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 t:x «4 (^ i. 
 
 ON THE 
 
 GEOLOGICAL FORMATIONS 
 
 ov 
 
 LAKE SUPEEIOK. 
 
 By THOMAS MACFARLANE 
 
 (From the Canadian Naturalist for May, 1867 J 
 
 Tlic ciystallino rocks of Lake Superior present many features 
 of interest to the lithologLst, and to the student of primary 
 geology; and the sedimentary rocks of that region, being ahnost 
 destitute of organic remains, have been the subject of much 
 discussion among scientific men, which can, nevertheless, scarcely 
 be said to have settled unequivocally the question of their age. 
 Having, as 1 believe, observed certain new facts i^oncerning the 
 compositior; and association of these rocks, which aie calculated to 
 
2 
 
 throw some light on tlieh* origin and age, I have attempted to 
 describe them in the following paper. 
 
 Four different formations are distinguishable on the north, south 
 and east shores of the Lake, where I have had an opportunity 
 of examining their constituent rocks and mutual relations, but the 
 same formations may be observed elsewhere in this region. These 
 formations have been designated as follows: The Laurentian 
 system, the Iluronian series, the Upper copper bearing rocks of 
 La'ke Superior and the St. Mary sandstones. The two first- 
 named (and older) formations usually occupy those parts of the 
 shores which .form high promontoVies and prcciijitous cliffs, and 
 they constitute, almost exclusively, the areas which have been 
 explored in the interior. On the other liand, the Upper rocks 
 and St. Mary sandstones are never found far inland, but occur 
 close to the shore in comparatively low-lying land and rocks. 
 They seem to have had, as the theatre of their eruption and 
 deposition, the bottom of the Lake, at a time when its surface was 
 at a higher level than it is at present, although not so high as the 
 general surface of the surrounding Laurentian and Huronian hills. 
 
 I. — THE LAURENTIAN SYSTEM. 
 
 Under this name it has become usual, in Canada, to class those 
 rocks which, in other countries, have been regarded as forming 
 part of the primitive gneiss formation, of the primary or azoic 
 rocks, or of certain granitic formations. 
 
 The most prevalent rocks of the Laurentian series on Lake 
 Superior present a massive crystalline character, partaking much 
 more of a granitic than of a gneissic nature. Some of these I shall 
 endeavour to describe first. To the north of the east end of 
 Michipicoten Island, on tha mainland, there is a very large area 
 of reddish-coloured granite, which exhibits, in a marked degree, 
 the phenomena of divisional planes, and huge detached blocks. 
 The rock is coarsely granular, has a specific gravity of 2-6G8 to 
 5Z-676, and consists of reddish orthoclase, a small quantity of 
 a triclinic felspar, dark green mica (also in small quantity), and 
 greyish white quartz. The mica is accompanied by a little 
 epidote, and an occasional crystal of sphene may be detected. A 
 e.w miles to the east oi Dog River a grey granite occurs exten- 
 sively, which does not show any divisional planes. The felspar of 
 this variety is yellowish white, with dull fracture, and is fusible 
 without difficulty. It is associated with black, easily fusible 
 mica, in considerable quantity, and with quartz, which is occa- 
 
3 
 
 pinnally bluish tinted. The ppecific jrravity of the rock ih 2-750 
 to 2-703. Liirijo-f^raincd granite is of very frequent occurrence 
 on Montreal Kiver and on tlie coast betwixt it and Point-aux- 
 iMines. It consists principally of ortlioclase, in pieces from one 
 to several inches in diameter, a comparatively small quantity ot 
 quartz, and a still smaller proportion of white mica. The 
 promontory of firos Cap, at the entrance of the Lake from River 
 St. IMary's, is composed of coa'-se-j^rained and characteristic 
 syenite. In some places its liornbleiide is soft, seems decomposed, 
 and is accompanied by epidotq. The rock is seldom free from 
 quartz, and some of it contains so nmch as to be justly termed 
 syeiiitic (rranite. A cliloritic <rranite appears to occur at a few 
 points on the north side of Bachewalmunt.' Buy, and a suiall- 
 grained f^ranite, consisting exclusively of fcls])ar and quartz, 
 occurs in large masses at the north-western extremity of the same 
 Bay. It has not the structure of granulite, and might be properly 
 named aplito or granitelle. 
 
 These rocks are all unequivocally granular, without a trace of 
 parallel structure. They far exceed in frequency and extent those 
 which possess a thoroughly gneissic character ; indeed, character- 
 istic gneiss was only observed at Goulais Falls and at Point-aux- 
 Mines. The rock of the latter locality varied from the closely 
 foliated, resembling mica schist, to that of a granitic character. 
 Granitic gneiss is found on the north shore of Bachewahnung Bay, 
 between Chippewa Biver and Bachewahnung Yillage, on the road 
 between the latter and the Bachewahnung Iron Mine, in the 
 neighbourhood of the BegUy Copper mine, and at other points on 
 the north shore of Bachewahnung Bay. 
 
 Almost equal in frO(|uency to these thoroughly granitic and 
 gneissic rocks, there are found certain aggregates of rocks which 
 present different lithological aspects almost at every step, and 
 which can only be generally described as brccciated and intrusive 
 gneissic, granitic, or syenitic rocks. There is, however, i:o bo 
 detected a certain unitnnuity in the manner of their association 
 with each other, which is of the greatest interest, and several 
 instances of which it is now proposed to refer to. On the north 
 shore of the Lake, about twenty-five miles west of Michii)icoten 
 Harbour, one of these rock-aggregates may be observed. Here 
 fragments of a dark schistose rock, consisting of felspar and horn- 
 blende (the latter largely preponderating), are enclosed in a 
 coarse-grained syenitic granite, and both are cut by veins ot 
 
another pjranitc containiii<^ much less liornblende than the second- 
 mentioned rock. These veins are, in their turn, intersected by a 
 vein of tine-fjjrained ,u;ranite, consisting;' of (quartz and felspar, with 
 traces only of mica or hornblende. The specific fj;ravities of these 
 different rocks were found to be as follows: — 
 
 Ilornblendic schist 2-8.'}() 
 
 Syenitic granite 'J'7S7 
 
 Granite 2(508 
 
 Fine-grained granite 2()3() 
 
 That the specific gravity of the last-mentioned rock should be 
 
 greater than the one preceding, is attributable to its containing 
 
 more quartz. Figure 1 gives a representation of the phenomena 
 
 here observ^ed. No chemical analysis of these rocks is required to 
 
 Fig. 1. 
 
 a. Fragments of honibleudic schist. 
 h. Euclosing syeutic granite. 
 
 c. First intersecting granite. 
 
 d. Second Intorsoctinsj; OTauite. 
 
 show that the newer they are the greater are their contents in 
 silica. This is evident as well from their specific gravities as from 
 their mineralogical composition. The following relations, similar 
 to these are observable on the north side of the Montreal 
 lliver, at its mouth. The prevailing rock here is small-grained 
 granitic gneiss, which contains lighter and darker coloured portions, 
 according as the black mica which it contains is present in smaller 
 or larger quantity. A triclinic felspar is also noticeable in it. 
 Pieces of this rock are seen to be cut ofi" and enveloped in a 
 
fiiior-jrruined uranito, of a much lighter colour than tlio pjiioiss, 
 and coniparativcily poor in the bhick mica. The specific jrravity 
 of tlio <rnei,sH is 2-(Ht7, and that of the <rranite, 2'()4H. Veins of 
 lar;^o-<;rained trranito, containim^ very little mica, traverse both 
 of the rocks just mentioned. The appearance of these rocks 
 is shewn in Figure 2. At tlic falls of the Chi]»pewa or 
 
 rig- 2- 
 
 
 
 'mrnm^^. 
 
 '//O'/'j"'/'' - • • * ♦. ^ 
 
 a. Granitic gneiss. | h. Fine-grained grani«e. | c. Large-gmined granite. 
 
 Harmony River, which empties into Bachcwahnung Bay, the 
 predominating rock is highly granitic gneiss, consisting of reddish 
 orthoclase, quartz and dark-green mica. It is rather small- 
 grained, and, when observed in mass, shows sometimes a schistose 
 appearance, the direction of which ranges from N. 10° W. to N. 
 57'^ E. Occasionally, in the more micaceous portions, broad 
 felspathic bands occur, with selvages rich in mica, forming the 
 nearest approach to gneiss. The direction of these bands is 
 altogether irregular. This is also the case with veins of large- 
 grained granite which intersect the rock just described. This 
 
6 
 
 granite consists inaijily of red ortlioclasc, witli a coini)arativt'ly 
 Miiiall ((uantity of (juartz, with wliicli a still sniaiU'i' (juaiitity of 
 urcenisli mica is associated. The spccitic gravity of the p-aiiitic 
 i^ni'iss is 2-l)7G, and that of tlie coarse-irraiiied rock of the veins 
 ]i\}\)L On the north-east shore of tlu; JJay, ciosi! to the landing 
 place of the Jii\i:ley .Mine, rocks are observed consisting' jirincipaily 
 of granitic gneiss, in liand specimens of which, no parallel structure 
 can be detected. At some }>laces, however, in larger ma.sscs, a 
 schistose appearance is observable, with a strike of N. 75'^ E. This 
 rock, which is syenitic, contains masses and contorted fragments 
 ot gneiss very rich in hornblende. Both the fragments and 
 enclosing rock are intersected by veins of large-grained granite, 
 containing little or no hornblende or mica, Tn the most south- 
 easterly corner of Bachewalmung Hay, rocks occur, which, altliougli 
 they are totally devoid t)f any apj)roach to gneissie structure, 
 and possess ■ very different composition, bear some resemblance in 
 the manner of their association to those just described. A. dark- 
 coloured, snuill-grained mixture of felspar and greeidsh-black 
 mica, with occasional crystals of reddish orthoclase, and, more 
 rarely, of greenish-white oligoclase, is enclosed in and intersected 
 l)y another rock consisting of a coarsely granular mixture of 
 orthoclase and soft dark-green mica, enclosing crystal of orthoclase 
 (but no oligoclase) from one-quarter to three-quarters of an inch 
 in 'diameter. Both of the rocks might be called micaceous 
 syenites, but as they possess a ])delorphyritic structure, they 
 probably belong to the rock species called minette. The matrix 
 of the first-mentioned and darkest coloured rock is fusible, 
 but the orthoclase which it encloses is less readily so. In botli 
 vocks, where exposed to the action of the waters of the Bay, the 
 micaceous constituent has been worn away, and the grains and 
 crystals of orthoclase project from the mass of the rock The 
 specific gravity of tiic small-grained rock is 2'85, and tliat of the 
 coarse-grained enclosing rock 2-05. They are both intersected by 
 narrow vcms of granite, consisting of I'elspar and quartz only, tlie 
 specific gravity of which is 2.62. At Goulais Falls, about fifty 
 miles up the Goulais Bivcr, gneiss occurs, which is very distinctly 
 schistose, contains a considerable quantity — about onc-tliird — of 
 brownish black riiica, inter huninated with quartzo-felspathic 
 layers, in which a transparent triclinic felspar is observable. The 
 gneiss possesses a specific gravity of 2-7-1: to 2"7G. Its strike and 
 dip are variable ; the former seems, however, to average N. 55® E., 
 
and the liittcr vnrios fioui IP ) 20^ nortli-wostward. It is 
 iutert-itratilifd with u (^iiiall-tjraincd ;^'raiiitic giioisH, contaiiiin;: 
 much lcs!4 mica than tlu; hist — ahout oiio-twentioth oidy, — no 
 triclinic felspar, mid having a spccitic gravity of 27 1 to 272. 
 The same fjrranitic gneiss intersects tiie characteristic gneiss in 
 veins, and both of these roeks are cut by a coars(!-grained granite, 
 ahnost destitute of ndea, and coinjdetely so of schistose structure. 
 The strata of the gneiss are much contorted in various phices. 
 The iiiterse(!tiiig granitic gneiss and granite are alujost eijual in 
 ({uantity to tlie gneis.s itself; and although they occur as irregular 
 veins, they are, at the point of junction, as firmly united with 
 tlu' gneiss as any two jiieces of one and the same rock could 
 well bo. Figure iJ is intended to represent the relations 
 observable at (Joulais Fulls. Between Goulais Falls and the 
 
 Fig. 3. 
 
