf '''**• * "''"•'" ™°^^'"«"* ^"d «o«ion cycle ^ri^ fjf^'^.h ?T" ^''^^^-h-h dosed the Oligo^ne Penod. (3) trachyte lavas somewhat similar to those of Frank- JricTr^.T:'^ *2; ^'■' ^- ^- ^^"~" >" ^^e Kamloops dt tnct m the Intenor Plateau, where they have been proved d^^ ontologically. to be of Miocene age. ^^n Proved, palae- A great period of time. then, has to be added to the Miocene tiont'bl° '"t *"'. '"A°' ' ^^^ °' "°«'°" °f sufficientXra! bon to be capable of eroding valleys where formeriy there were upW '''°^"°"* '"'='' ""*"'* ^'°P^ ^ *ose of 'h^ duri„^^t;^ considered the amount of erosion accomplished uplift, the amount of erosion accomplished since the uplift will be now dealt with, since it. too. has a bearing on the a« of Ae older surface. The steep-walled entrenched valleys Sow the S^re^hen -1 ^'1^^'"°""' *« practically all completed before the Gaaal penod. as glaciation has modified but slightly the pre-Glacial valley forms. The time limit, then, in this^ Sd?!,. rTT "^^.^^ "'°^'°" ^^'^ ^"^^ tinie of uSt and the Glaaal period (Pleistocene). mntJ*"^ acconipanying figure (Figure 4) shows in a diagram- matic way the d^erent stages in the development of the^nt ^i^T" ""'^ *u' comparative amounts of erosion a^m! Plished dunng each stage. In the figure two early Tertia^ the m "' '"'•'"'"'• '^''' '^ "° ~"d-'-« evidence S o? thr.^r!i !° '"^T ^'^^ ^«^' ^'^°"Kh the charactS of the upland topography to the west of the Franklin valley hl!f t '*H.L' " T^'"* ^™™ *^« '^^"^ that much more dme has to be added to the Miocene than is subtracted from the Pleu! tocene to arrive at the date of the erosion cycle in vhich the oSr mature topography was produced. « >n v nich the post- cvde'eTn'SL'tK' ^^f' u*° '"^"" **^** "^^ ^^^"»" «"»i°n cycle extended through the most of Pliocene time and that the great uphft probably took place towards the dose of the Pliocene or beginning of the Pleistocene. 'Daw«n (G. M.): BuU. Geol. Soc. of Am.. Vol. XII. 1901. pp. 89. 90. 35 Flgure4. Diagrams showing relative amounts of erosion before and after uplift. A— Dninaie at bcflnniiig of PUoceoe time; a-a. Cntaceoui eroilon nufan: b-t, PaM-Oli(ac«w eroiion nirface; c-e. Pliocene eroaon nirface; Ti, early Tertiary river depoat; r4. Miocene trachyte flowt. B — Dtainaie prior to late Pliocene uplift. C — Drainage after Pliocene uplift aw] prior to gtociaiioo. D — Drainage after gladation. w -«!i|l "H 36 Dates of Principal Pekiods of Erosion in Frankun Mai Area. i ; Introductory Statement. The determination of correct ages for Tertiary erosion sur faces is of vital importance, owing to the bearing upon palaonto logical studies of the Tertiary faunas and floras of western Amer ica, as well as their use as a convenient datum plane to correlate the igneous history and the periods of ore deposition of the west em Cordillera. Illustrations of such applications of physio graphy to igneous intrusion and ore deposition will be seen ir Chapters IV and VII, on General Geology and Economic Geology The Franklin district, with its fairly complete Tertiary rock record, is an exceptionally favourable field for the study ol Tertiary physiography and geology. In Franklin there is evi- dence of three well-defined periods of erosion. The first was in the Cretaceous; the second during an interval between the post- Oi<(;ocene deformative period and the outflow of Miocene lavjs; and the third in Pliocene time. It was in the last-named period of denudation that the present upland topography was formed, although the preceding two have influenced to some degree its development. The field facts to support these conclusions will here be discussed, and the reader is referred to Chapter IV, on General Geology, for age determination and correlation of the various formations mentioned. Cretaceous Erosion Cycle. Eocene conglomerate was found to lie directly upon the Jurassic granodiorite batholith on McKinley mountain— a fact indicating that sufficient erosion was accomplished to re- move the entire cover from off the batholith. That the batholith consolidated under a great thickness of cover rock is shown by the character of mineralization that has been produced by it in the oyeriying Palaeozoic formations. Contact metamorphic ore deposits of oxides of iron and sulphides in lime silicate gangues 37 have been formed, which indicate deep-seated conditions with probable pneumatolytic action at time of intrusion. A great thickness of cover rock must, then, have been removed during the Cretaceous period. Post-Oligocene Erosion Cycle. As bearing on this period of erosion, the following facts are cited : (1) Miocene trachyte flows were found to lie uncon- formably upon a gentle undulating surface of erosion produced upon deformed early Tertiary deposits (Plate XVIII). The early Tertiary deposits (Eocene-Oligocene) have a prevailing dip to the northeast. Wherever the grits, however, were found in contact with the trachyte, they dipped under it. The geological map shows the flat attitude of the Miocene lavas where they lie upon the uptilted early i ortiary sediments, the latter even extend- ing below the level of the present Kettle valley-bottom; (2) the rhyolite porphyry found on McKinley mountain is of a coarse texture, indicating that it is either the basal portion of a once extensive lava flow or that it is the vent its»»lf. In either case it is apparent that a considerable thickne- Se How has been removed by erosion. From the above facts it is evident that ar - sion interval elapsed between the time of deformation of the early Tertiary sediments and the outflow of Miocene lavas. It is to be noted, however, that the erosion in no place within the district reached the base of the early Tertiary sediments and was in no way comparable to erosion following the Laramide revolution. The Miocene lavas in Franklin always lie upon early Tertiary sediments. It will be seen later that this erosion period is believed to have played an important part in the Tertiary history of this section of the Cordillera, in that it is largely responsible for the stripping-off of vast sedimentary records of the early Tertiary. Pliocene Erosion Cycle. The recognition and results of the Pliocene period of erosion have already been discussed full> in a preceding section. It l\ 38 is sufficient, then, to merely state Iiere that the present upla topography is largely the work of this last cycle of erosion whi( under the special conditions of the district, eroded the valh where formeriy there were divides. Regional Application of Frankun Details. Having thus considered the Franklin records of past erosi cycles, the conclusions arrived at from their detailed stu( will now be compared with those supported by facts from t whole of south-central British Columbia and northern Washin ton. Very little detailed physiographic work has been done this section of British Columbia since Dr. G. M. Dawsoi death in 1901. Dr. Dawson recognized an ancient penepla surface upon which remnants of Oligocene and Miocene deposi lay. He assumed it, however, to be of Eocene age,» "chief beu.jse no deposits referable to the Eocene or earliest Tertiai have been found in this part of the Cordillera." This erosi< surface has since that date been generally referred to in geolog literature as the Eocene peneplain of British Columbia, and hi been extended and correlated to only a slight extent both ini Washington* and Alaska.* Recently an erosion surface hi been recognized in northern Washington and from field evideni 1^}^° ^ discussed in following paragraphs) it has been coi eluded to be of Eocene age, correlating it with Dawson's Eocer peneplain to the north in the Interior Plateau of British Co umbia.^ Some theoretical considerations will now be introduce* in order that further bearing of these facts may be apprehende< Granting that a peneplain exists in a given geological perio< such a peneplain (1) may remain at approximately the same levi throughout the succeeding period, or (2) may be depressed d rectly a fter its formation, or (3) may be elevated. Therefore ^Dawson (G. M.): Bull. Geol. Soc. of Am., Vol. XII, 1901, p. 89. ^Umpleby Q. B.): Washington State Survey Bull. No. 1, 1910, p 11 .««. ^■'""'i' ^^- "-^ '■ Geography and Geology of Alaska. Prof . Paper.' 41 190o, p. 279. ♦Umpleby (J. B.): Jour, of Geology, Vol. XXII, 1912, pp. 139-147. 39 lent upland sion which, the valleys LILS. ast erosion iled study s from the I Washing- en done in Dawson's peneplain le deposits ,» "chiefly it Tertiary lis erosion in geologic i, and has both into jrface has i evidence been con- I's Eocene •itish Col- itroduced, irehended. al period, same level ressed di- rherefore, 89. ), p. 11. Paper, 45, 39-147. even if a peneplain existed in the Eocene, it may have been formed in a preceding geological period. The fact that Eocene lake sediments exist on a peneplain means (1) that the peneplain was formed in the preceding geological period and persisud into the Eocene, or (2) that it was completed in the very eariy part of the Eocene period. It can hardly be conceived that a peneplain, the product of such a long cycle of erosion, could be made in a small fraction of a geological period. Furthermore, the idea of Eocene peneplanation complicates matters in that the advocates of such a hypothesis, in order to account for the deep valleys in the Eocene peneplain down which Miocene lavas flowed, have to involve a great regional uplift following Eocene peneplanation which does not correlate with the physical his- tory of the Cordillera elsewhere. It is true, as has been shown, that there was a minor period of crustal disturbance and erosion before the Miocene lava flows, a period in which there was in progress a stripping-off of loose continental sediments throughout the whole country. There is no evidence, however, of a great uplift at that time, such as it is necessary to assume in order to account for the deep valleys in the Interior Plateau of British Columbia, Republic district' in Washington, and Bitterroot range' in Montana and Idaho. Such deep valley cutting as is certainly the case in the Interior Plateau, shown by lava filHngs, could be more readily and simply explained by the great regional uplift of the Laramide Revolution, which resulted in the forma- tion of the Cordillera to the east of the Interior Plateau country. This line of reasoning brings one to a conclusion possibly very little more secure than Dawson's, but certainly just as secure. I n comparing the geological events of the I nterior Plateau with those in the mountainous Cordillera to the east, as illustrated at Franklin, the hypothesis of a Cretaceous period of peneplanation is much more tenable. Furt irmore, it ex- ' Umpleby (J. B.) : Republic Mining District, Wash. Geol. Surv. Bull. No. 1, p. 11. 'Lindgren (W.): A Geological Reconnaissance across the Bitterroot Range and Clearwater Mountains in Montana and Idaho; U.S. Geol. Surv. Prof. Paper, No. 27, 1904. « 40 pUun. many field f«:t. which could not be interpreted under t hypothec of an Eocene period of peneplanation lntJi°' ^^' »t *«« noted at the contact of the Eoce Intenor PUteau and the Miocene Basalt Plateau, that^ aj^jommg along a definite line and the one at leait 2.000 f. higher than the other, with the lower surface poMeMinTco ..derable neHef.- Thu. the Columbia rivr,o^TKeTl ill M^ Po» -Cretaceous, the Interior Plateau region to t^ north bemg uplifted relatively higher than the regi^at p«ae. tT'" ZS^ ^°'r''^ ^'^ P"**^"- ThTdraiigeTe was probably «,uthwaid. as in Franklin. Such a hySthS would urther explain the finding in the Tertiary bK" Repubhc District fish «main. which have not ^et^nfoun to the north m the Interior Plateau country tnrJal^^^ '"'?" ^^"^ *••« f^^ that the Kettle Ri> formatu.n (Eocene towards the heads of the old north and »ut ul^^. '" ^u i*^'^'*' ~"**''» ««~ heterogeneous c^ g omerates with admixed tiUite as at Franklin, while farther so^ at the Intemauonal Boundary the formation includes only wel rmTJTr""''- ^^"*^*^-^o™ and well assorted X« «„o,/- »°"«»ry enclosed withm the deep, broad pros on valley S^rih T T"u **^ °^ *^^ ^^""^^^ d^tri-t- The geograS d«tnbutK,n of the older Tertiary formations contSg S J^rilL J^"* fluvial transportation indicates that the drafn! age was north and south.« The north and south alignment ol Tertiary beds at Phoenix. B. C. which may repre^nfthrslm d":rric:t"Tt ^^- 1"* '' ™"«' ^^^^ ^° ^« ^'p'^h: aistnct. At Phoenix, however, no very coarse conelomerate mem^r ex^. although it is possible thaTone may have S ^d have been removed in the post-Oligocene cycle of erosi^ No^t evidence has been stated with'regard to the dS,n Ke.W and a^'ToSrto ^l^^^ZP^ "^' '""" ' "^ "^ See Phoenix Map, No. 16A, G.S.C., 1911 Umpleby U- B.): Wash. Sute Surv. Bull! No. 1, 1910. p. 19. PL ^Jae 41 of tramport of early Tertiary •tream gravels for this region. It is impoasible, th««fore, to make conclusive inferences as to the direction of flow for the Tertiary drainage. However, as no observations of a Cretaceous erosion surface south of the I nterior Plateau have been recorded,' the present site of the Colum- bia lava plains was probably in early Tertiary time a region of subsidence, with delta deposition from the rivers flowing from the north, where the regional uplift was greatest. Slow subsi- dence with aggradation following such a period of maximum up- lift would soon fill up all the irregularities of surface caused by the incision of the Cretaceous drainage. The lakes and rivers of the lower drainage areas and delta country of the Oligocene would naturally support fish life, fosuls of which have been found and described.* The main reasons for doubting the validity of an Eocene period of peneplanation are as follows: — (1) The valleys in the old erosion surface filled with Miocene lavas and lake beds which lie unconformably' upon pre-Oligocene formations (dacite conglomerate in case of the Republic district) are too deep to be accounted for by any known Tertiary uplift between the Laramide revolution and the Pliocene uplift. (2) The fact that there is in the Republic district in Wash- ington evidence similar to that in Franklin, of an erosion cycle between early Tertiary and lower Miocene, which there, too, has not cut down to the bottom of the old erosion valley, would indicate a period of time between the lower Miocene and deforma- tion of dacite conglomerate sufficient to remove great records of early Tertiary sediments and lava flows. It is thought that this erosion interval was not responsible for the deep, broad 'Smith (G. O.) and Calldn* (F. C): U.S. Geol. Surv. Bull. 235, p. 90. Smith and Calkins, in discussing the differentiation of the Cascade mountains, state: "An example of this is found in the occurrence of an Eocene pene- plain in the Interior Plateau region, while in the Cascades peneplanation of Eocene a{^ has not been recognized, and indeed in central Washington the Miocene !avas are known to rest upon a surface possessing considerable rdief." 'Wd^. Geol. Surv., Bull. No. 1, 1910, p. 24. *Umpleby (J. B.): Republic Mining Dist. Wash., Wash. Sute Surv. BuU. No. 1, 1910, p. 24 top. 42 between the early Tertiary «,d the Miocene bed., lie^ ?C?' ill *?'• *'y *^* unconformity between the e Tert»ryl^.„d the bwalroclc. would be ^puS h«rf V K. U •'^°" '"rfa" "uch as the one in quettion a hardly be developed from a. yo. »hful a topoentohv a.^ of Si ^ °""* *fi— -ide revolution in tKort f^ ?or^ati^" Pfriod (before p«-01igocene deporition Z formation), aa ducusaed in detail on oaee 33 Th, i « rtlTefrr'T^^-^^.^"^ eroIiorc^eJeandl'^;-^ tL iJf? r. *T P"^""^ ^ *" incredibly short tii The Miocene lake beds' lie in the Republic district unc formably upon the d-nte (rhyolite in Franklin) ^Le"' ^tn the'Sr-Sl-"'' " ™"°^ *™'°" cycle interJenTng aZun jTh '"• ^J '*^'"' "*«^^' ''°**v«'' i" order account for the unconformity between the dadte conjrlomer and the underlying Paleozoic formations, to ^fTST^^ the dame conglomerate was deposited, and not to the OHgoS resenl ! cT ™^^*^ *^** '^' "PP*^ '"''-ce of erosioT^ resente a Cretaceous rather than an Eocene peneplain, and ^ ml ".vf *J: " 1"" *° invigorated erosion folding the L« «e rcSieflv P '* *^' u^** conglomerate is of earfy TerT^ age (chiefly Eocene); that the unconformity represents a n ^osioncyde following costal disturbance. w'hS^^^^ tor the 8tnppmgK>ff of considerable early TerUarv nT -ri pnor to the deposition of the Miocene lake Lis ^ '" in the R* ^ J/~?^? *°"'^ "°* 0"'y account for the deep valle m the Republic district, but also others so common through" !^ '^''^ '^'■'y Tertiary sediments contain practically n dt. i^p^i* 2S' ^'™" *^ '^'"^ *'"'*'" '*^' '° '•«' ""'y Miocene. (O, I I mconfortnity . The deep, ht Laramide m the early I. estion could phy as that lort fraction ion end de- e Laramide inaugurated srred to the short time, trict uncon- nglomerate. rvening be- ilar to that in order to nglomerate the origin )lift, before ' Oligocene. rosion rep- . and that : the Lara- y Tert' . y ts a n f espo, jle ' m> mal leep valley liroughout oenix and tically no ocene. (Op. 43 vein quartz, indicating lack of thorough decompodtion of an ancient soil naturally associated with a peneplain. If there had been an extensive period of penepianation, in the Eocene, such evidence would be expected of it similar to that found in the Pliocene sediments, which in many placet contain auriferous quartz drift (Klondike beds), and the Creta- ceous sandstones. (5) The early Tertiary sediments in Frr.nklin are character- ized by extensive alluvial cone deposition and tillite (for further details see page 63), which point towards rugged alpine condi- tions in the surrounding sedimentary mountains, such as would naturally be exnected following the Laramide revolution. There is no evidence there of any Eocene period of erosion such as would produce an erosion surface comparable to the one rec- ognized by Dawson and Umpleby. Future work in other areas may yield critical evidence on this problem of Cretaceous penepianation in the western Cor- dillera; it would appear to consist chiefly of the following re- lations: (1) Finding that the Upper Cretaceous sediments are entirely different in lithological character (colour, texture, etc.) from those of the Eocene-Oligocene formations; the former being such as to indicate peneplain conditions before uplift, the latter sediments characteristic of regions undergoing rapid erosion in a generally cooler, more humid climate, with coarse basal mem- bers of conglomerates, arkosic grits, and tuffs, grading into finer sediments towards the top of the section. (2) The finding in other portions of British Columbia and northern Washington of F.ocene sediments within the entrenched valleys, capped by Miocene lava flows or lake beds, as is the case in the Franklin and Republic districts. (3) By determination of the relative areal extent of the upland surface with its shallow water sedi- ments, to that of the deep valleys filled with Miocene lavas. In so doing, one would be able to draw inferences as to the de- gree of penepianation in the Cretaceous cycle of erosion and compare it with that of the Pliocene. From the data so far available, the Cretaceous surface of erosion appears to have reached a higher degree of peneplain development, with a much coarser topography than that of the Pliocene. As the old Creta- 44 ceoui Peneplai., is irequei.tly capped by extensive Uv. through the Int.-,. . IMateau country, one would be gukJ obtainins «,ch inf, nation by the occurrence of tongu extensions of -. » -valley, where the CreUceou. u jnter-flues -^av. ..„ s. «pt bare of a part or M of their f, lava cover. The Age ti uh, P .*lfD I'OPOGKAPRV OF THE IntkR M OF Bmish Columbia. .um.SL« ^'J "'"'" " ' -'^yo^thepre^^it mou, ■umm^ a. an hhent.,;, , fr. ,he ancient Eocene erosion ^Z^T ' '''L '"' ' '^ P^"" °^ this an, «OMon surface .« b» u - ^oned among some geolo, ..peaaUy by D ly.. 1 !.... u.ce was ««* L erosioS^u^ the evidence advanced in the f.wegoing di«n,s«ion undoubt •ubstannates. However, there is ground for the conclusion «/™nS^ J". '^l ""bequality of the present moun ;Zh!? "'^ " *° *•* Cretaceous e««on «,rface is an < d^Tr JiLu^^l "* "'°*""' '" ^ Boundary C, diatrict of Bntish Columbia, of a gently undulating upland toi raphy bevelhng Miocene Uvas. would indicate that the tnct to die west and southwest of Franklin had been 9ubi« to some degree of erosion in the Pliocene. The Pliocene era cycle may not have reached the stage of development the Cn oous one did before uplift, and. therefore, did not show as ^ .IT' J!^- *^° P^^^'^K e'-«»ion cydes-the Cretace ^J. P«'t-01.Kocene-would to some extent influence perfection of the last one (Pliocene). In conclusion, it is of interest to note that whatever c ditions may have prevailed throughout other sections of - 'Daly (R. A.): Geol. Surv. Canada. Ann. Kept.. 1904. Profe^or D «w no evidence of a period of peneplanation in the Interior PIatea^^.t; Mountam, have not the broad, flat top. expected, but are generaUy^?^^ SLTuJTt;^'*? °7' '"'" *". '*'°''»' *° * "»«« worn dot^ in ,^e c^U d«udat.on. Accordance m altitude of «,mmit. b far from perfect, a^ . «xj^nce a. doe. ex«t can be explained by other conditiS^'^1' ■M 45 ^e lava flows be guided in of tongue-like ceoua upland f their former E Intkrioi ent mountain i erosion tur- this ancient le geologists, «ion surface, undoubtedly ndusion that ! Cretaceous, nt mountain ce is an open ndary Creek pland topog- iat the dis- ■n subjected cene erosion t the Creta- show as flat Cretaceous fluence the British Columbia Cordillera during late Mcsozoic ami early and late Tertiary times, in the Franklin district, at least, there are three well-defined periods of erosion, the first in Cretaceous, the second (a minor one) in post-Oligocene, and the thinl in Pliocene time; and it was in the last-named period of denudation that the present upland topography was formed. Here in Franklin, then, situated well within the British Columbia Cordillera, the same conditions of long denudaticm prevailed in the lliocene as have already been identified south of the International Boundary, where similar upland surfaces were in cour : of development. Recent studies ' have shown that there exist upland surfaces in many widely separated districts in the Cordillera south of British Columbia which are likewise the result of a long cycle of erosion in late Tertiary time, and which imply widespread degradation and the dcvdopnient of the topography to a state of late maturity and local penepianation. 'Atwood (W. W.): :mu. G«oI.. Vol, XIX, pp. 449-453, IMl. Smith (G. O.): U.S. G«oI. Surv.. Geol. Atlas U.S., Folio 106, 1904. Crow fW.): Ibid., Mon. XXVII, p. 202, 1896. Spenier (A. C): Ibid., Prof. Paper No. 26, p. 12, 1904. BaU (S. H.), Spurr (J- E.), and Carrey (G. H.): Ibid., No. 63, p. 52, 1908. Rich 0- L.): Jour. Geo!., Vol. XVIII, pp. 601-632. 1910. For aa analytical lumniary, tee Bowman (I): Pfayiiagraphy ol ths Unitsd Sutss, in Forest Physiairaphy, pp. 342-368, 1911. atever con- ons of the 'rofcMor Daly lu, and sutes: ally of conical I one cycle of ect, and such of mountain 46 CHAPTER IV. GENERAL AND STRUCTURAL GEOLOGY. GENERAL STATEMENT. currenatf tt''*'' '" ''~""* ^•" ^ ^^«" ^^ ^^e mode of ranor igroous intrmions and lava «„„, «™PM « tim« S VIST'S 3S xf^.^' "t S;' "'^'^ °" *"- has almost completely striooed th. K 1 ,f°"*'""«l ^''ostoi 47 "roof-pendants."' The roof-pendants occur chiefly in the tec- tonic depression between the two mountain ranges, and it is with the largest one of these remnants of a former roof that this report has to deal. Fortune has indeed favoured the preserva- tion of this particular one, in that upon it lava cappings have protected in some perfection a record of early Tertiary sedi- mentation and igneous activity. Records of former continenul and valley glaciation are present within the district and are fully discussed in Chapter III, on Physiography. Table of Formations. i i Quaternary Tertiary .Recent Soil, subsoil. Pleistocene Fluvio-glacial material, (gravel, sand, silt); morainic material. . Miocene Midway Volcanic group. Minette and augite microdiorite dykes. Pulaskite porphyry dykes and plugs. Al- kalic basalt and tra- chyte flows; ejecta- menta. Trachyte flow. Shonkinite - pyroxenite and augite syenite volcanic core. Porphyritic syenite chonoliths. Oligocene Monzonite and micro- monzonite stock. Oligocene or Eocene. . . Kettle River formation ; — conglomerate, ar- kosic grit, acidic tuff, and rhyolite flows. ■Daly, (R. A.) : The Mechanics of Igneoui IntniMon. Amer. Jour. Sci. (4), Vol. XV, pp. 269-298. I 48 Mesozoic . Palaeozoic ■ Jurassic Carboniferous a. Nelson granodi varies from gi to diorite; gneiss ■ Gloucester cryst limestwest mem- which con- 'UtcrofM in ! map-area. ted on all }f the dis- ad, dome- re capped Original Structures. The original structure of the rocks comprising the group has been greatly obscured, owing to: (1) their massive character; (2) their large content of eruptive material, and (3) the fact that they have been chloritized and silicified in the zone of cementa- tion to such a degree that their bedding is seldom discernible or cannot be distinguished from the planes of jointing and shear- ing. For these reasons the structural data of the complex are meagre and unsatisfactory, as is also any attempt to estimate the probable thickness of its sedimentary members. The ar- gillites and quartzites, which occasionally display traces of origi- nal structure, have a general strike from a few degrees east of north to 45 degrees west of north, and dip from 35 degrees to 60 degrees to the west and southwest. Secondary Structures. Jointing is the most prominent secondary structure pres- ent, and although well devdoped in the rocks the directions are not constant over considerable areas, a fact due probably in part to the complexity of the stress to which they have been subjected and in part to the heterogeneous character of the rx)ck compl-'x. The master joint planes in many places corre- spond in a broau way to the regional strike of the bedding planes, where the latter are observable and may represent them. Brecd- ated and sheared zones were noted in places throughout the tx)cks of this group, but in no place was schistosity found to be developed, nor has the compression which these rocks have undergone developed any well marked slaty cleavage. Conditions of Deposition. From the obscure nature of the structure in the rocks of this group, inferences as to mode of deposition and subsequent deformation must necessarily be of a speculative nature. It is known, however, that the lowest member of the group is a silicified argillite containing obscure plant remains, while other members are of an eruptive origin. Some of the latter were no doubt laid down as tuffs and lava flows or intruded as por- 50 s.8ted of argillaceous and siliceous m^' whIchTn " m 81 ica. Igneous activity supplied tuflfs lavas A»)rJ regular masses of eruptive material. ' ^''*'' ^' Corre/o/ton. tersJlL' Sitt tr"'.""""'^ " ^•^^•^ "*^°'°^*-' <=•' It J^S? '^'? "°'^" '«'■»'<>» "«96. p'Tb."" '^""°°'* ^"P """^^ 'a«- Kept. G.S.C.. VII. P.. # ,W- 51 lie sedimentary ments, indicat- depth greater I 80 far as can near an upper irished. The leposition con- > during long ■ or less rich dykes, and ir- ogical charac- oenix (Knob- liwest, in the V have been the Franklin ^eloped as in re very little « in the more group rocks Jar series as outh of the "ally united at they may irboniferous. rocks, how- mp. Owing between the which, very tentatively Gloucester Formation. Distribution. This crystalline limestone or marble formation (for detailed description of rocks, refer to page 97, Chapter V) occurs as irregular, detached masses and elongated ovals or lenses in three distinct and separate belts, which trend in a general north and south direction with steep dips to the west. The most easterly belt is exposed on the west slope of and near the b£ise of the Gran- ite range on the Dane property, opposite Gloucester city; and the most westerly one is on the IXL property on McKinley mountain. The most extensive and thickest belt, however, is the central one, which extends from Twin creek southward, along the west slope of Franklin mountain and across Franklin creek, up to the McKinley mine. Where this belt occurs on the west slope of Franklin mountain, it is locally known as the "Lime Dyke." It forms a very prominent, bare, white, rock shoulder. Here the marble attains a width of about 300 feet, which is a maximum for the district. On the eastern borders of the lenticular shaped masses exist, generally, zones of cal- careous ronglomera::e, made up of well rounded quartz pebbles with occasional stray fragments of other rocks. Such zones in places, as in the case of the Banner occurrence, have been subjected to brecciation and shattering, with subsequent in- filtration and cementation by calcareous and siliceous solutions. From an economic standpoint, this Gloucester formation is important in that the ores of contact metamorphic origin with lime silicate gangues are closely associated with it, and are found either at its borders, as in the McKinley mine, or in mineralized zones within it (page 167). The mineralizefi lime silicate zones often show pore spaces and cavities, due to shrink- age, consequent upon metasomatism and expulsion uf C0| (see Plate XXIII). lix. Boundary VII, Pt. B, Method of Deposition and Correlation. The Gloucester crystalline limestone resembles, very closely, the Brooklyn formation of Phoenix and Deadwood in the Bound- S2 ary district, and occur* in similar, generally lenticular shaped masses within the altered tuffs and breccias. No fossils have ever been found in these formations. It is possibly of the same age as the crystalline limestone occurring farther south, which Daly includes in his Atwood ieries of Carboniferous age, correlating it with the limestone in the Rossland mountains. About 100 miles northwest of the Franklin district, be- tween Kamloops and Little Shuswap lake, there is a grey, coarsely crystjdline limestone of the Cliche Creek series (Car- boniferous), which Dr. G. M. Dawson^ mentions as containing obscure fossils. He examined it under the microscope and found it "to be a coarsely granular aggregate of fragments of calcareous organisms about half of which are crinoidal, and have a pale- brown colour, which distinguished them from the rest of the mass. This minute structure is well preserved. The remain- ing moiety of the rock is principally composed of fragments of small corals. Fusilina are also abundant, well preserved and characteristic and differ from the crinoids and corals in the milky opacity of their shells. Several brachiopods in poor preservation were also found, among which is a rhynchoneUa and a shell which may be Hemipronites crinistria." A large foraminifer columbiana was found in the Marble Canyon lime- stone* — the upper member of the C4che Creek series farther to the west in the same district. In 1901 Dr. Dawson* stated that "rocks of the Carboniferous period are probably present in several parts of the system of Gold Ranges [FrankUn is well within them] but practically no paUeontological evidence of their existence has yet been obtained." Some of the spotted crystalline limestones collected from opposite the mouth of McKinley creek, in the Franklin district, were examined under the microscope, and found to contain crinoidal columnals showing internal canals as well as an organism that resembles, in its outlines but not internal structure, a fusulina. The latter was too obscure for definite determination. 'Dawson (Dr. G. M.): Report of Progress G.S.C., 1877-78, P. 808. •Dawion (Dr. G. M.): Quart. Jour. Gcol. Soc., 1879, p. 6D. *Ibid. : Bull. Geol. Soc. of Am., XII, 1901, p. 70. Jii: S3 It wenu highly protwUe, then, that the Gioucetter cryital- Une limestone, as well as other similariy related crystalline limestones from districts to the south and west throughout the Boundary country and in Republic district in Washington,* were originally deposited in the same Carboniferous sea as the limestones of the Ciche Creek aeries. The limestones through- out this section of the British Columbia Cordillera may correlate with the Madison limestone to the south in Montana. The conglomerate at the base of the Gloucester formation, composed of well water-worn quartz and quartzite pebbles, is, presumably, following the evidence of the limestone lenses, of marine origin, and probably represento the early period of its deposition. RELxnoNs OF Fkanklin Gkoup to Gloucester FOBMATION. The question of relationship between the Gloucester for- mation and the Franklin group is a difficult one, on account of the meagre structural data obtainable, due to later meta- morphism from below, and erosion from above. The occurrences of the Gbucester marble are chiefly con- fined to a single north and south belt near the middle of the district, and only a few sniall and scattered lenses are found else- where within the Franklin group. These remnanto are small and insignificant compared to the Franklin group, and whether they are intercalated lenses or remnants of a different formation is difficult to ascertain in Franklin. As bearing on the problem, however, the following facts may be sUted, which indicate that a positive conclusion cannot be derived from this district. (1) The narrow lenticular masses of marble lie within the altered tuffs and eruptives of the Franklin group. (2) The walls of the lenses are essentially parallel, and the lenses have a vertical elongation comparable to their horizon- tal elongation, since the deep valleys cut by erosion have not revealed fewer exposures than the upland. (3) The exposures are inde pendent of topography. (4) The lenses tend to exist 'Umpleby {J. B.): Geol. and Or« DepoMta of Republic Mining Dist., Wa»h. G«ol. Surv. Bull. No. 1, 1910, p. 17. its ? ■ i i i: ^ ■ ■ i K-JI 11' '1 S4 in line, and the imaUer onet have a greater thickneM in com- panion to their length. (5) There is a synclinal structure to the lens on McKinley mountain. (6) The contacts between th« Franklin group and the Gloucester formation are always sharp and well defined. (7) The intrusive rocks associated with and cutting the Franklin group were not observed to cut the Glou- cester formation (At the McKinley mine tongues from the Jurassic granodiorite batholith do cut the marble). (8) While the strike of the bedding planes in the marble corresponds in some places to that of the elongation of the lenses, in other places it corresponds to the regional strike of the Franklin Group sedi- mentaries. (9) Boulders and pebbles of the Gloucester formation and associated conglomerate, as well as of the Franklin group rocks, are found commonly within the Eocene conglomerate. In favour of a hypotheris of intercalated marbles is the oc- currence of a single dominant belt of discontinuous lenses just as abundant in the valley bottoms as on the hill tops. In favour of the hypothesis that they are remnants of a different formation is the fact that the Gloucester formation has not been seen to be cut by the intrusives which are found in the Franklin group and are related to the latter. Further- more, palseontological evidence points towards a correlation between the Gloucester formation and the upper member of the C&che Creek group.' This upper member or Marble Canyon limestone lies conformably upon the argillites and cherty quartz- ites of the lower Cftche Creek group. If the Gloucester marb\ be regarded, then, as the erosion remnants of a once extensive formation, this implies that mash- ing has proceeded to an extent sufficient to pinch a synclinal axis into elongated lenses and to compress the folds to such a vertical height that the limbs are now practically parallel. The dominant lenticular shape and less prominent offset character of the outcrops may be due to pinching out and shear- ing off of formerly more extensive and continuous beds, as a result of the complex dynamic metamorphism to which the PaUeo/oic formations of this district have been subjected. That ■Dawson (Dr. G. M.) : Geol. Surv. Canada, Report on Kamloopa Map Sheet Kept., 1896, p. 468. 55 intenw distortion and shearing action has taken place is shown by the presence of generally brecciated and mashed conglomerates and tuffs about the borders of the limestone lenses. It is further indicated by mineralogic distortion in the marble itself, where there has been slipping along twin planes in the larger calcite individuals of the rock, with production of an imbricated structure. JURASSIC. Gkanodiorite Batholith. General Characters. The rocks grouped under this heading embrace granular intrusives varying in composition from syenite and granite to dionte, and including some homblendite. For detailed de- scnption refer to Chapter V, page 100. They are ail more or less altered by d>n mic metamorphism, and many of them are mashed to gneisses. There is a gradual transition from the av- erage type, which is a grey granodiorite, to other less common varieties. This is true with one exception, and that is in the case of a homblendite which occurs sparingly in two localities, one on the west side of Franklin creek as a border basification ad- joining a mam contact, and the other as "schlieren" in the grano- dionte west of the Beaver meadows. In the former case the hornblendite appe irs to have segregated and consolidated at the bathohthic border. Then it apparently was shattered and in- jected by acidic magma (Plate X). In the southeast corner of the district angular inclusions of older rocks occur within the batholith. Distribution. The rocks of this group, as shown on the accompanying map, are well distributed throughout the area, but have by tar their best development at the borders of the quadrangle. Were they show by their contact relations with the older forma- Ill tiona that they are all part* of a tingle broadly dome-shaped batholith underlying the whole district. Erosion is rapidly stripping the bathoiithic cover rocks and laying bare more of the intruded granodiorite. In some places, notably on McKinley mountain, apophyses appear to have been given off from the batholith into the over- lying rocks, producing intense metamorphism. Aplite dykes are quite common cutting the granodiorite in the contact zones. The rocks composing this batholith are readily distinguished from the younger monzonites and syenites belonging to an alkalic group of Tertiary age which occur within the district. The latter are comparatively fresh, and do not show the broad metamorphic effecu from having been subjected to great mounuin making movements, as do the rocks of the batholith. Furthermore, the bathoiithic rocks are prevailingly light grey in colour and contrast sharply with the darker coloured Tertiary intrusives. The granodiorite rocks have been profoundly affected by younger invading intrusives, as shown by pneumatolytic action along fracture planes in the granodiorite, which has been the means of producing veins of green secondary epidote. The Tertiary intrusives, on the other hand, are rarely epidotized. The epido- tized surfaces in the granodiorite preserve the freshest glacial strix. Structural Relations. Intebnal. The rocks composing the batholith have com- monly yielded to differential pressures during mountain building periods by mashing and flowage producing gneissic structures. This is well illustrated in the northwest and southeast comers of the quadrangle, where the foliation strikes N. 30' W. This is the average trend for the folded and tilted rocks in the district. Where the granodiorite is embayed or surrounded by the more resistant greenstones and cherty quartzites of the Palaeozoic series it has yielded to dynamic stresses, chiefly by brecciation and shearing without the production of gneissic structure. It may be inferred from these facts that the batholith at the time of the main orogenic movement was in the zone of 51 combined flowage and fncture. Tho« portiom of the maw weU within the bathdith appear to have yielded most readily to the ra^onal stieMea by rock flowage producing gneiaa. while thoae portioaa, iiobted from the main maaa and well within the re«atant PalcoMic cover which waa in the zone of fracture appear to have yielded by brecdation and shearing. All part* now opoaed were eaaentially at the same depth, ao that the above cffecta are to be ascribed to differences in the character of the rock masses surrounding the granodiorite. The shear- mg of the granodiorite has been an important factor in iu min- eraliMtion (page 172 Chapter VII, Economic Geology). Figure 5. Jmnting in Jurainc granodiorite. Secondary structure within the bathdith is present in the form of joint planes in two or three directions, the main set striking in a northwest and southeast direction with steep dips pnerally to the northeast or southwest. Older sets of jointing have been subsequently completely recemented, the cementation bemgaccomplished by pneumatdytic action attending possibly the Tertiary igneous intrusions. The pneumatdytic action loilowed certain joint pUne systems in the granodiorite, produc- mg veins of pale green epidote 3 inches wide in some places. Ihis feature is best seen in the granodiorite cover rocks on the concave side of the syenite chonolith (Figure 5). 58 ExRBMAL. RtkUion tt OUtr PormaHons. ApophyMt from the twtholith Iwve been intruded into tiie Palooeoic cover mckt, and both have Mibeequently undergone refional movement, resulting in local faulting of dykea, and metamorphiam. The rocks of the Franklin group, however, had already received their main folding before the invaeion of the batholith and intrusion of apophyses. This is shown by the regular char- acter of the cootacta which dominantly plunge away from the main mass of granodiorite, towards the tMtt cover rocks. The granodiorite contacts cut the older PaUeosoic rocks irrespective of their structure, and display sharp well-defined boundaries, with nothing to indicate that they have been subjected to the mountain making movements that have folded and metamor- phosed the oMer rocks. The intrusion of tongues from the batholith and intense contact metamorphiam of cover rocks probably took place at great depths, under considerable pressure or hydrostatic head afforded by the weight of a great thickness of superincumbent material. The most intense contact metamorphism has taken place in the Gloucester marble formation, where by the expulsion of COi and the substitution of SiOi, the carbonates have altered to silicates, with formation of such minerals as garnet, epidote, tremolite, diopside, etc. This deep-seated contact metamor- phism with wide aureole is in strong contrast to the contact metamorphism produced by granular rocks intruded close to the surface, which show intense action at the immediate contact, but do not affect rocks beyond a zone a few yards in width (page 80, syenite-shonkinite formation). On the ridge west of Franklin creek occur small outliers of the Franklin group lying upon the batholith. They consist of altered eruptives whose contacts with the granodiorite are not always sharp and well defined, but when they are the con- tact surface appears as in Figure 14D. Relation to Younger Formations. On McKinley mountain the early Tertiary rhyolite porphyries and conglomerate-grit formation are both found capping the granodiorite batholith. Such a relation shows that the ancient roof of the batholith 59 must hav« been Mibjected to a period of pre-Tertiary denudation long ernrtigh to completely remove it and expow the underlying rocks. The .tmtact ol the overlying Tertiary formation with the bathniith i« chariicteriwd by the prewnce of many pulaskite porphyry dykes. The pulaskite porphyry dykes are younger than both formations, and are found ebewhere in the district to cut all the formations with the exception ol the lamprophyre dykes. They form in places irregular pinkish patches or veneer upon the intper surfaces of the batholith. The rxKitact of the granndiorite with the Tertiary mon- lonite lies beneath a drift-covered depression running north from the Royal Tinto property, but south of the Royal Tinto it could be obserx-ed, and the monzonite then appeartYi as a stock intrusive into the okler granodiorite. On the Mountain Lion daim, which adjoins the Gloucester on the west, a splendid exposure was studimi of the contact between the Tertiary alkalic syenite and the Jurassic gninodio- rite. Contact metasomatiMn. with transfer of (ddsfiar an J de- velopment of secondary hornblende, extendcl for u least 10 feet from the actual conuct, and was most inten«- n.xt th syenite. Below Little's property, on the east side of the east branch of North Fork of Kettle River valley, the granodiorite is cut by a lamprophyre dyke (augite microdiorite) as well as by many syenite porphyries. On the Crystal Copper claim, a narrow short tongue from the und«-lying alkalic syenite intrusion has penetrated the granodiorite cover rock. Mode of Origin. The relations of the granodiorite body are such as to lead to the conclusion that it is a batholith which has reached the upper crust chiefly by means of the process of magmatic stoping, in which fragments of the roof have been broken away and the magma has passively risen to fill the places made vacant. The significant features bearing on the above mode of origin of this batholith are itemized below. fiO (1) Wide areal distribution. The granodiorite mass has not only an extensive development within the district itself, but extends for miles in the surrounding country. (2) The plunging character of its contacts with the older formations. Wherever exposed on steep valley slopes, the con- tacts of the granodiorite with the older formations always plunge away from the main grijiitic mass and towards the older invaded formations, indicating the downward enlargement of the igneous body. (3) The entire lack of sympathy between structural planes in the invaded formation and the form of the intrusive body as exhibited in both Franklin and Kettle valleys. (4) The presence of isolated roof remnants of the Palaeo- zoic rocks within the granodiorite west of Franklin creek. (5) The general high degree of homogeneity in composi- tion and texture of the rocks composing the intrusions. (6) The occurrence on McKinley mountain of long and narrow apophyses from the mass, indicating, as Daly' points out, high liquidity at time of intrusion. (7) The abundance of angular inclusions near the con- tacts, and freedom from them in the interior. The fact that the batholith was liquid enough and had sufHcient hydrostatic head to inject apophyses into the overlying cover rocks, as it did at McKinley mine, with production of intense contact meta- morphiam, would seem to indicate that the intrusion took place against a heavy load of superincumbent strata, and that con- nexion with the surface was not readily established. No lavas have yet been found referable to the Nelson granodiorite. The cover, however, was above the zone of deep-seated metamor- phism or rock flowage, as indicated by the structure of the rocks and the entire lack of injection phenomena near the main con- tacts. The objections to a laccolithic origin for this batholith are: (1) the contact surfaces of the batholith cut across the bed- ding planes of the invaded formation, and do not conform to them as in the case of the simple laccolithic intrusion; (2) there is no 'Daly (R. A.): The Mechanics of Igneous Intrusion. Amer. Jour, of Sd. (4), Vol. XV. pp. 269-298, Vol. XVI, pp. 107-126 (1903). 61 evidence of a bottom surface to the granodiorite mass, nor of splitting of invaded formation, as would be expected if it had been intruded with production of parting of cover from the bot- tom and a lifting of the cover. The marginal assimilation hypothesis is further debarred because the contacts are in all cases sharp and distinct and cut at all angles across both sedimentary and eruptive forma- tions, which would not be the case if assimilation at margins had taken place. If the granitic intrusion were due to mere active intrusion on the part of the batholith, it would be expected to conform to the structure of the overlying formations, which it does not. Age and Correlation. The relative age of the batholith is known, in that it is younger than the mountain making movements which closely folded the Franklin and Gloucester formations, and which prob- ably took place at the close of the Palasozoic period. On the other hand, it is older than the early Tertiary conglomerate. This limits the age of this formation to the Mesozoic. It ia known from its contact relations with the younger conglomerate and grit formations— which, as has been noted, lie directly upon the granodiorite on McKinley mountain and elsewhere — that a long period of erosion took place after its intrusion and before the beginning of Tertiary time. Although tlie former thickness of the batholithic cover is not definitely known, the broad ex- posure of the granodiorite by erosion during this interval sug- gests that its invasion is to be correlated with the Jurassic in- trusions rather than later. On the West Kootenay map sheet* the Franklin granodio- rite is mapped as part of the Nelson granite, which is there re- ferred to the post-Jurassic. The same batholith extends southward to between Christina lake and Grank Forks, where it is more gneissic in structure; and it has been described by R. A. Daly,« who states that it is structurally and genetically a "Geol. Surv. Canada, Map Sheet No. 792. •Daly (R. A.): Kept, of Chief Aitronomer, Dept. of Interior, 1906. I 62 parallel to the Remnell and Osoyoos granodiorite batholith* of the Okanagan country,' which he refers to the Jurassic. It seems safe, then, to refer the Franklin granodiorite batholith to the Jurassic, which correlates it with many other similar batholithic bodies throughout the Cordillera. EOCENE^LIGOCENE. Kettle River Formation. General Statement. The Kettle River formation of Franklin has preserved, through the character of its sediments and contemporaneous lavas, so widely distributed throughout the district, a rather complete record of early Tertiary conditions in this section of the Columbia mountains. Distribution. Protective lava cappings are largely the cause of the splendid preservation of the remnants of a once more extensive forma- tion, which, as will be shown later, is of continental origin. It extends in a broad belt running northeast and southwest from Tenderloin mountain to McKinley mountain, and reaches from the mountain summits down to the valley bottom, where it fills old valley bottoms even deeper than those of the pres- ent day. The formation has been stripped for at least 2 miles to the west, leaving bare the Miocene syenite and shonkinite- pyroxenite, whose cover rock it was at the time of alkalic intrusions. Thickness. The Kettle River formation is much thinner in some parts of the district than in others. The maximum development ap- pears to be in the vicinity of the junction of Franklin creek ' Daly (R. A.) : The Okanagan Batholith of the Cascade Mountain System: Bull. Geol. Soc. of Am., Vol. XVII, July 1906, pp. 329-376. 63 inth the East Branch, where the creek has exposed to view about 100 feet of conglomerate. This represents only the basal porfaon, however, of a once more extensive and thick formation On Frankhn mountain the lava caps about 500 feet of grit and conglomerate. The differences in thicknes«!s are due in part to irregularity of original deposition, but chiefly to subsequent erosional effects and the positions of old Tertiary drainage courses* Structure. The formation has been affected by more pronounced fold- ing and tilting than that affecting the volcanic rocks capping them. The causal stresses appear to have been in some cases local, for in one exposure the strata are found horizontal while in others they are steeply inclined. The prevailing dip of the formation, however, averages about 45 degrees to the northeast The original dips probably varied from 30 degrees m the coarsest matenal to inappreciable dips for finer sediments. The sedi- ments have apparently undergone considerable tilting and d-for mation followed by a period of erosion before the trachytir- lavis were poured out. This is indicated by a well pronounced uncon- formity between the two formations. Faulted pebbles from the Kettle River formation, composed of Franklin group green- stones, are seen m the accompanying photograph (Plate XI A) Many pebbles over a large area in the conglomerate are thus broken showing that the effect of the force was distributed throughout the mass of the rock.' Local faults of small throw both normal and reverse, are present (Figure 6) in the grits and «■ . of the Ketde River formation, especially in the vicinity of the younger alkalic intrusions. ConditioK of Deposition. In order to arrive at a conclusion as to the origin and mode „II ^'''°° ^"^ ^''y '^^^'^^'^ sediments, the field facts will be first considered briefly. I893' n"m^V^^?^"*' ^"^ "' '***'' Specimen.: U.S. Geol. Surv. S;,^iL) ^^^*^ '""■'•^ •*'''"•" '"^ Skkiyou mounuin in northern 64 The arkosic grits and finer conglomerates of the formation are of white and grey colours, and are composed in large part of limpid quartz and fresh feldspar that shows very little attri- tion or signs of sifting water action. They are essentially rhyo- litic grits in many places and occur intercalated with rhyolite Figure 6. Normal fault with small throw, bdow post-CHigocene erosion surface on Tenderloin mountain and to west of main fault (Vertical section). flows (Plate XI B). Cross-bedding, current markings, and rarely, ripple marks are to be seen in many exposures. The finer grained arenaceous and tufaceous portions contain obscure plant remains in one locality. The coarser phase contains well water-worn fragments of the more resistant older rocks, and passes in places into a very coarse heterogeneous conglomerate, made up of well-rounded to subangular boulders up to 2 feet and more in diameter, embedded in a firm compact cement. 65 The exposure shows traces of rude stratification in places It contains imperfectly decomposed and incompletely leached sediments, such as light to dark impure limestones, argillites and conglomerates. The boulders are chiefly of sedimentary^ and metamorphic rocks, with a very small proportion of grey granite. No Valhalla granite nor alkalic rocks, so common now in the distnct, were found in it. Very few pebbles of vein quartz are present, mdicating no thorough decomposition of an ancient soil, but some well-rounded boulders, with thick weathered rims and oxidized surface skins, may represent boulders from older conglomerate formations. A subangular boulder 2 feet in diameter, within the conglomerate near the bridge over Franklin creek, showed striations and scourings that very closely resemble glaaal work. Pebbles and boulders, some of which are soled from other parts of the same formation, also show similar effects The photograph (Plate XI A) shows the facetted and striated character of some of these subangular pebbles. In comparing some of the larger glacial-like pebbles from the Kettle River formation in Franklin with local tillite in the vicinity of New Haven, Connecticut, a great similarity was noted The pebbles from the local tillite. however, did not have as great a proportion of well developed concave surfaces as did those from the Kettle River formation. Comparative studies of tillite of Alpine glacial origin and that of continenUl ice sheet origin would aid considerably in the solution of such problems in sedi- mentation. The Franklin district lies well within the Gold Range of Dawson' (a unit of the Columbia Mountain system) which IS considered by him to have been one of the main axes of elevation in the Canadian Cordillera. From the field facts here stated it is inferred that the topog- raphy of the period following the great Laramide Revolution was of a decidedly rugged and Alpine character; that Franklin then as now occupied a tectonic trough or depression between the Lanboo and Granite ranges; and that the latter ranges were composed in large part of highly folded and broken sedi- mentary and metamorphic rocks. __J^e climate was probably humid and cool, as indicated by 'Dawwn (G. M.): Bull. Ceol. Soc. of Am., XII. p. 61. 66 the white leached sediments and grey colours with presence of carbonaceous shales containing plant remains.' The coarse conglomerates were mainly deposited in alluvial cones about the margins of the basin. The material was swept down on steep slopes from the rugged summits, where rock breaking and disintegration through frost and water action pro- gressed with great rapidity and dominated over rock decay. The mountain slopes were probably too steep to support vegeta- tion and thus unfavourable to the accumulation of humus in the soil to accomplish rock decay. On steep mountain slopes rapidity of mechanical work obscures rock decay, even if it does go on. The rocks on the summits possibly in the vicinity of snow and ice, would be chilled below the freezing point at night and raised above the melting point during the day. Such rapid alterations form a most efficient means of breaking up solid rock. Under such climatic and physiographic conditions as have been inferred it would not be surprising to find that Alpine glaciers existed and supplied their quota of material to the basin below, which would thus explain the glaciated charac- ter of some of the boulders and pebbles in the coarse hetero- geneous phase of the conglomerate. In the basin itself a drainage system was in course of de- velopment, but owing to contemporaneous flows of rhyolite and deposition of acidic tuffs from the nearby McKinley vol- canic vent, the drainage, as shown by the erratic nature of the sediments, was in a decidedly disorganized condition. For con- siderable intervals some areas were marshes and lakes in which acidic tuffs were deposited in evenly stratified beds. In the vicinity of these marshes or flood-plains vegetation flourished. The rhyolite flows contributed very largely to the early Ter- tifiry sediments. On the west slope of Tenderloin mountain is exposed a bed, 4 feel thick between bedding planes, of even-grained arkose with a few large scattered pebbles of argiilite and quartzite mixed in, which would seem to indicate very rapid sedimenta- tion by turbulent waters, or possibly stones dropped by floating ' Barrell (J.) : Climate and Terrestrial Deposits: Studies for Students. Jour, of Geo!., Vol. XVI, pp. 293-294 (1908). 67 ice or tnei. The ^^uiable texture of the formation in many places would indicate restricted or rapidly changing conditions of sedimentation. Current markings and stream bedding on the east slope of Franklin mountain, and also at the base of Tenderioin mountain, indicate that the course of the early Ter- tiary drainage was west of south. CmrekUioH. The Kettle River formation of the Franklin district may possibly be correlated with the Coidwater group (Oligocene?) of Dr. G. M. Dawson' lying farther to the west and south, and many scattered localities throughout the Boundary district.* Lithologicaliy the Phoenix arkosic grits and tuffs are the same as those from Franklin, but the formation there lacks the very coarse heterogeneous conglomerate phase of the latter more mountainous region. There, too, they antedate tiie period of main volcanic eruptions, and appear to have been locally upturned and denuded before the Miocene period. It is with some doubt that they have been referred to the Oligocene. The age assignment and correlation of the early Tertiary formations of southern British Columbia have been based chiefly on palaeobotanical evidence, and physiographic evidence such as is present in the Franklin district has been entirely neglected. There is a great paucity of organic remains in this formation, possibly because of the volcanic nature of the materials com- posing it, and this is true in many other districts. This fact, along with the isolated positions of the known fossiliferous localities, makes it a difficult matter to construct a satisfactory and connected section of the Tertiary formations of British Columbia. Dr. D. P. Penhallow has recently (1908)* made a detailed rtudyof the plants from the various localities, collected by G. 'Daw«M (G. M.): Kept, oo Kamloops Map Sheet. Ann. Kept. G.S.C., Pt. B, Vd. VII, pp. 68-71 B. y . 'LeRoy (O. E.): Summary Rept. Pboeniz CajB|> G.S.C., 1906, p. 67. Boundary Creek Map Siiert No. 818. 'Penhallow (D. P.): Kept, on Tertiary PUntu of British Columbia. Gaol. Sunr. Canada, 1908. 68 M. Dawwn and Daly (1903-1905) and by Umbe (1906). In this report the localities are spoken of as being a series of lakes, many of them small and often widely separated from the main formation, which is very irregular in outline. Penhallow con- cludes from rather unsatisfactory and limited plant evidence that the Kamloops beds (Coldwater group), which resemble lithologically the Kettle River formation of Franklin, belong probably to the Oligocene, certainly not higher, possibly lower. For the Quesnel beds, from his analysis of the plant specimens present, he concludaa Eocene, with a strong tendency to I^aramie. The Tranquille beds, which are distinct from the Coldwater group as shown by Dawson in the Kamloops district, he "assigns to the lower Miocene provisionally." The Kettle River formation in Franklin will be tentatively referred to the Eocene-< )Ugocene period between the laramide revolution and the time of crustal disturbances followed by the erosion cycle which preceded the great Miocene volcanic period, as shown by the unconformity in the Franklin district between the two Tertiary formations. Early Tertiary Rhyolite Flows and Tuffs. General Statement. Rhyolite flows preceded by acidic tuflfs, took place con- temporaneously with and subsequ itly to the deposition of the Kettle River formation. The remnants of once extensive flows now occupy small areas following, chiefly, old Tertiary river courses. The glassy quartz and fresh feldspar so common in the arkosic grits of the Kettle River formation were probably derived from them, and in some places it is difficult to draw the exact line between the arkose and the rhyolite itself, on account of the blending of the one into the other. Where the rhyolite has poured out on the sticky silty bed of a lake or flood-plain the contacts are clear (Plate XI B). In the case shown in the photograph, gravity has been overcome in part by the viscosity of the magma, and the silt is in the process of being 69 taken up by the Uva. Throughout the rhyoUte, cherty indusioiu are frequently found. Somewhat analagous conditions have been reported from beds of the same age in the Republic district, Washington,' where dadte flows have uken up conglomerate boulders and enclosed them. The formation is known as the dacite conglomerate. DislribuiioH. The greatest thickness of rhyolite and rhyolite porphyry occurs as a capping on McKinley mountoin, where it forms bluffs and almost perpendicular escarpments, as above the McKinley mine. Isolated erosion remnants of the youngest rhyolite flo»^ in the district occur scattered on the summit to the west of the main capping. A continuation of probably the same flow was found on Franklin mountain, where it is capped by the younger trachyte. These represent the basal portions of once extensive rhyolite flows whicli filled up an old valley with a comparatively thin deposit of conglomerate and grit in it. At a period immediately preceding the volcanic eruptions of rhyolite, the accumulations of gravel were not deep on MciCinley mountain west of the main drainage channel, and the rhyolite 18 even found resting direcUy upon the Jurassic granodiorite. Structural Relations. The rhyolite displays flow (or fluxion) and banded struc- tures in places, due probably to the different proportions of water contamed in the different parts of the molten lava which were drawn out in the direction of the flow. Inclusions of chert are found m the rhyolite and rhyolite porphyries, and were prob- ably taken up in the lava in tlie manner shown in the photo- graph (Plate XI B) of a specimen from near the base of ^he forma- tion near Franklin creek. The viscosity of the lava has apparent- ly partly overcome gravitational influence and has forced up the probably moist sticky skin of silt along certain lines, attenua- ting It b etween ridges, and is in the process of drawing it up and 'Umpleby (J. B.): Wath. State Surv. Bull. No. 1, p. 20. ro T' — J • -■ V . ■ . ■ " . 'Cdarse-^H(osic ^ritfffhyo/itich ' 2S f ' ^Rhyq/ite ^ . ( Figure 7. lUiutrative of character of sedimentation in a portion of Kettle River formation (Eocene-CHigocene) ; northeast of Maple Leaf claim. n including It Emenon' mentk>i» trap theets in New Jeney betoK pound out ov«r muddy bottom, with ^mewhat dmUw f»uto. He writea that "the heat pi«luc«i .trong upwaid convection currento and comapondingly .trong indraught from the Mde. which carried muddy water, out over the Mir- face of the trap while it wa. .tiU flowing and covered it with a qu«itityof alareou.mud." However, in thi. ca.e therhyolite lava wa. probably too vi^ou. for convection current, to operate. The rhyohte. are vewculur in place., having elongated ga. cavitie. IJ mche. in length, a. ob^rved near the under- lying gnt contact. Variation, in textuie from rhyolite to quarta porphyry (rhyolite porphyry) take place tranmtionally on McKinley mountain. The curved character of the jointing in the rhyohte porphyry may be well Men. expowd in the McKin- ley Creek gap above the McKinley mine. The border of a rhyo- hte remnant on McKinley mountain diaplayed alao curved jointing a. well a. a unique type of joint .tructure (Figure 8) not obKrved elsewhere. The exothermal effect, of the rhyolite upon the conglomerate and gnt are objured on McKinley mountain, owing to .ubw- quent mtruMon. of pulaskite and pulaakite porphyry dyke, near the contact. At the eastern border of the main rhyolite porphyry remnant, volcanic agglomerate composed of rhyolite porphyry wa. found below the flow itself, hi the conglomerate- gnt formation. The fragments vary in character and size from place to place, and show no stratification nor definite arrange- ment of the ejectementa. They have evidently worked their way down into the unconsolidated conglomerate. Mode of Origin. aWH.J'lf/'**"*^! ?^ considerable evenly bedded, water-laid ^dic tuB near the ba* of the Kettle River formation, with oc- c^ional large pieces of rhyolite lava scattered at random in rhvnHtlT ^"' ^"^ «'"8lo'"«'-ate (Figure 7). indicate that the rhyohte flows were preceded by explosive outbursts of coarser 1899. 6 'Emerson (B. K.); Bull. G«,l. Soc. An... Vol. VIII. pp. 59-86. Plate. 3-9, *«»OCOfY MSOWTION TBT OMIT (ANSI and ISO TeST CHART No. 2) 1 1 K If m 72 fragments and volcanic dust that settled down in the basin numriies and flood-plains. Here it became worked over by the erratic drainage system, as has been shown to have existed in the basin at this time, due to the constant shifting of river courses by contemporaneous volcanic activity. Rh/o/ite porphyry Jurassic f^anodfar/te FigUK 8. Oiaiacter of jointiiig at border of early Tertiaiv rh^ite porphyry remnant lying flat upon Jurassic granodiorite, west of mam flow on McKinley mountain. The location of the vent or vents from which these erup- tions took place is rather difficult to conjecture. Certainly from the lack of attrition and fresh appearance of the mineral constituents of the grit, it would appear that the source of sup- ply was not far distant. The vents were in all probability con- fined to the valley or basin and not to the enclosing sedimentary mountain ranges, for no rhyolite boulders or pebbles were found in the conglomerate of the alluvial cones, as one would expect 73 if the venta had been on the summits or outer slopes. On the otiier hand the fluvi^tile material confined to thVintermonJ ba8m« made up m large part of rhyoliticarkose. The eruption of lavas ,n the early Tertiary, as wiU be «*n also in the c4 of tl^^ r °! '^^ 'i!'