 
 
 a. Gneiss. | h. Granitic gneiss. | c. Coarse-gnu ned granite. 
 
 point where the line of junction between the Laurentian and 
 Huronian rocks crosses Goulais River, there are numerous 
 exposures of gneiss()id rocks, but characteristic gneiss is of rare 
 occurrence among them. At several places hornblende schist, 
 in fragments, is observed enclosed in a gneissoid granite. Some 
 of them are longer than others, and have their longer axes 
 running N. 50^ to 60'' W. Hand specimens of the enclosing 
 granite show little or no mark of foliation, but when seen in 
 
8 
 
 place, n faint parallel strticturo is olisorvablo, tlie strike of whieh 
 is N. M^ to (10^' W. Moth tlio lioriihlciiclic fra^;nicnt.s and 
 the jiiii'lssoid iiranitt! are cut l»y vins of newer uranite. On the 
 Honth-east .shore of (Joulais Hay. a heautifiil irroiip of wytMiitie 
 roeks is exposed, the mutual relati(tns of which are similar to tho.se 
 above <le.serihed. l''rairnient>of liornhlende rock or sciiist, varyinj^ 
 from half-an-inch to three feet in diameter, arc; enclosed in a 
 coarse-LTrained .syonitie granite, in which, oeeasiotially, a rou<j;h 
 ])aralK'li.-^m of tln'hornhleiidc individuals is observable, the direction 
 of which is N. 57*' K., and coincides with that of the longer axes 
 of the hond)Iendic iVajinuMits. The sitecific j,fravity of the horn- 
 blendie rock is 2'!t 4 to IMMI, and of tin.' enclosing:; uranite 2"74. 
 JJoth are intersected by a coarse-grained ur.-mite, havinj^ a spiicilic 
 gravity (tf 2-01 only, and containint;- little or no liornblende or 
 mica. The appearance here described are represented by Fit;'. 4. 
 
 a, IlorMl)Ien(lo seliist. h, Syenitie pneis^i-jrraiiile. e, Coarso-fjrainofl pranito 
 
 The mutual relations of the.'ie brccciatcd and intrusive 
 rocks in eij;'ht different localities, some of thoni upwards of one 
 hundred miles apart, have here been described, and it will be 
 observed that, in every one of the instances mentioned, the oldest 
 rock is the most basic in constitution, and this appears to be the 
 ease, without regard to the mineralogical composition or structure 
 of tiie rocks associated together as above described. It matters 
 not whether the older rocks be brccciatcd or entire, hornblendic or 
 micaceous, granular, schistose or porphyritic, it is always most 
 deficieut in silica. It appears, further, that the newer the rock 
 
«J 
 
 wliich (Miclo.sos or iiciiotniti'H oldrr ones, tlu< inoro silicoous it 
 Ik'i'oiiu'S. Oti rcrcrctico to tlic »^[u'('ilic ^ravitioN nhovo «;ivt'ii ul' 
 tlif vnri<»uH rocks, it iiii^ht \h p(»sr<l that tlicir relations iin to 
 lii njrc; ini;^lit lie ('((iially well oxpreshcd l»y sayiiiLr, tlu; (ddor the rock 
 tlu! heavier ; the more roei'iit. the lighter it is ; and, in tlic 
 majority oC instances, thi." iij)|>li<'s. Htit, as in the case of thi' rock- 
 auizrcjate occurriiiu to the west of Mielilpicoten llarl)onr, wlieii 
 Ave come to the very newest trranitie veins, eiMisistinu cnly uf (irtho- 
 elasi! and (|nartz, those art; the heaviest whieii contain most of th(! 
 hitter mineral, its mean speelic gravity heini; 2'«>r), whil(! that ol' 
 orthoclasc! is oidy 'i'T)'). It is to h(! remendjercid that these newest 
 veins arc altojxotlHir ditterent in ai>|»earance from certain veins of 
 hiriie-irrained fxraiiito, witli distinct side joints, which nre occasion- 
 ally found intersectinti tliesc rocks, and the oriLiin of which lias 
 been indicated by l>r. Ifunt in lii.s recent valuable report on 
 mineral veins. Near I'oint-anx-Mines a vein of this nature is 
 found, the rock of which is jteuniatite, consisting of orthoda.se, 
 quartz, and <:reenish white mica, together with occasional grains 
 of ))iirple copp(!r, copper pyrites, jialena, ajid molybdenite. 
 
 It may not be out of jtlace here to advance certain considera- 
 tions reunrdin,:^ these Jiaurentian rocks, and especially concerning 
 the peculiar rock ngyrei^ates just described. The relations of 
 those rocks to each other we have seen to be as iollows : — The 
 older the rock the more basic is its nature, and the riclier it be- 
 comes in triclinic felspar, hondjlende, and mica. The newer the 
 rock the more siliceous it becomes, and the more such minerals as 
 orthoda.se and quartz predominate. It can scarcely be supposed 
 that this relation i.s an accidental one, for it is observable in every 
 one of the instances above given, the localities of many of which 
 are very far distant from each other. It would seem to be the 
 consequence of an unvarying law winch w^as in operation at the 
 time when these rock,; were first formed. At first sight, the facts 
 above described would appear to militate against the idea of the 
 igneous origin of these rocks, and, in fact, the relation is a similar 
 one to that which has been observed among the constituent 
 uiincrals of granite, and which is one of the chief difficulties in 
 explaining the origin of that rock on the igneous hypothesis. In 
 granite the quartz is frequently found filling up the interstices 
 between the other minerals, and sometimes it even retains impres- 
 sions of the shape of the latter. Nevertheless the felspar and 
 mica are the most fusible, and the quartz the most infusible of 
 
10 
 
 
 the constituents of granite. Similarly, the older basic rocks, among 
 the brecciated and intrusive aggregates above described, are the 
 most fusible, while the newer rocks, being most siliceous, are most 
 infusible. At first sight, it is difficult to conceive how a basic and 
 fusible rock could solidify from a melted mass previous to a more 
 siliceous one. But the geological relations of these rocks are such 
 as to afford the fullest proofs of their igneous origin. It may be 
 urged that such an origin for the oldest and more basic fragments 
 does not appear proved, but their similarity in mineralogical 
 composition with the intrusive members of the aggregate is in 
 favour of such a view. Furthermore, these older fragments 
 shew, in every instance, such an analogy as regards their relation 
 to the intrusive rocks that they cannot be regarded as accidental 
 fragments of other rocks brought from a distance. If their origin 
 were of this nature, they would not invariably be more basic in 
 composition than the enclosing rock. The fact of their always 
 bearing a certain relation, as regards composition, to the enclosing 
 rock renders it unlikely that their source is similar to that o^ 
 boulders in a conglomerate or fragments in a breccia. On the 
 contrary, it would appear more reasonable to regard them as the 
 first products of the solidification of the fluid mass from which 
 the granites, and other rocks above described, resulted. In 
 pursuing this subject further, it would appear not unreasonable 
 to base some such theory as the following upon the facts above 
 stated. The area now covered by these rocks must at one time 
 have been occupied by a mass of fused silicates. The temperature 
 of this fluid magma and of the surrounding crust has been 
 intensely high, although perhaps very gradually on the decrease, 
 and the extent of the igneously fluid material mu'st have been 
 such as to render uniformity in its chemical composition an 
 impossibility. Variations in its composition, as well as in the 
 maimer of its solidification, may therefore be supposed to have 
 obtained in different parts of the fluid area. According to th 
 proportion of silica and bases present where crystallisation com- 
 menced and progressed, hornblendic rock, mica syenite, or com- 
 paratively basic granite, first assumed the solid form, leaving a 
 part of the fluid or magma beneath or on the outside of it still in a 
 plastic state, but changed in its chemical composition, and rendered 
 more siliceous than the original magma. If the solidiflcation com- 
 menced at a point where the fluid mass was comparatively undis- 
 turbed, the granular varieties of the rocks above described may have 
 

 5 rocks, among 
 iribed, are the 
 20US, are most 
 w a basic and 
 )us to a more 
 ocks are such 
 . It may be 
 sic fragments 
 mineralogical 
 grcgate is in 
 LT fragments 
 their relation 
 as accidental 
 f their origin 
 iiore basic in 
 their always 
 the enclosinrr 
 r to that 0^ 
 iia. On the 
 them as tlie 
 from which 
 jsulted. In 
 mreasonable 
 facts above 
 at one time 
 temperature 
 has been 
 he decrease, 
 have been 
 position an 
 1 as in the 
 ied| to have 
 ling to th 
 sation com- 
 te, or com- 
 leaving a 
 it still in a 
 id rendered 
 Jation com- 
 vely undis- 
 i may have 
 
 "k 
 
 11 
 
 been produced. If, on the other hand, the solidification took place 
 while the fluid mass was in motion, the hornblendic and micaceous 
 schists and gneisses were most probably the results of this process, 
 and the strike of those would indicate the direction of the current 
 at the time of their Ibrmation. The rarity or indistinctness of 
 parallelism in the Laurentian rocks of Lake Superior shews, how- 
 ever, that no very constant and persistent motion in one direction 
 took place in the fluid mass which produced tliem. This first 
 solidification of part of the fluid magma most likely continued for 
 a long period, and i^pread over a large surface ; but there seems 
 at last to have arrived a time when, from some cause or other, 
 these first r(jcks became rent or broken up, and the crevices or 
 interstices became filled with the still fluid and more siliceous 
 material which existed beneath theni. Gradually, this material 
 solidified in the cracks, or in the spaces surrounding the fragments, 
 and the whole became again a consolidated crust above a fluid mass 
 of still more siliceous material. Further solidification of this 
 latter material doubtless then took place, and continued until a 
 second general movement of the solidified crust opened other and 
 newer crevices, which became filled with the most siliceous ma- 
 terial which we see constituting the newer veins among the rocks 
 above described. 
 
 Although the theory here given as to the origin of these rock 
 aggregates is in thorough harmony with the facts related concern- 
 ing them, it is doubtless possible to urge objections against it 
 founded upon the relative fusibility of their constituent rocks. 
 There is no doubt that the point of temperature at which these 
 various rocks become fluid under the influence of heat is higher 
 with the newer than with the older rocks, but it does not follow 
 that in cooling they solidify, that is, become quite hard and solid 
 at the same point of temperature at whicii they fuse. Bischof 
 describes ■•n experiment which proves that the temperature at 
 which ceri dn substances solidity does not at all correspond with 
 their fus-j .^. point. lie prep., red a flux, consisting of common 
 glass anu carbonate of potasli. which fused at a temperature of 
 800" II., and melted it along with some metallic bismuth in a 
 crucible. This metal fuses at 200^, and solidifies with a very 
 uneven surface, on account of its tendency to crystallize. Although 
 the difference between the fusing point of the bisnmth and of the 
 flux amounted to 600*^, nevertheless, when the crucible cooled, all 
 the irregularities of the surface of the metal were found to have 
 
12 
 
 imprinted themselves upon the lower surfjice of the solidified flux, 
 a very plain proof being thus furnished that at a temperature of 
 200" li., the flux was still soft enough to receive the impression of 
 the solidifying metal. If we further observe the various fused 
 slags which flow from diff"orent furnaces, we shall obtain some idea 
 of the manner in which the rocks above described may have be- 
 haved during their solidification. The scoriae of iron furnaces are 
 usually very acid, containing as much as 60 per cent, of silica. 
 They generally fuse at a temperature of 1450° C. As they flow 
 out of the breast of the furnace, they may be observed to do so 
 very leisurely, to be sluggish an viscid, but nevertheless to con- 
 tinue fluid a long time, and even in some cases to flow out of the 
 building in which they have been produced, before solidifying. 
 On the other hand, slags from certain copper furnaces, or from 
 those used for puddling iron, are more or less basic, containing 
 from 30 to 45 per cent, silica. As they flow out they are seen to 
 be very fluid, and to run quickly, but they solidify much more 
 rapidly than iron slags. Yet these basic slags fuse at about 1300° 
 C, or about 150° less than the more acid slags. Those who have 
 been accustomed to observe metallurgical processes will not find it 
 difficult to conceive how a very siliceous slag might continue fluid 
 at a temperature at which a more basic one might become solid. 
 We conceive, however, that the rocks which we have described 
 must have solidified under circumstances altogether diff'erent from 
 those under which furnace slags cool. We suppose that these 
 rocks must have solidified at temperatures not very far below their 
 fusing points ; ihat the temperature of the atmosphere, and of the 
 fluid mass itself, had sunk somewhat beneath the fusing point of 
 the more basic rocks before solidification began, and that at this 
 point it was possible for the basic rocks to crystallize, while a more 
 siliceous magma still remained plastic. This latter supposition 
 does not appear unreasonable when the experiment above referred 
 to, and the behavior of furnace slags above described, is taken into 
 consideration. 
 