*^""' *PP«" *° ^^^ fo»°wed pS^) "°* '*'**' '"°""**^" ""^ ^P^ ^*•'• l-he great thickness, coarse texture, topographic relief J^a^te base, thinning out of flow north^on FranS mountain, have ^M been noted in the case of the McKinley ityohte paphyry capping, and point towards the likelihood Z rtshavmg been the original volcanic vent and source of volcanic ^"^fJ^^^'^-'^'- "The rigidity it ha. shown al«> ^ !J^?!?*"* ""'«*"'*= disturbances, as well as the finding of no other hkely vents elsewhere, either within or without the distnct, pomts strongly towards such an inference their ^trtZ^u**^^''^"'' "^^ °°* «*«°<1 f" fro™ ~!l iTl?' i!"** **' ^ *"*' "*y '«»^ be*"* «rried down in ^y the streams as mud flows, deriving their content, from «^ of volcamc ash accumulated near the vent, but the light gnashes so common near the base of the formation were probably rapidly deposited a. dust showers from the volcano, a^^y have been worked over by the streams during quiescent Subsequent to the eruption of rhyolite flows and contem- poraneous depodtion of sediments, crustal movement affecting ^J°l!fr'!L'^*'' ^^ south-southeast lines. dUturbed SL S^- f ** «^"™^t8 a"d flov/s to the northeast-east, but the McKmley Mountam mass preserved to a great extent iu ongmal attitude. This disturbance was followed b/a long period of erosion represented in the unconformity exposed on all three mountains. ^^ Age and Correlation. c^aH"^ ^T^ °1 ^^ contemporaneity of the rhyolite with the w^lomerate and gnt lies: (1) in the mamier in which they were ^^ ^u T ^*^. *" °*^*^' "^^ «'«J"K ''^^^ the bedding plane, of the formation; (2) in the similar mineralogic composi! 1 M i 1 f I 74 tion of the arkosic grit and the rhyolite, both of which contain the same limpid quartz and fresh feldspar; (3) in the finding of rhyo- lite agglomerate well within the conglomerate-grit formation on McKinley mountain below the main and younger rhyolite flow; and (4) the finding of acidic tuffs in the basal members of the Kettle River formation, which represent chiefly the light dust or ash into which the molten lava was blown by the violent volcanic explouons preceding the outflow of lavas. These show- ers of ashes were probably accompanied by torrents of rain, due to the condensing vapours (example, Pompeii eruption), but such rain falling on volcanic ashes, tuffs, and lavas, would quickly be lost or absorbed. The presence of a marked unconformity between the early Tertiary formation and the Miocene volcanic series represents an erosion period in which much of the early Tertiary record was stripped off. It is probable that the rhyolite eruptions may be connected with the intrusion of the Valhalla quartzose granite (page 103, Chapter V), of post-Cretaceous age, which forms the Cariboo range to the west and whose mineral composition resembles closely that of the rhyolite. OLIGOCENE. MoNZONiTE Stocks. General Statement. This is a medium to coarse granular rock of a greyish black colour, with dark pyroxenes scattered through the light coloured feldspathic constituents, the contrast between the two giving the rock a mottled appearance. It occurs in two stock-like masses, one in the northwest and the other in the northeast comer of the district, and is always closely related structuraUy and mineral- ogically to the alkalic rocks which it preceded. Structural Relation. Internal. The texture and composition of the formation fcmain very constant throughout the mass, and what little . pi' 75 variation there is tends to produce a rock more ferric, but never more salic than the type. This is in marked contrast to the younger mtruBon. which reached to the surface and shows striking differentiation. Frank/m ^XMjp ^ greenstone /foot Figure 9. F«,hed .pllte dyke. «« mc«qite at b«e oC Tenderioin mountain. The monzonite is cut by aplite dykes which are faulted in «f^ ^!r" ^^' ^""^ frequently, however, it is cut by systems of pulaskite porpyhry dykes, as in the nortiiwest comer of tiie map-area. The Tenderloin monzonite stock is cut at its western ortremity by an irregular intrusion of micromonzonite (page 105 Petrology). In two localities near tiie Royal Tinto claim, which IS situated on tiie concave side of the syenite intrusion, tiie mon- ZTi " ^l''^ ^ *°"«"«' (P««« "7. Petrology) from tiie syenite which unu..iiie8 it. 'w 76 In some places the monzonite is sheared and slightly brec- ciated, and in such zones mineralization by sulphides and magne- tite has ensued (page 175, Royal Tinto claim). The production of the shearing and intrusion of syenite apophyses was in all probability connected with the chonolithic intrusion. The mon- zonite as a whole is much fresher and does not show the effects of regional dynamic metamorphism as does the Jurassic granodiorite. External. Relations to Older Formations. The contact between the granodiorite and the monzonite, although in the majority of cases in drift covered depressions, was found near the Royal Tinto property to be sharp, with little variation in the monzonite, but the granodiorite had developed a strongly micaceous phase. The Palaeozoics, where exposed in contact with the monzonite, showed practically no variation from their normal metamorphic conditir ". Relations to Younger Formations. The Tenderloin mon- zonite stock was found to be capped by conglomerate and grit in places, the former lying loosely as erosion remnants, often too !nnall to map, while the grit was indurated. This induration could hardly be due to the syenite intrusion, for the occur- rence is over a quarter of a mile from the s>'enite chonolith. The syenite of Tenderloin mountain, as shown by its contact relations to the topography, is almost vertical, and the contact aureole it has produced is limited to within 50 feet of the main contact with the Kettle River formation. It is thought, then, that the monzonite reached the Kettle River formation at a time prior to the post-Oligoceae erosion cycle, which carrie I away great thicknesses of superincumbent Kettle River formation. The contacts between the younger alkalic intrusives and the monzonite are always sharp, with no evidence of weldiig, in- dicating a hiatus between the two intrusions long enough for the latter to become thoroughly consolidated. Mode of Origin. Contact relations of the monzonite with the older formations, which point towards down« ard enlargement of the mass, indicate 77 its intrusive nature, and, considering the size and shape of the body, homogeneity in texture, and mineral composition, it in all probability solidified under a thick cover of Tertiary forma- tions. No evidence of a laccolithic or! in or of an outlet to the surface is present, and it is assumed that the intrusions are in the form of irregular stocks or small bosses which may unite below to form a larger intrusive mass. Age and Correlation. The monzonite is younger than both the Jurassic granodio- nte and the Kettle River formations. It is much older than the Miocene alkalic intrusives, as shown by sharp, non-welded contacts. This limits its age to an interval between the Eocene and the Miocene. Igneous intrusion in this section of the Cor- dillera has been frequently associated with deformative move- ments of the crust. Assuming this generalization, which may be true only to a limited extent and not of world wide application, the monzomte will here be referred to the period of crustal disturbances which inaugurated the post-Oligocene erosion cycle. Ihe monzOTite consolidated under a much greater superincum- bent load of Tertiary continental deposits than did the younger al- iHUic intrusives, and there is no evidence to show that it had access to the surface. Monzonites of a somewhat similar lith- ologicand geologic character occur at Rossland. B.C., where they have been tentatively referred to the post-Jurassic.' '^''e Franklin monzonite is hypabyssal in the sense that It has reached nearer the surface than the deep seated Jurassic !!^!:'w"**: '* '* ^"^^^^ intimately associated with and in- truded by the younger alkalic intrusives. The pale green diop- side, so diaracteristic of the younger augite syenite and pyrox- enite, and entirely absent from the granodiorite, is present in tfte monzonite as an essential constituent. The accompanying photograph (Plate XII) shows the megascopic resemblance be- tween the monzonite and the much 3/ounger augite syenite. ^"^'^*^ ^'' *=^ always be readily distinguished, however, by the wJ^I^t ^^' V'- i!"'- ^"P*- °" ^'^^'^' B- C-. Can. Geol. Surv., 1906. West Kootenay Map Sheet No. 792, 1904. 78 trachytic structure of its feldspars. Both on account of its geologic and mineralogic relations to the younger alkalic series, the monzonite is considered to be co-magmatically related to them, but naturally not so highly differentiated as they are, on account of the monzonite's less alkalic nature and because it did not reach the surface to form lava flows and thus promote differentiation — a process discussed in Chapter V, Petrology. MIOCENE. Alkalic Intrusives. General Statement. The alkalic intrusives will be considered as three distinct units, in order of age: (1) porphyritic syenite, (2) shonkinite pyroxenite, (3) augite syenite. The last two were intruded almost simultaneously. Porphyritic Syenite Chonoliths. « The porphyritic syenite forms comparatively small, ir- regular shaped intrusions on both sides of Franklin creek, and is less alkalic than the younger types. The three main occur- rences are: (1) on the west flank of Franklin mountain intrusive into the "Lime dyke;" (2) on Syenite hill near the west border of the district; and (3) a small crescentic shaped outcrop on the ridge west of Franklin creek, whose concave side "Mints towards Syenite hill. It is characterized by the loni; elongated feldspar laths, showing often fluidal arrangement parallel, in a broad way, to the main contacts. On Syenite hill the unstriated feldspar laths are 2 inches and more in length, and have borders of a lighter coloured feldspar which is a plagioclase. The crystals in places radiate from one centre, as seen in the photograph (Plaf XIII). This feature may possibly indicate stagnant conditions in the magma at the time of crystallization. *Daly (R. A.) : Classification of Igneous Intrusive Bodies; Jour, of Geo!. (1905), Vol. XIII, p. 485. .1 79 MicroKopic study has shown that this rock is verv nrob- *b!y the intrusive equivalent of the oldest trachytic flow on McKinley mountain. Both intrusive and extrusive show the tendency towards radial or starry grouping of the feldspars. The crescentic shaped outcrop farther north, as well as the lona narrow outcrop crossed by the Banner trail, is probably an offshoot from the same intratelluric parent magma which sup- plied Syenite hill and the effusive trachytes. The porphyritic syemte is less alkalic than the younger syenite, and shonkinite- pyroxemte intrusives, in that it conUins some accessory quartz and considerable microperthite. S/enite iptite Figure 10. Eadog ' rte-pyronnite M of shonlcinite-pyroxenite within augite -J" Koyal Tmto property. Shonkinite-Pyroxenite. ■m ^Ki' ,'" ^ ""^"*' P''^ °f the augite syenite chonolith. This black differentiate from the augite syenite which has. tn places, large augite phenocrysts up to 1 inch in length scattered through a general groundmass of pyroxene with interstitial 'Si m 4 4 ^ SO fillings of alkalic feldspar, is locally known as the "BUck Lead." It occurs chiefly at the nuu-gins of the syenite intrusion, al- though this is not always the case. On the Averill property m the northwest corner of the quadrangle, as well as on the Maple Leaf property above Gloucester City, the "Black Lead" or shonkinite-pyroxenite is surrounded by syenite (Figure 10). In many places the augite syenite was seen to pass i. pidly into the shonkinite-pyroxenite (page 137, Petrology, Chapter V). At a contact, however, exposed in a shaft on the Averill property, the shonkinite-pyroxenite appears to have been shattered and injected with syenite aplite material. The accompanying photograph (Plate XIV) shows the sharp contact and contrast between the two extremes of differentiation. The distribution of the "Black Lead" is indicated on the geological map. It has been opened up by numerous prospect pits and tunnels. AugUe Syenite ChonoHth. The augite syenite can always be reaQ.ly distinguished by the characteristic trachytoid structure of its feMspar laths (Petrology, page 105, for details). This irregular shaped intrusion is distrib- uted over the north half of the map-area, and extends from the northwest comer southward and eastward to the base of Tender- ton mountain, forming a broad arc crncave to the northeast, with a general dip in that direction. Structueal Relations. Internal. The main endother- mal features in connexion with this formation are: (1) the pres- ence of endogenous inclusions and "schlieren" of shonkinite- pyroxenite within it; (2) the local variation in texture and com- position of the mass from place to place, as, for instance, from nephelimtic syenite to melanite syenite; and (3) the injection by syenite aplites, of the contacts between the pyroxenite and syenite. Inclusions of monzonite were found in the syenite. External. The syenite shows intense contact metamorphic effects upon all the older formations, but this is confined to the immediate contact. The width of contact zone or contact aureole depends directly upon the character of the country rock which is intruded by the syenite. 81 In the caM of the Franklin group tuff anH greenstone, the nwtamorphic effect was found to extend onlv a few feet, fhe a oompanying field sketch (Figure 11) illustrates the character of the contact. For at least 15 feet in places, the country rock is saturated with secondary hornblende, but certain portions of the wall rock were less affected, as shown in the sketch. i->i'/^ I «^^i ^^9/m: syertrtt Contact meUmorphic „^^^ ^''^•'^orphic ion« rranMin^roup ^»ith. «o^ .tudie. of the Kettle River foS.at£„ in cTt^ withX •ywiite) .howed that the pyroclaatic trachyte penetratedTJ Figure 12. Crenutation in Kettle River banded chert m. .uBte «««i^ contact; eaM lide of Kettle riw. ^ ^^'* !Jj!fu? '•*/ *'"*'? '"*° *^* «^*- No trachytes occur in the Kettle River formaUon except in this locality. There the syenite has permeated and saturated the conglomerate l^dfinT^J for at least SO feet from the main contact. Meta«,matic rj^la^! ment .s md:cated by the preservat..n of original structure of both conglomerate and silt. Pseudomorph, of syenite Ster the more permeable pebbles and matrix oca- The fine sik a httle farther from the contact, has been i... -ted to a d^ 83 brittle chert. The indurating effect of metuomatic replace- ment upon the Kettle River conglomerate is well illustrated bv t»tc accompanying photograph (Plate XV, cf. Plate IX, of the sr.me formation in unaltered condition). The matrix, instead of the boulders, stands out in relief on weathered surfaces. The rounded boulders and pebbles that have been replaced present rough surfaces (Plate XI A). In some of the replaced boulders, titanite and a little chalcopyrite were found. The quartzites and quartz pebbles show the least alteration, but the former, on close examination with a pocket lens, shows the presence of minute alkalic feldspars with characteristic trachytic structure. As already noted, the alkalic rocks are conspicuous by their absence in the Kettle River formation. The silty and fine-grained grits, some 30 feet from the syenite contact, are meUmorphosed to dense cherts, whose original bedding planes are well preser\v> . md show minute faulting in places. The chert breaks with a sharp conchoidal fracture which never follows the original bedding planes. This is the first case, to the writer's knowledge, of an in- trusive granular rock having been found in contact with what was an unconsoUdated gravel and sandstone formation at the time of intrusion. Similar roetasomatic contact metamorphism was noted on Franklin n">untain between the same formations (Plate XVI). Below the Maple Leaf iwoperty on Franklin mountain, the al- kalic syenite has bowed up its cover of conglomerate and grit, which has been subsequently largely strip ped off. The evidence of bowmg-up is present in the disturbed structure of the grit for- mation. Here local normal and reverse faults of slight throw are present, as shown in field sketch (Figure 6). The faulting is prob- ably due to a slight subsidence of cover following the bowing up and consolidation of the syenite. On Franklin mountain, above the Maple Leaf p.-on. rty, the trachyte is found very nearly in contact with the underlying 2^nite. The actual contact is in a depresuon and drift covered. Both pulaskite porphyry and quartz porphyry are found in- trusive mto the syenite and shonkinite pyroxenite. tl 84 Mode of Origin. Thermal variations, as well as those of gas content in a molten magma, are more pronounced in prox- unity to the earth's surface than at great depths, and should affect small bodies of magma more readily than large bodies. It is natural, then, that the allcalic intrusives of Franklin, which reached so near the earth's surface, both on this account and because of their alkalic nature, should show more marked dif- ferentiation than the more deep seated monzonite and Jurassic granodiorite. Injection phenomena are absent at the main contacts of the syenite into the older formations. Aschistic (undifferen- faated) dykes of syenite, however, occur on the concave side of the chonolith intnision. They are short and narrow, and all he well below the upper limit of the intrusion. The absence of injection at the main contacts may be due to the fact that the intrusion did not take place under a very great cover of superincumbent material, and, therefore, lacked the necessary hydrostatic head to produce such effects. The narrow syenite dykes cutting the cover formations may have their origin in tensJon cracks produced by shrinkage in the cover subsequent to the intrusion and consolidation of the magma. In contrast to the limited contact metamorphism produced by the syenite chonolith. stands that accomplished by the deep seated granodiorite batholith which affected the adjoining forma- tions hundreds of feet distant from the immediate contact. The theoretical discussion of the rocks in the group be- longing to the southern British Columbia petrographic province, with their mode of intrusion and differentiation, will be dealt with at the end of Chapter V. on "Petrology." Age AND Correlation. The syenite, as has been shown in the preceding discussion, is younger than the monzonite and the Kettle River formation. This is indicated by the manner in which narrow syenite tongues have been intruded into the cover rocks, which include monzonite, on the concave side of the in- trusion. Furthermore, it is the intrusive equivalent of the trachyte, which will be shown later to be of Miocene age. This refers the intrusion without doubt to that great Miocene epoch of Igneous activity so general throughout the Cordillera. ss Midway Volcanic Group. Trachyte Period. General Statement. The lavas of this group are the extrusive equivalents of the intrusive alkalic rocks which have been already considered. They vary in composition from al- kalic basalts to phonolitic trachytes. The alkalic basalt is the extrusive equivalent of the shonkinite-pyroxenite; the phono- litic trachyte, of the nephelinitic syenite. They occur as rem- nantal lava cappings on all three mountains, and represent parts of a former flow which poured out into an old river valley, as shown by the synclinal structure of the contacts. An unconformity exists between the Kettle River formation and the trachyte lava flows, indicating a period of crustal move- ment along north-northwest and south-southeast lines, with tilUng of sediments and intercalated and capping rhyolite flows to the northeast-east. This was followed by a period of erosion which produced the surface of unconformity. Structural Relations. Internal. Pyroclastic agglom- erates, bombs, and weU banded basaltic tuffs intercalated with trachyte flows occur on the east slope of McKinley mountain, m the basal portions of the Tenderloin lava capping, and spar- ingly on the Franklin Mountain lava remnant. The accompanying photograph (Plate XVII), taken of the diff-exposureon the east side on Tenderloin mountain, shows the intercalated character of the basaltic tuffs, vesicular and amyg- daloidal trachytes and alkalic basalts, all of slightly different structure and appearance, which accounts for the striking strati- graphic appearance of the whole series. Towards the summit of Tenderioin mountain the flows become more massive, with less intercalated tuff. Vesicular and sconaceous structure so prominent in places is due to the expansion of imprisoned vapours and gases in the molten lava. The gas pores or vesicles are filled in places by calcite, quartz or chalcedony, and are almond shaped (amygdaloidal) owing to their elongation by movement of the lava before consolidation; and hence the common parallel arrangement along the direction of flow. 86 The alkalic basalts show columnar jointing in many places, caused by contraction during the cooling and shrinking of the lava. External. The grit immediately below the trachyte cap- TpI^ °^*!?f. P'**^Pl*°"» "^^^ ^™"* °f Tenderloin mountain tflate XVIII) was found to contain pyroclastic fragments of trachytic tuff for at least 5 feet from the contact. This indicates that the lava and tuffs were extruded on an unconsolidated sedi- mentary formation, for nowhere else in the Kettle River formation were found products of Miocene volcanism. The grits are slight- ly mdurated in places along the contacts. The surface upon which the Miocene volcanics were de- posited appears to have been of a gently undulating character. Ihis surface was faulted on Tenderloin mountain (Plate XVIII) probably during the late Pliocene uplift. Mode of Origin. The lavas and pyroclastics of this period of Igneous activity are thought to have been extruded from a vent towards the south end of Tenderloin mountain, for the fol- lowing reasons: There are two prominent monzonite mounds at the south end of Tenderloin mountain, between which lies a depression formed in syenite. The syenite shows pronounced trachytic structure, with feldspar laths oriented in a general way parallel to the contact. The contacts are nearly vertical as shown by their relation to the topography. This syenite IS the intrusive equivalent of the trachytes intercalated with the pyroclastics occurring on the same mountain higher up. The well stratified pyroclastic tuffs and intercalated lavas were found to dip away from the syenite. There is present at the south end of the remnantal capping much coarse pyroclastic material con- Msting of bombs and smaller angular fragments of vesicular and sconaceous nature (Plate XIX), such as would be expected near a centre of eruption. As this is the only known occurrence of the intrusive equivalent of the lavas and tuffs on Tenderloin mountain, and considering its position, topographic expression, and the offshoots that have been given off from the main mass, which here is m an almost vertical position, it seems safe to infer that this syenite depression represents the eroded crater of an ancient Tertiary volcano. A hypothetical restora- 87 88 ■H '■ bon of the volcano is shown in Figure 13, which appears as one of the Vesuvian (Strombolian) type. The fact that the upper portion of the vent must have been in the readily eroded Kettle River formation would account for the present low altitude of the old volcanic core. Some of the large rounded fragments in the cappmg, as exposed on the west slope of the mountain, may represent some of the boulders ripped off from the Kettle River formation at the time of eruption. Age and Correlation. It is known that the trachyte period followed the erosion cycle subsequent to the crustal disturbances and monzonite intrusions, with the consequent uptumints and tilting of the Kettle River formation to the north- east-east. This would correlate it with Dr. G. M. Dawson's period of Miocene volcanism as developed about 100 miles north- west in the Kamloops district,' in the Interior Plateau of British Columbia. Dawson* draws attention to the fact that the Tertiary rocks in the southern part of the Interior Plateau do not form such extensive unbroken sheets as they do farther north and west, a fact due, he states, to the probably more mountainous and rugged character of the country at the time of their de- position, and also to extensive and severe disturbances and de- nudation subsequent to that tijne. His provisional scheme* for the Tertiary rocks met with in the Kamloops sheet is as follows:— Feet Early Pliocene. Beds of upper Hat creek and north part of Pavil- lion mountain. (Elsewhere: Horsefly gravels [yellowish cement), and quartz drift of Klon- dike) Later Miocene. Upper part of great volcan'i; series, widely spread over the region. Composed of basalts and VII ^or**",^^ ^■'" ^'" *° K*™'°0P» Map Sheet, Ann. Rept. G.S.C., VII, 1890| p, 71 B. •Dawwn (G. M.): Geol. Mag., Dec. 11, VIII, p. 158, 1881. *0p. Cit., p. 176 B. 89 basalt breccias with smaller quantities of melaphyre, mica trachyte, mica andesite, and various porphyries. Greatest thickness be- tween Nicoamen and Nicola, about 3,100 Tranquille group, chiefly volcanic material arranged in water. Tranquille, Nicola valley, etc. Com- posed of fine-grained tuffs and other volcanic material well bedded. Greatest thickness, about 1 ,000 Earlier Miocene. Lower part of the great volcanic series, Nicola valley. Clear mountains, Kamloops lake, etc. Mainly augite porphyries and agglomerates, tuffs, mica porphyries, picrite porphyries. Greatest thickness apart from centre of erup- tion, about 5 3QQ OUgocene. ' Coldwater group. Near confluenceof Coldwater and Nicola, Copper creek. Hat creek, etc. Compos- ed of conglomerates of arkosic grit and acidic tuff. Greatest thickness on Hat creek, about. 5,000 14,400 Younger Period of Dyk Intrusions. General Statement. All the preceding formations are cut by younger dykes and plugs of alkalic syenite (pulaskite type) and pinkish pulaskite porphyries, the latter predominating throughout the district. The youngest dykes of aU are dark laraprophyres, includ- ing minettes and augite microdiorite, the former bearing a genetic relationship to the pulaskite. Pulaskite Porphyries. The pulaskite shows great vanation m texture from centre to border of dyke, a variation which is dependent upon the width of the intrusive and the ra- pidity of consoUdation. West of the McKinley mine, on the north slope of the mountain, a pulaksite dyke has the typical spotted pulaskite porphyry texture (Bird's eye porphyry of the pros- 90 11 pector) at its borders. The centre of the dyke is a gtanular fades and was found in one place to contain inclusions (Plate XX) of older formations. Many of the dykes show evidence of contact chilling in the dense character of the rock, with feldspar phenocrysts larger and farther spaced from each other (page 136, Petrology, for explanation). FrartkKn group s/terett efypt/ve 'l^RperP>ihiuoKj\ jurassK ^^■anohyry had intruded into a semi-S" ^1^^ . "*^. °' *^* Kranodiorite-pulasldte porphyry and mon«m,te are sharp and straight, as are also those with the conglomerate and gnt, a fact which indicates that the latter was m a consolidated condition at the time of the intrusion in f^'ff-^Tu "^^ P"'*""^** ^'P^y^ dykes so common diffl 1"^"^' '""ru"*?" '**'^"** "y»*«™» of intrusion m d^ere. portions of the district. For imitance. in the north- west corner a dominant northeast and southwest system Zr be noted dipping verticaUy in most places. In the south^t co^er they strike north and south. Where they ;:^ertrS^e mto the Jurassic granodiorite they dip to the west, a fact which explain, m part the peculiar shaped outcrops on the st^p Itt- are variable m direction over small areas. A prominent curv^ pul^kite porphyry dyke outcrops on the AveriU pro^ as shown on the map. Where the pulaskite porphyry cuK^ conglomerate and grit formation on the westSde ofthe Kettie nver the dykes dip steeply, as a rule, to the east. Wvt«r~?™°"u^'' evidently favourable location for tiiese dykes «sa^ong tiie upper border of tiie granodiorite bathoH^ h fZr^ '" t'f °" '**=^"'«y '"°""^"- In many ^^ it forms a pmkish veneer or irregular shaped coating to die StZt';"''"'- f"«*Pf*<*«'--asniletrsmSl' unimportaiit to map. In one locality near the centre of tiie west border of tiie map area, a hillock of pulaskite porphyry o^Tn i"to^i°™ 1' ™'f ^^^"'" P'"« °' -^^- It isTnt^iv" TcSi^frhrml'^"' ''"' ~"-^-diPPin««eeply towards The pulaskite intrusives on the east side of tiie Kettle nver and towards tl.. ix,rder of the quadrangle are mo^ pt^ ft^and a^ume more gr-^nitic fades, forming larger irregular S i Lnil^ ' r™*"' ^"'^^' ^''•^^ '^ ""o^" ^ the Rostand aijcau syemte and gramte. in I ,1 h: 92 Lampkophykes. a very interesting lamprophyre-minette dyke is exposed on McKinley mountain for over a mile in length, pinching in width to 10 feet and swelling up to 150 feet in places. It persistently cuts through a whole series of formations. Figure 14A shows the minette dyke in contact with early Tertiary rhyolite porphyry above the McKinley mine. Where the rhyo- lite porphyry is most massive it does not outcrop. The accom- panying photograph (Plate XXI) of this dyke cutting a brec- dated grit near Last Chance ravine on the McKinley Mountain summit, shows the character of the contact as well as a striking differentially weathered surface. The outcrops of this rock decompose readily, and specimens for microscopic study had to be collected from the No. 1 tunnel of the MrKinley mine, where a 4}-foot minette dyke follows a Palaeozoic limestone-tuff contact. A small inclusion of the pulaskite syenite was found in this minette dyke. Age and Correlation. It is known from the contact nJa tioiig of these youngest dykes in the district, with the Kettle River formation, which was in a consolidated condition at the time of their intrusion, that they are referable to a period later than the Miocene lava flows. Field relations point towards their close connexion geologically and petrologically with the great Rossland alkali syenite and granite batholith to the east in the Granite range, which in all probability underiies at least the eastern portion of the Franklin district. The pulaskite rocks of Franklin resemble very closely those occuiring so commonly throughout the Boundary district and examined in detail at Phoenix' and Deadwood.* QUATERNARY. Boulder Clay or Till. This is found on the upland surfaces along with glacial erratics. It consists of hard, sandy clay, with stones and boulders scattered abundantly and irregularly through it. It is generally of a light brown colour. The erratic boulders are chiefly of granite transported from the northwest. 'LeRoy (O. E.): G.S.C., Summary Rept., 1908, p. 66. •Ibid., 1910, p. 128. 93 Fluvi(m;lacial Alluvium. .« ^VK ?'""'*' ?^ '^*" '■°""''«* '*'''''«'• 'gobbles, and bould- ers, with lenses of coarse sand. The boulders are predomi- nantly granite and are comparatively fresh. The deoosit. form a valley fill in Franklin creek over 100 feet thick, and rem! SvSvIue" "^^^'^ °^''"' ^'" '" *''* "*'" ^«t'« These deposits represent the work of alluviation rJuring wlTT^"u P^""* °^ ''^'^y glaciation, when the streams were burdened with glacial debris. Uter. with further retreat tJ J ' *•'* "J'^'"' ^"'''^ ^'■°™ ^"^ free f'om waste and began to cut down their previously built up material. Chmatic oscillations have brought about different periods of aggradation and degradation, with the production of river ^l^y.'^T '"!!*'^*'? '" ^'^"'^'" ^"^^ valley, and which are furthe. discussed in the chapter on Physiography. Coarse gravels, sands, and silts of the more resistant rocks mr 9S Although the conglomerate, m a rule, ia of a ..eterogeneous character, the pretence, in some localities, of a rude parallelitm in the case of some of the flatter boulders, indicates that a cer- tain amount of sorting by water has taken place during iu deposition. The conglomerate, as typically developed throughout the ar^a, contains boulders and fragments of practically all the older formations. It includes even such imperfectly decomposed and incompletely leached sediments as banded li to dark impure limestones with differen.ially weathered surfaces, ar- gillites, and coi jlomerates. The more resistant rocks, such as pure and impure quartzites, cherts, sandstones, greenstones, feldspar porphyries, and porphyrites, predominate, and stand out in bold relief upon weathered surfaces of the conglomerate (Hate IX). Some of the conuined pebbles are faulted (Plate XI A). Grey granite and quartz pebbles are present in relatively small amounts. No alkalic intrusive nor extrusive rocks, so common elsewhere throughout the district, were found in the conglomerate. A subangular boulder 2 feet in diameter, within the con- glomerate near the bridge o a ; angle of c Ac is 17 degrees Apatite is not very common, but when present occu^ i stout prisms. Titanite is abundantly develo.ied in wedg. shaped crystals. Epidote is present in large grains up to 1 mn in length. The pleochroism varies from colourless to deep r^c ween Titanite is crowded around the borders of some of tl grains of epidote. Chlorite and limonite are rlteration products 103 This black granular rock is of a very coarse grain, and on account of being made up almost entirely of hornblende has been called homblendite. Valhalla Granite. The Valhalla granite docs not outcrop within the limits of the Franklin map-area, but forms an extensive batholith to the west and north of the district. It has been examined by R. W. Brock, and described by him m the explanatory notes accompanying the West Kootenay Map Sheet' as follows:— "This is a medium-grained, light-coloured, very quartzose granite. The feldspars are orthoclase, microcline and plagioclase (albite to andesine). Microgranitic intergrowths of quartz and feldspar are common. Green biotite and hornblende are the coloured constituents. Apatite, titanite, orthite. zircon, and iron ore are common .... Aplite, pegmatite and ode- nite dykes accompany its intrusion. It is older than the Ross- Jand alkali-granitic rocks, but newer than the other plutonics. It has largely escaped mineralization." Monzonite. The monzonite of Franklin district varies in granularity from medium grained to coarse grained; in composition it is a monzonite of a somewhat dioritic type, which in places passes into diontic fades. Considering its mineralogical composi- tion as a whole, and its affinities with alkalic rocks, it seems better described as a monzonite than as a diorite. It has a charac- tenstic mottled appearance due to its large content of ferro- magnesian constituents. It occurs in stock-like masses in the northwest and northeast corners of tL- district. A good average type, taken from below AveriU's shaft, jras^jlected for petrographic examination, with the following Megascopic. Phanerocrystalline; medium grain; feldspar Slightly dominant over ferromagnesian constituents; medium grey colo ur; equigranular fabric. 