 It becomes a question of much interest as to whether these rocks 
 are to be regarded as constituting one and the same, or several and 
 distinct, geological formations. There cannot be a doubt as to the 
 fact that some of them are of more recent origin than others ; but, 
 on the other hand, many of the veins above described do not pre- 
 sent such distinct joints as are visible where trap 3r basalt dykes 
 traverse sedimentary strata. Although the cementing material 
 
 4 
 
 oftl 
 
 the 
 
 are] 
 
 uni 
 
 majl 
 
 othi 
 
13 
 
 Hfied flux, 
 )eratiire of 
 pressioii of 
 ious fused 
 some idea 
 ' have be- 
 rnaces are 
 
 of silica. 
 
 they flow 
 d to do so 
 ss to con- 
 out of the 
 )lidifying. 
 i, or from 
 iontuininff 
 re seen to 
 uch more 
 »ut 1300° 
 who have 
 lot find it 
 inue fluid 
 me solid, 
 described 
 *ent from 
 lat these 
 slow their 
 nd of the 
 point of 
 t at this 
 ie a more 
 
 3se rocks 
 eral and 
 as to the 
 rs ; but, 
 not pre- 
 t dykes 
 naterial 
 
 
 of the brecciated rocks above described difi'ers in composition from 
 the fragments which it encloses, we nevertheless find that the two 
 are usually so intimately combined with each other as to behave 
 under the hammer like one and the same rock. There is, in the 
 majority of cases, no joint to be Ibund at their junction with each 
 other; and in fracturing tliem, they very often break just as 
 readily across as along the line which separates them. It would 
 appear, therefore, that, although these rocks solidified at dilFcrent 
 times, the dates of their formation were not sufiiciently i'ar 
 distant from each other to enable the previously existing rock to 
 cool thoroughly before it became penetrated by or enclosed in the 
 newer one ; that consequently the older rock, being in an intensely 
 heated condition, readily amalgamated at its edges with the next 
 erupted and fused mass, and formed with it a solid compact whole. 
 Apart from the difficulties which would doubtless attend any 
 attempt to distinguish separate geological groups among these 
 rocks, it wculd appear just as unreasonable so to separate them, as 
 to r<i|gard each distinct stratum of sedimentary rock as distinct 
 geological formations. According to Naumann, a geological 
 formation consists of a series of widely extended or very numerous 
 rocks or rock-members (^Gcbirgs-glieder), which form an indepen- 
 dent whole, and are by their lithological and palfeontological 
 characters, as well as by their structure and stratigraphical suc- 
 cession (^Lagcrungs foJge), recognisable as contemporaneous (geo- 
 logically speaking) products of similar natural processes. According 
 even to this definition, it would appear just to class all the rocks 
 above described, in spite of the distinctly intrusive character of 
 some of them, as belonging to one and the same geological forma- 
 tion, — in short, to the Laurentian series of Sir W. E. Logan, 
 or the Primitive Gneiss formation of Naumann. The last-named 
 geologist certainly distinguishes a separate granite formation, but 
 the rocks included in it are generally more recent than the primi- 
 tive gneiss or primitive schists. Where, as in Silesia, in Podolia on 
 the Dnieper, in the central plateau of France, in Finland, in Scan- 
 dinavia, and in the Western Islands of Scotland, granite occurs 
 in similar intimate association with gneissoid rocks as on Lake 
 Superior, Naumann always regards it as part and portion of the 
 primitive gneiss. As early as 182G, Ilisinger, in his work on 
 Swedish mineralogy, shewed that the granite which occurs in 
 intimate combination, by lithological transition and otherwise, with 
 the primitive gneiss of Scandinavia, was of contemporaneous origin 
 
14 
 
 with it ; and in the Pyrenees, La Vendee, Auvergne^ the Black 
 Forest and Huni?;ary, according to Coquand, Riviere, Rozet, Reng- 
 ger, and Beudaiit respectively, the gneiss and granite of these 
 countries cannot be separated into distinct formations, but form one 
 and the same mass of primitive rock. 
 
 II. — THE HURONIAN SERIES. 
 
 The rocks of this system, as developed on Lake Superior, 
 present at first sight rather a monotonous and uninteresting aspect 
 to the student of lithology. Largo areas are occupied by schistose 
 and fine-grained rocks, the mineralogical composition of which is, 
 in the most of cases, exceedingly indistinct. These rocks are, to 
 a very large extent, pyroxenic greenstones and slates related to 
 them. On closer examination, they are found to exhibit many 
 interesting features, and it is possible to distinguish among them 
 the following typical rocks : — 
 
 Dl((b((sc. — The granular varieties among these greenstones 
 belong to this species. It is developed at several points on 
 Goulais River, at some distance to the west of the Laurentian 
 rocks already referred to. It is usually fine-grained, pyroxene is 
 the preponderating constituent, and chlorite is present in con- 
 siderable quantity in finely disseminated particles. The felspar 
 is in minute grains, and, in many instances, it is only on the 
 weathered surface of the rock that its presence can be recognized. 
 One variety of this rock from the Goulais River has a specific 
 gravity of 3-001. Its colour is dark green, and that of its 
 powder light green. Tlie latter, on ignition, lost 2-29 per cent, 
 of iis weight, and changed to a brown colour. On digestion with 
 sulphuric acid, 22-99 per cent, of bases were dissolved from it, 
 which circumstances would seem to indicate that the felspathic 
 constituent is decomposable by acids, and is therefore, in all like- 
 lihood, hibradorite. This rock is underlaid to the south-west by 
 greenstone schist, striking N. G5° W., and dipping 75*^ north- 
 eastward, and is overlaid by amygdaloidal diabase and greenstone 
 slates, striking N. GG'-' W., and dipping 49° north-eastward. 
 Granular diabase is also met with a few miles higher up the river 
 from the rocks just mentioned, associated with porphyritic diabase 
 and diabase schist, the latter striking N. 55° to C5° W., and dip- 
 ping GO'' north-eastward. Similar rocks were observed on the 
 hills between Bachcwahnung and Goulais Bay, and at several 
 points on the north shore of the lake between Michipicoten 
 
15 
 
 the Black 
 •zet, Reng- 
 3 of these 
 t form one 
 
 ''1 
 
 Superior, 
 ing aspect 
 ■ schistose 
 which is, 
 ks are, to 
 elated to 
 
 bit many 
 
 "1 
 
 )ng them 
 
 .5 
 
 ^enstones 
 
 H 
 
 oints on 
 
 9 
 
 urentian 
 
 9 
 
 "oxene is 
 
 '9 
 
 in con- 
 
 m 
 
 5 felspar 
 
 '..^^. 
 
 on the 
 
 
 ognizcd. 
 
 t 
 
 specific 
 
 
 t of its 
 
 
 er cent. 
 
 
 on with 
 
 'S 
 
 Vom it, 
 
 fl 
 
 Ispathic 
 
 ■ 
 
 all like- ' 
 
 V 
 
 west by 
 
 '!-'M^m 
 
 nortli- 
 
 
 enstone 
 
 jV 
 
 stward. 
 
 mm 
 
 le river 
 
 of 
 
 iiabase j 
 
 1 
 
 id dip- 
 
 m 
 
 on the 1 
 
 1 
 
 several 1 
 
 9 
 
 :)icoten 
 
 fl 
 
 Harbour and Island. In the neighbourhood of, and on tjie road to, 
 the Bachewahnung Iron Mine, they are also plentiful. Not unfre- 
 quently the pyroxene in them assumes the appearance of diallage. 
 
 AugiUporphyrii . — The porphyritic diabase above referred to is 
 a small-grained diabase, in which arc disseminated crystals of 
 pyroxene, about three-eighths of an inch in diameter. The specific 
 gravity of the rock is 2901). Its fine powder has a light 
 greenish grey colour, which changes on ignition to dark brown, 
 2.01 per cent, of loss being at the same time sustained. Hydro- 
 chloric acid dissolves from it 2H'48 per cent, of ba*-u s. 
 
 Calcareous Diabase. — The amygdaloidal diabase above men- 
 tioned is the same rock as is termed by Naumann Kalkdiahase. 
 It is a fine-grained diabase, somewhat schistose, in which oval- 
 shaped concretions of granular calcspar occur. The latter are 
 not, however, always sharply separated from the mass of rock, 
 which is slightly calcareous. The amygdules, if such they can 
 be called, have their longer axis invariably parallel with each 
 other, and with the schistose structure of the rock. 
 
 Diabase Schist. — This rock occurs much more frequently than 
 either of those just described. It is, indeed, difficult to find a 
 diabase among these Huronian rocks which does not exhibit a 
 tendency to parallel structure, or which does not graduate into 
 diabase schist. But the latter rock occupies considerable areas 
 by itself, not only on Goulais River, but also on that part of the 
 north shore referred to in this paper. The liigher hills to the 
 north-east of Goulais Bay consist, to a large extent, of this rock. 
 Apart from its schistose structure, it possesses the characters of 
 diabase. For example, a specimen of the rock from the north 
 shore has a specific gravity of 2-985. Its powder, which is light 
 grey, changes on ignition to light brown, losing 1-43 per cent, of 
 its weight. On digestion with hydrochloric acid, it loses 14'21 
 per cent, of bases; and with sulphuric acid, 16-12 per cent. It 
 is fusible before the blow-pipe. Many of these schists are 
 pyritiferous and calcareous, and these graduate frequently into 
 greenstone slate. 
 
 Greenstone and Greenstone Slate. — The rocks above mentioned, 
 being small-grained, are recognizable without much difliculty ; 
 but, besides these, and occupying nmch more extensive areas, 
 there occurs finely granular and schistose rocks, many of them 
 doubtless of similar composition to the above mentioned diabase 
 and diabase schist. Where the transition is traceable from the 
 
16 
 
 latter rocks to those of a finer grain, the same names arc perhaps 
 applicable. But since this is not always the case, it would seem 
 advisable to make use of other terms for them until their compo-' 
 sition is more accurately deternnned. The names aphanite and 
 aphanite slate have been applied to rocks such as these, but since 
 the former term has been applied by Cotta to compact melaphyrc, 
 it would seem better for the present to continue the use of the 
 otlier terms, compact i^reenstone and greenstone slate, especially 
 since the signification of the first of these has been so limited by 
 Naumann as to denote pyroxenic greenstones only, thus di.stin- 
 guisliing them from the hornblendic greenstones or Dioritcs. 
 These pyroxenic grcensioncs, or fine-grained diabases, frequently^ 
 contain more chlorite than the coarser-grained varieties. They 
 are very frequent on the Goulais lliver, ia the district between it 
 and Bachewahnung Bay, and in the neighbourhood of the 
 Bachewahnung Iron Mine. One specimen from a point four 
 miles north-east of Goulais Bay yields 21 ^-l per cent, of bases to 
 sulphuric acid. Its powder is dark green, changing on ignition to 
 dark brown, and losing 1-72 per cent, of its weight. These 
 greenstones are seldom destitute of iron pyrites. Quartz never 
 occurs in them as a distinct constituent, and ev3n in veins It is 
 rare ; but there are a few occurrences of greenstones which are 
 lighter in colour, more siliceous, and harder than others, and 
 which have possibly become so by contact with quartzose rocks. 
 On the other hand, they are frequently found impregnated with 
 calcaieous matter. By assuming a schistose structure, these 
 greenstones often graduate into greenstone slate, an apparently 
 homogeneous rock, generally of a dark greenish grey colour and 
 slaty texture. The latter character is sometimes so marked, that it 
 becomes difficult to distinguish it from clay slate. The greenstone 
 slates however, would seem to differ from the latter rock in the small 
 quantity of water which they contain, their generally higher 
 specific gravity, and in their yielding nothing which would form a 
 good roofing slate. On the other hand, they are related to the 
 greenstones and diabase schists not only by gradual transition, but 
 in some of their physical characters. For instance, a greenstone 
 slate from Dog Eiver, on the north shore, of a dark grey colour, 
 has a specific gravity of 2-738, and loses 1-C2 per cent, of its 
 weight on ignition, in which operation the colour of its powder 
 chnnges from a greenish white to a decided brown. It yields to 
 hydrochloric acid lG-4-1, and to sulphuric acid 10-29 of bases. 
 
e perhaps 
 )uld seem 
 ir compo- 
 site and 
 but since 
 elnphyrc, 
 30 of the 
 3.spccially 
 mited by 
 IS distin- 
 Dioritcs. 
 equeutly 
 They 
 itween it 
 
 of the 
 int four 
 bases to 
 lition to 
 These 
 z never 
 n& It is 
 lich are 
 rs, and 
 3 rocks. 
 2d witli 
 !, these 
 •arently 
 ur and 
 
 that it 
 enstone 
 e small 
 higher 
 form a 
 to the 
 )n, but 
 instone 
 :joIour, 
 
 of its 
 •owder 
 3lds to 
 les. 
 
 17 
 
 SUi<'eo)iii Sldfc. — In many places bands of such dark coloured 
 slate as that just described are interbedded with others which 
 are lighter coloured and more siliceous. Such banded slates may, 
 for instance, be observed on the north-cast shore of Goulais Bay. 
 Here the darker slate is very evenly foliated, ot a dark greenish- 
 <^vvy colour, and has a specific gravity of 2-li85. Its powder is 
 light green, changing on ignition to light brcvn, and losing 2'02 
 per cent, of its weight. It yields to sulphuric acid 10-75 of bases. 
 The rock of the lighter bands is highly siliceous, and in fusibility 
 c((nal to orthoclase. The powder has a reddish gvoy colour, 
 which changes on ignition to brownish grey, U-54 per cent, of loss 
 being at the same time sustained. Hot sulphuric acid removes 
 only :}'79 per cent, of bases. A similar association of slates is 
 found at a point bearing 41" 30' E.from the east end of IMichipi- 
 coten Island. Here, a series of lighter and darker coloured bands 
 of very decided slate occur, striking N. 78° to 80 ° W., and 
 dipping 50 '^ to 52 ° northward. They are overlaid by a band 
 of dark green slate, which contains granitic pebbles, and this band 
 is again overlaid by light coloured slates. Small bands may be 
 observed to leave the dark green slates and to join with those of a 
 lighter colour. The latter are not only lighter in colour, but harder 
 and less dense, and occasionally show ou their cleavage planes a 
 silky lustre. A specimen gave a specific gravity of 2*681, and its 
 powder, which was almost quite white, lost 1-12 per cent, on 
 ignition, becoming slightly brown. It fuses only in fine splinters, 
 and, generally, the fusibility of these slates is the greater the 
 darker their colour. 
 
 Chlorite. Schhsf. — Some of the greenstone slates occasionally 
 contain an unusually large quantity of chlorite, and sometimes so 
 much as to form chlorite schist. This schist forms the side rock 
 of the Palmer Mine on Goulais Bay. 
 
 Qnartzite. — This rock is of less frequent occurrence than I had 
 anticipated. It is most frecpient on the west and south-west side 
 of the hills between Bachewahnung and Goulais Bay, and in the 
 district north-eastwards from Sault Ste. Marie. 
 
 Jlemafite. — This mineral often occurs in such quantity as to 
 constitute rock masses. It will however be referred to under the 
 economic minerals of the series. 
 
 Greenstone Breccia, — The occurrence of angular fragments of 
 other rocks in the greenstones above described is by no means rare, 
 and the resulting breccias are common between Bachewahnung 
 
18 
 
 ^ 
 
 and Goulais Bays. In the majority of nstanccs where the matrix 
 is granular, the fragments are angular ; on the other hand, where 
 the matrix becomes schistose, the fragments are generelly roumlcMl, 
 and there results the slate conglomerate so characteristic of the 
 Iluronian series. 
 
 Slate Coiighnnmtfe. — This rock is extensively developed at the 
 mouth of the Dore lliver, some distance to the west of ^lichipi- 
 coten Harbour. Its matrix is the greenstone slate above described. 
 The boulders and pebbles which it encloses seem, for the most part, 
 to be granite, and are rarely quite round in form. The most 
 of them are oval or lenticular shapud, and then their outlines are 
 scarcely so distinct as in the case ci those which approach more 
 closely to the round I'orm. Very trc(|uently those of a lenticular 
 form are drawn or flattened out to such an extent that their 
 thickness decreases to a quarter or half-an-inch, and they are 
 sometimes scarcely distinguishable from the slate, except by their 
 lighter colour. Part of the rock exhibits merclv a succession ol' 
 lighter and darker coloured bands, the former of which sometimes 
 resemble in form the flattened pebbles above-mentioned. On 
 account of the presence of these lighter bands, it is often impos- 
 sible to select a piece which may be regarded as the real matrix of 
 the rock. As in the case of some of the rocks above described, 
 the light bands are more siliceous and less den.se than the darker 
 ' .les. The latter are, not unfre(|ucntly, calcareous. A specimen 
 of this character had a density of 2-7()8 to 2-802. Its powder 
 was light green, which changed on ignition to light brown, with a 
 loss of 2-75 ])er cent. On treatment with sulphuric acid, it effer- 
 vesced strongly, and experienced a loss of 3(585 per cent. Iron 
 pyrites impregnates the matrix (piite as frequently as calcareous 
 nuitter. The direction of the laniination in the matrix is parallel 
 with the longer axis of the lenticular pebbles, and where the boulders 
 are large (they seldom exceed twelve inches in diameter) and 
 round, the lamination of the slate winds round them, and resumes 
 its normal direction alter passing them. Occasionally a flattened 
 pebble is seen bent half round another, and, among the very thin 
 pebbles, twisted forms are not uncommon. The nature of the 
 pebbles, especially of those which have been flattened, is sometimes 
 very indistinct. The quartz is generally easily recognized in the 
 larger boulders, but the felspar has lost its crystalline character, 
 and the mica is changed into dark green indistinct giains, where it 
 has not altogether disappeared. Besides the granitic pebbles, 
 
r» 
 
 19 
 
 there are others vvliieh scorn to consist of quartzitc. An idea of 
 
 tlic structure of this rock is attoniptcid to be i^iven in fij^ure 5. 
 
 Fig. 5. 
 
 it 
 
 es, 
 
 a. Graiiit J Ixnildov.s, and long drawn masses. h. Schistose matrix. 
 The manner in which those rocks are occasionally associated 
 with each other is calculated, as in the case of the Laurentian 
 rocks, to suggest to the observer some definite ideas regarding 
 their origin . Equally instructive is the manner in which they 
 adjoin tiio Laurentian areas at several points on the north shore, 
 between Michipicoten Harbour and Island. I paid some attention 
 to that point of junction which lies to the west of Eagle River, 
 the precipitous cliifs to the east of which consist principally of 
 diabase schist and greenstone slate. A few miles to the west of 
 those cliifs, and at a point bearing N. 29 ® E. from the east end of 
 Michipicoten Island, the Laurentian granite is penetrated by 
 enormous dykes of dense basaltic greenstone (having the peculiar 
 dolcritic glitter when fractured), which contain fragments of 
 granite. This greenstone is also seen in large masses, which c;i,n 
 scarcely be called dykes, overlying the granite and enclosing huge 
 masses of that rock, one of which I observed to bo cut by a small 
 vein of the greenstone. Fronj this point to Eagle River those 
 two rocks alternately occupy the space along the shore, seldom in 
 such a manner as to show any regular superposition of the green- 
 stone on the granite, but almost always more or less in conflict 
 with each other. The greenstone, however, becomes more frequent 
 towards the east, and at Eagle River it has almost wholly replaced 
 the granite, and assumed a lighter colour and an irregular schistose 
 
20 
 
 structure. The strike of these .seliists is, at places, quite incon- 
 Htant ; they wind in all directions, and whi»t appear, at first si^rlit, 
 to be quartz veins, accompany tlieir contortions. On closer 
 inspection, however, of the laruost of these, they are seen to be of 
 granite, ^ ut whether twisted fragments of that rock or really veins 
 of it, is, at first glance, very uncertain. Observed superficially, 
 they have the appearance of veins, but they do not preserve a 
 straight course, and bend with the windings of the enclosing schist. 
 They often thin out to a small point and disappear, and, a few 
 feet or inches furt' n* on in the direction of the strike, reappear 
 and continue fiu' a short distance. Sometimes a vein thins out at 
 both ends and forms a piece of granitic material of a lenticular 
 shape, always lying parallel with the lamination of the enclosing 
 slate. Figure G is a representation of the phenomena here 
 described. 
 
 a. rragmeutvS and contorted pieces of granite. 
 1). Slates enclosing same. 
 
 At another point of junction, on the north shore, to the east of 
 that above described, there is a large development of similar 
 basaltic greenstone. Its constituents, with the exception of iron 
 pyrites, are indistinguishable ; it has a greenish black colour, and 
 a specific gravity of 3. Its powder has a dark green colour, which 
 changes on ignition to dark brown, with a loss of 1-79 per cent, of 
 its weight. It yields to sulphuric acid 18*41 per cent, of bases. 
 
21 
 
 of 
 lar 
 on 
 nd 
 ch 
 of 
 
 It exliibits nuniorou.s (livi.sionnl pianos and u tcMidoncy to Hlaty 
 Ktructure, the direction of which is not, however, parallel with 
 that of the divisional pianos. It contaitis nuniorons IVa^nionts 
 and lonj; drawn contorted masses of liranite, which are l)est dis- 
 cernible on the worn surface of tlie rock, and not readily so where 
 it is fresljly fractured. To tlie eastward it chan^'es to a much 
 liarder li<;ht <^rey siliceous rock, liavinsj; a s])ecific j^rnvity of 27()i) 
 oidy. Tn fine powder this rock is white, but on ijiuition becomes 
 brownish, and loses tlS.'i per cent, of its wci<2;ht. It yields only 
 4-02 per cent, of bases to sulphuric acid. At one place it seems 
 to contain frajiments and twisted pieces of the dark ^rcenstci e, and 
 further eastward it assumes the character of a breccia, t "anite 
 frajjjments being enclosed in the slaty rock, which is at some points 
 darker, at others liy-liter, coloured. The fragments arc sometimes 
 quite angular, and Sv-^metimes rounded off, and not sliarply separ- 
 ated from the matrix. Their longer dimensions arc invarialdy 
 parallel with the lamination of the matrix. The distance over 
 which the transition extends renders it impossible to give any ac- 
 curate sketch of the phenomena described. 
 
 Similar relations are observable at the junction of the two 
 formations in the north-east corner of Bachewahnung Bay. Here 
 the greenstone is compact, but still possesses the glittering basaltic 
 fracture. The Laurentian rock is a highly granitic gneiss, and 
 pieces of it are enclosed in the dark greenstone, which at one place 
 seems to underlie the granite. A reddish grey felsitic rock, witli 
 conchoidal fracture, is observed at the point of junction. East- 
 ward from it banded traps occur, striking N. 55° W., together 
 with greenstone — breccia, and conglomerate. On ascending the 
 hills behind this point another breccia is observed, of whicli the 
 matrix is greenstone and the fragments granite. 
 
 With regard to the succession of these rocks, it will doubtless 
 be found a matter of very great difficulty to establish any such, 
 even if any order of superposition of a tolerably regular character 
 should exist among them. That this is not very likely to be the 
 case, will appear from the considerations yet to be advanced re- 
 garding the origin of these rocks. As to their general strike, it is 
 scarcely possible to give any such, but within certain limits a 
 tolerably constant strike may be observed. In the Huronian area, 
 betwixt Goulais River and Bachewahnung Bay, although there are 
 occasional north-easterly directions, the strike generally ranges 
 from N. 40° to N. 80° W. On the north shore it is generally 
 
•>'J> 
 
 cnHt and went, H»'Mom (hn-iiitiii^ iiioro than 20° to tlio nortli or 
 Nouth of tliOH(! points. TIu) rollowinu (dwcrvationH were luado in 
 tho n((ij;hlionrlioo(l of Kn^do lUvor, iit [wjints wlicrc tlu- AntvH iip- 
 poaicd most regular: N. H.'t" K., dip 4')^ northward; N. 80^^ W., 
 dip HI" nortliward; N. 45*^ K., dip .'Jt'^ tiortli-wcstward. 
 