'Map Sheet No. 792, Geol. Surv. Canada. I I 104 Microscopic. Under the microscope the following minerals are disclosed: andesine, orthoclase, microcline, and augite as essential constituents; iron ore, apatite, biotite, hornblende, and quartz as accessory constituents; with chlorite, epidote, kaolin, and limonite as alteration products. Biotite is allotriomorphic with respect to the other minerals. It has a strong pleochroism between very pale yellow and deep olive brown. Its period of formation overlaps the pyroxene but commenced later, as some of the pyroxenes have interior zones filled with biotite shreds. The pyroxene is a clear, pale green diopside of wide extinction angle. Rutile needles are developed through the biotite in places, the latter being in spots surrounded by grains of iron ore. The plagioclase feldspar occurs in short, thick laths, which are generally quite idiomorphic. They have elongated sections in places which show both Carisoad and albite twinning, the lat- ter with very thin lamellae. Determination by the Michel Levy method proved it to be andesine of composition Ab|An». It shows zonal structure in many places. Orthoclase is allotriomorphic and fills up the interspaces. It is altered in part to kaolin. The hornblende is the common green variety and of rare occurrence. Zircon is present in short, thick crystals up to 5 mm. in length. Apatite is present in stout crystals, as well as titanite and iron ore, the latter occurring in large grains. Quartz appears here and there, associated with orthoclase. Kaolin and chlorite are alteration products. The structurs of the rock is hypidiomorphic granular, and it has about equal amounts of alkalic and plagioclase feldspar, which combined only slightly dominate over the pyroxene and biotite present. A chemical analysis of the monzonite made by the Mines Branch yielded the following results: — SiO, 51.76 A1.0, 16.71 FejOj 2-58 FeO 5.37 MgO 5.09 CaO 7-30 tos Narf) . ICO * Total H,0 , TiOi ::::::::::::: a MnO " CO, J 09 04 66 27 10 76 MiCROMONZONiTE. A border fades of the monzonite ZlVrr T' "'^^ °^ '^^ ^'*« ^^' """"^""it* stock, dose to Gloucester creek. It was found to indude in placed small fragments of the coarser normal type of monzonite showing Tnl^wT^T- ^' "^P'"*"*' P^'^^'^'y ^ «"«htly later intru^ .on. which, judging from its finer texture, solidified more quickly tnan the main stock rock. A specimen from this locality appeared as follows— Megascopic. It is a fine-grained crystalline rock of a red- dish grey colour, composed in large part of fddspar with ferro- magnesian minerals wdl disseminated through the mass. It breaks with an uneven, hackly fracture, displaying films of lime, coating many surfaces. ' ♦K. f^^'"^"'^: The microscope shows it to be composed of the following minerals: apatite, magnetite, titanite. hornblende, plagiodaae. augite. quartz, caldte. kaolin, and chlorite. The apatite is m needles and small prismoids. The augite occurs as a few large scattered phenocrysts of dark green diopside. wh! J.h T" ^°™'''«."^f •« P^^"t in long slender needles, while the plagioclase displays a trachytoid arrangement of its laths, induding within it considerable magnetite. The quartz appears to be secondarily infiltrated. produi"**' '^°''"' ^""^ ''''°"**' ^'^ P'**"* ^ *''«^^*'°" Augite Syenite. an JIi''i ^'^^y''""^?^- -^^anular rock in the district, forms Slne^^ r ^^ '?''"''°"' "^'"'^^•"K from the northwest corner of the quadrangle southward and eastward to the eastern boundary, forming a broad arc concave to the northeast, with a ■ Ui t-n r« Vi 106 general dip in that direction. The intrunve aaeumet an ali:.ort vertical attitude at the baae of Tenderloin mountain, t - r-ob- able Bite of an old volcanic vent. Other smaller, isolated areas of less alkalic and slightly older syenite occur: (1) on the west flank of Franklin mountain, (2) on Syenite hill near west border of the district, and (3) a •ma^l crescentic shaped outcrop on the ridge west of Franklin creek. An average specimen of the augite syenite from the Maple Leaf property was found to have the following characteristics:— Megascopic. On e. freshly fractured surface the rock hat a medium grey colour; is phanerocrystalline; medium grained; dommantly feldspathic, with the tabular orthoclases arranged in trachytoid texture; granular fabric; uneven hackly fracture. Microscopic. Under the microscope the following minerals are seen: alkalic feldspar, pyroxene, hornblende, as essential constituents; iron ore, titanite, apatite, biotite, and melanite, as accessory constituenu; chlorite and kaolin, secondary. The feldspars are all alkalic, developed tabular on b (010) with cleavage parallel to c (001). They are frequently twinned after the Carisbad law, and form about 56 per cent of the rock The presence of a trace of nephelite was indicated by a chemicai test which gave gelatinous silicate, but it must be very small in amount as it could not be determined optically. The pyroxene is a very pale green diopside, the same as that in the shonkinite-pyroxenite ("Black Lead"), and is much cracked and broken. It forms about 24 per cent of the rock. A dark green hornblende occurs with the pyroxene. The two minerals are very frequently found together in stout, well •haped crystals from 1 to 2 mm. long, the pyroxenes forming a core surrounded by the hornblende. The hornblende appears to be paramorphic after the pyroxene.' Such uralitized pyroxenes are readily recognized in cross sections. The hornblende and feldspar in places have crystallized simultaneously. Some of the hornblende is primary, as shown by crystal outhne. Hornblende forms about 14 per cent of the rock 'IddingB a. P.): The Eruptive Rocks of Electric Peak. Kept. U.S. Geol. Surv., 1890-91, p. 606. 12th Ana. 107 Iron ore it rather abundant (about 2 ner cent^ in .».,ii j &r"'H-rT'"' " ^ ""^ ^y naLTrnu:ofT"tu' T tanite exhibits the usual diamond and wedee sharJ rrli f ' with a leucoxene-like alteration product. hfo^'fbouTf J per cent of the rock Biotite is seen in scatteredTe^.l," hJu! definue crystal outline, and is the common brown p.eol^hrdc Melanite garnet is present in dodecahedral outlines or rounH ed and uregular forms. It shows zonal structure h^,a^"nd' ha. ut^te frequenUy developed in it. The meLi tel^'of a brownish to brownish yellow colour, and forms ab^^ a half o^ Z Z T °L?* '°''- """^ P"^"- °^ ""'a Jte ?n a sy^iite :!l'^Zr^:A'''"'^''^'''- ^-'o^- and ".t nroJJi* °'*^". n^ crystallization for the various minerals was pr^Wy as follows: iron ore. apatite, titanite. hoSenr pyroxene, biotite, melanite. orthoclase mmenae. of thJT^ ComposUion or Mode. The relative quantities meth'i.~rr;,r'^^' ^ '-^-^^^ 'y ^^^ Alkalic feWspar ^^^.^^ Pyroxene ' ' 24.0 Hornblende ' i^ a t 14'0 Iron ore , _ Titanite JJ Apatite y.y^[y.'.'.'.'.'.'.'.''' i!o Melanite garnet q's Remainder q- 1000 by th?L'tirSL.!^fL*"'''*°'^ *"*"^' '"^''' » «'"d'^-«i out tS: ^nstit;™^""'" """^'^ ^™ •"'^"•--^ ^">"«h- Brancht^iS'^foCsl''^ ^'"^"'" "^'^ ''^^ ^^ ^^"^ 108 cw percent S'Oi 55.16 A'tOi 17.30 FetOi 3.58 FeO 2-81 MkO i.gg CaO 4. go NaiO 3.03 KiO 8.73 Total H|0 1.40 TiOi 0-36 MnO 008 COi 1.40 100-53 Melanite Syenite. One variety is a melanite ayenite from the Maple Leaf property, whose characteristics are as follows. — Megascopic. PhanerocrystalUne, holocrystalline texture; medium grained; equigranular; light grey colour, mottled with smaU black ferromagnesian minerals; dominantly feldspathic, with elongated lath shaped crystals which exhibit fluidal ar- rangement, giving a tabular or trachytic fabric. Microscopic. In thin section, the materials are apatite, magnetite, zircon, titanite, garnet (melanite), alkalic horn- blende, biotite, muscovite, orthoclase, fluorite, chlorite, and kaolin, which are given in their probable order of crystallization. Apatite is present in, usually, small prismoids; is always perfectly fresh, and may occur as uiclusions in any of the other constituents. Iron ore is scattered irregulariy throughout the rock in cubes and grains. Zircon is in short thick prisms. Titan- ite or sphene is in typical wedge-shaped crystals or smaU spmdle-shaped granules, reddish brown in colour. Melanite is extremely well developed in octahedral forms, measuring OS to 1 mm. in diameter. It includes in places, magnetite, titanite, and apatite. It is of a greenish to dark brown colour, but is bleached in places to a yellowish tone. 109 A hornblende with an extinction angle of 18deKr«..s isprwenf it vane, rom green to brown iu colour; has strong pIcJhS' and con«denng it, colour and a^ociation, i, ju5g^ to ^^ «. «»jl>cnature. pjobably near arfved«,nite in compositio^ The biotite I. the green variety common in certain alkalic rock., and occur, in .hred. and irregular masses a^SS w«h other ferromagnesian minerals. It forms in place Jt- tered mclusion. in the feldspar. Fluorite appears in .mall bluish masses filling cavitie. or crack, m the vicinity of the garnet. It i, probably of pneu matolytic ongin. deposited during the period when ga«. of magmatic ongm ro«. through the mas. of recently conilidati twin2^i'°1»'^ " the prominent feldspar and shows Carlsbad twinmng. ?...croperth.te is al«, present. Orthoclase wa. found included .„ the melanite garnet, as in the accompany^sttch micrograph (Figure 15). H-nymg sKPtcn occuIJ^-'"*"" °^ '"'''^''* «'""'* '" * 'y^'"''' « rare. It. Z^Zu J °°* ""^'"r" ~"»tit..ent of alkalic igneou, Xt'.V I ■ "''P''!'"«-»yenite. phonolite. leucitic and ne- phehtic lava. ..mentioned in many places in the literature « i* melanite syenite could be classed with ledmorite provided that not too much stress be laid upon the presence o ^Z^T "^' '''"■'^ ™"- "'•^'^ ^^P'^- -«'-' -P'e'ite Porphyritic Syenite. ch.^^""^" ""^"^'^ °^ '^'^^^y °'^^'' ^«"'te mo^t peculiar in character, occurs on Syenite hill west of Franklin creek It displays unusuaUy long crystals, up to 2 inches n fenlth o un^nated feldspar, with thin b<;rde'rs or ri^s o" "lighter col Ser:*^ "''^ " ^ P'^^°^'^- 'T'^^ crystals tplal Figure 15. A— Micro-»lcetch to show skeletal crystal of melanite (black) enclosing orthoclase; melanite syenite from Franklin moun- tain; magnification, X40. B — Micro-sketch to show skeletal crystal of melanite (black) enclosing orthoclase; augite syenite (ledmorite) ; after S. J. Shand; magnification, X24. Ill It ha* timiUir mkroioopic chtracterittica to that of the nomMl type, but it more addic in that it has accessory quartz. It haa a much greater proportion of micropertJtitr than had the other feldapar of the foregoing type. The utrromagnnian mineral ia iMmbtende altered largely to chlorite :. Skonkinit0-Pyrax«niu. This rock occurs as a basic differentiate mainly at the bor- ders of the augite syenite intrusion, and is locally known as the "Black Lead." Its geologic relation to the syenite and mon- sonite has already been discussed in the preceding chapter. The shonkinite-pyroxenite maintains a fairly uniform character throughout the district. A type specimen which came from the prospect shaft on the Averill property is as follows: — Migaseopie. Phanerocrystalline; coarse grained; black to dark green colour; dominantly composed of pyroxene. In the coarsest grained forms the augite crystals are so large and abun- dant as to give the rock a strongly porphyritic appearance. Microscopic. The following minerals are present, and are given in their probable order of crystallization: apatite, titanite, magnetite, pyrite, chalcopyrite, hornblende, biotite, augite, orthoclase, and microcline, quartz, chlorite, and calcite. The apatite is present in small prisms of euhedral as well as anhedral forms, and is enclosed in magnetite, augite, and feldspar crystals. Magnetite and pyrite are rather abundant in occasional euhedral but chiefly irregular forms. The iron ori forms about 6 per cent of the rock. Titanite is present in characteristic wedge-like crystals. Common green hornblendes occur as irregular small masses within the augite. Magnetite is always abundant in the vicinity of the hornblende. The augite present is of a green to greenish brown colour; is idiomorphic with respect to the orthoclase and microcline. Extinction angles measured in plane 010 vary from 31 degrees to 41 degrees. Some crystals are twinned on orthopinacoid a (100). The augite shows excellent prismatic cleavage and forms about 73 • 13 per cent of the rock. j1 I if > \ ^ »■■ 1 ,,.^, !f 112 Biotite is ' :xy sp nngly developed, and occurs in small well formed .(eis of e ordinary pleochroic brown variety, usually in th a. ^ t^ Orthoclase v- -uis aUotriomorphic with respect totheaugite and fills in all the interspaces. It is in places partly altered to kaolin. Microcline appears in a similar manner to the ortho- clase but shows less alteration. It is characterized by the "gridiron" structure between crossed nicols. The alkalic feld- spars make up about 17 per cent of the rock. Quartz is present only in small grains in the feldspar. Chlorite to a minor extent is present as an alteration product of the ferromagnesian min- erals. Calcite occurs in narrow branching veinlets traversing the rock constituents. Mineral Composition or Mode. The determination on mineral percentages by the Rosiwal method gave: — per cent Augite 73-13 Feldspar 17-06 Apatite i-oe Iron ore 6-06 Hornblende 1-47 Biotite 0-77 Titanite 0-41 Remainder 0-04 100-00 It is seen from these figures that augite forms by far the greatest bulk of the rock (nearly three-quarters), with alkalic feldspar next, and iron ore third in importance. A chemical analysis of this rock made by the Mines Branch resulted as follows: — SiOj 45.90 AljOs 6-59 FejO, 7.58 FeO 8-19 MgO 7.70 CaO 18-00 113 NaiO 2-16 K,0 1.46 Total H,0 1-20 TiO, MO MnO 0-20 CO, lOj-OS The texture of the rock is very coarstly granular, with large phenocrysts up to 1 inch, scattered throughout a general groundmass of pyroxene of all sizes from 1 to 2 mm., with in- terstices between the crystals filled with alkalic feldspar. The original type of shonkinite, which is a marginal fades of a sodalite-syenite at Square Butte, Montana, is a rather coarse granular rock, consisting of predominant augite, with orthoclase, albite, and anorthoclase, apatite, biotite, iron ore, sodalite, traces of nephelite, cancrinite, and zeolites.' Besides the Square Butte occurrence, this rock is also found at Yogo peak in the Little Belt range, where the augite crystals are not so large and idiomorphic as at the former locality and the rock has a greater proportion of biotite.* In the Bear- paw mountains shonkinite is again found in the peripheral part of an alkalic syenite stock.» BrSgger* in his work on the Monzoni rocks cites an occurrence of a "pyroxenite" with large crystals of orthoclase as a portion of a differentiated mass, and points out its resemblance to shonkinite. In comparing microscopically the Franklin type with those from Montana it was seen that they closely resembled each other, both having the characteristic pale green diopside with con- siderable alkalic feldspar, but the Franklin shonkinite contains, 'Weed (W. H.) and Pirsson (L. V.) : Highwood Mountains of Montana: BuU. Geol. Soc. of Am., Vol. VI (1895), p. 415. •Ibid.: Igneous Rocks of Yogo Peak, Mont., Am. Jour, of Sci., 3rd Ser., Vol. I (1895), pp. 467-479. *Ibid.: The Bearpaw Mountains, Mont., Am. Jour, of Sci., 4th Ser., Vol. I (1896), pp. 283-301, 351-362, Vol. II, pp. 136-148. ^Eruptionsfolge eruptivgestaine I^edazzo, 1895, p. 66. Triad. Enip. Predazzo, 1896, p. 67. 114 on the whole, a much larger proportion of pyroxene, and hence the name shonkinite-pyroxenite seems best fitted for its de- scription and classification. Rossland Alkali-Granitic Rocks. The batholith situated about 2 miles to the east of the district was mapped by R. W. Brock,' and the rocks described as follows: — "The commonest rock included under the Rossland alkali- granitic group is a reddish to pink granitic rock, in which glassy pink and some greyish feldspar are the most conspicuous con- stituents. The dark constituents, while very noticeable on ac- count of contrast in colour, are present in subordinate amounts. Its principal constituents are orthoclase, microperthite, albite, perhaps anorthoclase, sometimes quartz, sodalite, and probably other feldspathoid minerals, biotite, hornblende, diopside, magnetite, apatite, zircon, titanite, and orthite. The alkalis form 12 per cent of the rock. The rock shows a number of fades from granitic to probably essexetic types, but an alkaline syenite or pulaskite type is the commonest Their relationship to the Tertiary volcanics has not been satisfactorily proven but it appears as if they might be closely connected. A genetic relationship exists between them and the Tertiary volcanics of the Boundary Creek district. The dykes from these rocks include granite and syenite-porphyries, granophyr«s, quartz- porphyries, etc. Younger than these 'light' dykes are dark lamprophyric ones including fourchites, camptonites, monchi- quites, and mica lamprophyres. "These are probably the complementary basic dykes con- . -cted with this eruption •' DYKE ROCKS. The dyke rocks of the Franklin district present a great variety of rock types, and may most conveniently be described 'West Kootenay Map Sheet, No. 792, G.S.C. sib. 115 under the general terms aschistici (undifferentiated) and dia- schistic (differentiated), with their subdivisions. The terms are limited here to the dyke intrusions, alone, and not to such complementary masses as the pyroxenite and syenite. The aschistic dykes occur as tongues or apophyses from igneous bodies: they have the same mineral composition as the main mass, and differ from it only in their texture. The diaschistir dykesi on the other hand, represent extreme divergences from the main parent stock and differ in their composition; the lamprophyres are the basic extreme, and the aplites the acidic extreme. fGranodiorite porphyry f^"^**'^^"''^P°'T*>y^ yr- J Syenite porphyry of Aschistic j Quartz porphyrj' [Syenite porphyries Tenderloin mountain Pulaskite porphyry Diaschistic ■ fGranodiorite aplite Monzonite aplite Syenite aplites Umprophyres /^'"f«« . ,. l^Augite microdionte Coarse phase of syenite aplite Syenite- aplite porphyry Ast Cranodioritt porphyry. The granodiorite porphyries are found in tongues or apo- physes, extending out from the main granodiorite batholith, and can best be seen at the McKinley mine. They are so highly meta- morphosed in places that they are difficult to distinguish mega- scopically from some of the Franklin group altered eruptives. 'Brtigger (W. C): Die Eniptivgertein- Krirtianiagebietes, Vol. I, Uie Gesteine der Gronidit-Tinguait-Serie (I8y«^ pp. 125-153. .1 116 A specimen from the Franklin mine open-cut (locally known as the "Glory Hole") was found to have the following charac- teristics: — Megascopic. It is a greenish grey rock, dotted throughout with dull white feldspar and black, generally altered, hornblende phenocrysts, which give the whole rock a decidedly porphyritic structure with ai aphanitic groundmass. It has an uneven hackly fracture. Microscopic. Under the microsc pe the rock appears to be a fine-grained, holocrystalline rock with a porphyritic fabric. The phenocrysts consist of idiomorphic green hornblende and plagioclase feldspar with subordinate quartz. The groundmass is made up of a fine aggregate of orthoclase, plagioclase, and quartz. The orthoclase is largely kaolinized. On account of the similar mineralogic characteristics, as well as geologic relations between the granodiorite batholith and this dyke rock, it has been classified as granodiorite porphyry. Quartz Porphyry. This rock forms irregularly shaped dykes, generally near the contacts of the monzonite and syenite, and is younger than either of them. A typical specimen from the White Bear prop- erty was chosen for description: — Megascopic. It >f a light grey colour; is porphyritic, aphanitic; has clear rounded quartzes and dull feldspar pheno- crysts in a fine-grained groundmass; has hiatal (sempatic) fabric; breaks with conchoidal or splintery fracture. Microscopic. Under the microscope the following minerals are present: apatite, biotite, andesine, orthoclase, quartz, epi- dote, and chlorite. The quartz phenocrysts (average 2 mm. in diameter) are partiy corroded, and contain embayments of the groundmass. The groundmass is cryptocrystalline. The rock is a typical quartz feldspar porphyry, and on account of the an- desine feldspar present in it, it may be related to the monzonite, which also had andesine well developed in it. 117 Augite Syenite Porphyry. This rock occurs as small dykes penetrating the cover of the augite syenite intrusion on its concave side. A specimen from the Crystal Copper property appeared as follows:— Megascopic. Holocrystalline; porphyritic> aphanitic with elongated orthoclase phenocrysts averaging 2-5 mm. in length oriented often parallel to each other; light greyish colour'; uneven fracture; feldsophyric groundmass. Microscopic. The following minerals are present: apatite, titanite, melanite, orthoclase, chlorite, and kaolin. The ortho^ clase shows Carkbad twinning, and is elongated on clinopinacoid (010) face with cleavage parallel to base (001). The augite has broken down into chlorite, calcite, and kaolin. The melanite occurs as brownish to brownish yellow octahedral forms up to 1 -6 mm. in diameter. The rock differs from the main syenite i.. ics structure, which mdicates a hiatus between time of crystallization of feld- spar laths forming the phenocrysts and those of the groundmass. On account of the close similarity between the minerals of this rock and the parent alkalic syenite, and the finding of melanite garnet in these dykes, they are considered apophyses from the syenite intrusion which underiies the district in which they are found. Syenite Porphyry of Tenderloin Mountain. A different phase of syenite porphyry was found only in one locality, on the south end of Tenderioin mountain, where it cuts the trachytic and basaltic tuffs near their contact with the underiying grits. It has the following characteristics:— Megascopic. Holocrystalline; porphyritic aphanitic; pur- phsh grey, with large pink feldspar phenocrysts up to 10 mm. in length; breaks with an uneven conchoidal fracture. Microscopic. Under the microscope the following minerals were determined: apatite, in large and prominent euhedral crystals; large and small magnetite grains; titanite, zircon, ohgoclase, orthoclase, showing Carisbad twinning; epidote and chlonte as alteration products. The phen crysts of orthoclase, I 118 oligoclaae, and apatite are in a microgranitic groundmass of the bai..e minerals. A chemical test for nephelite gave slight gelatini- zation, but it must be present in very small amounts, as micro- scopjc examination did not reveal it. The texture of the ground- nuss is trachytoid. Pulaskite Porphyry. Pulaskite porphyry is a very common rock in the Franklin distnct, and forms several definite systems of dyke intrusions, cutting all the other rocks with the exception of the lampro^ phyres. It U locally known as "Bird's eye porphyry." A typical specimen from the junction of McKinley trail with the Grand Forks road has the following characteristics:— Megascopic. Holocrystalline; has a few scattered large pmk feldspar phenocrysts (up to 3 mm. in length) in apharitic groundmass, with a few small biotite Hakes in places; pinkish colour; uneven fracture: dull lustre. Microscopic. Under the microscope were distinguished the followmg minerals: apatite in needles and prismoids; magne- tite, biotite, hornblende, augite (pale diopside), orthoclase in starry grouping in places, oligoclase, alblte, and chlorite. This rock has a trachytoid structure and has considerable biotite. It resembles closely in mineralogical composition the pulaskite' type of alkali-syenite, and this term has been used m classifying it. It can always be readily distinguished from any other syenite porphyries by its pinkish colour and the spotted effect which the scattered feldspar phenocrysts give to the rock on weathered surfaces. Pulaskite may be defined as a type of alkali-syenite, be- tween a normal syenite and a nephelite syenite, with biotite as chief ferromagneaian constituent. Nordmarkite is a quartz- beanng pulaskite. DiASCHISTIC. Granodiorite ApHte. Apiite occurs in the form of narrow dykes and dykelets traversi ng the granodiorite as a rule near its contacts with the 'Rcwenbuach (H.): Intrusive-Gesteine, II, 1, 1907, p. 146. ^M si 119 other formations. Hand specimens show a light greyish roclc nf the sugar-granular texture of typical aplites ^" A specimen behind Chisholm's cabin whenexamm-^ a the microscope, was found to be a fi^e-gmrned t^L^ k-"" mucture of quartz and. mainly, unstriat J e Idspt t^^^^^^^^^ clase .s^p^sent .n idiomorphic coastals. The biotite'TsI £S: Monzonite Aplit:. This rock is found sparingly in dvlcM r..tt,„„ *u It resembles the granoSforitrap J " '"^f T "-"'^^^ Syenite Aplile. Coarse Phase of Syenite Aphtb- tu- i • , cutting the monzonite in sev^S plac^ it ?'' "^"^ " '°""^ feldspars pr^tin/ vet f"^, ' ''/^""^ °^ *='^^^«« °f ^^e F«"o, presenung very angular surfaces. 120 Megascopic. Holocrystalline; porphyritic aphanitic; ligh grey in colour; fine grained; hiaul (dopatic); uneven fracture dull earthy appearance. Microscopic. Under the microscope the following mineral were observed: apatite in needles and prismoids; biotite shreds small amounts of accessory pale diopside; orthoclase laths con siderably kaolinized; some ferromagnesian mineral altered t chlorite; secondary calcite replacing mineral which former!; filled angular interstitial spaces and may have been nephelite Calcite appears to have replaced some of the diopside. The rock displays trachytoid structure, with the feldspa phenocrysts not very well defined. There is too much ferro magnesian mineral in the rock to call it a bostonite, so the tern syenite aplite has been adopted. Minette. The main lamprophyric rock is a minette, which outcropi for over a mile in length on McKinley mountain and varies ii width from 10 to 150 feet. The specimen whose characteristic are here given, was taken from the No. 1 tunnel of the McKinlej mine, where fresh samples could be obtained of this readilj weathered rock. Megascopic. Holocrystalline; fine grained, average mud less than 1 mm.; compact; dark greenish grey colour; biotit( appears as flakes scattered through the rock; phenocrysts of i greenish pyroxene seen in places; dull; hackly fracture. Microscopic. The following minerals were found present iron ore, apatite, biotite, augite, orthoKlase, plagioclase, and i trace of olivine, as well as calcite, chlorite, and kaolin. Iron ore grains frequently clustered around the augite: suggest a pushing of the already formed magnetite grains b> tx >» growing augite. The interior of the biotite is a brownish ochre yellow, be- coming deep brown at borders. This zonal structure, so common in the biotite of minettes, is seen best in basal plates. In sec- tions perpendicular to the cleavage, the pleochroism varies between pale yellow and deep brown. It is bent in places and 121 occurs chiefly in irregular masses, although in place, it presenu ES^ T ^ °h!ST- J'?^^'='^»'«' » "Chiefly an unstriatraJ kalic one clouded by incipient kaolinization. The plamoclaae IS generally much fresher than the orthoclase. and is prS^ntl^ much less amounts. Chlorite, calcite. limonite. and kaolin are present as alteration products. The lath-like feldspars give the rock a trachytoid struc- mLl'T?. ^^", ^!?'°^' ""^ mineralogic relations of the minettes to the pulaskite porphyries indicate that they are closely related genetically. ^ The Franklin minette has a greater proportion of augite and 1«« hornblende than the minettes from the Little Belt mountains, Montana.* A chemical analysis of the minette made by the Mines Branch resulted as follows:— ^»9« 13-85 ^f!?' 3-43 FeO 5.24 ^^ ■; 8.48 ^^^ 7.8O f^ 3-34 *^«0 3.0s ]:p?'"'0 :;:: 3.30 Jl^^ 0.62 jj:^ 0.15 *-"• 1.00 Augite Micr-xlioriie. 100-60 svenJp H T^ TH'? ^ ^ ^^y""* '="**^"8 ^''« granodiorite and a ^erilu^'"' "^""^ "-'"'^'^ '''°'"'^- ^* "^ ^^ ^°"o-n. mouISTtf^h^'^' f,!rPP'"' °' ""= '«"«>"• R«*» of the Little-Belt ""ountau... Montana, 20th Ann. Rept. U.S. Geol. Surv., Pt. III. 1899, p. tu. . I 122 Mtgascopic. Holocrystalline; fine grained; dark greenish grey colour; seriate, inequigranular fabric; uneven fracture. Microscopic. Under the microscope green diopside appeared in irregular and rounded phenocrysU;andesine feldspar, showing tonal structure, is in idiomorphic lath shaped forms, with allo- triomorphic orthodase in places; biotite is largely altered to chlorite, but shows deep brown pleochroism at bonlers; magnetite dust and apatite needles are present. The structure of the rock is panidiomorphic, and somewhat resembles kersantite, except that it has augite ss a dominant ferromagnesian constituent. On account of the dioritic com- position of this fine-grained rock and the abundance of augite, it has been classified as an augite microdiorite. EXTRUSIVES. The extrusive rocks will be described under the following headings: — fRhyolite and rhyolite porphyry Trachyte Phonolitic trachyte (Alkalic basalt ; Agglomerate and bombs 2. Pyroclastics j Trachytic tuffs [Basaltic tuffs Flows. Rhyolite and Rhyolite Porphyry. The oldest Tertiary lava flows present in the Franklin dis- trict are certain rhyolites which were in part contemporaneous and in part subsequent to the deposition of the Kettle River formation. (For full details with regard to structure and areal extent see former -chapter on General and Structural Geology). These rocks vary from holocrystalline types, practically quartz porphyries in structure, texture: and mineralogic composition, to semicrystalline types having flow and vesicular structure. 123 A ■pecimen uken from the west side of I a.» ru MKToscoptc. Under the microscope it was foiin,< .« «. of: apatite, zircon, iron ore (ovrite rn»l j^ • . ''°"'"" are rare, the latter occurring in olao^ « inT • ^ '^ ^"~" Michel Uvy method Itn^J^^ (Ab^n.) deternmed by the posed »n^' . '*''^'"'"°«»P«itwasfoundtobecom- ofcorro^lT""?" Porphyritic. with prominent phenocrysts 124 SiO, 69-60 CaO 0-68 NaiO 3.97 KiO 5.84 Trachyte. This is the commonest as well as the youngest flow rock i the district. It forms protective lava cappings to all '.hree moun tains, and varies slightly in composition from a phase approach ing phonolite in some places, to one approaching basalt in othe places. In structure it varies from porphyritic to dense an< vesicular. A norma! type from the east slope of McKinley mountaii was chosen for description : — Megascopic. Holocrystalline; porphyritic aphanitic; light t( dark grey, with purplish tinge; dull lustre; dense, subconchoida to uneven fracture. Microscopic. Under the microscope the following minerals were observed: apatite in prominent prismoids; magnetite ii small disseminated and octahedral grains; biotite showinf through alteration, sagenite webs; labradorite; orthoclase ir small prisms. The chemical test for nephelite gave slight gela^ tinization, but the mineral could not be definitely determinec in the slide, and if present must be as minute interstitial fillings The feldspar and biotite phenocrysts are enclosed in a ground- mass composed of a felted mass of the same minerals, with trachy- toid structure and fluxional arrangement. Another type, from an older flow, occurring on the east side of Last Chance ravine on McKinley mountain, is described, as it is of interest in showing the similarity between the large, fresh, unstriated feldspar and brown hornblende of the flow rock and that of its hypabyssal syenitic equivalent on Syenite hill not far distant. Megascopic. Holocr>stalline; porphyritic aphanitic; green- ish grey colour with slight purplish tinge; hiatal (dopatic) fabric; uneven fracture. Microscopic. Under the microscope the following minerals 125 were noted : magnetite, hornblende, augite. plaRu>cla«., un«ri-,ted feldspar. apatUe. chalcedony, chlorite, and kaolin. Th" aS W„ Cnrj '°P*'^^^"^ '« "- 'ar^ely chloriti^eS The brown hornblende » partly resorbed. and has magnetite ,1...! at .U border. The feldspars are plagioclase. anZ u triat^ vanety. the atter in long crystals with, in places. raLlX^ and ~ned like those characteristic of the porphyrittc Tyen , ' STmoidT r ':!;i'*'- ""'^ ^'^^''^ occuVabundantir n pnsmoids. Corroded quartz grains are rarely present ChLl dony fill, some of the pore spaces. The roc'kTTyp ical^'j^ ! phynt|c. with a groundmass of trachytoid texture of t Jrl^JT'' •/'°'" ' •' ''.