 In tho forc^'niiiii; d(>si'ription an atlcuipt has hcciii made to 
 (U'linoatc! with li(U'lity thi-niost important loatur(\s(d' tlie lliironinn 
 lltrmation as dcvclojx'd on I^nko Snpcrior. It is now proposed to 
 fi'ivc a i'air uustraim'd interprt'tation (»r tlu; cijaraclm's stampc'd 
 upon tho rocks of that series. The fact (d' the Laurentian ^^ranite 
 beii -^ pierced, as above described, by lluronian rocks, and liie fact 
 of tlieir endosinii fraj^ments of such Liranite, prov(!s incontcstal)ly 
 tliat .some (d'thcni are of eruptive o"i,i>in, and of later aj;e tlian the 
 liaurentian series. The enclosure of the hu«;o sharj)ly angular 
 fragments of granite in the very basic grecn.stone, above described, 
 stands in intimate connection with the enclosure of smaller and 
 contorted granite (Vagmcnts n a matrix of similar chemical com- 
 position, but different (slaty structure. The appearanccH visible 
 near Kagle Jtiver, of which figure (> is an illustration, prove that 
 enclosed granitic fragments sometimes undergo modifications of 
 form through contact with certain Iluroidan rocks. In Foster 
 and Whitney's Lake Superior Kejuirt (Part II., pp. 44 and 45), 
 analogous phenomena are described, but the exactly opposite con- 
 clusion is arrived at, viz., that the gratiitc is in the form of veins, 
 and is the newest rock. There would seem to bo only the two methods 
 of explaining the facts described : cither the granite forms veins 
 penetrating the schistose greenstones, in which case the latter are 
 the oldest rocks, or it is in the form of contorted fragments, in 
 which case the enclosing rocks nnist be of eruptive origin. The 
 fact that the granitic fragments do not cut but run parallel with 
 the slates which enclo.se them, is the strongest argument against con- 
 sidering them to be veins. The supposition that tliey are long drawn 
 and contorted fragments seems to be most in harmony with the 
 facts stated, and with what is known as to the relative ages of the 
 Laurentian and Huronian rocks. The true explanation most 
 likely is, that the basic greenstone, after envolophig the granitic 
 fragments, continued for some time in motion, and, previous to 
 solidification, softened and rendered plastic the fragments, which 
 then became drawn out in the direction of the flow of the igneous 
 mass, and forced to accompany its sinuosities, and that the motion 
 of the fluid mass previous to and during solidification developed in 
 
2:i 
 
 45), 
 
 con- 
 
 .•cins, 
 
 tliods 
 
 veins 
 
 er nvo 
 
 its, in 
 
 The 
 
 with 
 
 t coii- 
 
 rawn 
 
 h the 
 
 )f the 
 
 most 
 
 ;itiitic 
 
 us to 
 
 v'hich 
 
 icons 
 
 otion 
 
 ed in 
 
 tlio <;ro(MistoiuMts schistose strncturo. T\w otlu^r fads, dosciilMMl 
 iihovo as observable at a considerable distance east of Kaj^le lliver, 
 shew that soniethini; more than a mere moditieation of form is 
 eansed l)y the action of basic p'constone npon granite fragments. 
 Not only ar(! the latter there observed to be enclosed in, softened by, 
 and twisted around with the L'reenstone, but tlie phenomena (»bscrv- 
 i>d fully justify tlu^ supposition that tliey have been dissolved in 
 it, that is to say. acifually fused in and incorporated with its ma- 
 terial. The frai^UKMits are seim to be firmly joined toi;ether with 
 tlio enclosinur rock, espeeially wluu'e the; latter becomes more 
 siliceous. Furthermore, tlieir sharp an,u;lcs are often rounded off, 
 indicatinii; plainly that these parts were first melted away by the 
 fluid f^reenstone. Moreover, the product of tiiennion of tiie lattcir 
 with the dissolved parts of the granite is plainly visil)le. It is the 
 siliceous slate rock described above as forming:; in places the matri.K 
 of the breccia. Tiiis siliceous rock, the specific j^ravity of whi(rh 
 is much lower than that of the lireenstone, is further seen to be 
 twisted about witli the latter in such a manner as, in its turn, to 
 envelope parts of the <j;reenstone, thus shewinjj; that motion assisted 
 the incorporation of tiie two. The reddish grey fclsitic rock, 
 mentioned as occurrinjr at the junction of the two formations in 
 tlie nortli-e!..-it corner of Bachevvahnunj>; Bay, has doubtless had a 
 similar origin to t'uit of this siliceous rock, and it is not unlikely 
 tliat the banded traps and fdates, so frequently found amonij; 
 lluronian rocks, are attributable to a similar mode of formation. 
 Closely connected with the breccias just alluded to, so far as rc- 
 ,u;ards the cause of its peculiar structure, is the Tluronian slate 
 conglomerate. It is impossible to examine closely this rock with- 
 out bcin<i; impelled to the conclusion that its origin is not very 
 different from th;;t of the breccias ; that its matrix lias been a 
 fused mass, flowing slowly but constantly in the one direction ; 
 and that its boulders are merely fragments which have been lialf 
 melted and rounded off by contact with the igneous rock. The 
 oval, twisted, lenticular and long drawn forms of the boulders are 
 such as could never have been produced by ordinary attrition, and 
 they frequently furnish examples of such intimate amalgamation 
 with the matrix as are never found in aqueous conglomerates. 
 Further, tlie fact of the boulders being frequently drawn out into 
 what are simply bands of liglit coloured slate, not only disproves 
 the sedimentary origin of the conglomerate, but indicates the 
 manner in which the association of greenstone slate and siliceous slate 
 
24 
 
 ;i})ovc (lissoribod li;i vo hw.n formed, Tlicy li.'ivc Himply boon produood 
 wlioro no tumultiiouH motion wfiH at hand tliorou^lily to irujorporato 
 tlio material of the ^reenstono with that derived from the Koftened 
 fraLMiKiiitH, but when; a Hteady eontinuouH motion, always in the 
 one dirciotion. drew out the materials of the diffcirent HlatoH into 
 loni,' bands Huh by side with caeh oth(;r. It thus .seems to ns 
 r(!asonal>l(!, and (juito compatible with a weientific interpretatifm of 
 the facts above ;,'iven, to explain tlio ori;;in of by far the <,Teater 
 iiiiird)er of the above (snumcrated lluronian rocks upon a purely 
 if^noouH theory ; and it has occurred to us t})at many of the in- 
 stances oi' local metamorphism, recor<led by j.'eolo^ists, in which the 
 contact of an i;^n(!ou8 rock caused tl <; silicification or lamination 
 of anotluir, mi;.d)t be capable of thoroii^di explanation in a maruier 
 similar to that in which we have tried to account fiir the ori;^in of 
 till! breccias, con<:lom(!rates, riiliceous ^rcsenstones and ban<led slates, 
 wlii(;h constitute such a larire ]»art of the lluronian series. 
 
 The lluronian seri(!S, whatever its niod<' of origin may have 
 b(!(!n, must undoubtedly b(! re^'arded as an ind(!pend(!nt ^^[(lolo^'ical 
 formation. It has b(;(!n represcsnted as bein;^ " a, mixture of the 
 St. Alban's ^T-oup of the upper Taconic with thcTriassic rocks of 
 Lake Superior, the trap native-copper bearing rockn of Point 
 Kc(;wecnaw, and the dioritie dyke containin^i; the copp(!r pyrites of 
 Bruce mine on Lake llunni"''' but surely such a description 
 is based upon a misconception of Sir VV. E. Lo-j-an's views on the 
 subject. Until its discovery by Sir William, the liiuMnian formation 
 was unknown to jreolo^^ists as a s<!parate and independent system, and 
 even now it is ordy in comparativelv few countries besides Canada 
 that it has been shown to exist On a former occasion, in the 
 columns of the NuturaliM f [ endeavoured to shew that the 
 Azoi(r schists of T(!ll(!mark(;n, in Norway, were almost identical 
 in litholo^'ical characters with the lluronian rocks, and \)r. J. J. 
 I{i;^sby % shortly afterwards insisted upon the fact of their being 
 the same Ibrmations. J)r. Higsby is of opinion that the lluronian 
 also occurs on the l'j»pcr Loire, in France, and that it is a totally 
 distinct i'ormation from the Cambrian, with which it has hitherto 
 b(!cn customary to associate it. The Huronian forms part of 
 what Nauinann calls the primitive slate ibrmation. 
 
 * Marcou; TIio Taconic and Lower Si) ariun Kocks of Vermont and 
 Canada. ' 
 
 t Vol. vii, p. IK?. 
 t Quart. Joura. Gcol. Soc. Vol. xix, p. 41). 
 
25 
 
 V.H of 
 
 )tioii 
 
 II tlio 
 
 ation 
 
 , i»nd 
 
 un.'ida 
 
 in t.Iio 
 
 the 
 
 tical 
 
 J.J. 
 
 )eiii,^ 
 
 )rii!iii 
 
 otiilly 
 
 luuto 
 
 i-fc of 
 
 it uiid 
 
 Hosidos tli(! black and t^roonirih black dykon which occur in th<^ 
 nci^^hboiirhood of, and Htatid in oonncction with, Huronian rocks, 
 tiioro arc others which occur at a iistancc from Huronian anuiH, 
 and whos(! rockn differ soni<!what IVoin thoHC of that formation. 
 This in th(; cnno, for instance, witli a Hct of dykes which occur on 
 the W)uth-c;ist sliorc of Oouhiis H.-iy, cuttin;^ Laurent ian rocks. 
 Th(!y are tliere separated from iho. j^neissoid rocks by very distinct 
 joints. They vury in thickness from nine to Hevcnty f(!(!t, nnd 
 strike N. T'i*^ to 75S W. Tn the widiist veins the rocik is firu! 
 ^'rained at tlie nnh and sjiiidl f^rained in the ccmtre, so thiit i-\o.u 
 there it is difficult to determin(! its cf)nstitu(;ntH. 'fhey seem, 
 however, to be dark f^reen pyroxene and j^(!yish felspar, with 
 magnetic and minute; ^'rains of iron pyrites. 'I'hc ro(;k has a 
 specific ^'ravity of 2974. Its powdcsr, from which a ma^^net (ex- 
 tracts ma'.Mietite, has a ^ey colour, which chancres on i^niition io 
 a dirty brown, with a lo.ss in weif^ht of 1(17 per cent. Ifydro- 
 chloric acid produces no eflervescencc, but removes 21 74 f>er cent, 
 ofba.ses. Sulphuric acid removes 20-83 per cent. The presence 
 of maf^netite and absence of chlorite would .seem to indicate; that 
 th<*- rock inclines mon; to the nature of dolerite; than diabase. A 
 similar vein of fine LT.iined rock pen(!tratcs the syenite of (Jros 
 Cap, on the summit of that hill, striking!; N. 40 ^ W. A v<!ry 
 larjjje ma.ss of small grained doleritic rock likewise t)ccurs at the 
 mouth of the Montreal River, on its south bank. It probably 
 forms a dyke of very \tn-<n', dimensions in the <(ranitoid pu-i.-s 
 there. It consists, seeminj^ly, of black aujrite, white; or •^•(;yish 
 white felspar (on some; of the cleavatrc; planes of which parallel 
 Htrisc are distinctly obs(;rv.ible), and majrnijtite. Its spee^ilif 
 gravity is 3-090. Its powdtir yields magnetite to the magnet, and 
 does not eff'ervesco on treatment with sulphuric acid, which re- 
 moves 11 -IS per cent, of bases. Other dykes of this nature cut 
 the reddish granite of the nf)rth shore opposite Micliipicot(!n 
 Island, and, nearer to Michipicoten Harbour, a sixty feet dyke of 
 diorite cuts the grey granite;. It is fine; graine;el at the; .sifle-s, but 
 granular anel e;ve;n porpliyritic in the; e-cntre;. Its diree;tie)n is N. 
 tllj * E. About a mile furtlieir east arie)tbe;r dyke occurs, which 
 se;ems te) ejontain fragments of granite. (Jlose te) the laneling plae;e; 
 e)f the Be;gle;y Mine, in Bae;he;wahnung Hay, a dioritic dyke, bear- 
 ing N. 80* E., cuts gne;i.s.se)id rocks Kurthe-r invcstigatiein is 
 necessary to determine what relation, if any, these dykes bear to 
 the Huronian series. 
 
21) 
 
 I 
 
 III. Ui'PER Copper-bearing Series. 
 
 The name ol' the Upper Copper-bearing Rocks of Lake Superior 
 was fiiven to this series by Sir W. E. Lopjan, to distinguish it from 
 the Iluronian or Lower Copper-bearing Rocks. The geographical 
 and geological position, lower altitude, regular bedding, and pecu- 
 liar lithological character of these Upper Rocks cause them to be 
 easily recognised and readily distinguished from the Huronian. 
 They have been separated into an upper and lower group, the 
 latter of which seems, however, to be confiiieil to the north-west 
 parts of the lake. Along its eastern shore, between Sault St. 
 Marie and Michipicoteti, there are frequently found, betwixt the 
 water and the high Pluronian or Laurentian hills, narrow strips 
 or patches of the rocks of the upper group, which often jut out as 
 small islands into the lake, and doubtless extend out great distances 
 beneath its waters. Such limited strips of these rocks are found, 
 for instance, skirting the base of Gros Cap, along the south shore 
 of Bachewahnung Bay and at Cape Gargantua. But besides 
 these and much more important for the study of the upper group 
 of the Upper Copper-bearing series, there are occasional xtensive 
 developments of its rocks, many thousand feet in thickness, such 
 as at Cape Mamainse, ]Michipicoten Island, and Point Keweenaw 
 on the south shore. These rocks have been generally described 
 in the Geology of Canada as sandstones, conglomerates, stratified 
 traps and amygdaloids. In referring to them more minutely, the 
 following rock-varieties may be distinguished as belonging to the 
 upper group of the series : — 
 
 Graiinlar Mclophijre. — A large number of the rocks of this 
 series which have hitherto been described as traps and greenstones, 
 belong to this species. The simplest variety of it is seen at the 
 north-west end of Michipicoten Island, and consists of two 
 minerals only, a felspar and a greenish black mineral. The 
 felspar is the principal constituent, possesses a red, almost pink, 
 colour, which it loses on ignition, and being readily fusible and 
 but slightly decomposed by acids, is most probably oligoclase, or 
 closely allied to that species in composition. The dark coloured 
 mineral is easily fusible and has the appearance of augite. Some 
 of it appears soft and decomposed, and has most probably been 
 converted into delessite. These two minerals are combined into a 
 small grained, distinctly compound rock, which does not effervesce 
 with acids, and whose red colour is visible at a considerable 
 
27 
 
 distance. It is veiy seldom however that this rock is observe*! 
 with such a bright colour, or with constituents so distinctly 
 separated. Much more frequently the felspar has a dark reddish- 
 brown colour, and the grains of augite or delessite have a very 
 indistinct contour. This is the case with some of the melaphyres 
 of Mamainse and CJros Cap. When the brown coloured felspar 
 predominates, and the augitic or chloritie constituent becomes 
 scarcer and even more indistinct, rock-varieties are developed 
 belonging to the sj)ecies Porphyrite, hereafter to be described. 
 When, on the other hand, the dark greenish constituent gains the 
 upper hand, and is recognisable as consisting almost exclusively 
 of delessite, it gives rise to the variety of melaphyre next 
 described. 
 
 Delessitlc Melaphi/re. — This rock has a greenish-grny colour, 
 and consists of a granular mixture of felspar and delessite, with 
 small portions of nuignetite and undecomposed augite. In some 
 instances mica is also found as a constituent. The delessite, 
 besides occurring in small grains, often fornjs larger rounded 
 particles and amygdules, without however imparting to the rock 
 n a very marked amygdaloidal structure. The rocks enclosing the 
 
 cupriferous beds of the Pewabic and Quincy Mines, and that from 
 the Quincy adit are examples of this variety, and have already been 
 described by me in this journal.* The delessite which enters 
 so largely into their composition can scarcely have been one 
 of the original constituents, and has probably resulted from 
 the gradual alteration of augite, since authenticated instances 
 are on record of the conversion of that mineral into delessite and 
 green-earth. The specific gravity of these rocks varies from 2.83 
 to 2.89. When ignited they lose 1.82 to 3.09 per cent, of their 
 weight, the powder changing from light greenish-grey to a light 
 brown colour. Digested with hydrochloric acid from 32.44 to 
 35.72 per cent, of bases are removed from them, the greater part 
 of which belongs to the chloritie constituent. While the variety 
 of melaphyre first above described is seldom found with 
 amygdaloidal structure, the delessitlc melaphyres are exceedingly 
 prone to be developed as amygdaloids. In this case the rock 
 contains amygdules of small size but very numerous, and they are 
 either tilled with delessite alone, or are lined with a coating or 
 rind of that mineral, in which latter case calcspar generally 
 
 Vol. iii., Second Series, p. "i. 
 
I 
 
 I 
 
 28 
 
 of the cavity. Quartz or 
 ainygdaloids the matrix of 
 
 agate 
 which 
 
 IS 
 
 is 
 
 fills out the centre 
 comparatively rare in 
 delessitic melaphyre. 
 
 Compact Melaphyre. — When the small grained melaphyres 
 above described become so fine-grained as to render the recognition 
 of their constituents impossible, there results the fine-grained traps 
 which are so numerous on the south-west coast of Mamainse and 
 on Michipicoten Island. These rocks vary from reddish, bluish, 
 greenish, or greyish black, to decided black in colour, and possess 
 not unfrequently conchoidal fracture and resinous lustre. Their 
 specific gravities vary from 2.67 to 2.898, and they fuse before 
 the blowpipe to glasses of black or brownish black colour. 
 Occasionally their material becomes less homogeneous, and presents 
 the appearance of an intimate mixture of reddish grey and green 
 coloured specks, which may perhaps represent partially developed 
 constituents. They exhibit various phenomena as regards 
 divisional joints. Some possess a rudely columnar structure, 
 others have planes of separation forming various angles with the 
 plane of bedding, several shew a tendency to separate into flags, 
 w' ile a few instances are observable of curved shaly separation, 
 (Krummschaah'ge Ahsonderung) . Transitions can frequently be 
 traced from these compact melaphyres to others approaching in 
 character to porphyrite. For instance, to the west of the entrance to 
 the harbour on the south side of Michipicoten Island, there is found, 
 forming part of a bed of undoubted compact melaphyre, a rock of 
 a greenish-grey colour, with conchoidal fracture. It had a specific 
 gravity of 2.589, and could only be glazed at the edges before the 
 blowpipe. To the east of the same harbour entrance, another 
 rock occurs intermediate in character betwixt compact melaphyre 
 and porphyrite. It is black, impalpable, with imperfectly con- 
 choidal fracture. It bears some resemblance to pitchstone, but 
 difl'ers from that rock in its specific gravity, which is 2.774, and 
 in being readibly fusible to a black glass. It possesses a slightly 
 resinous lustre, and contains an occasional crystal of colourless 
 triclinic felspar. It exhibits planes of separation at right angles, 
 or nearly so with the inclination of the bed, and agate veins are 
 observable, which seem to accompany the divisional joints. This 
 latter phenomenon is also seen in some of the beds of compact 
 melaphyre, and in one of these, curved joints are visible, standing 
 at right angles to the plane of bedding and filled out with calcspar. 
 Brecciated quartz veins occasionally permeate these rocks, and 
 
29 
 
 agatic geodes are very frequent among them. The latter are 
 sometimes so frequent as to form amygdaloids, but they are 
 nmch larger, and never so numerous as are the cavities in the 
 amygdaloids of which delessitic melaphyre is the matrix. There 
 is further this peculiarity with the amygdules of the compact 
 melaphyres, that they contain little or no delessite, agate occupying 
 its place, with occasionally calcspar filling the centre of the geode. 
 
 TufaceoiiH Melaphyre. — Interstratified with the rocks above 
 described, and much more frequently associating with, and gradu- 
 ating into the delessitic melaphyres than the other varieties, there 
 are occasionally found beds of comparatively soft, dark brown, 
 porous rock, with almost earthy fracture and seldom destitute of 
 amydaloidal structure. These frequently carry metallic copper, 
 and constitute the ' ash beds ' so extensively worked in the mines 
 of the south shore. Although they are generally of a dark brown 
 or chocolate colour, as in the case of the ' Pewabic lode,' there are 
 rocks of this species which are bluish-brown and green coloured. 
 The matrix is generally fusible, and in places impregnated with 
 grains of metallic copper, sometimes of a very minute size. The 
 larger grains of the metal are frequently found in the amygdules, 
 either alone or accompanied by green-earth, calcspar, quartz, 
 delessite, laumontite, and prehnite. Besides the rounded grains 
 or ' shot copper ' of the amygdules, these rocks often contain 
 huge masses of metallic copper, with which small quantities of 
 native silver are associated. Large irregular patches and veins 
 of calcspar, and smaller masses of epidote are frequently met with 
 in these tufaceous melaphyres. 
 
 Porphyrite. - The transitions, which are frequently observable 
 on the south side of Michipicoten Island, from compact melaphyre 
 to porphyrite have been referred to above. Undoubted porphyrite 
 is to be found at the south-west corner of the Island. It possesses 
 a fine-grained greenish red matrix, containing small flesh-coloured 
 crystals of felspar, some of which have striated cleavage planes. 
 The specific gravity of the rock is 2.619, and the matrix is 
 fusible at the edges. In the upper part of the bed the matrix of 
 the rock becomes coarser grained, shewing distinctly felspar and 
 a darker coloured mineral as constituents, with the small felspathic 
 crystals still scattered through it. The felspar predominates in 
 the matrix and determines the colour of the rock, which is dark 
 red. Its specific gn'vity is 2.626, anc. it is fusible, although not 
 readily, before the blow pipe. It separates into blocks, with very 
 
}'■: 
 
 m 
 
 I*. 
 
 
 30 
 
 tlocided divisional phmcs, but of no regular form. Similar rocks 
 aic found at the south-east corner of the Island, where also rocks 
 rescniblinjj; pitchstone and pitchstooe porphyry are extensively 
 developed. The black shining impalpable trap, which has the 
 appearance of })itclistone, has a specific gravity of 2.573. It is 
 fusible to a brown glass, and sometimes contains small colourless 
 felspar crystals. Where these accumulate, there results the rock 
 resembling pitchstone porphyry. The crystals in this rock are 
 frequently recognisable as triclinic. The matrix is fusible to a 
 brown blebby glass, and the specific gravity of the rock as a whole 
 is 2.t)31 to 2.678. Since the specific gravity of the rock in which 
 no crystals occur is lower than that usually ascribed to melaphyre, 
 and since it is greater than that of true pitchstone, it would 
 appear reasonable to class both these rocks with the porphyrites, 
 or with these porphyries which contain no quartz, to which they 
 probably bear the same relation as true pitchstones bear to felsitic 
 or quartzose porphyries. 
 
 Melaphi/re Breccia. — Among the newest of the beds of compact 
 melaphyre, developed on Michipicoten Island, there are sometimes 
 observable beds of a breccia consisting of fragments of dark 
 brown melaphyre, cemented together by a reddish-brown trappean 
 sand. Occasionally the fragments appear rounded, and present 
 more of the character of a conglomerate. Similar rocks are seen 
 in the Point Keweenaw district. 
 
 Porpliyrltic Conghmerate.- At the south-west corner of Michipi- 
 coten Island there is visible a conglomerate bed, the boulders of 
 which consist principally of porphyrite, in which a few minute 
 felspar crystals are discernible. Some of the boulders are granitic, 
 and occasionally pebbles occur consisting of or containing agate. 
 These are enclosed in a matrix consisting of coarse-grained and 
 red-coloured porphyritic or trappean debris. In the upper part 
 of the Mamainse group similar conglomerates are found, but in 
 one instance the matrix seems to consist of the same crystalline 
 materi;d as the boulders and fragments, and is very firmly cemented 
 to these. The most interesting example of this rock is that of the 
 Albany and Boston mine, near Portage Lake. Here the matrix 
 of coarse-grained porphyritic sand is accompanied by calcspar, and 
 in some places fine metallic copper.* Other porphyritic conglo- 
 merates occur to the south of Portage Lake, some of the boulders 
 
 * This Journal, Vol. ill., Second Series, p. 9. 
 
 ii i 
 
81 
 
 of which consist of quartzose porphyry, and the matrix of some 
 of which contains quartz as well as calcspar. 
 
 Frhite-tuff. — Ovcrlyinfi^ the Albany aud Boston conjnjiomerate a 
 bed of so-called ' fluckan ' occurs, which is a fine-grained, dark- 
 red shaly rock, in which pieces of a greenish blue colour are 
 sometimes seen. Both substances are fusible before the blow-pipe, 
 and contain occasionally small grains and flakes of copper. 
 
 Polyganovs Conglomtrafe. — This name is applied by Nauniann 
 and Zirkel to those fragmentary rocks whose boulders consist of 
 two or more different rocks. Conglomerates of this nature are 
 especially frequent among the inferior rocks of the Mamainse 
 group, and among those of Keweenaw Point. The boulders of 
 these Mamainse conglomerates are chiefly of granite, gneiss, 
 quartzite, greenstone, and slate, and some of tlie newer beds con- 
 tain boulders of melaphyre and amygdaloid in abundance. Tlie 
 matrix is generally a dark red sand tone. 
 
 Sundstone. — Among the melaphyres and conglomerates of 
 Mamainse and Point Keweenaw an occasional stratum of sand- 
 stone is found of the same character as that which forms the 
 matrix of the polygenous conglomerates. 
 
 The manner in which the rocks above described are associated 
 with each other, is much more regular than the architecture of 
 the Laurentian and Huronian rocks. They are regularly inter- 
 stratified with eacli other, and even among the melaphyres and 
 porphyrites distinct bedding is observable. They do not 
 seem to have been disturbed to such a degree as to occasion the 
 formation of anticlinal and synclinal folds, and in each of the 
 principal areas of distribution a tolerably persistent strike and dip 
 can be observed. 
 