°'*' -"'"eralogic resemblance to that of the porphyntic syenite, is taken to be its effusive equivalent and us geologic relations prove it to be slightly older thin the more alkalic types of trachytic lavas. ' A type from the south end of Franklin Mountain summit where the trachyte is found capping the rhyolite. sh„3T"e presence of a pale green diopside; biotite is largely r^l^ and displays sagenite network of rutile needles. ThTs t^l^, Rssed downward at the base of the flow into vesicularTnd lag^ sconaceous phases, still retaining pale gieen augites. ^"^• A speamen from the south bump of Tenderloin Mountain u^ZTv- y *''* microscope, orthoclase phenocrysts ih?m^ J^"'""^. are present, and the rock on being t7sed ndStr '°"m '° ^'^^ ^ ^^'^ ^"■^''^ gelatinou^'si fcie Sr ChSr ?T- ""^'"''^ ^''■"^*"^^' ^"'J *a« evidently Diotite. Chlorite and calcite are alteration products. The ground rh;ricTures" ^'^"^ -' ^'--''- ^eldspars^Cnt mayt^dtrii^-atflw:'!^^" ^^^^ '^^ •^-^-'^ — - greytJor^'- "°'°^'^^^^"'"- = P^^P^vritic aphanitic; olive grey cc.our. uneven fracture; hiatal (dopatic) fabric. sjnite s^^; 'r ! jl^'^^bundant; magnetite; biotite with sagenite structure and largely resorbed; pale green diopside in 126 irregular masses; labradorite, and quite large orthoclase pheno- crysts (up to S mm. in length), in a felted groundmass of al- kalic feldspar showing trachytoid structure. A trachyte from the west side of Tenderloin mountain which presents reddish weathered outcrops was found on microscopic examination to have augite strongly developed through it, some of the crystals showing zonal structure. The groundmass con- tained orthoclase phenocrysts which included a nondescript isotropic substance. Plagioclase phenocrysts were highly al- tered, while caldte and chlorite formed alteration products. The presence of a very small amount of nephelite was shown by a chemical test which gave a slight gelatinization. This fades of trachyte appears to be an intermediate type between the normal trachyte and an alkalic basalt phase. A chemical analysis made by the Mines Branch, of the aver- •age trachyte, resulted as follows: — SiO, 60-34 Al,03 18-10 Fe,0, 2-71 FeO 1-28 MgO 1-36 CaO 1-82 Na,0 S-2S K,0 7-35 Total HiO 1-25 TiO, 1-00 MnO 0-05 CO, 100-51 Phonolilic Trachyte. A phonolitic phase from the escarpment above the Maple Leaf property appears as follows: — Megascopic. Holocrystalline; porphyritic aphanitic; red- dish grey colour; dense, subconchoidal imeven fracture; dull lustre. 127 Microscopic. Under the microscope are noted the following minerals: apatite, magnetite, titanite, leucoxene, alkalic feld- spar, augite, chlorite, and kaolin. Titanite and apatite are com- mon accessory constituents. The augite is a pale green diop- side, and forms phenocrysts in a very fine microcrystalline base which the high power objective shows to consist of mostly short, irregular tablets of feldspar mixed with a relatively large amount of granules of pyroxene and magnetite, enveloped and cemented by a cloudy, faintly polarizing substance of which no nearer characters can be given. The whole is dusted through with the alteration products, limonite, chlorite, caldte, kaolin, and prob- ably zeolites. The general character of the rock, with its entire lack of quartz or silica in the groundmass, indicates that it is a trachyte inclining towards the phonolite side, and this is fur- ther indicated by gelatinization obtained by chemical testing, although it is not, of course, absolutely certain that the gel- atinous silica may not come in part or wholly from zeolite pro- ducts. This rock as seen in outcrops on Franklin mountain tends to break with a platy parting, like many phonolites. Alkalic Basalt. A dark, basic looking lava occurring on the west flank of Franklin mountain is composed dominantly of a pale green augite in a felsophyric groundmass consisting of alkalic feldspar with much disseminated magnetite dust. On account of its high content of augite, lack of trachytic texture in ground- mass, and megascopic characters, it has been classified as an alkalic basalt. Between the trachytes previously described and this alkalic basalt type all transitions occur. The cilkalic basalt bears the same relation to the trachytes that the shonkinite-pyroxenite does to the syenite, and it may represent the effusive equivalent of the former hypabyssal rock. Some of the lavas, especially the basalts, are vesicular and amygdaloidal, and show chalcedony, intergrown with calcite, filling the gas pores, the whole surrounded by shells of epidote 4i ' ^ j If' Si ^^■B ^ ^^^^E '^ H riii JH 128 grains. The amygdules are generally oval shaped, due probably to flowage at the time of extrusion, which drew out and extended the steam pores in which the chalcedony and calcite were sub- sequently deposited. A chemical analysis made by the Mines Branch of the basalt, resulted as follows: — SiO, 49-60 AUO, 14-84 Fe,0, 414 FeO 3-45 MgO 7-58 CaO 7-72 Na,0 2-68 K,0 3-72 Total H,0 3-30 TiO, MO MnO 010 CO, 1-80 100 03 Pyroclastics. This division comprises all those rocks which consist of fragmentary materials varying in coarseness from volcanic blocks and bombs to true ashes and tuffs, and which were ejected from volcanic foci. On the east slope of McKinley mountain considerable agglom- eratic material is present, as is well shown in the accompanying photograph (Plate XXII). Here the large lava blocks are chiefly angular, and the agglomerate as a whole is altogether devoid of stratification. The basal portion of the Tenderloin lava cap on the west side of the mountain has considerable coarse ejectamenta, with round volcanic bombs up to 1 foot and more in diameter. Along with the larger rounded fragments there are smaller angular ones, as shown in the accompanying photograph (Plate XIX). The ejectamenta are of a vesicular nature and dark in colour, resembling the dkalic basalt. 129 The trachytic and basaltic tuflfs in the district are well strati- fied, and alternate between fine and coarse beds intercalated with trachytic and basaltic lava flows. A typical specimen from the east side of Tenderloin moun- tain, where the bed was intercalated with vesicular and amygda- loidal types, appears as a dense black, homstone-like rock, banded and breaking with a sharp conchoidal fracture. Weather- ed surfaces are often lime coated. Under the microscope it showed sharp angular fragments of basaltic lava of pilotaxitic texture, in a glassy groundmass with calcite cement. Similar basaltic tuffs were also found on Franklin mountain. THEOR iv '^NSIDERATIONS. Intkoductory Statement. The bearing of the foregoing petrographic details upon a few of the broader problems in petrology will be here briefly stated. The igneous rocks of the Franklin district may be con- veniently grouped under two main divisions: (1) Regional — batholiths and related intrusives. (2) Local— alkalic series of intrusions. The regional group includes the three batholiths (Nelson, Valhalla, and Rossland) and their lelated dyke equiva- lents. The rocks of this group are discussed in detail in the General and Structural Geology, Chapter IV (pages SS, 103, 114). It is with the rarer and more interesting rocks of the local group that this section has to do. Petrographic Provinces. The discovery of alkalic rocks in the Franklin district, on the western side of the Rocky Mountain Cordillera, has a distinct bearing upon the question of petrographic provinces, their extent and orographic relations. The term 'petrographic province' was first introduced by Judd,* who conceived the idea of genetic relationship of igneous rocks which show a certain •Judd (J. W.): Quart. Jour. Geo!. Soc., Vol. XLII, (1886), p. 54. 130 'consanguinity,' to use Iddings' classic term. The principle has since been greatly enlarged upon and applied to many widely scattered regions, by Iddings,' BrOgger,* Lacroix,* Pirsson,* Harker,* Adams,* and others. A petrographic province may be defined' as any definite area of the earth's crust where the igneous rocks have common petrographic characteristics or clan relationship, which serve to ally them together and delimit them from the rocks of other areas. The cause of this clan re- lationship between all the different rocks in the series has been thought to be due to the differentiation of one common magma, originally homogeneous. It has been urged by some* that there is a relationship between igneous activity, including differentia- tion, and crustal movements, but to what extent this can be universally applied is still a question of much dispute. The Franklin series of alkalic rocks belongs to a petro- graphic province in south central British Columbia which in- cludes Rossland and other isolated areas whose petrography has not yet been studied in detail. The rocks comprising the series resemble in many respects those of the central Montana petrographic province,* on the eastern side of the Cordillera. Future geologic work in the intervening area may demonstrate that the tvf» provinces are continuous. 'The Origin of Igneous Rocks: Bull. Phil. Soc., Washington, Vol. XII, (1892), p. 194. •BrOgger (W. C): Eruptivgesteine des Kristianiagebietes, I (1894). II, (1895). 'Roches alcaline de Prov. Petrograph d'Ampasinlava, Nouv. Arch. d'Museum, 4me. Ser., Vols. I et V, 1902, 1903. * The Petrographic Province of Central Montana: Am. Jour. Sci. (4). XX, July 1905, pp. 35-49. • Natural History of Igneous Rocks, Chap. IV, 1909, pp. 89-109. •Adams (F. D.) : The Monteregian Hilb, Jour. Geol. XI, pp. 239,.253, 1903. ' See Judd: Petrographic provinces or districts "within which the rocks erupted '•• ring any particular geological period present certain well-marked pcculia. .Lies in mineralogical composition and microscopical structure, serving at once to distinguish them from the rocks belonging to the same general group, which were simultaneously erupted in other petrogiaphical provinces." •Natural History of Igneous Rocks, 1909, pp. 12,330. •Pirsson (L. V.): The Petrographic Province of Central Montana: Am. Jour, of Sci. (4), Vol. XX (1905), pp. 35-49. 131 Harker* contrasts the great diversity of types east of the Rucky mountains in his Atlantic Province, characterized by alkalic rocks, with those on the west side of the Continental axis in his Pacific Province, characterized by subalkalic types. The finding of such diverse alkalic types in Franklin, west of the Continental axis, shows that such broad specific delineations of the boundaries of petrographic provinces, based largely on assumptions of orographic control, cannot be made.' Further- more, the remarkable similarity between the two provinces, one on either side of the Continental axis, renders very doubt- ful whether horizontally directed compressional forces influence at all the distribution and localization of petrographic provinces.* The rocks included in the series are as follows: monzonite, porphyritic syenite; augite syenite melanite syenite, nephelinitic syenite, shonldnite-pyroxenite; augite syenite porphyry, syenite aplite; trachyte, phonolitic trachyte, alkalic basalt, and pyro- dastics from agglomerates to basaltic tuffs. All the diverse rock types of the series nrs considered to be co-magmatically related. The oldest intrusives represent the least alkalic and contain accessory quartz, while the youngest are the most alkalic and show the greatest degree of differentiation. The evidence upon which their common in* atelluric origin b based consists of their chemical, minera . ->nd textural peculiarities. From a study of the micro-slides belonging .he series it was found that the general law formulated by Professor Pirsson for the central Montana province holds good for Frank- lin, namely: — "The petrographic province of central Montana is char- acterized by the fact that in the most siliceous magmas the per- centage of potash and soda are about equal; with decreasing silica and increasing lime, iron, and magnesia, the potash rela- tively increased over the soda, until in the least siliceous magmas it strongly dominates." 'Marker (A): The Natural History of Igneous Rocks, 1909, p. 103. 'The Natural History of Igneous Rocks, 1909, p. 102. •Op. cit., p. 330. 132 The mineralogic characteristics are dependent upon the chemical as well as physical conditions attendant upon crys- tallization. Augite. One of the most characteristic minerals, and an essential constituent of nearly all the types, is a pale green to colourless augite. No brown or purplish augites were found, not even when the titanic oxide reached about 1 -8 per cent (Rosiwal method), as it did in the case of the augite syenite. Orthoclase. Another most diagnostic mineral characteris- tic of all the rocks in the series, from the oldest to the youngest, 18 the alkalic feldspar. Albite was not found. This shows the dominance of potash over soda throughout the whole series. Monzonite, the oldest type in the series, has considerable ande- sine present, as well as orthoclase, while the porphyritic syenite has microperthitic intergrowths of plagioclase, with ortho- clase and narrow plagioclase rims about the larger phenocrysts of orthoclase (Plate XIII). All the others are entirely lacking in plagioclase. Microcline is present to a minor extent. Biotite. Biotite occurs as an accessory constituent, and is generally the brown, strongly pleochroic variety. It is a diag- nostic mineral of the youngest dyke and plug intrusions in the district, which are pulaskite porphyries and minettes. Hornblende. Hornblende is present in the monzonite and the porphyritic syenite, but is entirely absent in the younger types. Zircon is uncommon. Titanite and apatite are both com- mon accessory constituents in all the types. Of the granular types all, w»th the exception of monzonite and shonkinite-pyroxenite, show megascopically the typical trachytic structure of the feldspar laths. The volcanic equiv- alents show the same structure when examined under the mi- croscope. The photograph (Plate XII) illustrates what a close similarity exists in hand specimens between the monzonite and syenite, even though the former lacks entirely the trachytoid structure of the feldspar laths so marked in the latter. The mode of occurrence and structural relations of the different intrusions have cdready been discussed in the previous chapter. The sequence was concluded to be as follows, com- mencing with the oldest: — 133 1. Monzonite stocks. 2. Porphyritic syenite intrusions with their correspond- ing trachyte equivalents. 3. Main alkalic chonolith, with great diversity of types from shonkinite-pyroxenite to nephelinitic syenite; apophyses of syenite porphyry; extrusive equivalents of granular types, varying from alkalic basalts to phonolitic trachytes. All these diverse types of igneous rocks have been derived, without doubt, from a common magma reservoir, and present an excellent example of magmatic differentiation within a local area belonging to the south central British Columbia petrographic province. This differentiation has taken place prior to in- trusion' intratellurically, and there is no evidence of differ- entiation in place. This is shown by the variations in mineral- ogic and chemical compositions of the different granular types intruded at different times, and the finding of their effusive equivalents. Future detailed petrographic work, however, may somewhat modify this conclusion. Such work should be chiefly confined to the close examination of both lavas and granular types, with their field and chemical relations to one another, in order to determine to what extent the chemical variations of the extrusives correspond with those of the intrusives. Magmatic Differentiation. Having briefly considered the sequence and variety of rock types developed in the Franklin member of the south central British Columbia petrographic province, it is now in place to discuss the fundamental process of magmatic differentiation that causes them and under what conditions they are produced. The subject is still largely in the realms of speculation, although the physico-chemical side of the problem has been built up on a firm foundation and is making rapid advances. 'BrSgger terms the differentiation prior to intrusion primary, or 'deep magmatic,' and the one in place, secondary, or 'laccolithic' differentiation: Eruptivgesteine des Kristiana. gebestes, I (1894), pp. 178, 179. t-^'i. 134 There are two distinct controlling agencies that bear upon this broad problem: (1) mechanical, (2) chemical. The chemical side has received the most attention and will first be discussed, and the mechanical will be dealt with later. The Franklin series of alkalic rocks owe their chemical differences to intratelluric differentiation prior to intrusion, which has given rise to the different varieties of intrusive and extrusive rock types. The following chemical processes will be applied, which have a bearing upon this difficult theoretical problem. Magmas may be considered is complex solutions, the solvents being the silica, alumina, and alkalies, the rest the solutes. Under the possible causes of differentiation from the chemical standpoint, a fundamental process may be crystal- lization. If the solvent is in excess it will tend to crystallize first at the outer margins. However, the more closely the com- position of a magma approaches eutectic ratios, the less cap- able of fractionation it becomes. > The minerals in excess of ratios will be the first to crystallize and s^^regate to the outer margins of the intrusive. Why should the minerals in excess of ratios crystallize first at the outer margins ? This leads to the question of the conditions under which differentiation is produced. Many hypotheses have been advanced, and for his- torical reviews and summary analyses the reader is referred to Iddings,* Marker,* Clarke,* Pirsson,* and Daly.* The hypothesis advanced by Michel Levy,^ in which he emphasizes the importance of the "fiuides mineralisateurs," or water and other fluxes circulating in the magma under high ■Clarke (F. W.) : Data of Geochemistry, U.S. Geol. Surv. Bull. 491 (1911), p. 298. 'Origin of Igneous Rocks. 'Natural History of Igneous Rocks. *Data of Geochemistry. •Pirsson (L. V.): Petrology of the Highwood Mountains, Mont., U.S. Geol. Surv. Bull. 237 (1905), pp. 181-201. Pirsson (L. V.), and Rice (W. N.) : Geology of Tripyramid Moun- tains: Am. Jour, of Sci., (4) XXXI, 1911, p. 287. • Daly (R. A.) : Origin of the Alkaline Rocks: BuU. Geol. Soc. of Am., Vol. XXI (1910), pp. 87-118. ' BuU. Soc. Geol. France, 3d series. Vol. XXV, 1897. p. 367. 135 temperature and great pressure, deserves some consideration. Magmatic water and •''ises increase fusibility, diminish viscosity, and thus facilitate cryatallization. A complete segregation, how- ever, is not assumed; only a differential concentration of the magmatic components. Gases and vapours may have played an important part in the case of the syenite chonolith, as is indicated by (1) the granular texture of a magma that consolidated relatively near the surface, (2) the presence of fluorite in the melanite syenite, and (3) the intense permeation of the wail-rock, particularly the porous types, such as the Kettle River conglomerate and grit. BrOgger has demonstrated from his work in the Christiana region that great depth is not necessary for the development of granular rocks and contact metamorphism. A later hypothesis of probably great importance in certain cases was put forward by G. F. Becker, ' who showed that frac- tional crystallization may have been an important factor in differentiation. In this case magmatic differentiation is a se- quence of the general cooling process. The walls to the intruuon being cooler than the molten mass itself would facilitate the crystallization of the less fusible or less soluble minerals towards them. The process would be aided by circulation and convection currents. The resulting mother liquor (portion of maximum fusibility) would approach to that of a eutectic mixture. If the original magma were a eutectic mixture, fractional crystalliza- tion would not influence differentiation at all; but the farther removed the solution is from the eutectic point the greater its power to promote differentiation. It has been determined by physical chemists, through synthetic work in the laboratory, that the order of crystalliza- tion of salts or minerals depends on (1) their relative abundance, (2) their solubility in eutectic, (3) possibly their points of fusion. In the case of their relative abundance, the law of mass action' ■ Becker (G. F.) : Am. Jour. Sci., 4th Ser., Vol. IV (1897), p. 257. •"The reaction-velocity (the amount in gram molecules which is trans- formed from each system into the others in the unit of time) at any moment w proportional to the masses of the subeUnces then present." Text book of Inorganic Chemistry Holleman-Cooper, p. 78. 136 111 'Hi. will determine what silicates can L :m. It is found that the less soluble and fusible minerals are formed the earliest. There is a tendency also to set up as few centres of crystallization as possible. This is shown in the usual coarseness of phenocrysts found even in rapidly chilled rocks; for instance, the pulaskite porphyry ("Bird's eye porphyry") at the chilled borders of the large pulaskite dyke west of the McKinley mine has quite large feldspar phenocrysts dotted sparingly through a dense ground- mass, giving the whole rock a spotted or "bird's-eye" effect. This is further shown in the case of a granular rock, the porphy- ritic syenite on Syenite hill, where the material in the central por- tion has apparently tended to migrate towards the sides and solid- ify upon the centres already established theie, rather than set up new ones. This ha'; resulted in the growth of quite large feldspar phenocrysts, up to 2 inches in length, some of which radiate from one centre (Plate XIII). The latter effect may be due possibly to local stagnant conditions in the magma during consolidation. The lai^e pyroxene phenocrysts in the shonkinite- pyrozenite ("Black Lead"), which give the rock in many places a decided porphyritic aspect, are probably phenocrysts of the first generation which had commenced to crystallize previous to intrusion. Factors Psomoting Circulation and Differentia- TiOH. The three most applicable hypotheses that have been ad- vanced to explain how differentiation proceeds will be considered here. They are: (1) diffusion, (2) convection currents, (3) liquation. Diffusion. This is controlled by the nature of the magma with regard to its degree of fluidity or viscosity, and is accelerated br pressure.* It is not a likely process in silicate magmas, unless there is much magmatic water or other fluxes present. So long, however, as crystallization is able to proceed, the viscosity of a magma is never too great to prevent molecular flow or diffusion, since it is through this that the molecules are able to arrange themselves in crystal form. Diffusion, assuming perfect miscibility of the magmatic solution, niay have been a major factor in the differentiation of 'Roatgeo, Wiedem, Ann., Vol. XLV (1892), pp. 98-107. 137 the oyenite chonolith prior to intrusion and may have produced the diverse types from melanite syenite to nephelinitic syenite. The criteria for distinguishing; differentiation controlled by this factor are the very gradual transitions from one type to another and their irregular distribution. Convection Currents. This factor, controlling certain phases of differentiation, would in turn be controlled to a large extent by mechanical conditions promoting bodily movement. In the case of the syenite chonolith, with its marginal phase of •honkinite-pyroxenite which is usually present, it is thought that the shonkinite-pyroxenite was intruded first, and before it had time to entirely solidify and become jointed the fissure was opened and the syenite intruded. The younger svenite found the lower contact of the pyroxenite the most favourable place for intrusion, except where the chonolithic mass steepened to form the Tenderioin volcanic vent. There the pyroxenite is found at both borders of the syenite. In places the syenite con- tains 'endogenous inclusions' and 'schlieren,' as, for example, at the Averill and Maple Leaf properties. The contacts between the shonkinite-pyroxenite and syenite are always well welded and pass rapidly from one to the other. This would seem to indicate that either the basic differentiate owes its origin to a liquation process, which implies immisci- bility of the magma solutions, as discussed under the next head- ing, or to separate intrusions. The liquation hypothesis is here untenable, because in it gravitative adjustment is a controlling factor. In the case of the Franklin chonolith there is no evidence of gravitative adjustment, so that the simplest explanation ap- pears to be that of separate intrusions. In the case of the shonkinite-pyroxenite area on the Averill property, movement in the consolidating magma about the basic ma.«a has possibly produced the shattering and brecciation along which the aplitic magma extract of maximum fusibility and liquidity would penetrate and crystallize. The force of crystallization would further accentuate the shattered appear- ance of the mass. Both magmas, however, came from the same magma reser- voir below, where they have been influenced to some extent in 13> f: their differentiation by this factor ui convection current!. Such influence would ceaae once the vl.- onity u( the magma rendered bodily movement impoMible, whil> might continue for a long time ii^ account in part for the variations ii. nite syenite to nephelinittc syenite. The chemical composition a < li i ;nion, on the other hand, -«c;nent to that period, and tlu' itvenite itself from mela- I r ) (iiity to surface of the magma may tw other conditii 1 1 ti n ■'(• h nited miscibility* of the magma solution, with grav .aJ'C idji>stm(:nt nnd separa- tion of the heavier basic extract 'irtu." < t of thr lighter acid one. This factor, then, is not e is no evidence of gravitative adjusti n. i. In .<-t, e basic differ- entiate lies generally on top of ' ^yc: i : fowever, it may have played an important part ia hitrat l!i. differentiation prior to intrusion, as shown by te two ^larpK differentiated magmas, augite syenite and shonkinite-pyroxenitc. It is possible that it was re^wnsible for the splitting of the parent homo- geneous magma into a basic heavier and an acid lighter portion. Where this factor has dominated in the case of differentiation in place, the basic margins should be regularly disposed at the borders with reference to the add portions. Where differenti- ation has taken place intratellurically, and two distinct magmas are intruded, the one slightly in advance of the other, the older magma is found generally at the outer borders of the intrusive mass, irrespective of the chemical composition. For example: At Mount Johnson, near Montreal, a vol- canic vent, one of the members of the Monteregian petrographic province, has been described by Professor Adams,* who found the basic essexite towards the centre of the neck surrounded by pulaskite. There, however, the pulaskite is older than the 'Fluids insoluble in each other. The Monteregian Hills — A Canadian Petrographic Province. Jour, of Geol., Vol. II (1908), p. 253. Also see G. A. Young: Geology and Petrog- raphy of Yamaska, G.S.C. Ann. Kept., XVI, Pt. H, pp. 8-4J. 1J9 esiexite. At Franklin, on the other hand, the basic p roxenite IS oWer than the augitc lyenite. and is naturally found chieflv at the outside borders of the intrusive mass. Igneous Activity and Mechanical Considerations. Having dis. usced in a summary manner, differentiation controlled by such physico-chemical agencies as "Ruides min- eralisateurs." fractional crystaliiiation. diffu!.ion, convertion currents, and liquation, the mechanical side of the problem as w.ll as that of igneous activity, will now be dealt with Here the nature of vulcanism in the Franklin district may be most safely inferred from both inductive and deductive reasoning. Dynamic movements of the earth's crust are of two kinds: continental building and mountain building The former implies broad continental uplift, dependent on vertical forces, and the latter depends upon compressional forces Pressure raises the melting points and tends to pre vent the .es- cape of dissolved vapour, and so to increase fluidity. Ga.ses in the molten mass, however, lower the mcltiuR points, and prob- ably more than offset the effect of pressure. In order to < «,rrelate the different periods of igneous ac- tivity, erosion, and dynamic crustal movements in the Franklin distnct, the following sequence of events is tabulated :— Eocene-Oligocene 1. Regional subsidence following the Laramide revolution, with deposi- tion of great thicknesses of con- glomtrate. grit, and contempora- neous rhyolites. 2. Deformation and monzonite intru- sions( ,') 3. Erosion cycle. 140 Miocene 4. Porphyritic syenite intruded, and early trachyte flow. 5. Erosion interval. 6. Shonkinite-pyroxenite and augite sye- nite intruded and poured out sur- ficially as alkalic basalt and tra chyte. 7. Period of youngest dyke intrusions, pulaskite porphyries, and lampro- phyres. Pliocene 8. Long erosion cyde. It is noted that the epochs of igneous activity followed periods of erosion, which were in turn inaugurated by crustal movements. It is possible that following such movements dynamic strains of an acute kind, in this mountainous district, may have promoted more rapid progress in differentiation. There is no evidence, however, to show that mechanical forces of the nature of lateral thrusts have been an essential factor in differentiation.' On the other hand, the batholiths that appear to be closely related to mountain folding and lateral thrust show no marked differentiation, and are, in a general way, homogeneous throughout. Igneous activity, which has given rise to the local group of rocks in Franklin, does not appear to have been closely related to orogenic movement; but the regional group, on the other hand, does appear to have been closely related to mountain making movements. It is to be noted that the Tertiary magmas found access to the surface only through the bottom of the Franklin Tertiary valley, which to the writer appears to have been developed in a synclinal basin, and that the main intrusion took the form of a concave arc conformable in a broad way to the early Tertiary formations. Where the intrusion had its outlet to the surface, 'Natural History of Igneous Rocks, p. 330. 141 however, the general northeast-east dip became vertical, as shown by contact relations on Tenderloin mountain. Similar instances of confinement of vulcanism to synclinal basins is present in the Neapolitan area, Italy,' where "vol- canic eruptions began somewhere between the end of the Pliocene and the beginning of the Pleistocene period, upon the bottom of a great synclinal basin, resembling those to be seen elsewhere in the Appenines, but in part drowned by the sea." In the Tertiary districts of central and southern Europe in general tile eruptions have found vent, not along the mountain range Imes themselves, but within the depressions between the various orographic lines. All through the long volcanic history of ancient volcanoes of Great Britain, Sir Archibald Geikie found that the orifices of discharge for the erupted materials have been opened along low grounds and valleys rather than on ridges and hills * Geilde also found that the volcanoes in Great Britain have been active on areas of the earth's surface that were sinking and not nsmg. This generalization would apply also to the Franklin district. It is of general interest to note that the relatively close proximity between tiie granular intrusives and their extrusive lava equivalents in Franklin agrets well with Sir Archibald Geikie's generalization that "volcanic action is n ' deep seated but has its source not many hundred feet below ground."* It further emphasizes the great importance of "fluides mmerahsateurs" in the consolidation of molten magma, and mdicates how a comparatively slight deptii of erosion might remove all traces of lava extrusives, and expose simply their granular and intrusive types. The chemical generation of heat by radioactivity may have been a potent factor in causing igneous activity, but too little IS known concerning it to consider it here. It is known that in Franklin, at certain definite periods in Its Tertiary history, local increase of temperature within the subterranean horizon took place. Relief of pressure may have l^if^'^ (Guiseppe): Quart. Jour. Geol. Soc.. LX, Pt. 3. p. 296, 1904. ^Oejkie (A.) : Ancient Volcanoes of Graat Britain, Vol. I, p. 470. Geikie (A): Text book of Geology, Vol. I (1903), p. 280. 142 resulted in volumetric expansion of the magma and eruption. Volcanic eruption broke forth from a vent on Tenderioin moun- tain, probably brought about both through terrestrial contrac- tion and its effects and the tension of absorbed gases and vapours. The shonkinite-pyroxenite and syenite (the 'live rocks,' accord- ing to Brun) before eruption were heavily charged with aqueous vapour and other gases under great pressure, and high tempera- ture. The temperature would vary considerably through: (1) heat lost by cooling, as the sudden expansion of gases released at the beginning of volcanic eruption would exert cooling effects on the residual magma; and (2) heat evolved by chemical changes. The pressure, too, was a variant during eruption, and must have fluctuated widely. When the pressure was released the gases escaped with explosive force and carried the liquid matter with them, which accounts for the bombs and other vesicular ejecta- menta on Tenderloin mountain. The process also produced a great quantity of fiery spray, which solidified in the form of volcanic ash and formed the basaltic and trachytic tuff beds of both Tenderloin and Franklin mountains. When the lava streams themselves appeared their efferves- cence had largely ceased, and the fluid or viscous lava cooled and consolidated quickly to a dense rock (the 'dead rocks' of Brun), very different in texture but not in composition from their original granular equivalents. By further pressure contemporaneous with consolidation, the temperature needed to produce complete fluidity is raised, and this fact is emphasized by the phenomena of resorption dis- played in the lavas of the district. In conclusion, it is of general interest to petrologists to know that the Franklin district presents another example of magmatic differentiation among alkalic rocks of a new petrographic prov- ince in south central British Columbia. 143 CHAPTER VI. GEOLOGIC HISTORY. Introductory Statement. The geologic history of the Franklin district has as its major features: sedimentation and igneous activity in the upper Palaeozoic; erosion and batholithic invasion in the Mesozoic; continental sedimentation, igneous activity, and erosion in the Tertiary ; and continental and valley glaciation in the Quaternary. The records of ancient geologic history before the late Palaeozoic era are entirely wanting in this district, and crustal disturbances, batholithic invasions, and erosion cycles, all on a large scale, have in their respective turn closely folded and broken, undermined, and removed full details of former events, leaving bare now only scattered fragments of a once complete record. Such a fragmental record of the late Palaeozoic, much obscured by antiquity, has been left exposed in Franklin. From that date until the end of the Mesozoic it will be possible to trace clearly only the major events, and the minor features must necessarily remain unknown or at best be only conjectured. With the approach of modern geologic time, how- ever, the records beco.ne more numerous and their meaning is more evident. In the Franklin region a part of the early Tertiary record is preserved by protective lava cappings, while the more recent events in its geologic history have been disclosed through physio- graphic study of the present significant land forms. Upper Paleozoic Time. The Franklin geologic history, in so far as its rock records permit, must necessarily commence with the upper Palaeozoic and very probably with the Carboniferous. To get a broad view r= rri ii im 144 of prevailing conditions at this time it seems advisable to utilize rock records of the same age from the Selkirk mountains to the east, as well as the Interior Plateau to the west, and in doing so to try and amve at some broad suggestive generalizations. One may picture at this time a sea slowly transgressing from the east and subject to minor oscillations of level upon a rela- tively low lying land surface, with general off-shore marine conditions to the west and inshore conditions on nearing the broad continental area which supplied the thicknesses of upper Palaeozoic sediments. This area probably extended horn Al- berta to Labrador. The oldest sediments in Franklin are of an argillaceous character with plant impressions, and probably represent old shore conditions about an upper Paleozoic island or along the main continental coast. From such islands or shores or from volcanic vents rising above the sea-level, volcanic ac- tivity burst forth at intervals and deposited vast amounts of pyroclasuc tuffs having angular fragments along with the nor- mal argilhtes and sandstones. The sedimentary materials are all fine grained and indicate deposition in waters without strong currents (Lower CAche Creek series of Dawson, KnobhiU group at ^'oenix of LeRoy, and Franklin group). Subsidence con- tinued and in the course of time volcanic activity ceased The inshore argillaceous conditions of Franklin may have migrated eastward to the present site of the Selkirk mountains, substitut- ing, instead, open sea conditions with scarcity of land-derived sediments in which probably the Gloucester limestones were deposited with their crinoidal fauna (Upper Cftche creek* and Biooklyn limestone at Phoenix).* The greatest and best pre- served sections of this limestone are found farther to the west in the Kamloops district where orogenic movemci.t has not been so intense as in Franklin. This marine transgression extended not far east of the Purcell range where the thin records of it have been entirely removed. With the maximum extension of marine condiUons, minor oscillations of sea-level or of climate evidently prevailed, on account of the more minutely interstiati- 'Dawson (G. M.): Report of Progress G.S.C., 1877-78, p. 80 B LeRoy (O. E.): Report on Phoenix Mining Camp G.S.C., Memoir 21. 145 fied condition of the inshore calcareous and argillaceous sedi- ments (Slocan series calcareous argillite and argillaceous lime- stone.) Close of the Paleozoic. This long period of quiet with only uniform and widespread crustal movements, was brought to a close by a series of great disturbances which lasted for a long while. The region was up- lifted above the sea and the areas of greatest thickness of inter- stratified argillites and limestones, such as dominated the inshore areas, were subject to close folding as well as regional uplift, while those rigid areas of massive limestones, although elevated en masse, were, however, more competent to resist erogenic strains and yielded by open folding and tilting. This resulted in a more highly mountainous district to the east, composed of the more readily folded and broken sedimentaries, while the lime- stone and more massive sediments of the west were relatively low lying. The great crustal disturbances which closed the Palaeozoic period inaugurated conditions of continental erosion and sedi- mentation which have lasted to the present time. Mesozoic Time. Triassic Period. There is no evidence in the vicinity of Franklin or neigh- bouring districts to the east, to indicate that any marine trans- gressions since that of the Carboniferous have taken place. However, there is evidence in the Kamloops district ' that the Triassic marine waters extended over the CSche Creek series (equivalent of Franklin and Gloucester formation). There the Nicola series lies unconformably upon the latter formation and consists of thin irregular beds of limestone, some argilliies, and eruptive materials, while the sedimentaries show evidence of subaqueous deposition and bedding,^ but no proof, Dawson ■ Dawson (G. M.): Kamloops Map Sheet, p. 50 B. Report, p. 5jB. Ill f'^iJ 146 rtates. » far has been found of subaerial deposition. During the Tnassic penod. then, the Franklin district probably formed a part of the highlands which supplied waste Tr the'de ™Son countrv T" l^J "^"^ '?^'*^' ^""^ '" ^« Interior ffatea^ Zu7:- I "^^ decomposition, from sedimentary evidence at that time dominated over mechanical disintegratioZ theS was probably one of moderate relief. .me region Jurassic Period. nr^K^K^'T"'*" ^•^^^*'°" ^^^ batholithic invasion took place probably dunng the Jurassic. It was at this time that th^ Nelson granodionte was intruded and the contact metamorphic ores deposited in the overiying calcareous cover rociS Cretaceous Period. the H^^ "»«tal movements and uplift of the time invigorated the drainage and brought about a new cycle of erosion which lasted all through the Cretaceous period and removed the ItS cover overlying the Jurassic batholith. so that early TeSI^ conglomerate, grit, and rhyolite lie directly upon the Jurassic granodH>ntes on McKinley mountain in the Franklin S" Jh^t Tf .°K^ rr"" 'f °" ^"^^^ '^^ P^"fi^ Cretaceous and that of the Albertan plains, at this time was brought down to a surface of low relief with local peneplanation in the Interior Plateau country. This surface stood 2.000 or 3,000 feet lower m relation to the sea than it does now. Laiiamide Revolution. the t^tir'^ °^ *^' Cretaceous the Cordillera received one of the greatest orogemc disturbances in its history. The whole Cordillera was uplifted and folded in places and a new cyde of er^ion inaugurated. The Interior Plateau country was uplift^ u- I, ^^fX ^'"^''''at similar to that of the present. The ^e !^m: tt °""""^ *° ^^ ^* *" probably'prod; J': 147 The larger topographic features such as the internuMit trough within which the Franklin district lies, and the Cariboo and Granite Mountain ranges, were outlined during this moun- tain making epoch. Some parts of the Jurassic granodiorite batholith yielded to the crustal stresses by mashing with the production of gndssic structure, while elsewhere, particulariy in the neighbourhood of its roof rocks, it yielded by brecciation and shearing with local mineralization along the shear zones. Connected with these crustal disturbances and relief of stress was possibly the intrusion of the Valhalla granite along the axis of the Cariboo range. Extrusive equivalents of this granite appear to have penetrated the synclinal basin and poured out in the form of rhyolitic lavas contemporaneous with the de- position of rhyolitic grits and conglomerates of the Kettle River formation (Eocene). Here in Franklin, as in the European Alps, the volcanic eruptions may have avoided the closely compressed folds along the mountain axis and found easier access to the surface through the basins and plateau stretches of the Interior Plateau country. This feature is also striking in the case of the Miocene igneous activity as will be seen later. Tertiary Time. Eocene-Oligocene Period. Such were the conditions of mountain growth that left the Cordillera with a very rugged and youthful relief which at once maugurated a new cycle of vigorous erosion and subaerial de- position. The axes of the sedimentary mountain ranges then WCTe the same as the present granite ones, but their topographic relief was much greater. The uplift and deformation brought about a change in climate for this section of the Cordillera, from the subtropical of the Cretaceous to one of coolness and humidity in the Eocene, as evidenced by the thoroughly leached light coloured sedimenu with carbonaceous shales and sandstones bearing plant remains in one locality. The coarse heterogeneous conglomerates con- taimng scratched and facetted boulders and pebbles point !i ! i. 148 towards rugged alpine conditions in the surrounding highlands, with even local glaciers supplying their quota of material to the conglomerates which were being deposited in alluvial cones at the base of the ranges. hr^J'^u''"^'"^^ °f *•'* Eocene-Oligocene period, although broadly the same as the modern, was in a decidedly disorganized condition due to (1) damming eflfects of contemporaneous lava flows and (2) the migration of the conglomerates of the sub- aenal cones from the borders of the basin. Local lakes and flood-plains existed where volcanic dust accumulated and vegeta- tion flounshed from time to time. Minor oscillatory crustal movements following the Laramide revolution and preceding the deformauve period at its dose, may have also affected the drainage and sedimentation. Fluviatile deposition went on rapidly as shown by (1) the coarseness of much of the material depMited; (2) the presence of abundant cross bedding; and (3) the distance between the bedding planes of the grit in places. The streams with strong gradients were loaded with coarse waste and rapidly aggraded their courses. The drainage of the time was cut deeper than that of the present day, a fact that might indicate that the region stood higher then than it does now Ld probably about the same height as it did after the Pliocene uplift Volcamc activity in the eariy stages of the period was of an explosive nature and beds of fine acidic tuff, as well as large and small blocks of rhyolite. were laid down in the basin and worked over by the streams. This was followed by minor rhyohte flows which are seen ,t present intercalated and tilted with the arkosic grits and tuffs. Sedimentation continued until the valleys were all filled up. Towards the end of the period volcanic activity reached its culmination with the outpouring of a great rhyolite porphyry and rhyolite flow preceded by Sr"*^ »r..^f ^"'^y mountain. This flow, as shown on Franklin and McKinley mountains, filled up an old valley which had been cut down almost to bed-rock. The bed-rock here was a^poi^on of the Cretaceous surface of erosion on Jurassic grano- 149 Oligocene Period. Following this long period of continental sedimentation epeirogenic movement took place probably contemporaneous with the mtrusion of the monzonite stocks.' The movements affected north-northwest and south-southeast lines resulting in uptilting of the beds to the north-northeast. The McKinley Mountain rhyolite, however, preserved its rigidity to a great ex- tent compared to the more readily disturbed grits, tuffs, conglom- erates, and minor rhyolite flows. The crustal disturbances inaugurated the new cycle of erosion which was so largely responsible for the stripping off through southern British Columbia, of vast thicknesses of eariy Tertiary sedimentary and volcanic records. It is impossible to estimate to what extent the KetUe River formation has been removed from localities where it once existed. This erosion interval is indicated in the Franklin district by an unconformity, which shows that the disturbed sediments had been eroded to an undulating mature siage of development with a broad and shallow river valley. The pre-rhyolite porphyry river was forced to take a new course and followed the east border of the resistant flow rock. By the close of the long erosion cycle. however, which preceded the Miocene lava flows, it had regained in part its former course, as shown by the manner in which the Miocene trachyte caps it on Franklin mountain. Miocene Period. Following long erosion, igneous activity broke forth ex- plosively from a vent on Tenderioin mountain and deposited basaltic and trachytic tuffs and ejectamenta, followed by ex- tensive trachyte flows which fille<{ the low depressions and main al- luvial filled valley of the later mature land surface. The intrusive shonkinite-pyroxenite ("Black Uad") and augite syenite, which supplied the surface flows, even reached the unconsolidated coarse gravels and silt of the Kettle River formation, producing intense contact metamorphic action which affected the formation •The forerunners of younger alkalic intrusions in the Miocene. IJO for nearly SO feet from the immediate conuct. The "Black Lead 'ores are referred In part to this period. c^J'^J't^T^u^ "^^^^ P°^'"^ penetrated the fl^ I^ ? ****°''*^ °" •*• ~"*=«^« "de. The trachyte flo« dtered the courts of the previous river and thT^ nve« were developed at the boitler. of the flow, the Lte^ one going to form the main Kettle river. ^^ Uter, in Miocene time, when there was sUII a deeo mantl. I'JSSLTh'"? ■*"" *"' •«lin,enurie.. the pul^lTe^n^ Ae g^t R«dand bathoUth to the east, which comprise " ^ pm of the Granite range. Batholithic inva«on and i»! Sn^"" """ '" f P~**""^y ~°''*^»«* with LT J„ matang movements a. shown by the definite dyke system, main- tamed in certain localities. ■y»wras main- T^nnTI'r-^*"'*^"'"^ *''^ Po-t-Oligocene erorion surface on T^eriom mountain probably took place at this time, aat^emte dykes of tiie same age were found cutting die same c^tact in a •imilar manner to the fault. ««»« in a ev*r l^J? 1° *'''?"" '" *''*"'^'" ^''^^ t*** P"""kite magmas sThe^sTd:^ ss." ^°"" '^^ " ^^ -- '-"^ <^o rf„irJ'"L-T '"*™'«»"» °^ tJ»i» epoch were the lamprophyre dykes which probably took place in late Miocene time Sid S^ be connected with ti,e younger lava flows of basalt, rem^^o^ which are found in the Interior Plateau country.' Pliocene Period. movie's tu'lT^' ""^ °' '^~"" "^'^»y »"d ""«tal rrr^^ . ^'"*"*' ^"^ f^"*^"' «t«We conditions with 7f;-„I? 1", * "°''°" "y"'" **•* P""*"* "P'^d topograph^ ^ !^'^'" ^^ '""*• °*^ '*• °"P"' ^d it is probably conSuoui throughout the rest of soutiiem British Columbia. T^ep^^^ dnunage system was outiined and a coarse textured top^I^j! ?iS?"° •^^- **-^= Karaloop. raap sheet. h 151 produced. The land at this time was some 2.000 feet lower than .t .s at present. The early Pliocene auriferous quartz drif" would imply long subaerial decay and stability of lev.| «>me. what analogous to condition, during the Cretaceous j^neplana- tion at the end of the Meso/oic era. when sandstones, ligriites clays, and such products were deposited in contrast to the coarae mechanical sediments of the early Tertiary after uplift and moun- tain making. Thus both the Mcsozoic and Tertiary en-s in this region ended with the land reduced to post-maturity and I(Hal i^ne- planation. ' Quaternary Time. Pleistocene Period. The diastrophism which closed the Tertiar>- was in the nature of a broad differential uplift which permitted the in- T'!f^ I!i"^^ ^ '"""^ '**" ^^P'y '"to the land surface with the production of steep-walled. V-shaped valleys. Since S*f.irK^f ~"7" '" '^^ ''"^y Quaternary were not fill,.! and shifted by lava flows, as they were in the early Terti.iri the present nver courses are antecedent with respect to the Plio- cene surface of erosion. The present Cariboo and Granite ranges TrL f J^" "".!? °^ maximum uplift as they were in other periods of diastrophism. The district was probably much higher than at present as Dawson- has presented evidence to show that tLlT!^\T' '*'^,^'"^" ^ f*^^ higher than at present, which means that there may ha ve been a land barrier between the Arctic SiTf jta^e'^aun^f ''-'' ''''''' '-™^"'"« ^'^ -'-- CU^r ^"■'''T^^'''^' ''^^* *^" ^^''f^^ to this pre- Olacial period in the Pleistocene. Moulf^trp" -^^ ^l: °." "•* ■*'" Physiographical Geology of the Rocky Mountam Region .„ Canada. Tran,. Royal Soc. Canada, S^tion IV. ^S, 'Smith (J. P.): Amer. Jou.-. Sci. (4). Vol. XVII, p. 226. 11 'I ' il ih II 1S3 Glacial Ptriod. The mo«t modern geologic evenu recorded in the hiatory of the Franklin dittrict are thoM connected with glaciation. The CordiUeran ice sheet covered the whole region with the po^ «ble exception of a few high peaks on the Cariboo range, which stood as nunaUks above the ice surface. It but slightly modt^ied the upland topography, leaving striae and scourings in pUcw», but on retreating left morainic drift and erratics strand*^ ^^ on the upland. The ice cap gave place to alpine valley and cirqir ^u,ettH* which slowly retreated unUl the time of the Keewatin ice sheet extension to the east, when the second main period of valley glaciation took place. It is to this period that the strongly glaciated valley forms (such as U-shaped valleys, lateral moraines, stria, etc.) owe their origin, and the valley trains of outwash material were deposited. Recent. With the retreat of the valley glaciers the streams, unbur- dened of their morainic load, began to degrade their valley fills. A series of terrace-steps mark successive periods of aggradation and degradation dependent upon climatic oscillations. The last events are connected with the slow normal weather- ing agencies of frost, ice, snow, rain, and humus, which are faciliuting the disintegration and decomposition of the rock formations, with formation of subsoil and soil. Summary of Geologic History. Palecotoic. Carboniferous. Deposition of Franklin group sediments (ai^llites, quartzites, and tuffs) followed by that of the Glouces- ter limestone formation in an eastward transgressing Car- boniferous sea. Great uplift and orogenic movements brought the Palaeozoic to a close and inaugurated new and lasting con- ditions of continenul erosion and sedimentation. * First period of valley glaciation. 153 Mesotoie. Triatsic. Frankl.n district undergoing rapid erosion and applying materiaf for \i. ola group rocks to the west. J^rastic. Regional uplift associated witl> the intrusion of granodionte batholith with apophyses injected into cover rock and formation of contact metamorphic ore bodies. Cretoc««M. Long period of denudation in which the batho- Uthic cover of sedimentary and meUmorphic rocks was almost entirely removed, The MeMsoic closed with the post-Cretaceous uplift and Laramide mountain buiUing Franklin intermont trough formed. The Valhalla acid granite batholith is referred to this period. Tertiary. Eocent-Olieocene. Continental sedimentation with -reat depowtion of tectonic conglomerates and tillites and with .-on- temporaneous and subsequent rhyolite Hows in the b.isin itdf The rhyohtes are very probably the extrusive equivalents of the Valhalla granite batholith. Interval of crustal disturbances; intrusion of monionite stocks, the forerunner, of Miocene alkaljc intrusions; bng erosion cycle. Miocene. Intrusion and extrusion of alkalic magmaa (•honkimte-pyroxenite and augite syenite) with all associated dykes and ores. Phocene. Formation of present post-mature upland in tranklm during long extended erosion cycle. The Tertiary closed with a great differential uplift. Quaternary. Pleistocene. Entrenchment of deep valleys; Cordilleran ice sheet followed by first period of valley glaciation; second penod of vaUey glaciation— Keewatin stage-with alluviation. Recent. Formation of terrace-steps; subsoils and stream gravels formed. 154 CHAPTER VII. ECONOMIC GEOLOGY. HISTORICAL INTRODUCTION. 1,'' \.l:i The first mining claims to be located in the Franklin camp were the Banner and the McKinley, which were both staked in the summer of 1896. The locator of the Banner claim was Frank McFarlane, after whom the camp was named, while Jos Wilcher located the McKinley claim. The Gloucester and ad- joining claims were located by Thos. Newby in the summer of 1898. These were followed by the White Bear in 1899, the Maple Leaf in 1902, the Evening Star in 1903, the Buffalo in 1904, the IXL in 1904, and many others. In 1900 a government trail was cut to the camp from Grand Forks, and the same year a 200-foot cross-cut tunnel was driven on the Banner claim to tap a vein encountered in a shaft. This was the main development work up to that time, as only open- cuts and small prospect pits had been attempted on the other properties. The year 1906 saw the greatest activity in Franklin, when considerable development was carried on and practically all the ground in the mineral belt was staked out. Town sites were surveyed, and the lots put on sale. Cabins were rapidly erected, and the camp was boomed extensively by mine promoters who freely made use of the newspapers in advertising this as a new and promising copper camp. That same year witnessed a gold placer rush of prospectors to Franklin on the news that gold nuggets had been found at Dinsmore's, about a mile below Gloucester City. This turned out to be a case of salting by a prospector, who was detected before he could dispose of his prop- erty and had to decamp in haste. The McKinley was the premier property at this time, so far as exploitation was concerned, showing some hundreds of feet of tunnelling and considerable surface stripping and trench- 155 ing. It had been bonded for two years to a company on behalf of eastern capitol. for $200,000. The year 1906 saw some dia- mond dnlhng done on the Banner claim, as well as development work on the Gloucester group, bonded by the Dominion Copper Company, whUe in the same year the Fee Brothers did some work on the Maple Leaf property. Following this boom period, a reaction set in and there was a period of depression up to 1908, when the completion of a wagon road from Grand Forks to Gloucester City made the camp more accessible, and mining activities were continued for a short period. The years 1909 and 1910 saw comparatively httle prospecting and mining done, as the majority of the claims by this time had been crown granted and allowed to lie dormant Development work was carried on in the summer of 1911 on the McKinley property, under bond by the British Columbia Copper Company. Besides the work done on the McKinley assessment, development work was carried on on the Dane and Avenll groups, the Union, Buffalo, and Royal Tinto claims. The Ust of mining claims arranged in alphabetical order A f . V ^^^' ^^^''^' ^'"^' Alpha. Alto Fr.. Antelope, Athelston, A. X.. Banner. Banner Fr., Big Cub. Black Bear Blue Jay, Bryan, Buffalo, Bullion, Buttercup. Bystander Columbia, Cottage, Crystal Copper. Doris Fr., Eclipse, Egan- viUe Evening Star. Florence. Franklin. Gloucester. Gloucester tr., G. H.. Golden Age, Grande. Hanna. Henneken. Hit-or-Miss Homestake. Ida. Iron Cap. Iron Hill. IXL. Jumbo. Last Chance. Little Cub. Lucky Jack, Maple Leaf. May. McKinley, Montana. Montezuma, Mountain Lion. Munstar. M. S., Nakusp, Nellie Newby Fr.. Old Dominion. Omar, Opher, Ottawa. Ouray, Pinto' Rio. San Francisco. Shelby. Standard, Thnot. Tiger, Tiger Fr Union, Verde, Violet Fr., Wallace, Waveriy, White Bear. Yellow Jacket; all together, seventy-five claims. All of these are crown granted, with the exception of the Blue Jay claim. TYPES OF ORE DEPOSITS. The ores of the FranUin district present a diversity of types Of considerable interest to economic geologists. The metalUf- li^^il 156 erous ores of the district, as will be later shown, are the result of four distinct periods of mineralization— two in the Meaozoic and two in the Tertiary. As a basis for dividing the ores formed during these several periods of mineralization, the genetic types, which are very distinct, have been employed. In this way the following classification of the ores of the district has been com- piled and will be used in the report for purposes of description:— I. Mesozoic deposits. 1. Contact metamorphic type Sub-types: a. Pyrite-chalcopyrite b. Galena-blende c. Magnetite-pyrite (Dependent upon in- trusion of Jurassic granodiorite batho- lith. If in 4: II' 2. Fissure veins. 3. (a) Contact zones (b) Shear zones in granodiorite Dependent upon both intrusion of Jur- assic granodiorite batholith and crustal movements during the Laramide revolution. 11. Tertiary deposits (Miocene). 1. Segregation type— "Black Lead." 2. Contact metamorphic type. 3. Replacement along shecu* zones. From the above, it may be noted that there are contact metamorphic deposits of two ages, the one in the Mesozoic and the other in the Tertiary. Summary Description of Types. The Mesozoic type is characterized by the presence of such lime-silicate gangue minerals as garnet, epidote, diopside, tremo- lite, and the ore minerals, including sulphides and oxides of iron, with some chalcopyrite. The mineralized zone extends in widths varying from to 100 feet, about rudely lenticular shaped masses of marble. The marble which belongs to the Gloucester forma- 157 tion of Carboniferous age, has a closely compressed synclinal structure, with a general steep dip to the west. The basal forma- tion 18 an altered tuff and greenstone of the Franklin group, which IS heavily pyritized in the vicinity of the mineralized zone. The ore lies within die mineralized zone and forms rudely tabular shaped masses or shoots, chiefly at the immediate bor- der of the barren marble. The contact between the marble and the mineralized zone is usually very sharp. The contact on the other hand, between the altered tuff and the mineralized zone is very gradual, and it is difficult to tell where the ore ends and the country rock begins. The ores are divided into three sub-types, one characterized by predominant pyrite-chaico- pynte, a second by galena-blende, and the third by magnetite- pynte. The galena-blende type follows the limy portions of the mineralized zone, where contact metamorphism has not been so powerful, while the pyrite-chalcopyrite and magnetite types on the other hand, follow dominantly the siliceous portions! The deep-seated parent igneous rock which has produced the metamorphism is granodiorite. which cuts the ore and marbJe in several places. ^"llSg^^"^ ^^^^' ^ ^^^P^""" of the McKinley mine. The Tertiary contact metamorphic ores stand in stiT» contrast to tiie Mesozoic type in their exceedingly small develop ment and different mineralogic characters. The ore is chal- copynte. pyrite. sphalerite, galena, malachite, and azurite in a gang..e of impure quartzite and grt*nstone. with consider- able 8= ondary hornblende, alkalic feldspar, and epidote. The sulphides are intimately intergrown. indicating deposition simul- taneous with rock alteration. The igneous rock in this case is an augite syenite and shonkinite-pyroxenite. For further de- tails, see description of Maple Leaf property, page 174 The fissure veins are very few in number. They vary in wid h from a few inches to a couple of feet, and are traceable finina^Z^^'l T ""''^ '^°'' ^'*^"«- '^^^y ■'^'^ the simple fiUmg ^ and show crustification. No definite fissure system was noted. They are considered to be of the same age as the Mesozoic contact metamorphic deposits. 158 Contact Zones. Another type of ore occurrence is confined t« the contact of the Jurassic granodiorite and the Franklin group metamorphics, and is present in both, although chiefly in the latter. No marble is present, and the lime-silicate gangue minerals are not as abundant as in the typical contact metamor- phic deposits. The mineralization is referred to both the time of mtrusion of the granodiorite batholith and to crustal movements during the Laramide revolution. Shear Zones in Granodiorite. Certain zones in the Jurassic granodionte have yielded to crustal stresses of mountain making penods through shearing or slipping movements along defi- nite planes (planes of scission or simple shear), which are in- dined to the greatest pressure. Mashing, on the other hand, Ukes place m planes normal to the greatest pressure. The shear zones have been favourable places for minerali- zation. The ore is disseminated chalcopyrite and pyrite with some molybdenite in a quartz and calcite gangue. The molyb- denite is m small flakes; the chalcopyrite generally with calcite '". .rT*«^ P'^"^- The country rock is sheared, calcified, and sihcfied granodiorite. The shearing and mineralization are reJerred to that accompanying the mountain making at the close of the Mesozoic. Segregation Type. The ores belonging to this type are locaUy known as the "Black Lead" ores. The ore minerals are chalcopyrite. pyrite, and some bornite in a gangue of shon- tamte-pyroxenite. This formation is a basic marginal phase of the augite syenite. It is thought that they have both been derived from a common parent magma through a process of differenuation prior to intrusion. The chalcopyrite and bornite are often found surrounded by orthoclase feldspar, or in small ma-sses cloeely associated u-ith it. The pyrite, on the other hand, IS generally disseminated in small grains through the ferro- magnesian constituents. For details, see page 172. Replacement Along Shear Zones. Magnetite and pyrite occur spanngly along certain shear zones in the Tertiary mon- awute as replacements. The hydrothermal metasomatism is correlated with the intrusion of the younger alkalic rocks 159 DETAILED DESCRIPTION OF PROPERTIES. MESOZOIC DEPOSITS. Contact Met amorphic Type: McKi>fLEY Mine. The ores belonging to the contact metamorphic type of epigenetic ore deposits have received the most attention. Of this class of deposit, the most typical example is the McKinley mine. It was located by Jas. Wilcher on August 1. 1896 and recorded just three days before the Banner claim on Franklin mountain. It is situated on the north slope of McKinley mountain (altitude. 3,500 feet), about U miles west by pack trail from the crossing of Franklin creek by the road to Gloucester City The accompanying block diagram (Figure 16) shows the amount of development work done, which, besides open-cut work and trenching, includes over 400 feet of tunnelling. There are other small occurrences of this type of deposit throughout the district, but the McKinley property, on account of the greater amount of development work done on it. furnishes the only opportunity for extensive observation, and is. therefore described in detail. The less important occurrences are dis- cussed at the end of the section. The ores are closely associated with the Gloucester marble formation, and as a rule near its borders. See block diagram (Figure 16). The nearest outcrop of the granodiorite batholith is some 1.500 feet distant, although apophyses from it are found in the vicmity of the ore and a considerable mass of granodiorite porphyry outcrops about 150 feet above the No. 1 tunnel McKinley mountain is here capped by a thick mantle of rhyolite porphyry of early Tertiary age. The rudely lenticular masses ot marble have a closely compressed synclinal structure striking northeast and southwest with steep dips to northwest. There are two distinct lenses of marble, with different types of ore at their borders. Between the marble on the one side and the altered tuff on the other, an intervening mineralized zone generaUy occurs, w m 160 nilL d«rj;„^'*? '"" ° '? '°° '***• ^^ *«« ««-t could We ..usually «ct«„ely .han>. but the oreXir^LT; ~net:, tSm'^lv ""n^rT* *"'' °" ^""^ "PP^^^'' ""^-'tS: totel Iw W II ^ ^^"^ *''^* '" "^y P'««» it is impossible to tell where the ore ceases and the country rock beginsThe P^LltZ •" *"* "°'''"^' ^"-^'^ ^P-ntTeTimi^or theorel^nrL'f '''°'" ''"^^ Py"*« mineralization, but the ore ,8 confined to zones in the vicinity of the barren marble The ore passes gradually into a garnet rick at itTtorir »n!i from garnet into pyritized alteL tuff^and i^p^^t"' ^^ mmerahzation is here correlated with the intrusionXhTjur J^c g^anc^ionte batholith and was accomplished before tSJS of extensive erosion in Cretaceous time. The reasons fo^thS oorrelauon are the inferences to be drawn from (^he p^nt t^^^tSirfl^r^'^'-^''^'' " .amet/eidoL''rm" eS^on ^ItZ ■^'^ ""P'^ deep-seated conditions of mia^ «^Uon with possible pneumatolytic action by water above TmT^ temperature (+365»C.. and with pressure over 2W atmospheres) given off from a large igneous body. ™;„ ^^^°^^y deep-seated igneous rock in the vicinity of the mine and intimately associated with the ores and ZnTry rodT The Jurassic batholith is believed to be younger than the regional metamorphism of the Pal«>zoics. hs Tntac^s ^e always found, where exposed on steep slopes, toXnge in a regular manner away from the main bathoHtl ic m^ tow^s i. 161 the main cover formation. This implies (1) downward enlarge- ment of the igneous mass; and (2) an independent relationship between batholith and the structure of the cover rock. Fur- thermore, the granodiorite does not show the intense regional metamorphism that the cover rocks exhibit. From these facts, it is inferred that the cover rock had received its major folding and regional metamorphism prior to the batholithic intrusion. This inference is important in that it may account for the locali- zation of the mineralized zones and included ore shoots in the vicinity of the barren marble contacts. Regional compression and folding would result in zones of mashing and shearing, particularly along the contacts of two different Paljeozoic formations. Such zones have afforded favourable places for ore deposition by the mineralizing solutions which were given off under great pressure and temperature from the parent granodiorite magma. The ore shoots do not appear to be con- nected with any definite system of fissures. On the other hand, on account of their irregular form, lack of structural walls as the ore passes transitionally into barren rock, and the intimate re- lationship the ores bear to the calcareous rocks, they are con- sidered to be metasomatic replacements of sheared and mashed calcareous rocks by mineralizing solutions under conditions of high pressure and temperature contemporaneous with batho- lithic intrusion. The marble itself proved an impervious forma- tion and may possibly have borne a precipitating relation to the ore solutions, although there is no direct evidence to support such an hypothesis. The ores may be divided into the three following distinct types:— (1) Pyrite-chalcopyrite (2) Galena-blende (3) Magnetite-pyrite The galena-blende type follows predominantly the limy por- tions of the mineralized zone, where conuct metamorphism has not been so powerful, while the pyrite-chalcopyrite and mag- netite types, on the other hand, follow dominantly the siliceous portions. '!yl W 162 The mineralized zone in which the ore shoote occur i. irregularly distributed, and. a« has already C inSca J he. always dose to the Gloucester barren ^ble '^• bleni T ".'"