 The general strike of the rocks of the Mamainse group is N. 
 203 to 50° W., and the dip 20'^ to 45» south-westward. They 
 are beautifully exposed along the west coast of Mamainse, and 
 the highest strata of the group form the south-west extremity of 
 the cape. The lower part of the group consists of granular and 
 delessitic melaphyres, polygenous conglomerates and sandstone. In 
 the upper part compact melaphyres and porphyritic conglomerates 
 predominate. The total thickness of the group, according to an 
 approximative measurement, is 16,208 feet, of which the conglo- 
 merates occupy 2,188 feet. The succession of the beds along the 
 coast is quite regular ; but on attempting to follow them inland, 
 they are found to thin out and disappear, while others take their 
 
32 
 
 u 
 
 places. This is especially the caso with the conglomerates. Were 
 the beds continuous throughout, the section above given ought to 
 be repeated on the south coast, and round to Anse-aux-CrCpcs. 
 But there, although some of the mclaphyre beds have the same 
 strike and dip sis on the west coast, there in not the same regularity, 
 nor the same |ilcntiful development of conglomerates. There 
 are moreover evidences of great disturbances and of a conflict 
 between the rock of some of the igneous beds and a sandstone, 
 which here appears in highly contorted and sometimes vertical 
 strata. On coming round the south coast of Mamainse, from 
 Anse-aux-Cr6pes, strata of sandstone are observed very nmch 
 disturbed and dipping inland. As near as it can be ascertained, 
 their strike is about N. 85" W., dip 25° to 40° northward. The 
 sandstone is red coloured, and contains streaks and spots of a 
 cream coloured fel,<pathic substance, which also forms bands crossing 
 the stratification. Many thin cracks filled with calcspar also 
 traverse the beds. The same saiidstone continues for about a 
 hundred and forty yards further to the w')st, becoming still more 
 disturbed, and containing between its layers the felspathic 
 substance. The strike, where the beds are at all regular, is N. 10° 
 W., and dip 52° eastward. Further west it changes to N. 52° 
 E., with dip vertical, and in places 75° >S. W. Here the sandstone 
 becomes utterly broken up into a breccia, which has pieces from 
 one inch to a foot in diameter invariably angular, and a matrix 
 consisting of the white felspathic substance above mentioned, with 
 occasionally calcspar. Further westward the measures are 
 concealed for two hundred yards ; then strata of bluish-grey 
 calcareous sandstone are exposed, striking N. 40'^ E., and dipping 
 75° S. E. From this point for three hundred yards further north- 
 westward, disturbed sandstone occupies the coast where the 
 measures are not concealed. It is followed by a breccia similar 
 to that already mentioned, with angular fragments of sandstone, 
 and then by beds of trappean rocks, striking N. 75° W., and 
 dipping 40° S. W. Rocks of this nature occupy the coast, where 
 not concealed, for one and a half miles further north-westward. 
 Here sandstone again becomes visible, in strata almost vertical, 
 but nevertheless much bent. It is covered by a breccia consisting 
 of sandstone fragments with a trappean matrix, and this again is 
 surmounted by regular trap. In many places there would seem 
 to be the clearest evidence that the trap lies unconformably upon 
 the upturned and contorted edges of the sandstone. Besides the 
 
33 
 
 
 breccia above mentioned, other rocks of a peculiar nature are 
 found at the junction of the sandstone and trap. One of these 
 is indistinguishable from quartzose plirphyry, and another seems to 
 consist of fragments of trap bound together by this same (juartzose 
 p^^phyry. There are good grounds for supposing that the latter 
 rock is the product of the action of the more basic trap upon the 
 sandstone, and results from the igneous amalgamation of the two 
 rocks last named. These confused rocks occupy about a quarter 
 of a mile of the coast. To the north-westward, although the 
 sandstones occasionally protrude, they become nmch less frequent, 
 while the overlying melaphyres become much more regular, and 
 gradually assume the same strike and dip as the strata on the 
 west coast. The hills to the north of Anse-aux-Crepes consist of 
 the same beds of melaphyre and conglomerate as were observed 
 on the west coast, with similar strike and dip. 
 
 The eruptive origin of the melaphyres and traps of this group 
 ip «^;videnced not only by their crystalline character, and by some 
 oi their relations in contact with undoubted sedimentary rocks, 
 but also by their occurring as intrusive masses in the gneiss of 
 Point-aux-Mines, and in the granitoid gneiss of Chippewa Falls. 
 At the latter place the melaphyre is in the form of a d\ke, and at 
 l*oint-aux-Mines it is seen to form a dome-shaped mass, completely 
 surrounded by gnessiod rocks. Furthermore, the lower members 
 of the Mamainse series are intersected by numerous dykes, con- 
 sisting of compact melaphyre. In some of them, the constituents 
 of that rock are distinguishable, but most of them are almost 
 impalpable, vary from a reddish-brown to a dark green colour, and 
 frequently exhibit at their sides bands of slightly different colours, 
 which run parallel with the side-walls of the dyke. 
 
 The average strike of the Upper Copper-bearing rocks of Michi- 
 picoten Island is N. 68'^ E., and the dip 25° south-eastward. An 
 approximative estimate of their thickness is as follows: — 
 
 Granular, delessitic and compact melaphyres, 
 
 and conglomerates 10,000 feet. 
 
 Compact melaphyres with agate amygdules. 4,500 " 
 Resinous traps, porphyrites and breccias. . . 4,000 " 
 
 18,500 feet. 
 
 If we compare the rocks of Michipicoten Island with those of 
 Mamainse, it would appear that the inferior rocks of the latter 
 group do not come to the surface at Michipicoten Island, and that 
 
34 
 
 the higher rocks of thn Michipicotcn p;roup have not been de- 
 veloped at Miinininsi', or lie bcnejitli the wuti-rs of the hike to the 
 Houvh-west of the promontory. It would therefore iippear just, iti 
 eHtiiuatiii<^ the thicknes.s of the Upper Copper-heariiit^ rocks of the 
 eastern part of Lake Superior, to add to the jMaiuainse series tlio 
 abov3 nieiitioiu'd 40(10 feet of resinous traps or porphyrites, which 
 would make the whole thickness at least 2(^,000 feet. The rocks 
 of the west and soutii shores of Mi<'hij>icotcn Island present the 
 most reji;ular appearance, and it might be expected tliat those of 
 the soiith shore would, from their strike and dip, repeat them- 
 selves on the east side. But, as in the case of Maniainse, such an 
 expectation is disap})ointed. On examining the roeks of the east 
 shore, the upper beds, consisting of the porphyrites above men- 
 tioned, secni regular enough, but beneath these come breceiatcd 
 melaphyro, delessitie melaphyre cut by a porphyritic rock, and 
 others in which the evidences of bedding arc very indistinct. 
 Among these rocks the two following may be particularised as 
 occuring in large masses. The first has an impalpable flesh-red 
 or reddish-grey matrix, wherein occur numerous grains of dark 
 grey quartz, and also light-coloured soft particles, which 
 seem liable to removal by atmospheric agencies, giving 
 the rock where this has taken place a porous appearance. 
 It also contains light red and ash-grey crystalline grains of 
 felspar, and ' Miers which appear earthy and decomposed. 
 The matrix is fusible, in fine splinters only, to a white enamel. 
 The rock has an uneven fracture, a specific gravity of 2.493, and 
 is probably a porphyritic quartz-trachyte. The other rock, which 
 occupies a very considerable area, partakes more of the character 
 of felsit'"': jiio'-phyry, although the felspar crystals are very often 
 indistinct. It contains, besides these, numerous grains of greyish 
 (juartz, sometimes one-eighth of an inch in diameter, and a fine- 
 grained, dark red, difficultly fusible, matrix. The specific gravities 
 of three different specimens were found to be 2.548, 2.579, and 
 2.583. The bedding of the rock, if it possesses any, is very 
 obscure ; but it shews in places a tendency to separate into flags. 
 It has a very rough uneven fracture, and is probably also 
 ((uartzose trachyte. At the north-east corner of the Island it 
 seems to overlie, unconformably, beds of trap, which here assume 
 something like the ordinary strike and dip, viz., N. 72"^ E., dip 
 25*^ 8. E. 
 
 The islands which lie opposite the mouth of the harbour on the 
 
 ■! 'i 
 
 
86 
 
 south shore are coniposoci of a peculiar rock, which is nowhere 
 visible on the main island. It consists of a reddish-brown ini- 
 palpable matrix, with a hardness but slij^htly inferior to that of 
 orthoclase, in which minute spots of a soft yellowish-white material 
 arc discernible. There are also li;j;hter flesh-coloured grains ol)- 
 servablo, which seem to be incipient felspar crystals. The njatrix 
 is difficultly fusible to a colourless blebby fi;lass, and the specific 
 gravity of the whole rock, where freshly broken, is 2.409. A 
 piece slightly bleached to a greyish-white, from its adjoining 
 a crack in the rock, gave a specific gravity of 2.477. Some parts 
 of it exhibit a slightly porous structure, but this was not the case 
 with either of the pieces whose specific gravity were determined. 
 The rock has a very uneven fracture, and is probably trachytio 
 phonolite. The occurrence of these traciiytic rocks on Michipi- 
 coten Island is very interesting, for they are the only ones of the! 
 region which have in other countries been found in connection 
 with undoubted volcanoes. 
 
 The general strike of the strata of the rocks of Point 
 Keweenaw, at least in the neighbourhood of Portage Lake is N. 
 30° to 40° E., and the dip 55^^ to 70° north-westward. The 
 melaphyres predominate, although polygenous and porphyritic 
 conglomerates are also frequent. The copper-bearing tufaceous 
 melaphyres seem to be more plentiful here than in the other 
 areas, or at least the mines to which they give rise are more 
 extensively worked. 
 
 At the other points in the east shore of the lake, where rocks 
 of the character of melaphyre have been observed, the area 
 occupied by them is very limited, and confined to narrow strips of 
 beach and rocky ground, between the lake and the much more 
 elevated Laurentian or Iluronian rocks. In the most westerly 
 cove on the south shore of Bachewahnung Bay, red sandstone is 
 observed striking N. 12'^ W., and dipping 15" south-westward. 
 It is interstratified with conglomerate, the boulders of which are 
 principally of quartzite, dark green slate and red-jasper conglo. 
 merate, which have doubtless been derived from the Huronian 
 hills in the rear. They range in diameter from one to twelve 
 and even eighteen inches. The matrix is generally red sandstone, 
 but the interstices are sometimes filled out with quartz. A short 
 distance along the shore to the north-east exposures occur of a 
 reddish-brown melaphyre tuflf, containing amygdules of calcspar 
 and quartz, the matrix of which is very soft and decomposed- 
 
86 
 
 Tho bodM nprear to strike N. S" K., and dip 25"^ to 20-' weMt- 
 wnrd. They would thonsforo 800!n lt» bo cont'oriiinbh^ with tlio 
 H<'uidst(>!»n mid coiij;l(mierato. Kurtlicr Morth-oa.stwiir»l tlio rock 
 becomes more cumpuet, of ii reddish <j;ie(;n eoloiir, niid exhibits 
 curves of ij^neous flow. The ;.'eo(h's become imieh less tVe(pient 
 and consist almost exclusively of «;j^ate. The next rock to the 
 north-cast is a li;j;ht red sandstone, striking N. 05'^ W., and 
 dippinf^ Uf)"^ to •10-' N. K. Its contact with the trap is not 
 visible, but its dip is such as to lead to the supposition tliat it has 
 been disturbed bv that rock. There is u ijrreat thickness of this 
 sandstone exposed here, in strata fre(juently vertical, striking 
 generally cast and west, or to the north of west, and exhibiting 
 dips varying from ilf)-' N. to 57" S., and at least two anticlinal 
 axc8. From what has been stated here and also concerning the 
 south shore of Maniain>^c, it would appear that there is evidence 
 of the existence of a sandstone of greater age than the bedded 
 nielaphyrcs and conglomerates, and it would appear not unreason- 
 able to suppose that it belongs to what has been called tlie Lower 
 group of the Upper Copper-bearing series. 
 
 The trap rocks which surround the south-west base of Gros 
 Cap, although comparatively seldom amygdaloidal, are readily 
 distinguished as melaphyres. They arc sometimes coarse-grained, 
 cansisting of reddish-grey felspar, soft dark-green iron-chlorite 
 (delessite), and occasional .-^pots of yellowish-green epidote. From 
 this they graduate into finer-grained varieties, but they very 
 seldom become impalpable, or their constituents altogether indis- 
 tinguishable. Sandstone was not observed in contact with the 
 traps, but a large uiass of (juartzose porphyry is seen at a short 
 distance from the shore. 
 
 Another large development of traps and sandstones occurs to 
 the north of Pointe-aux-Mines, where an occasional bed of 
 tufaceous melaphyrc is also found. 
 