*"'" ^" '^^'"'Pyrite. pyrite. magnetite zinc blende and galena; and gangue minerals are garnet 6^0^ tremohte,diopside. quartz, chlorite, and caldte ^"'^ m.„^ »°»or"K " « brief description of the ore and gangue distri^^d^c^^ulsCm^TtUan'"' •""1^''^ *" ^'^'^ S.W^S- .^-^'-HTSroTtl^H^rne^.^^^ disseminated through the altered tuffs and eruptives W 'f .t .s copper-bearing, and on weathered surfari^eaS^Tra^ yeltow. with, in places, pur;.!^ tarnish CAo/copyrtVe (C«fe5.) generally accompanies the p.rite and wa^ not found disserninated through thelLs alteri ro. kl as was the c^ with the latter mineral. It is always in ^/niS' sive form and never in disUnct crystals Sphal^ite iZnS). Sphalerite, or zinc blende occurs in specks and small masses, with galena and pyrite i^ Te 1^ ^ofthr °' ''' "'""^"^"^ ^*'"^' -• ^onnstan "e. near th" Oalena (PbS). Galena is present, dosely associated an^ contemporaneous with the sphalerite in the less'highrmeum^r phosed part of the mineralized zones metamor- Magnetite (Fe,0,). Magnetite is present in massive form a ong with pyrite. replacing calcareous rock at th^^t boZ of the lower marble lens on the McKinley property I i^Z dominated .n small grains through the garnS sulphide rS and appears as .ndusions in the garnet, but more fr^ueX along with caldte fillings. The latter has a slightlv r JS tonl Umonite {2Fe^,+3H^). Limonite is found in the shallow form of fine-gramed aggregate, that have replaced the caldum 16J carbonate of the marble. Smal! amounts of it are found associated with tremolite, diopside, garnet, and pyrite in the altered cal- careous rocks. Colette (CaCot). Calcite in coarse and fine granular form composes the Gloucester formation and is one of the most abund- ant gangue minerals. It seldom, however, forms as large a part of the altered marble close to the ore as it docs of the less altered rock in which contact metamorphism has not been so active. It has been largely replaced by the sulphides and lime- silicate minerals and is now found in veinlets in some places, cutting through the grossularite garnet. Azurite (2CuCo, {OH)t) and Malachite (CuCotCu (O//),). Some splendid specimens of blue and green basic carJjonates of copper were found in the oxidized portions of the ore bodies. Garnet. The calcium-aluminium garnet, grossularite (Cai Al, (SiOi),) occurs commonly associated with diopside in large dodecahedrons. It is present usually in reddish massive forms at the borders of the ore shoots, and is traversed in places by minute cracks filled with calcite and quartz. It exhibits a slight irregular birefringence not uncommonly seen in gross- ularite. Epidote is present in abundance, intimately intergrown with pyrite. It is of a yellowish green (pistachio) colour, and occurs m considerable masses in some portions of the mineralized zone. Tremolite (CaMgt{SiO,)i) occurs in veins up to three- quarters of an inch wide, traversing irregularly the sulphide ore. It is in radiating aggregations. Diopside (Ca{MgFeKSiO»h) is found associatctl with epi- dote and garnet and some of the sulphides. It resembles epi- dote somewhat under the microscope, but is slightly different m colour and shows distinct prismatic cleavage. Chlonie. This greenish alteration product is of common occurrence throughout the metamorphic rocks, and was found in greatest abundance at the contact of the eruptives with the al- tered calcareous rocks, where it is quite massive and intimately associated with calcite and chalcopyrite. [If m i 164 Paragmtsis of the Or* atul Gangue Mirmals. Concerning the assodation f)f the various ore and ganitue minerab with reference to thi- order and mode of their formation, there it not much to be said. The lime-silicate gangues were found intimately intergrown with the sulphides, as is charact' ri»- tic of a true contact metamorphic ore deposit.' Both have practi- cally formed simultaneously at the time of extensive cor tact metamorphism resulting from batholithic intrusion of grano- diorites. Valuts. Ut'r- . ^ The highest values at present come from ore taken from the open-cut or "Glory Hole" in McKinley Creek bottom; where assayed, it carries 001 ounce gold, 11.10 in silver, and 2-70 per cent copper. The ore from the open-cut above the mouth of No. 1 tunnel ran 0- 01 ounce gold, $1.42 in silver, and 2 -50 per cent copper. The small ore shoot in No. 2 tunnel, on the east side of the marble lens, is said to have assayed 0-01 ounce gold, $5.60 silver, and 5 per cent copper. Carbonate ore from farther up- hill, on the same contact with barren marble, ran 0-01 ounce gold, $2.70 in silver, and 2-60 per cent copper. The above figures represent the best ore on the property, and the average values would run vary much lower than those given. Genesis and Correlation. The accompanying table gives a summary outline of other occurrences of contact metamorphic ore deposits: — 'Lindgren (W.): Character and genesii of certain contact deposits. Trans. Am. Inst. Min. Eng., Vol. XXXI, 1902, p. 227. 165 hi ^ il II 111 II « jji m II a u II liii ua 11^ 113^ i> 3 j ■ ji 111 X a G 11 11 111 u ^ f^ m 111 HIM I 1 I III U ll lltl^i »!* gS III! llll^ hi uduhQuO l« l{ » ^ Hi 3^« 5^? MKaoCOPY HSOIUTION TBT CHART (ANSI and ISO TEST CHART No. 2) ^ rJPPLIED \M/K3E In 1653 Eos! Moin Street ,?^i^".'Ji "" """^ '♦609 USA (716) 482 -0300-Phore ("6) 286-5969 - Fo. fl hi ■ ' in it ' i I ft ! I ft f pi ki n f?! r-4ir 166 From this table may be noted the pronounced similarity be- tween the Franklin ore and gangue minerals, and those of many widely scattered districts throughout the western Cordillera It IS to be noted, too, that the parent intrusive rocks are domi- nantly granodiorite types and of very neariy the same age. The mtruded rocks are chiefly limestones of upper Palsozoic age The Franklin contact metamorphic ores resemble those of f hoemx most closely in their mineralogic characters and belong to the same chalcopyrite-magnetite class. They differ from them however, m not having, in so far as has been observed, specula- nte, and tn havmg a greater percentage of pyrite. At Phoenix however, erosion has not exposed so much underlying grano- dionte 05 it has in Franklin. Furthermore, the Paleozoic rocks at Phoenix had not undergone so much regional metamor- phism pnor to Jurassic granodiorite intrusion as they had at l-ranklin. The Franklin occurrence has somewhat similar structural relations to that of the Elkhom mine, Montana, described by W. H. Weed.' The auriferous and argentiferous ores there occur in irregular shapes beneath an arch of altered shale, either along its contact with the crystallized dolomite or as great stocks of ore enclosed in the dolomite. The ore bodies are situated in the crushed dolomite, forming the saddle of anticlinal folds which have in part been broken up into a brecaa. The breccia lies beneath a rather impervious cover of altered shale (homfels), which is also folded. The crushed rock served as a channel for solutions rising from the depth. In the case of Franklin, however, the folds are compressed synclines, but the mashed and sheared contact zones have in a similar manner, as at Elkhorn, afforded channels of ingress for the solutions rising from the depths. Thus the McKinlev mine, like the Elkhom mine, is a good example of the influence'of fold- ing upon the localization of ore solutions and development of metasomatic ore deposits. Tremolite is a frequent component of marbles produced by regional metamorphism. Regional metamorphism in Frank- ''° "^^ accomplished before mineralization, and nowhere out- 'Weed (W H ): Elkhom Mining District. 22nd Ann. Kept. U.S. Geol. Survey, Washington, 1902. ijl 167 side of the heavily mineralized zone was tremolite found. The fact that it does ocur in veins up to three-quarters of an inch wide, traversir r the sulphide ores, would point towards the trans- fer of magnesia from the parent magma. The question here arises as to whether the lime-silicate minerals simply represent a recrystallization, or whether they have received additional substances from the cooling magma. In the case of the McKinley mine, the mineralized zone in which these minerals are so well developed is of irregular- form and closely associated with intrusive granodiorite porpliyr!es. The ores apptir to be metasomatic replacements (pneumatolytic metasomatism) along mashed and sheared border zones of the barren marble formation. Recrystallization of impure calcar- eous rocks may account for some of the diopside and tremolite, but the main mass of such minerals, with their associated lime- silicates, sulphides, and oxides, is considered to be due to emana- tions from the parent granodiorite magma during the cooling process. There has been introduction of silica, iron, various sulphides, and probably magnesia from the magma. On the Yellow Jacket claim, small mineralized pockets of ore occur in garnetiferous zones within the barren marble and show the effects of shrinkage consequent upon expulsion of CO, (Plate XXIII). On the Dane group, some of the mineralized rock is present adjacent to a marble lens, but most of the prospecting has been done along major shear zones in the Franklin group altered tuff and younger porphyry dykes. Fissure Veins. The fissure veins are very similar to those of other regions and are of the simple filling type. The three main fissure veins that have been opened up are on the Banner, Union, and Little properties. Banner Claim. The Banner claim is situated on the west flank of Franklin mountain and is one of the pioneer properties in the camp.' 'Staked by Frank McFarlane, August 9, 1898. August, at Grand Forks, B.C. Recorded 17th of 12 168 The fissure, which has been opened up by a shaft about 25 feet deep, strikes N. 34° W. and dips steeply to the southwest. The ore is zinc blende, galena, chalcopyrite, and pyrite in a quartz gangue. It occurs in irregular shoots and shows in places crustification about angular and curved fragments of a friction breccia. The ore is reported to have assayed $18 per ton. The country rock is altered tuff, quartzite, and brecciated calcareous conglomerate belonging to the Franklin group. A cross-cut tunnel was driven farther down the hill in a direction S. 87° E., to intersect the vein in the bottom of the shaft. It was driven 175 feet, but did not reach the ore shoot exposed in the shaft. The first 95 feet is in a cherty altered tuff which ends at a strong slip striking N. 40° W. and dipping 45° S.W. From there, a dark grey quartzite extends for almost 50 feet and then a silicified and brecciated calcareous conglomerate is encountered. This latter formation is slightly minerall-ed and continues to the face of the tunnel. Some diamond drilling was done in 1906, but gave negative results. •1 ■ Union Claim. T'le Union claim was one of the first locations in the Frank- lin camp, although it was recorded under a different name and allowed to lapse. In 1906, P. McGinnis and L. Johnson staked it and the adjacent Idaho and Paper Dollar claims. The fissure which has been stripped for several yards, strikes S. 80° W., and is vertical. The ore is galena and sphaler- ite, with a little copper carbonate in a quartz gangue, and very much resembles that of the Banner. The vein is crustified and contains drusy cavities in places lined with quartz crystals. A picked sample of ore is reported to have assayed 24 per cent lead, 35 ounces in silver, $8.25 in gold. The country rock is greenstone (altered augite porphyrite) and a silicified cal- careous sedimentary of the Franklin group.' 'Twenty-three tons of ore shipped in 1913 from a newly diacovered extension of this vein on the Union group, averaged $80 per ton. Transportation charges were $16.50 and smelting charges $6. The group of claims include the Union, 169 Little Claim. The fissure vein on the Little property is located on the west slope of the Granite range, at an altitude of 3,700 feet. It strikes east and west, and has a vertical attl.ude. Some splendid specimens of vein crustification came from this locality. Mineralization by sulphides is slight; calcite, quartz, and siderite are well developed. The siderite appears in botryoidal and globular forms; the calcite as nail-head spar, and the quartz in small perfect crystals. The country rock is pyritic tuff and calcareous conglomerate of the Franklin group. Age and Origin. The fissure veins are referred to the intrusion of the Jurassic granodiorite batholith at the time when the contact metamor- phic ores were being deposited in the contact zone of the batho- lith. It is thought that fissure veins were formed in the cover rocks following batholithic invasion and consolidation, through crustal tension, thus permitting the mineralizing solutions to circulate and deposit sphalerite and galena in the deep vein zone. The sulphides were no doubt deposited at a considerable depth below the surface. The ores must have been formed before the close of the Cretaceous erosion cycle, for at that time they were as near the surface as at present. This is shown by the manner in which the Eocene deposits lie upon the basal rock formations, and even upon the granodiorite itself on McKin- ley mountain. Union Fraction, Idaho, and Paper Dollar. The total amount of ore shipped from the commencement of shipping in August, 1913, until December, 1914, was 1767 tons; 443 tons of which was shipped to the Trail smelter, the remaining 1324 tons to the Granby smelter at Grand Forks, B.C. A typical analysis of the Union ore is as follows: gold 0-92 oz. per ton, silver 26-5 ozs. per ton, iron 5-0%, silica 71-5%, alumina 100%, lime 3-8%, and a trace of sulphur. The ore shoot containing pyrargyrite (ruby silver) and the high silver values (glory hole shoot) was found to occur in the vein at its acute angled inter- section with a rhyolite porphyry dyke. The shoot which is being stoped in the el belcw contains chiefly gold values. The ore shoots are replace- mr .ots with commercial boundaries. ^J n 'IM I ; i 170 Th« Cretaceous is considered to have been a period of relative quiet and long continued erosion, so that it seems justi- fiable to correlate this mineralization with the Jurassic crustal and igneous disturbances. Contact Zones. This type is similar in many respects to the contact meta- morphic type already described. It differs from it in the fol- lowing respects: (1) the ores are confined to the i: -nediate contact of the granodiorite batholith and the Franklm group metamorphics; (2) the ores have a much smaller proportion of lime-silicate gangue than have the contact metamorphic type; (3) no marble is present and associated with the ore, as it is in the case of the typical contact metamorphic type; (4) both grano- diorite and Franklin group cover rocks are mineralized along the contact zone, although the chief mineralization is in the Franklin gro' i rocks. The claims located on this contact are from west to east: the Mountain Lion, Gloucester, G.H., G.H. Fraction, Iron Cap, M.S., and Crystal Copper, all in the north half of the quadrangle. Development. The first claim to be located on this contact was the Glouces- ter, which was staked on August 14, 1898, by H. Gamett and Thomas Newby. The G.H. and other adjoining claims were staked shortly afterwards. The Gloucester, G.H., Opher, G.H. Fraction, and Tiger Fraction comprise the Gloucester group, which was bonded by the Dominion Copper Company in 1906, and the British Columbia Copper Compa-iy a few years before that. Gloucester Claim. As more development work has been done on the Glouces- ter claim than any other, it has been chosen for the type description. The Gloucester claim is located on the Gloucester Creek slope of Franklin mountain, at an altitude of 4,200 feet A.T. The development work consists of a 40-foot shaft whose collar is in the Franklin group greenstone. A coss-cut tunnel was driven at a level 100 feet below the shaft head, with a view to 171 making connexions and determining the extent of the ore shoot encountered in the shaft. The tunnel was driven 180 feet through sheared and calcified granodiorite, and then a raise was run for 71 feet, all in the same . 'tered granodiorite which is a part of the main Jurassic batholith. Besides this work, there are innumerable small prospect pits and open-cuts on the property. No work has been done on the Gloucester claim since 1906. The ore occurs along the main contact of the Jurassic batho- lith with the overlying Franklin group rocks, but chiefly in the cover rock. The upper contact of the batholith was found to pitch to the south, as shown by its contact relations exposed in the steep ravines to the east of the Gloucester. Much useless expenditure of money and labour could have been saved if the relationship of ores to batholithic contact and dip of that contact had been noted before attempting cross-cut tunnel methods. The ore minerals are chalccpyrite, pyrite, magnetite, molyb- denite; the gangue minerals, calcite, quartz, epidote, chlorite. The ore and gangue minerals are intimately intergrown in some places; in other places, the sulphides appear to have been second- arily concentrated. At a depth of IS feet in the main shaft, several feet of chalcopyrite-pyrite ore with some molybdenite were encountered. This ore is said to have run $5.60 in gold per ton and from 8 to 20 per cent in copper. The best ore is in the Franklin group side of the contact, although it does occur to a limited extent in the altered grey granodiorite. Geologic Age of Mineralization and Origin. In the case of these ores, the Laramide crustal movement was probably more responsible for the localization of the ore than was the intrusion of the Jurassic batholith. The reverse is true for the contact metamorphic type. The primary sulphides and oxides were deposited at the same time as those on the McKinley property, but have since been concentrated along the immediate contact where shearing and mashing during the Lara- mide revolution promoted further circulation of mineralizing solutions. The absence of the Gloucester marble formation i f i - 1 T sm j 4,,it 172 may account for the restricted nature of contact metamorphic deposits here with the more pronounced secondary minerali- zation. On the G.H. claim, adjoining the Gloucester to the east, there is a body of magnetite and pyrite ore up to 40 feet in width. The ore, however, has only traces of gold, silver, and copper. The other claims staked on this contact— the Iron Cap, M.S., and Crystal Copper— have had very little work done on them. Many of them have similar associations of oxides and sulphides of iron in the Palaeoaoic cover rocks overlvinff the batholith. * Sheab Zones in Gkanodiorite. Copper and Riverside Claims. The best example of this type of deposit occure on the Copper and Riverside claims, owned by A. Gelinas and J. Sentei. These two claims are situated south of the quadrangle about 1 mile, and across the east fork of the North Fork of KetUe river from the lower Franklin townsite. The property was under bond to the British Columbia Copper Company in The ore is disseminated chalcopyrite and pyrite, with some molybdenite, m a quartz and caldte gangue. The molybdenite IS in small flakes; the chalcopyrite usually with caldte in the deavage planes. The country rock is sheared, caldfied, and sihafied granodiorite. The strike of the shear zone along which the mineralization has taken place is N. 55" W., and can be traced for some hun Ireds of feet. Age and Origin. The shearing and mineralization is here referred to that accompanying the mountain making at the close of the Mesozoic. TERTIARY DEPOSITS. Segregation Type, "Black Lead." The segregation type is locally known as the "Black Lead" ores. The claims located on this type of deposit are: Columbia, 173 Ottawa, Evening Star, Iron Hill, Buffalo, B'ue Jay, Avcrill group, Mountain Lion, Maple Leaf, and Lucky Jack, all of which are in the north half of the quadrangle. The Maple Leaf was located by H. W. Young on October 14, 1902; the Evening Star by Capt. A. L. Rogers on June 26, 1903; the Lucky Jack by Henry Wotlin in 1909; and the Averill group by B. J. Averill in 1910 and 1911. The development work that has been done on the various properties is not extensive and consists of numerous prospect pits and short tunnels. The general discussion will apply to all the "Black Lead" properties and any variations from the normal type will be noted. The ore is chalcopyrite, pyrite, and a little bomite, in a gangue of shonkinite-pyroxenite or "Black Lead." This formation is a basic marginal differentiate from the same parent magma that gave rise to the augite syenite. The chalcopyrite and bomite are often found surrounded by orthoclase feldspar or in small masses closely associated with it. The pyrite, on the other hand, is generally disseminated in small grains through the ferromagnesian constituents. The ore is usually near the outer margins of the shonkinite- pyroxenite and is very irregularly distributed. On the Buffalo claim, the ore is near a monzonite contact, and both the shon- kinite-pyroxenite and monzonite are cut by a northeast and southwest system of pulaskite porphyry dykes. A sa-nple taken from the shaft dump on the "Blue Stem" claim, one of the Averill group, was analysed at the British Colum*-' CtK\per Company's smelter at Greenwood, B.C., with the f ! ( I ults.— O'OS oz. per ton. 0-69 « « « .'per 1 -90% (this was a selected sample). Silica 48-20% as SiO,. Iron 6-80 as Fe. Lime 2300 as CaO. Sulphur 1-40 as S. The ore from the Averill group is higher grade than that from the Buffalo, and some bomite, as well as chalcopyrite, has been LU 174 Mgr^ated. The chalcopyrite on the Buffalo, though much leas in amount, ia more evenly distributed through the whole mass. The reasons for considering this ore a magmatic segregation are as follows: (1) the simplicity of the mineralogy, which does not go with ordinary ore development : (2) the gradation of oie into a basic igneous rock, which is ar. undoubted segregation from the same parent magma which gave rise to the syenite;' (3) the absence of pneumatolytic minerals in the shonldnite- pyroxenite, such as fluorite, sericite, tourmaline, chalcedony, etc.; (4) the fact that the igneous mass has not undergone re- gional metamorphism; (5) the distinctly igneous component minerals; (6) the peripheral arrangement of the ore, chiefly at the outer margins; (7) the rareness of minerals produced by thermal alterations, such as seriate, quartz, carbonates; (8) the relation of the component grains, which shows it to be an early crystallization. Contact Met amorphic Type. The only property where this type of ore is promment is the Maple Leaf, situated on the east flank of Franklin n ^untain. The ore is in the altered Franklin tuff and greenstone at its immediate contac. with the syenite and shonkinite-pyroxenite. The shonkinite-pyroxenite is here in isolated areas surrounded by the syenite, the one passing rapidly into the other. The ore is chalcopyrite, pyrite, sphalerite, galena, and the copper carbonates, malachite and azurite.* The sulphides are intimately intergrown, pointing towards deposition simultaneous with rock alteration. The gangue is impure quartzite and green- stone, with considerable secondary- hornblende, alkalic feldspar, and epidote largely derived from the syenite. Small amounts 'Simitar marginal basic differentiates from syenitic magmas occur in Montana and are described by Professor Pirsson in Amer. Jour. Sci. (4), Vol. XII, pp. 1-17, 1901. •A sample of the ore ran as follows: gold a trace, silver 4-3 ozs. per ton, copper 16-0%, iron 16-6%, siUca 31-4%, alumina 9-3%, lime 2-6%. and sulphur 13-8%. #)^ 175 of chalcopyritr were found in the Kettle River conglomerate where the latter was in contact with the syenite on the east side of the Kettle river. Here the conglomerate, for at least 30 feet from the contact, is saturated with the syenite magma, and pseudomorphs of syenite after the more permeable boulders are present (Plate XV). The contact metamorphic nflfects of the hypabysnal syenite chonolith, with its narrow cont ct :\ureole, stand in contrast to the broad contact zone produced by the abyssal granodiorite batholith. Replacements Along Shear Zones. On the Royal Tinto claim, owned by John Holmes, at the north end of Franklin mountain, some magnetite and pyrite are present as replacements along a sheared zone in the mon- zonite. The strike of this zone is northwest and southeast cor- responding to the strike of the syenite chonolith contact, which is distant 500 feet to the southwest. The shearing and mineralization, which was in the nature of hydrothermal metasomatism, in this case may be correlated with the intrusion of the nearby alkaiic syenite and pyroxenite. Origin of the Tertiary Ores. The field fucts, upon which the following tentative conclu- sions are based, are discussed in previous chapters. The Tertiary ores are considered to have primarily segre- gated along with the shonkinite-pyroxenite from a parent magma prior to intrusion and consolidation. This may have taken place by means of liquati'^'' and gravitative adjustment in i deep seated magma reser With intrusion and extrusion, both the shonkinite-pyro ate and syenite, which were immiscible solutions, became subject to the action of convection currents and diffusion, chiefly the former. Convection currents segre- gated the basic portions containing the ferromagnesian and sulphide minerals towards the cool walls. Both the shonk'nite- pyroxenite and the syenite reached the surface at the base of m li 176 Tenderioin mountain and formed alkalic basalt and trachyte flowt. When volcanic activity ceased, so did bodily movement in the magmas. Diffusion became dominant over convection as a factor in segregation, and produced the different types of syenite, with their gradual gradations from one facies to another. In the shonkinite-pyroxenite it further segregated the chalcopy- rite. The chalcopyrite associated with the orthoclase may be largely due to this youngest segregation through diffusion. 17- CHAPTER VIII. BIBLIOGRAPHY. The following list includes the main referent, in the preparation of this report: — consulted Adams (F. D) 1903.— 'The Monteregian Hills— A Canadian Petrographicai Province." Jour. Geol., Vol. XI, pp. 239-253. Atwood (W. W.) 1911. — "Physiographic Stur.-' in the San Juan District of Colorado." Ibid.. Vol. >\ iX, pp. 449^53. Ball (S. H.), Spurr (J- E.), and Carrey (G. H.) SeeSpurr (J. E.) Barren (J.) 1902.— "The Physical Effects of Contact Metamorphism." Amer. Jour. Sd. (4), Vol. XIII, pp. 279-296. 1907.— "Climate and Terrestrial I^eposits: Studies for Stu- dents." Jour. Geol., Vol. XV, pp. 160-190, 2S5-29S, 363-384. 1907a. — "Geology of the Marysville Mining District, Montana U.S. Geol. Surv., Prof. Paper No. 57. Becker (G. F.) 1897.— "Fractional Crystallization of Rocks." Ai «. Jour. Sd. (4), Vol. IV, p. 257. Bowman (I.) 1911.— "Physiography of the United Stotes, Forest Physio- graphy." pp. 342-368. 178 mm ' Brock''(R. W.) 1900.— Summary Rept. Kootenay District. Geol. Surv. Canada, Ann. Rept., Vol. XIII, p. 70 A. Brock (R. W.) 1906.— Preliminary Report of Roesland, British Columbia, Mining District. Geol. Surv. Canada, Pub. No. 939, pp. 14-15. 1906a.— "Operations in the Rossiand Mining District, British Columbia." Ibid., Summary Rept., pp. 62-65. 1901— West Kootenay map sheet. Ibid., No. 792. 1903.— Boundary Creek map sheet. Ibid., No. 828. Br6gger (W. C.) 1894-1898.— "Die Eruptivgesteine des Kristianiagebietes,I," Die Gesteine der Grorudit-Tinguait-Serie, pp. 125, 153, 178, 179; II, Eruptionsfolge Eruptivgesteine Predazzo, p. 66; Til, Das Ganggefolge des Laurdalits. Brooks (A. H.) 1906.— "Geography and Geology of Alaska." U.S. Geol. Surv., Prof. Paper No. 45, p. 279. Calhoun (F. H. H.) 1906.— "The Montana Lobe of the Keewatin Ice Sheet." Ibid., Prof. Paper No. 50, p. 56. Calkins (F. C.) and Smith (G. O.) See Smith (G. O.) Camsell (C.) 1910.— "Hedley Mining District." Geol. Surv. Canada, Mem. 2, p. 126. Chamberiir. (T. C.) and SaUsbury (R. D.) 1906.— "Geology." Vol. Ill, p. 66. Clarke (F. W.) 1911.— "Data of Geochemistry." U.S. Geol. Surv., Bull. 491, p. 298. 179 Cross (W.) 1896. — "Age of the Arapahoe and Denver Formations." Mono. XXVII, p. 202. Ibid. Daly (R. A.) 1903. — "The Mechanics of Igneous Intrusion." Amer. Jour. Sci. (4), Vol. XV, pp. 269-298; Vol. XVI, pp. 107-126. 1903a. — Geology of the Western Part of the International Boundary." Geol. Surv. Canada, Summary Rept., pp. 136-147. 1905. — "Classification of Igneous Intrusive Bodies." Jour. Geol., Vol. XIII. p. 485. 1906. — "The Nomenclature of the North American Cordil- lera." Geog. Jour., Vol. XXVII, p. 588. 1906a. — Boundary Commission Report. Report of Chief Astronomer, Canada, Dept. of Interior. 1906b. — "The Okanagan Composite Batholith of the Cascade Mountain System." Geol. Soc. America, Bull., Vol. XVII, pp. 329-376. 1910.— "Origin of the Alkaline Rocks." Ibid., Vol. XXI, pp. 87-118. Dana (J. D.) 1892. — "Descriptive Mineralc^y." Dawson (G. M.) 1879. — "Report on Exploration in the Southern Portion of British Columbia." Geol. Surv. Canada, Rept. Progress 1877-78, p. 80B. 1879a. — "On a New Species of Loftusia from British Columbia." Quart. Jour. Geol. Soc. London, Vol. XXXV, p. 69. 1881.— Geol. Mag., Dec. II, Vol. VIII, p. 158. 1894. — "Report on the Area of the Kamloops map-sheet, British Columbia." Geol. Surv. Canada, Ann. Rept., Vol. VII, Pt. B. 1896.—' 'Glacial Deposits of Southwestern Alberta in the Vicin- ity of the Rocky Mountains." Geol. Soc. America, Bull., Vol. VII, pp. 31-66. ill ISO 1901.— "Geological Record of the Rocky Mountain Region in Canada." Ibid., Vol. XII, pp. 59, 70, 89, 90. De Lorenzo (G.) 1904.— "The History of Volcanic Action in the Phlegracan Fields." Quart. Jour. Geol. Soc. London, Vol. LX. Pt. Ill, p. 296. Emerson (B. K.) 1897.— "Diabase Pitchstones and Mud Enclosures of theTri- assic Trap of New England." Geol. Soc. America, Bull. Vol. VIII, pp. 59-86. Garrey (G. H.), Spurr (J. E.), and Ball (S. H.) See Spurr (J. E.) Geikie (A.) 1897.— "Ancient Volcanoes of Great Britain." Vol. I, p 470 1903.— "Text Book of Geology." 4th ed.. Vol. I. p. 280. Harker (A.) 1909.— "Natural History of Igneous Rocks." Chap. IV pp. 89-109, 330. Iddings (J. P.) 1891.— "The Eruptive Rocks of Electric Peak and Sepulchre Mountain, Yellowstone National Park." U.S. Geol. Surv., 12th Ann. Rept., p. 606. 1892.— "The Origin of Igneous Rocks." Phil. Soc. Wash Bull., Vol. XII, p. 184. 1909.— "Igneous Rocks." Vol. I. Irving (J. D.) 1911.— "Replacement Ore-bodies and the Criteria for their Recognition." Econ. Geol., Vol. VI, pp. 527-561 , 619-669. Joerg (W.) 1910.— "The Tectonic Lines of the Northern Part of the North American Cordillera." Amer. Geol. Soc.. Bull.. Vol XLII,p.l61. 181 Johnson (D. W.) 1908. — "Relations of Geology to Topography. Principles and Practice of Surveying." Vol. II, Chap. 7, p. 246. Judd (J. W.) 1886. — "On the Gabbros, Dolerites, and Basalts of Tertiary Age in Scotland and Ireland." Quart. Jour. Geol. Soc. London, Vol. XLII, p. 54. Lacroix (A.) 1902, 1903. — Les Roches Alcalines Caract^risant la Province P6trographique d'Ampasindava, Madagascar." Nouv. Arch. Museum Hist. Nat. Paris, 4e S^r., Vols. I and V. URoy (O. E.) 1908. — "Phoenix Camp and Slocan District." Geol. Surv. Canada, Summary Rept., pp. 65, 66, 68. 1910.— Ibid., p. 128. 1911. — Phoenix Map, Geol. Surv. Canada, No. 16A. In preparation. — "Slocan District." Geol. Surv. Canada. L6vy (A. M.) 1897.— Soc. Geol. France, BuU. 3e S6r., Vol. XXV, p. 367. Lingdren (W.) 1901.— "The Gold Belt of the Blue Mountains, Oregon." U.S. Geol. Surv., 22d Ann. Rept., Pt. II, pp. 574, 582, 597, 598. 1902. — "Character and Genesis of Certain Contact Deposits." Amer. Inst. Mg. Engrs., Trans., Vol. XXXI, p. 227. 1904. — "A Geological Reconnaissance Across the Bitterroot Range and Clearwater Mountains in Montana and Idaho." U.S. Geol. Surv., Prof. Paper No. 27. Penck (A.) 1909.— "Die Alpen im Eiszeitalter." > •■ 182 Penhallow (D. P.) 1907.— "A Report on Fossil Plants from the International Boundary Survey for 1903-1905, collected by Dr. R. A. Daly," Royal Soc. Canada, Trans., 3rd Ser., Vol. XIII, Sect. IV. 1908.— "Tertiary Plants of British Columbia." Geol. Survey. Canada, Pub. No. 1013. Pirsson (L. V.) 1899.— "Petrography of the Igneous Rocks of the Little Belt Mountains, Montana." U.S. Geol. Surv., 20th Ann. Rept., Pt. Ill, p. 526. 1905. — "The Petrographic Province of Central Montena." Amer. Jour. Sci. (4), Vol. XX, pp. 35-49. Pirsson (L. V.) and Rice (W. N.) 1911.— "Geology of Tripyramid Mountain." Ibi'^ , Vol. XXXI, p. 287. Pirsson (L. V.) and Weed (W. H.) See Weed (W. H.) Rice (W. N.) and Pirsson (L. V.) See Pirsson (L. V.) Rich Q. L.) 1910. — "The Physiography of the Bishop Conglomerate, Southwestern Wyoming." Jour. Geol., Vol. XVIII, pp. 601-632. Robertson (W. F.) 1900-1906.— Ann. Repts. Minister of Mines, British Columbia. Rosenbusch (H.) 1905, 1907. — Mikroskopische Physiographie." Intrusive-Ges- teine II, 1, p. 146; Mineralien I, 2. 18.5 Russell (I. C.) 1899. — "A Preliminary Paper on the rie«l()j;y of the Cascade Mountains in Northern Washington." U.S. Gtoi. Surv. 20th Ann. Rept., Pt. II. Schuchert (C.) 1910. — "Palaeography of North America." Geo!. Soc. Ainer., Bull., Vol. XX, pp. 427-606. Shand (S. Jr.) 1910. — "On Borolanite and its Associates in Assynt." Edin- burgh Geol. Soc., Trans., Vol. IX, Pt. V, p. 384. Smith (G. O.) 1904.— "Mount Stuart Folio." U.S. Geol. Sir.-., (leoi. Atlas U.S., Folio 106. Smith (G. O.) and Calkins (F. C.) 1904. — "A Geological Reconnaissance Across the Cascade Range." Ibid., Bull. 235. Smith (G. O.) and Willis (R.) 1903. — "Contributions to the Geology of Washington." Ibid., Prof. Paper No. 19. Spenser (A. C.) 1904. — "The Copper Deposits of the Encampment District, Wyoming." Ibid., Prof. Paper No. 25, p. 12. Spurr (J. E.), Garrey (G. H.), and Ball (S. H.) 1908. — "Geology of the Georgetown Quadrangle, Colorado." Ibid., Prof. Paper No. 63, p. 52. Suess (E.) 1909.— "Das Antlitz der Erde." Vol. Ill, Pt. II. Tyrrell (J. B.) 1896. — "The Genesis of Lake A.^assiz." Jour. (jOuI., Vol. IV, pp. 811-815. Il i^n' 184 'Is Umpleby (J. B.) 1910. — "Geology and Ore Deposits of Republic Mining District, Washington." Wash. State Survey, Bull. No. 1, p. 11. 1912. — "An Old Erosion Surface in Idaho. Its Age and Value as a Datum Plane." Jour. Geol., Vol. XXII, pp. 139-147. Weed (W. H.) and Pirsson (L. V.) 1895. — "Igneous Rocks of Yogo Peak, Montana." Amer. Jour. Sci. (3), Vol. 1, pp. 467-479. 1895a.— "Highwood Mountains of Montana." Oeol. Soc. America, Bull., Vol. VI, p. 415. 1896. — "The Bearpaw Mountains, Montana." Amer. Jour. Sci. (4), Vol. I, pp. 283-30!, 351-362; Vol. II, pp. 136-148. Bli 1 11° I I! I Williams (J. F.) 1891.— "The Igneous Rocks of Arkansas." Geol. Surv. Arkansas, Ann. Rept. for 1890, pp. 1-391, 429-457. Willis (B.) 1887. — "Changes in River Courses in Washington Territory due to Glaciation." U.S. Geol. Surv., Bull. 40. 1898.— "Educational Series of Rock Specimens" (Diller). Ib;d., Bull. 150, p. 316. Willis (B.) and Smith (G. O.) See Smith (G. O.) Young (G. A.) 1904. — "Geology and Petrography of Yamaska, Quebec." Geol. Surv. Canada, Ann. Rept., Vol. XVI, Pt. H, pp. 38-43. dgr fl'iw noi).)not la oiMotiom niolTsbioT abunno) i-wii jljjsy! (j» juij.. -% i:i ■1' I' * \l '■'< m 186 ts* l'mi)'cl>y (J. B.i District, VV,ls!n,iLt.>ii." W.i-h Ma!t S...rvr\ Riill. N<; 1, p n. I'>12. - 'All 0!(! hr )-!(!. 1 -"irl.i.-- ii: lu.ii'.. (i- Agi .aid \'alu naa J>alum I'laiw-." Jonf. C.-ol., Vul. \XH, pp. Ii'>-14,' Wtitl W. Ii , ,.u.J Hirstoit d- v.; 1895. • iRm<.U!« Rix-ics o! Yo»>m i\.'.k, Muniaii.i ' Aiuci jour. S 1895a -"H»)?hw<^''l Mfftintatns nl M'vii,,,,. ' C.iA, -^ ,. Aimrira. Bull., Vol. VI, p. 41.5 1896 rhi' H«'art)iiw Mi-sintains. Mtwtaiia,' .\nui. J(h.[ ^-l 4; ,V<1 i pp. 2J<.>-J01. .vM-,;«^.J. Vol M. pf». 1.46-U' Wiliwm'* '.J }• ' Arkir, J Bj^itAKATioK or turn II. l .:■>!. 420-4 57. Lool^nC '6p Krttle river toward* Ten<]erlain mountain at junctioa with GIbWMtcr v«Jby (m hit). Stow* «U% giMiaM. bMi«»lilK iMlkqr. (See peceJa), • .janatum ' .>-.. <«.-ul Surv., Bu!!. 40 '..■^'':' f •iao-1. Sic( -i',' ti>" 'Diilft n.i.L, Bj!!. !.it). p .»!<) Wiilis i,B.'i and ^iH^.h U". O > S«" Mnilli !,( J. O. N'oung id. A.) 1904- 'trt>f>k>R^ and Petrography.' .ji Yamn-ska. Quf!>e>: ' O! - ;-, ' •.'; \-:. K ••• V--! XA'i F- H, Pi ' ta. 187 ■f»W i!t; III: iii- ^*^ ' III MtkM «> vBinAKTAJHra .ill sfgifl 5IIM!' i*(iil aiiiJ// IM ExrLAMATtON OT PLATB III. East side of Kettle valley; Boulder creek to rifht. Shows glaciated rock ridges and plunging character of the granodiorite contact (indicated by white line). (See page 22). t'cl 190 Explanation of Plate I\'. Looking down Franklin valley towards Kettle river^Shows terraced outwash gravels and deep incision of Franklin creek. (See page 26). m Ml if! i 4 Ma'- lyi < i out wash ^^'1 %.i/--' ^':}M'''' 1;^, .^:' • ;st -f .y '||»A.lH 10 IIOIT4kl!AJ1/.3 192 EXPIANATIOS OF PLATE V. Posc-Glactal gorge in Kettle River conglomerate on Franklin creek. (See page 27). hi ly.? I'IMK \. (See ]rm fpt , i!-f^--^!-^ : -JS^- T . .W JiifJ$t"V> ■AniT*./.t..r)T.ti lUur:' ii'vqqi. ' i.ni fteiiqxt t «Wf>d7 ^i>I lyn Explanation of Plate \III. Franklin mountain; Gloucester City in centre foreground, bhows scars on mountrin slopes due to rock slides. (Set page 28). 199 - ;>-'Si fJHfiHK"' 111)1 .f-.. 'ts,^' . V'^'. ■- < ■ ,«.,■' •&. 200 Explanation of Plate IX. Kettle River conglomerate "hoodoog.' (See page 28). .'01 ATF IX. £^ i :*ii ■ -if • L.t». .n. ^-:ri 202 (Explanation ok I'latu X. Brecciated Jurasnit hornblenilite with aplile tillinK- (S^' i^ge 102). lil -MM I'l Ml N. i U)i -ii#i'>"ii !fcfiijin) jiii , -•.i.fr|-n tfi.fi rl-jirl* -^jfe'* W" 204 Explanation of Plate XI. A. Pebbles from Kettle River formation. Pebbles on right and upper pebble on left are composed of augite syenite, which has replaced the original material of pebbles. In the centre are two faulted pebbles; the three remaining pebbles show scratched and facetted surfaces and resemble pebbles from a tillite. (See pages 83, 95). B. Vesicular rhyolite in contact with Kettle River silt. Shows thin bed in process of being drawn up and included by the rhyolite. (See pages 69, 71). 205 I'l-ATE XI. yenite, tre are >d and J3,9S). bed in jes 69, ff : rfi' ^Xf-^ •'. ^iijji: .■r. ff 206 Explanation of Plate XII. Specimen of post-Oligocene monzonite on the left; specimen of Miocene augite syenite on the right. (See page 77). ii mamm 207 »ugite \n ■ i ■ ■ i HOi. Ifik r f V. -I I^A> 208 Explanation or Plate XIII. Specimen of porphyritic syenite with elongated orthoclaie feldfpar phenocrysti with borders of plagioclaie. Radiate structure. (See pages 109. 136). in-ATE XIII. 209 icrysts . 136). jl i I ^r... ■' 210 Explanation ok Plate XIV. Specimen of shonkinite-pyroxenite in contact with syenite aplite; two ex- tremes of differentiation. (See page 80). 211 :J.«^rr ■ 't' ,\^ 5'. y *> *. 212 ciXPLASATION OF PLATE XV. Kettle River conglomerate at contact with alkalic syenite. Shows intense metasomatism accomplislit^! by a granular alkalic magma intrusive into an unconsolidated formation. Compare weathered surface here with that of same formation shown in plate IX. (See page 83). -'IS I'l-ATK XV. ense into ■nth m t-n m'- I/. I I 17% UTAjf J III Kwr*. ^w;* Wre ibg tsviM sUMl rii^r taMnud a» 9iu«((<: iiliJIi. ;^l*urwJ TsviH JusX lo afcWaU k^iiMcpn H ni.'l ■\ .'iJJBn'i- aiL&Jl£ Ai liitwlani-lrrj k) ■fmil jiii.i ! ■ I) '-) t: ■^■^'- ij^-"* 214 Explanation of Plate XVI. Specimen showing alkalic syenite in conuct with Kettle River grit and con- glomerate. (See page 83). (1) Exact conuct between Kettle River grit and alkalic syenite. (2) Kettle River grit (dark) in part replaced. (3) Alkalic syenite (light). (4) Partly replaced pebble of Kettle River formation. (5) Alkalic syenite included in grit. (6) Dark lines of grit included in alkalic syenite. 215 I'l.ATK XVI. •w. k> .i .U I*..-, u.. ,-,*.,S'(lih» !^«UiWMl1il^ ■vi'Jilif.H hat sHie-nAf l^i 216 EXPLANATIUN OF PLATE XVII. Stratified basaltic and trachytir tuffs intercalated with flow*, un east flope oi Tenderloin mountain. (See page 85). 217 '^I'i Mnmt«f -4fi0hiU ^ghiihftc !*« «w,,ib*.> vviH » r.t!,.c, LsTir I 218 Explanation of Plate XVIII. Faulted contact of Kettle River formation and overlying Midway volcanic group. (See pages 86). 219 X |2^ 3.6 4.0 12.0 li il.6 ^ rd^pyigjyHGE '653 East Moin Street Ro<:h«,t,r N., York 14609 US* (716) 482 - 0300 - Phone (7t6) 2ee-5M9-fo« 41 i-ll >-■■• AX/, s HT/..;'! M> y -Jy/A-ir-i li: I!;, ^ 224 Explanation of Platb XXI. Minette dyke in contact with brecciated Kettle Ri-r gnt^ Show, differ- entially eroded surface. McKJnley mountain. (See page 92). 225 sfc sfl I ■'^'^:.r- ^ -t 226 Pi - KXPLANATION OF PLATE XXII. Volcanic agglomerate (trachyte) on east ilope at McKinley mountain. (See page 128). i J H ? 227 I'l.ATE XXII. V ■_U-5t HIL «>^ 3*M^^.,fc J80<>,^«^.,-, '^.^4;^„, ,.,,„ ., .,.^ iJ-v 228 EXFLANATION OF PLAT« XXIII. Specimen of contact mcumorphowd calcareous rock, ihowing pore tpace* due to thrinkage consequent upon expulsion o( CO|. (See page 167). 22*) I'iMi XNtlJ fi i ii i 231 INDEX. A. Acknowledgments '*•'* Adams lake * Adams, Prof. ... '^ Alcock, F. J '.'.'.'.'.'.'.['.'. "* Alkalic basalt 2 " intrusives ** Alluvial cone. Tertiary ^* Alluviation 43, 66 Amphibole. '•'•26 Kmolite'" '''• '"'' '°^' '"*• ""• '""• '''' "'• "^' "«• >". 132, 157 Analysis of addic tuff '..^.. v.. ■.■.^.V;....,;;; "' '^^' '"' ''^ " " rhyolite from Franklin mountain. .... ,!! Antecedent drainage Apatite. .101. 102, IM, los! 106,108, llli 116. UT, 118. 120, 122. 123, I24! Aplite dykes... '", 127, 132 Apophyses ^^' " Arfttes ^* Argillites, siliceous " Arkosic grit "" Arrow lakes "' Aachistic dykes '^ Ash, volcanic ''^ Assays of ores. ','. Atw^ series....::.:;:.::;.....:-; '^- '"'• "'• "' Augite syenite chonolith. ... f^ Averill, B. J.. ^^ " group... '" - SropLy.. :;;.•..;.■... ;;;;..;;. 8o m' m Azurite ™; '"• "7 157, 163, 174 B. Bftchstrom Banner claim .rJVtr .,„ *''? Barren. Joseph "*' '^^' '^'' '^^ Basalt ^ Batholith. Franklin ....::;;;; o .^' If ^ 16 9, 100, 160 ft-ft 232 PAGE 46 BathoKthic invasion . .- Bearpaw mountains -, Beaver meadows . 135 Becker, G. F ... SioSr£io2. 104: 106; 108; iii;ii6. us. 119:120: 122; 123; ^^^.jj^ Bird's eye porphyry ' ^^ Bitterroot range - - - ^ j^j B'ackl-ead ,4158 „,", °^ 173 Blue.Jay ... 158,173 Bomit" 12 « origin of jjj Boston Bar series -« Boulder clay . j Boulders, erratic j Bowman, Isaiah ,« Brachiopods -^ Brecciated rones ' ' ' ' ' '.- --j British Columbia Copper company !"• »'"• "* " " Minister of Mines I'", .w o tow 3, 103, 114 Brock, R. W j jj Brogger. 8 Brooklyn crystalline limestone " formation ::;::::.is4V iss. 173 Buffalo claim 8 Cache Creek group 50 52 145 cSlt.^""' "'^: :::::::::::: 85:98; 99; 105:111,117; 120; 125. \ti\ m^ Cannon, H.B „ . .» Carboniferous ' ^g « described . . " historyof ^^ •••--• • - • ^5j Cariboo range lo, ii, i:r, * , , ^^ Caves. 57 Cementation .. . j. Sa'icfpyrite : : : : 12:83; m; i56:i57,' 159; 162; \6&:m:m'.iu cSntr96:97. 101, 102. 104. 105, 106. 108, HI, 116. !"• JJ8. »'; '^^' '^^ 11 76 Chonolith ', ,- Circulation in magma 233 Cirques pace Clarke, Mr 19 Climate 134 " Tertiary 3 Coalescence of mountains ^^ Coldwater Group of bawson '^ Cols 10, 67. 68 Columbia claim 19 ^ lava plain in Washington. '^^ Mountain system IS, 41 " river IS Coltmbiana 40 Condition of deposition S2 Conglomerate <>3 Contact metamorphic deposits. '*• " ' " type of ore deposits'. ';..'...'.■ \iia\ll zones 159, 174 " ageof.. !;■■;;;;;; '58,170 Continental building ''' deposits '^' Convection currents 46, 94 Cooper Bros '37, 175 Copper 3 " claim 164,171 Cordilleran ice sheet '^^ Correlation of augite syenite chonolitii. . . . . .'. >3. 22, 152 * Fr&nklin group « « ^. " '"''' Gloucester formation. . . . .* Gloucester formation ,, " granodiorite batholith. ' • * Kettle River formation " '^ Midway Volcanic group " monzonite stocks. ?? u K 77 ores " * " Tertiary rhyolites. ^t\ " " younger dykes „, Crater 92 Cretaceous 86 " cycle of erosion. *i.lS3 II . o erosion ... " history of . . . . . ^' ■ ■ ' . ^**' *' Cretaceous peneplain '*** peneplanation 1^ Crinoidal remains 39, 43 * structures ' 98 234 PAGE Crew-bedding "' |*^ Cnistification vein ■ • • - Crystal Copper property "'• ""^^'^, Current markings 64,67 Daly.R.A 15.16.22.44,46.52.61.68.134 Dane claim »5 ^67 « property 28. 51. »a Dawson. G. M 8, 9, 23, 34. 38. 44. 50. 52, 65. 67. 88, 145 151 Deadwood '"• " Degradation "• ^° Deloro springs Deltas Development of claims Diaachistic dykes • • • '.".q Differentiation '■"*• ""• « magmatic --^o. Diffusion Diorite Dominion Copper company Drainage « antecedent Pliocene * described « of the F»ene-01igocene period. " Pre-Miocene « present system « Tertiary Durocher. Mr Dyke intrusions, younger period * rocks Dykes Dynamic movements .155. 41 170 118 174 133 176 55 170 40 13 29 148 12 12 67 138 89 114 59 139 Elkhorn mine. Montana . Emerson. B. K. . Eocene erot.4on surface. . Interior Plateau, peneplain E. peneplanation sediments.... 166 71 68 41 40 42 of British Columbia ^^ 39. 41 9 il 235 Eocene-Oligocene ""^ob • described •^■' " " Pe"«J. history of " "u . ' '?*!*^" Early Tertiary and Miocene..,: '^'^t " PliS^ne '"'"^"''''' "^"'^ °f P"""l»' •*■■!«•» '■'''■'' 36 " regional application of Franklin details tt tvening Star 39 Extrusives. '54, 173 122 Faulting. Faults... ISO Fauna. See game. '^-^^ Feldspar. 78. 96. 100, 101. 10*. 105. 106. 108. 109. 11,. lift. „8. ,„ j^o Fee Brothers '"' '"' ^^*' *"• '^O. 127. 132. isr. 158 Field work '55 Fissure vein ores ' " veins 1* Flora. See timber. '''• "*^ Flows Fluorite 122 Fluides mineralisateurs '"^ Fluvio-glacial alluvium ^*' Foraminife 93 Formations described '^ Formations, table of ** Fossils 47 49 2 160 " Cache Creek series. .'.'.'.'.'.'.'.'.'.'..'', *''•!' " Franklin group. " Fox. C. A Franklin batholith * creek .... Franklin group. 21. 26. 27, 32. 51, 78. 93 conditions of deposition correlation *' described ■■■■■........ ^" distribution ** general characters ** original structures secondary structures *„ 49 236 PACE 7 "",[',',',,,.,........ 51, 78, 83, 85 upland ,, Franklin group of rocks " mountain valley . Fusulina . 8, 52, 98 » m w : i iM^ i mk. im^ ^W ' ll ^ si ' ^ K G. H. claim G. H. Fraction claim. Galena • -blende ores. . . .170, 172 170 .157, 162, 158, 174 157, 161 6 9*'"* '.[ 58, 108, 156, 163 Garnet i^q Garnett, H ^j Gas cavities. 141 Geikie, Archibald jy^ S«''"*'; ^ : '. .62. 68, 74. 78 General statement j^ Genesis of ores Genetic classification of mountains 16 16 Geographic classification of mountams ^^^ Geologic history « " summary of Geology, economic ^ " general * structural 152 154 46 46 22 Glacial forms •, j^ " period 'jjj • : historyof 22,24,56 " strue 22 Glaciation . j2 Glaciers. " Pleistocene " valley Gloucester city ',. « claim . cr^k... ■.";:.;: ^i, 22, 2s, Gloucester formation ^' **• ^**' ^"' described distribution Gold. 164, * placer rush. " ranges Gorges 21 25 51 170 32 159 51 51 171 154 52 237 Gradients of streams. . . '"'^'"^ Grand Forks , • , Jf Granite 3. 17. 154 " 3iia.v.:::; '■■■■■■'■':■:::::: is:suw.im Granodiorite ^ '^ Nelson Granodiorite-batholith, described distribution .. general characters of .. structural relations of i^ Gravels, auriferous ... Greenstones -„ w H. H^^'^^'A ;v- 131.134 Hemipronites crintstna 52 Holmes, John ,,, Koodoos 'J^ I. Idaho claim ,.„ « ^. loo state ,- Iddings. Mr j^ Igneous activity and mechanical considerations 139 " history - , u , , 36 rocks, occurrence of t^ petrography of jqq augite microdiorite j2j " syenites 11, 105, 138 " porphyry II7 basalt, aikalic j27 granodiorite aplite j jg porphyry II5 homblendite 55 (q2 melanite syenite 108 137 micromonzonite 75 1Q5 ""'"ette ! ! . ! 12! 120 monzonite 28, 59, 103 ' aplite 119 Nelson granodiorite 9 100 phonolitic trachyte 35 126 f I. \ 3M rACB Igneous rock», porphyrilk iyenite .; *??I I^a puUikite porphyo ". 118, 130 pyrocUutic. " quart! porphyry »•»• ||° Rowland alkali-granitic rocks "* rhyolite I" " porphyry "* ghonkinite-pyroxenite.ll, 02, 79. 85. 111. 136. 137. 138. 142 syenite aplite J|' " " porphyry *" syenite porphyries '* trachyte "• "* Valhalla quartsose granite '* Interior Plateau ***• " " "of British Columbia, age of ** ... 100 iMru»ivea Iron Cap claim ""• \'\ U UJII tt l'^ 104.106,120 lr\-ing. J. D 3. Japanese faunas. Johnson, L Joint planes Jointing . curved. Judd. J. W Jurassic age of Franklin granodiorite batholith . batholithic invasion described granodiorite history of 151 168 57 49 71 129 153 62 9 55 81 146 Kamloops beds district , °" Kaolin 96, 97, 101. 104. 105. 106. 108. 117. 120. 123. 125. 127 Keewatin glacier 1 1 i S7 Keewatin ice sheet ' l Keffer, Frederic Kerby. Forbes. M Kersantite 2 2 122 339 ir ..I • 'ACE Kettle river J2 jj ^^ ^^ Kettle River formation ' ! . !! 10 12 40 76 de»cribe«l ' ' ' ,. ditiribution g. structure of -, thicknesH of ^.j Kettle river, graHient of . . . . .. Kettle valley ,y Knobhill group - L. Lambe, I,. M „ Lamprophyre ....'........' U, 92 " dykes . '' ' 59 Laramide ^ " Revolution tg/ 29. 39, 42 " history of j4g uplift .'."..'.[. 10.42 Last Chance ravine ' q, ^'\:"'---. y----y^'--''^y.'.'.'.'.. '.'.'.'.'.'.. '.'.'.'. 69 capping* 2g_ ^2 " cliffs ' jg " flows j^ Ledmoritt: b.ienite 158, 172 Montana state ^9 Monzonite stocks ^^' \^y Moraine, lateral ^Mo Moraines ^3, 152 Mountain building • \^J Lion claim 59. 170, 173 « making at the close of the Palaeozoic 8 Mountains, classification of '" Muscovite "^ 241 N. fACB Needle*, B.C 3 Nephelinitic tyenite 85, 1,17 Ncphelitc ' I25 Newby camp 19 . * Thot 154^ ,70 Nicola wriet 9_ J45 Nunataka U.tSl O. ^•'B°«ne 38, 41, 67, 68 " deacribed 74 " deformative period 10 " hiitory of J49 Oligoclase , j7 Olivine j2o Ore deposition, periods of 35 Ore deposits, de»' ibed 14 formation of q types of 155 Ores, assay values of 164, 168, 171, 173 correktion I54 genesis of 164 minerals in 161, 162, 168. 172, 173, 174 sub-types I57 Tertiary 1 1 Origin of augite syenite chonclith 84 * " contact zones 171 " " fiss'ire veins 169 " " granodiorite batholith 59 " " Midway Volcanic group 86 " " monzonite stocks 76 " " pulaskite porphyries 91 " " Tertiary ores 175 " " " rhyolites 71 Osoyoos granodiorite batholith 9, 62 Ottawa claim 173 Oxides of iron 156 Ml rAOB PBlaowk T. >«. >»» • dctcribed ♦• • time, hiftory of M^ Paper DolUr cklm •« Ponigcnctit of the ore and gangue mincrali IM Penck.A W Peneplain ■'*. « Penhallow, D. P « Petrographk provincM *W Petrology detcribed •♦ " theoretical comidenktioM IW Phoenix. B.C 8. 40. 44 " (Knobhill group) M " ore* '** Phonolite *'* Physiography ^' Pirswn. L. V 3. "'. >3* Plateaui 39 PWwocenc 13. 23. 31. 1S3 " period, hittory of "> ■ See alM Glacial period. Pliocene 21. 31. 34. 153 " erouon >2. 3*. 37, 44 ' history of '50 Pncumatolytic action 56, 57. 96. 160, 167 Porphyritic syenite chonoUths 78 • • intrusions » Pcmt-Glacia! gorge cutting 27 Post-OIigocene erosion 37 Putaskite dyke intrusions 12 " porphyries 89 " porphyry dykes 59, 75 Pyrite 99, 102, 111, 123, 157, 158, 160, 162, 168, 172, 173. 174 " -chalcopyrite ores 157, 161 Pyroxenes 74, 104. 106. 136 Augite 79, 105, 111, 118. 120, 125, 127, 132 Dipoeide 58, 77, 120, 122, 125, 156, 163, 167 Pyroxenite H yuatemary 7, 92, 143, 153 " time, history of 151 24J rAOR Ouarti 79, 8S. 96. gg. lOJ, lOi. l(M, 105, 111, 116, 123. 152. 169 Qiwrtiitrt gg QuMncI bed* hH Radioaciiviiy 141 Ravine* 27 Recent I5j " hiiiory 152 RegkMMl uplift at clow oi Tertiary , l.j Remmcl granodiorite bathotith q, ft2 Replacrnwnt along shear inne* 158. 17S Republic district in Washington 39, 41 Rhynchonella 52 Rhyolite flows described 68 " porphyry 14H RWge. 27 Ripple marks ^1 Riverside claim 172 28 n 27 15 173 47 12 52 175 125 Rock-shoulders . Rock slides • structure, forms related to Rocky Mountain trench Roger J, A. L Roof-pendants Rossland alkalic syenite and granite " mountains Royal Tinto claim 155, Ru«'>e 104, Sagenite 124 S*lting 154 Schlieren 11, 55, 80, 102. 157 Schuchert, Charles 3 Sedimentary rocks, occurrence of 46 " " petrology of 94 Segregation typ*" of ore deposit 158. 172 Selkirk mountains IS • valley 15 Senter, J 172 Shand, S. J 109 Shear zones 158 " " in granodiorite 172 244 PAGE Sheared zones 31 Siderite \^ Silver '" * -lead ores _ Slocan series Sodalite-syenite ' ' ' -i^o :l. Sphalerite »^ »«. 168. 74 Square Butte, Montana j'_ Shocks »^ Stoping Stream bedding Streams, antecedent ij " gradients of '^ " interrupted ^ • rejuvenated ^J Stri* *" Striations on conglomerate boulder on Structural relations of augite syenite chonolith "O • » « granodiorite batholith 5* " 11 « Midway Volcanic group *' « « « monronite stocks '* « « « Tertiary rhyolite flows and tuffs 69 Structure of Kettle River formation ^^ Stupart, R. F ^ Suess, E Sulphide ore, origin of " Sulphides I" Syenite ". 1« Syenite chonolith "' ' hill 2 « porphyritic •"» • porphyry... *| Syntaxis of mountains " T. Table of formations ^ • « " Tertiary, Kamloops "* Tectonic basin *; " trough « Tenderioin ■ , "' « mountain 11.62,66.105.142 " volcanic vent "^ Terrace-remnants „ 'zz, - -steps 13.152 245 Ten-aces 26, 93 Tertiary 7, 10. 13, 14, 37, 40, 41, 43, 58, 67, 141, 143, 153, 156 Tertiary contact metamorphic ores I57 " continental sedimentation 18 " deposits 172 " drainage 29, 41 45 36 56 68 69 69 erosion " faunas and floras " intrusivcs Tertiary rhyolite flows and tuffs, described distribution structural relations of. . Tertiary. See also Eocene, etc. " time, history of I47 uplift '..'.'.'.'.'.'.'.'. 41 " lava 122 Thompson river 15 Till ■ 13, 22, 92 Tillite from New Haven, Connecticut 65 Timber 5 Titanite 83, 101, 102, 104, 105, 106, 108, HI, 117, 123, 127, 132 Topography 18 * age of 33 " alpine 19 " Tertiary 30 " upland 18, 44 Tourmaline 95 Trachyte extrusions 33 " periods 85 Tranquille beds 68 Triassic 9, 153 * period, history of I45 Troughs. 27 Tuff, acidic 96 Tuffs 11, 99 " described 68 Twin creek 25, 32, 51 Tyrrell, J. B 23 U. Unconformity between the dacite conglomerate and Palaeozoic 42 " « • g3,.|y Xertiary and the Miocene beds 42, 74 Union claim 155, 168 ?'f 246 V. PACE Valhalla granite '"^ Valley glaciation " " topography " Valleys ^' " hanging ^' » U-shaped 2* • V-ahaped *'• 21 Values in ores '"• Volcanic activity "° " eruption **2 " vents **• Volcanoes in Great Britain "* " Italy *** W. Water power ^2 Weed, W. H |^^ White Bear property ^^^' *'* Wilcher, Jas "*• ^59 Wotlin, Henry 1" Y. Yellow Jacket claim '^^ Yogopeak "3 Young, H. W >" Z. Zircon 97, 101, 102, 104, 108, 117, 123. 132 LIST OF RECENT REPORTS OF GEOLOGICAL SURVEY. Sin 1910, reports issued by the Geological Survey he: e been called memoirs and have been numbered Memoir 1, Memoir 2, etc. Owing to delays incidental to the publishing of reports and their accompanying maps, not all of the reports ha\ j been called memoirs, and the memoirs have not been issued in the order of their assigned numbers and, therefore, the following list has been prepared to prevent any misconceptions arising on this account. The titles of all other important publications of the Geolc^cal Survey are incorporated in this list. ^.kAma Memoirs and Reports Published During 1910. REPORTS. Report on a geological reconnainance of the re^on traverted by the National Tranicontinental railway between Lake Nipigon and CUy lake, Ont— by W. H. Collins. No. 10S9. Report on the geological position and characteristics of the oil-shale deposits of Canada— by R. W. Ells. No. 1107. A reconnaissance across the Mackenzie mountains on the Pelly, Ross, and Gravel rivers, Yukon and North West Territoriet— by Joeepn Keele. No. 1097. Summary Report for the calendar year 1909. No. 1120. MEMOIRS-GEOLOGICAL SERIES No. 1, Ceohgical Series. Geology of the Nipigon basin, Ontario —by Alfred W. G. Wilson. No. i. Geological Serieit. Geology and ore deposits of Hedley mining district, British Columbia — by Charles Camsell. No. 3, Geological Series. Palxoniscid fishes from the Albert shales of New Brunswick — by Lawrence M. Lambe. No. 4, Geological Series. Preliminary memoir on the Lewes and NordenskiOld Rivers coal district, Yukon Territory — by D. D. Cairnes. No. 5, Geological Series. Geology of the Haliburton and Ban- croft areas, Provinr e of Ontario — b ''"rank D. Adams and Alfred E. Barlow. No. 6, Geological Series. Geol'' at. Bruno mountain, prov- ince of Quebec — by John .. greaser. MEMOIRS— TOPOGRAPHICAL SERIES. No. 1, Topographical 6c> ies. Triangulation and spirit levelling of Vancouver island, B.C., 1909— by R. H. Chapman. Memoir Memoir Memoir Memoir Memoir Memoir 5. 7. Memoir 11. Memoirs and Reports Published During 1911. REPORTS. Report on a traverse through the southei-n part of the North West Territories, from Lac Seul to Cat lake, in 1902— by Alfred W. G. Wilson. No. 1006. Report on a part of the North West Territories drained by the Winisk and Upper Attawapiskat rivers — by W. Mclnnes. No. 1080. Report on the geology of an area adjoining the east side of Lake Timiskam- ing — by Morley E. Wilson. No. 1064. Summary Report for the calendar year 1910. No. 1170. MEMOIRS-GEOLOGICAL SERIES. Memoir 4. No. 7, GecUogical Series. Geological reconnaissance along the line of the National Transcontinental railway in western Quebec— by? W. J. Wilson. iii Memoir 8. No. 8, Ceclotical Series. The Edmonton roul fieM, Alberta — by D. B. bowling. Mbmoir 9. No. 9, Geological Series. Bighorn coal basin, Alberta — by G. S. Malloch. Memoir 10. No. 10, Geological Series. An instrumental survey of the shore-lines of the extinct lakes Algontiuin and Nipissing in southwestern Ontario — by J. W. Goldthwait. Memoir 12. No. 11/ Geological Series. Insects from the Tertiary lake deposits of the southern interior of Btitish Columbia, collected by Mr. Lawrence M. Lanibe, in 1906 — by Anton Handlirsch. Memoir 15. No. 12, Geological Series. On a Trenton hchinoderni fauna at Kirkheld, Ontario— bj Frank Springer. Memoir 16. No. 13, Geological Series. The clay and shale deposits of Nova Scotia and portions of New Brunswick — by tleinrich Ries, assisted by Joseph Keele. MEMOIRS— BIOLOGICAL SERIES. Memoir 14. No. t. Biological Series. New species of shells collected by Mr. John Macoun at Barklcy sound, Vancouver island, British Columbia — by William H. Dall and Paul Bartsch. Memoirs and Reports Published During 1912. REPORTS. Summary Report for the calendar year 1911. No. 1218. MEMOIRS—GEOLOGICAL SERIES. Memoir 13. No. 14, Geological Series. Southern Vancouver island — by Charles H. Clapp. Memoir 21. No. 15, Geological Series. The geology and ore deposits of Phoenix, Boundary district, Briti.sh Columbia — by O. E. LeRoy. Memoir 24. No. 16, Geological Series. Preliminary report on the clay and shale deposits of the western provinces — by Heinrich Ries and Joseph Keele. Memoir 27. No. 17, Geological Series. Report of the Commission appointed to investigate Turtle mountain, Frank, Alberta, 1911. Memoir 2f. No. 18, Geological Series. The geology of Steeprock lake, Ontario — by Andrew C. Lawson. Notes on fossils from limestone of Steeprock lake, Ontario — by Charles D. Walcott. Memoirs rnd Reports Published During 1913. REPORTS, ETC. Museum Bulletin No. 1: contains articles Nos. 1 to 12 of the Geological Series of Museum Bulletins, articles Nos. 1 to 3 of the Biological Series of Museum Bulletins, and article No. 1 of the Anthropological Series ' . Museum Bulletins. ,.,... Guide Book No. 1. Excursions ii< eastern Quebec and the Maritime Provinces, parts 1 and 2. Guide Book No. 2. Excunioni in the Eastern Townships of Quebec and the eastern part of Ontario. Guide Boole No. 3. Excursions in the neighbourhood of Montreal and Ottawa Guide Book No. 4. Guide Book No. 5. Manitoulin island. Guide Book No. 8. Excursions in southwestern Ontario. Excursions in the m-estern peninsula of Ontario and Toronto to Victoria and return via Canadian Pacific and Canadian Northern railways: parts 1, 2, and 3. Guide Book No. 9. Toronto to Victoria and return via Canadian Pacific, Grand Trunk Pacific, and National Transcontinental railways. Guide Book No. 10. Excursions in Northern British Columbia and Yukon Territory and along the north Pacific coast. MEMOIRS-GEOLOGICAL SERIES Mbhoir 17. No. 2S, Ctoloncal Series. Geology and economic resources of the Larder Lake district, Ont., and adjoining portions of Pontiac county, Que. — by Morley E. Wilson. Memoir 18. No. 19, Geological Series. Bathurst district. New Brunswick — by G. A. Voung. Memoir 26. No. 34, Ceologica' Series. Geology and mineral deposits of the Tulameen district, B.C. — by C. Camsell. Memoir 29. No. 32, Geological Series. Oil and gas prospects of the north- west provinces of Canada — by W. Malcolm. Memoir 31. No. 20, Geological Series. Wheaton district, Yukon Territory — by D. D. Cairnes. Memoir 33. No. 30, Geological Series. The geology of Gowganda Mining Division — by W. H. Collins. Memoir 35. No. 29, Geological Series. Reconnaissance along the National Transcontinental railway in southern Quebec — by John A. Dresser. Memoir 37. No. 22, Geological Series. Portions of Atlin district, B. C. — by D. D. Cairnes. Memoir 38. No. 31, Geological Series. Geology of the North American Cordillera at the forty-ninth parallel. Parts I and II — by Reginald Aldworth Daly. Memoirs and Reports Published During 1914. REPORTS, ETC. Summary Report for the calendar year 1912. No. 1305. Museum Bulletins Nos. 2, 3, 4, 5, 7, and 8 contain articles Nos. 13 to 22 of the Geological Series of Museum Bulletins, article No. 2 of the Anthro- pological Series, and article No. 4 of the Biological Series of Museum Bulletins. Prospector's Handbook No. 1; Notes on radium-bearing minerals — by Wyatt Malcolm. MUSEUM GUIDE BOOKS. The archaeological collection from the southern interior of British Colum- bia—by Harlan I. Smith. No. 1290. MEMOIRS-GEOLOGICAL SEKIES. Memoir 23. No. 23, Geological Series. Geology of the coast and islands between the Strait of Georgia and Queen Charlotte sound, B.C.— by J. Austen Bancroft. No. 21, Ctological Serits. Report on the clay and «hale de- positx of the western province* (Part HI)— by Hcinrich kics and JoMph Keele. _. . . , ^, , . , . , •„ No. 40, Geological Strirt. The basins of Ncl»on and thurclull rivers— by William Mclnnes. No. 41, Geological Series. Gold fields of Nova S)K>tu— by \S. Malcolm. , . . ,• • , c • w No. 33, Geotoiical Series. Geolcwy of the Victoria and Saanirh map-areas. Vancouver island, B.C.— by C. H. Clapp. No 42, Geological Series. Geological notes to acconip.iny map of Sheep River gas and oil field, Albt ta— by U. B. Dowling. No. 36, Geological Series. St. Hilaire (Belocil) and Rougeniont mountains, Quebec— by J. J. O'Neill. . , », No. 37, Geological Series. Clay and shale deposits of New Brunswick— by J. Keele. No. 27, Geological Series. Preliminary report on the serpentines and associated rocks, in southern Quebec— by J. A. Dresser. No. 25, Geological Series. Portions of Portland Canal and Skeena Mining divisions, Skeena district, B.C.— by R G McConnell. . , , , » l No. 39, Geological Series. Clay and shale deposits oi the western prosinces, Fart III- by Heinrich Rics. No. 24, Geological Series. The Archaan geology of Rainy lake —by Andrew C. Lawson. , . . , , , No. 26, Geological Series. Geology of Mother Lode and Sunset mines. Boundary district, B.C.— by O. E. LeRoy. No. 35, Geological Series. Kewagama Lake map-area, Quebec — by M. E. Wilson. No. 43, Geological Series. by C. H. Clapp. , .... No. 45, Geological Series. Moose Mountain district, southern Alberta (second edition)— by D. D. Cairnes. No. 38, Geological Series. The "Fern Leilges tarboniieroui flora of St. John, New Brunswick— hy Marie C. Stopea. No. 44, Geological Series. Coal fields of Manitoba, Saskatche- wan, Alberta, and eastern British Columbia (revised edition) —by D. B. Dowling. , ^. , , No. 46, Geological Series. Geology of Field map-area, Alberta and British Columbia— by John A. Allan. MEMOIRS-ANTHROPOLOGICAL SERIES. Memoir 43. No. 2, Anthropological Series. Some myths and tales of the Ojibwa of southeastern Ontario— collected by Paul Kadin. Memoir 45. No. 3, Aritkropologicat Series. The inviting-in feast of the Alaska Eskimo— by E. W. Hawkes. _ , u ,.r u Memoir 49. No. 4, Anthropological Series. Malecite tales— by W. H. Mechling. „, , ,^, • • Memoir 42. No. 1, Anthropological Sertes. The double curve motive in northeastern Algonkian art— by Frank G. Speck. MEMOIRS— BIOLOGICAL SERIES. Memoir 54. No. 2, Bic^ogical SerUs. Annotated list of flowering planU and ferns of Point Pelee, Ont., and neighbouring distnctt— by C. K. Dodge. Memoir 25. Memoir 30. Memoir 20. Memoir 36. Memoir 52. Memoir 43. Memoir 44. Memoir 22. Memoir 32. Memoir 47. Memoir 40. Memoir 19. Memoir 39. Memoir 51. Memoir 61. Memoir 41. Memoir 53. Memoir 55. Geology of the Nanaimo map-area- ^!;; i: Memoirs and Reports Published During ?«L-. MEMOIRS-GEOLOGICAL. Mbmoir 58. No.4a,C*olotualS*rits. Texada island— bv R. G. McConncU. Mbmou 60. No. 47, Ceulotital Strus. Ariwig-Antigunuh diitrict— by M. Y. WitUanw. Memoirs and Reports In Press, January 20, 1915. Mbmoh so. No. 51, CtoUpcai Striti. Upper White River diitrict, Yulcon — by D. D. Caimee. Memoii S6. No. 56, fieolotieal Series. Geotogy of Franlclin Mining camp, B.C.— by Chai. W. Drvsdale. Memoir 62. No. 5, AnlkroPolotical Series. Abnormal type* of (peech in Nootkd — by E. Sapir. Memoir 62. No. O. Anthropoloticai Series. Noun re ■~H -/jIz.-. Tl u ij /| A a LEGEND Culture Hoods and IraiUm^ Packtndb Shafts Bridges l^nsids ftxMpccts Water Tl {cim^mmrati, m*tmc frit . madU ei^) UPPER JURASSIC CARBONirEROUSO? Granodiaritc^iass GkuOMtBT a Symbols FUaure-vcm Gedo^cal toun dai y {pmHuf, mamafy dttmnuntd,) Geoio^jical boisdazy GMlolicallMwmdnj Taiilt »«r Sip aoid strike (Baciid striaa Struct Sedchr FRANKL wi BI ^Jmdk. r* ■ "— <>■■ » ««~«r ir CKOrymtmie IftM Mil T3 ^BCm^ CI a 14 Tiy P •n TVnnids X IVcapects Water 2^^ Lakes and streraas Woteroomca ^B& iutgMiaaii flmr Belief K Contoura 128« 4sao Structural sectkn akx^ line AB MAP 97 A CtmuaAmW NKLEV ME^IVG CAMP WEST KOOTENAY BBmSH COLmiBIA. Scale . n^89 XatrcB 2000 recT to i inch GEOLOGY c.w.imrsoALL. imi. TOPOGRAPHY c.w.imrsaiL£. ,^, TOPOGRAPHICAL BASE RATED GRAOC 5 (1 Hon. L. CooEHRt. Ministch: R.^ OEOLOaiCAL MINERAL CLAIMS. FRANKLIN MINI ^'••—••^^fMmtt ^Mi riM STtR; R.W.Bbock. Deputy Minister. 90ICAL SUMVCV OUTLINE MAP MINING CAMP, WEST KOOTCNAY. ac.