 Besides the rocks above described, there are found on the low 
 ground betwixt Goulais and Bachewahnung Bays, betwixt the latter 
 and Pancake Bay, and on many of the islands of the east shore, 
 large areas of red sandstone, almost horizontal, which are supposed 
 to be the continuation of that occurring at Sault St. Marie, and 
 usually called the St. Peter Sandstone. The true relations of this 
 rock to those of the upper group of the Upper Copper-bearing series 
 have not yet been made out. It closely resembles, in litliological 
 character, the sandstone described above as occurring in almost 
 
;{7 
 
 lihits 
 
 iictit 
 
 tint 
 
 iitid 
 
 not 
 
 liiis 
 
 til I'm 
 
 
 vortinil ntriitii on tli.. south shore of* Hachowahiiuiii; Buy. 'Mic 
 (Hstiirl)imc(> of tho latter is reasonahly attributiible to the neij;h- 
 hourini; tiicl.'i'hyreM, in whieh cuho the Haudstoiie would Iki th« 
 earlii-r nx-k. On the other liund, as Sir W. K. Lopm observes, 
 '• the e(uitr;ist between th«! «reneral iuo«h'rat<' dips of these saiid- 
 •' stones and tlie hiirher inclination of tlu; ij,'iU'oiis .strata at 
 " (iar^jjaiitua, Maniains*-. and (Jros Cap, eonibined with the faet 
 " that the sandstones always k«.'ep to th<' lake side of these, whilo 
 *' none of the many dykes whieh eiit the trappean strata, it is 
 " believed, are known to intersect the sandstones (at any rate on 
 *' tho Canadian side of tho lake), seem to support the suspicion 
 " that the sandstones may o"(!rli<! uneonformably those rocks 
 " which, associated with the trup, constitute the copperbearinji; 
 *' series."-'^ Tho followin;:; facts ure confirmatory of this view. 
 Tn the bay immediately south (vf Point-aux-Mines, where the 
 Mamainse series adjoins the Iiaure;itian rocks, the lowest member 
 of the former is uneonformably (nerlaid by thin bedded bluish and 
 y(!llowish-<i;rey sandstones, strikin;^ N. 50*^ E., and dippinj:; 1^*^ 
 north-westward. The lowest layer is a conglomerate, with t;ran;tie 
 and trappean boulders, and a bluish, fine-j:;rained and slaty matrix. 
 It is about six feet thick, and is followed by thirty feet of the thiu 
 bedded sandstones, some parts of which might yield good flag- 
 stones. Some of the surfaces of these arc very distinctly rippli;- 
 marked. Above these come thin, shaly, rapidly disintegrating 
 layers, in which are found .spheroidal concretions from five to ten 
 inches in diameter. It h not j)os,sible to a.scertain the total 
 thi(fkness of the.se sandstones, since they descend beneath the level 
 of the lake. They are similar in lithological chnractcr to the 
 sandstones which occur on the north side of Point-aux-Mines. 
 Although there is no doubt that these sandstones uneonformably 
 overlie the melaphyre series, still their lithological characters are 
 very different from those of the horizontal red sandstone above 
 referred to. The latter is evenly small-grained, is coloured red by 
 iron oxide, and contains here and there small pieces of red shale, 
 which liuvc evidently furnished the colouring matter. It 
 frequently consists of evenly bedded red and yellowish-grey 
 layers, and exhibits sometimes the phenomenon named by 
 Naumann, discordant parallel-structure, and byLyoll, diagonal or 
 cross stratification. 
 
 Geology of Canada, p. 85. 
 
I 
 
 m « 
 
 (h-l 0^^ 
 
 
 38 
 
 In enquiring next as to what geological formation iu Europe 
 most closely resembles the Upper Copper-bearing series of Lake 
 Superior, the opinion expressed by Delesse ought not to be lost 
 sight of, viz., that the constituent mineral^iave the same meaning 
 and importance for eruptive rocks whiclS-wganic remains have 
 for those of sedimentary origin. Therefore, where the pala3onto- 
 logical evidence does not entirely contradict it, that derived from 
 lithological resemblance ought to be allowed its full weight. The 
 melaphyres of the upper rocks being interbedded with conglomer- 
 ates and sandstones, the age of the latter may be ascertained 
 approximatively by enquiring under what circumstances and 
 during what period the melaphyres of Europe were developed. 
 Upon this point Naumann thus expresses himself : " With regard 
 " to the eruption-epochs of the melaphyres, there appears, indeed, 
 " to have been many of them, but the most occur in the period 
 " of the Rothliegende, or in the first half of the Permian forma- 
 " tion, and all are probably more recent than the Carboniferous 
 " system This applies at least to the melaphyres on the south 
 '' side of the Hundsriick, to those of the Thuringian Forest, of the 
 " neighbourhood of the Hartz, of Lower Silesia, Bohemia, and 
 *' Saxony. Many of these melaphyres were deposited soon 
 *' after the commencement, others towards the end, of the 
 " Rothliegende period, and generally the latter, in many coun- 
 " tries, shews a decided coincidence, both as regards time 
 " and space, with the formation of the melaphyres." Zirkel, 
 in his recent work on " Petrographie," gives a description 
 of the melaphyre deposits of Germany, of which the fol- 
 lowing is a translation: " In districts which are older than the 
 " Carboniferous formation melaphyre rocks are but seldom found. 
 " The melaphyres of the southern Hundsriick and of the Pfalz, 
 " whose stratigraphical relations are better known than their 
 " mineralogical composition, appear in the Carboniferous system 
 " or the lower Rothliegende. This melaphyre region extends 
 " from Diippenweiler to Kreuznach, a distance of twelve miles, 
 " with a breadth between St. Wendel, Birkenfeld, Kirn, and 
 '* firrumbach of several miles. Very few irregular masses are known, 
 " but, on the other hand, numerous veins have been observed with 
 " thicknesses varying from four to sixty feet. They possess 
 " mostly a vertical dip, cut sharply the Carboniferous strata, and 
 " often extend on their strike considerable distanw;. The mass 
 " of the vein frequently encloses fragments of the side rock, slate- 
 
39 
 
 clay or sandstone. But most frequently in this region, the 
 melaphyres present themselves in the form of beds, which arc of 
 very variable dimensions, (often only five to ten feet, sometimes 
 two hundred feet thick,) and lie, for the most part, evenly 
 inserted between the strata i»f the Carboniferous system. Some 
 of these can be traced for a distance of two miles. Cesides 
 these a melaphyre layer appears in this rcj^ion, extending over 
 many square miles. It is superinq)osed upon the upper strata 
 of the Carboniferous system, andui>on it rest the Conglomerates, 
 sandstones and slate-clays of the Uothlicgendc. This great 
 covering of melaphyre is at its edges accompanied by melaphyre- 
 tuffs, which are in many places developed as melaphyre-amygda- 
 loids. In very few instances only has it been observed that 
 these melaphyres liave exerted altering influences upon the side- 
 rock. Within the limits of the Rothliegende melaphyres are very 
 frequent. According to Naumanu the melaphyre of Ilfeld in 
 the Hartz, must be regarded as a thick layer bedded into the 
 Rothliegende. It nevertheless in places lies immediately over 
 the Carboniferous system, on account of its extending beyond 
 the edges of the lower strata of the Ilothliegende. Naumann 
 also mentions a mass of melaphyre which in Tyrathal covers the 
 junction of the Greywaeke with the Ilothliegende, and in its 
 ' further extension overlies also the latter formation. The 
 * melapb^.e-amygdaloid of Planitz, near Zwickau in Saxony, 
 ' forms also a covering regularly inserted into the Rothliegende, 
 ' above its inferior strata. On the western declivity of the 
 ' Oberhohndorfer Hill, near Zwickau, the melaphyre which here 
 ' contains numerous green-earth and calcspar amygdules, shews an 
 ' interesting intercalation with the brownish-red slate-<'lays of the 
 ' Rothliegende, irregular lumps and patches of which being as it 
 ' were kneaded into the niass of the melaphyre. The melaphyric 
 ' rock of the Johann-Friedrich and Zabcnstadter Adit, in Mansfeld, 
 ' is evenly interstratified in the Rothliegende. G. Leonhard 
 ' mentions that in the Rothliegende of the neighbourhood of 
 ' Darmstadt, at Gcetzenhain and Url^erach, the melaphyre forms 
 ' distinct outbursts of considerable size in the form of domes 
 ' {Kuppcn,) which consist in the centre of solid melaphyre, and 
 towards the periphery of amygdaloidal rocks, and shews in 
 places both flagstone-like and columnar separation. In Silesia 
 the melaphyres appci'r in two places : in the country between 
 LoBwenberg and Lachn, where they, according to the investi- 
 
m 
 
 I' I 
 I* J 
 
 r • 
 
 |H 
 
 ?1 
 
 ^ 
 
 40 
 
 " gations of Beyrich, occur in several courses, striking from 
 " north-west to south-east, intersecting the Rothliegende, and 
 " in still more extended measure at the edge of the great 
 " bay opening towards south-east in the Grauwaclve at Landeshut, 
 " in which the carboniferous formation and the llothliegende 
 " have been deposited, and in which they form, according to Zobel 
 " and V^on Carnal, a range extending from Schatzlar to Neurode. 
 " In north-eastern Bohemia, according to Emil Forth, and 
 " Jok<?ly, malaphyres are found as numerous, and sometimes very 
 " thick layers, in the Rothliegende. Jok61y describes, in the 
 *' district of Jicin, five beds of nielaphyre in variou:-! parts of the 
 ** Rothliegende, which exhibit very distinctly observable strati- 
 " graphical relations. They prove to be, for the most part, true 
 " nielaphyre streams, which have flown like lavas, and in visible 
 " connection with undoubted vein-like outbursts. According to 
 " Perth, the neighbourhood of the nielaphyre veins is fre(|uently, 
 '' for great distances round, a field of melaphyric ash and 
 " scoriae."-'^ 
 
 From these quotations it is plain that, in Europe, nielaphyres 
 only made their appearance during the Carboniferous and Fermian 
 periods, and especially characterised the latter. The occurrence 
 of porphyritic conglomerates in Germany is similarly limited. On 
 this point Zirkel says : " As porphyritic eruptions principally fall 
 '* in the period of the Rothliegende, so the whole of the clastig 
 " rocks of the porphyry family stand in close connection with .he 
 " deposition of is strata, to which they have also contributed a 
 " considerable amount of material. For instance, coarse porphy- 
 " ritic conglomerates form members of the Upper Rothliegende 
 " in the Oschatz-Frohburg basin, in the Dohlen basin, at Wieser- 
 •' stiidt in the Hartz, and in the north-western part of Thiiringia. 
 " At Badeii, in the Black Forest, the deepest strata of the 
 " Rothliegende consist of porphyritic breccia and the middle 
 " strata of conglomerates." f Even polygenous conglomerates, 
 such as those above-mentioned, are especially frequent among the 
 carbi niferois and permiani strata of Europe. Naumann thus 
 briefly characterises the Rothliegende of Germany, which he 
 considers as equivalent to the English lower New Red Sandstone 
 and the French gres rouge : " The Rothliegende appears in so 
 
 * Zirkel; Petrographie. ATol. ii., p. 71. 
 t Zirkel ; Petrographie. Vol. ii., p. 529. 
 
 n 
 
41 
 
 •' niaiiy of the couutrios of Germany, and in such great thickness, 
 "' that, in its mode of de^'elopment there, av>' recognise tlie normal 
 '• type of this remarkahle sandstone formation. The pigment of 
 " the sandstone, consisting principally of iron-oxide, the frequent 
 '• occurrence of conglomerates, the often repeated change in the 
 " size of grain of its rocks, the association with porphyries and 
 " melaphyres, the very frequent layers of claystones and porphy- 
 '• ritic conglomerates, the great poverty, and often contplete 
 " absence of organic remains. — all these are characters by which 
 '' the Ilothliegende is distinguished as quite a peculiar sandstone 
 " formation."'!'' That not om of the peculiarities here emphasised 
 by Naumann are absent from the upper group of the Upper 
 Copper-bearing rocks of Lake Superior, will be evident to any 
 one who has observed thorn or carefully gone through the 
 description above given. It therefore becomes a matter of .uich 
 importance, and deserving of the most careful study, to ascertain 
 whether this resemblance is a mere coincidence, or whether there 
 is reason for supposing that any part of these I 'pper CopiHir-bearing 
 rocks "Wft-of Permian age. 
 
 * >"auniann; Leliibueb dor Oeognosic. Vol. ii., p. 5H4. 
 
 CTCTbO"