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Mapa. platas. charts, ate, may ba filmad at diffarant raduction ratios. Thosa too larga to ba antiraly includad in ona axpoaura arm filmad baginning in tha uppar laft hand cornar, laft to right and top to bottom, as many framas as raquirad. Tha following diagrams illustrata tha mathod: Las cartas, planchas, tablaaux. ate. pauvant itre filmte A das taux da riduction diff*rents. Lorsqua la documant ast trap grand pour itra raproduit an un saul clicha, il ast film* a partir da I'angla supirieur gaucha, da gaucha i droits. at da haut an bas. an pranant la nombra d'imagaa nicassaira. Laa diagrammas suivants illustrant la mtthoda. 1 2 3 1 2 3 4 5 6 Miaocopv nsoiuTioN tbt chart (ANSI and ISO TEST CHART No 2) ^ /APPLIED IN/MGE l.ic ar« '653 ;s1 Main Stre«t ^J5 Roches!^'- frt* Yo'k 1*609 USA ■■^= (716) 482 - IJ300 - Phone ^S (^'6) 2S8 - 5989 - Fox DEPARTMENT OF MINES Hm. Utaam Braiw, Mimmt R. G. McConibll. Dtrvn Miiofna. GEOLOGICAL SURVEY WiLUAU Mclmnt, Diucniio GmLoowt. i MEMOIR ml No. U, Gbouigical Snuu Timiskaming County, Quebec ■Y M. E. Wllion OTTAWA GomiNMSM faumma Bukbau 1918 Ko. 1<'>5 m CANADA DEPARTMENT OF MINES Hon. Mabtin BumikLL, MiNitna; R. O. McCunnku., Dkh tv Minktbb. GSOLOGIGAL SURVEY William McInnb*. DiBwrtiNo (^bcm.cx.im. riV,MI;llli No M, OBOI.OOICAL SRBIB« Timiskaming County, Quebec BY M. E. Wilson 29278c OTTAWA Government Printing Bvreai' 1918 No. 1695 CONTENTS. CHAPTER I. Introduction General statement and acknowledgments. Geographical position of area Means of access Agricultural possibilities Climate Native inhabitants Forests Fauna Early explorations and surveys Previous work Bibliography PAGB 1 1 3 3 5 5 7 7 9 11 12 14 CHAPTER II. Physiography Laurentian plateau Topographic development. . . Introductory statement. . . Pre-Cambrian history Pre-Palxozoic palzopiain . Post-PaUcoaoic uplift Continental ice sheets . . . . Denudation Deposition . 16 16 17 17 17 18 20 21 21 22 Post -Glacial lacustrine epoch 23 Marine epoch . Timiskaming region Rocky uplands Distribution Relief Drainage Clay belt Relief Drainage Linear valleys Origin Faulting Other possibilities Conclusion* Age Overdeepening of Timiskaming trench. Topographic hitrtory 23 24 24 24 24 27 29 30 31 34 37 37 38 39 39 40 41 CHAPTER III. PACK Geology of the Ottawa basin 46 General statement 46 Basal complex 46 Grenville belt 48 Timiskaming belt 48 Abitibi group 49 Igneous rocks 49 Extrusive 49 Intrusive SO Sedimentary rocks 50 Agglomerate and tuff SO Slate and phyllite 51 Iron formation 51 Ferruginous dolomite 51 Pontiac series 51 Larder Lake series 52 Timiskaming group 52 Kirkland Lake series 52 Timiskaming series 53 Fabre series S3 Belt of Ottawa gneisses 53 General statement S3 Lithological character 54 Foliation and banding 55 Structure and relations of the three great basal-complex belts 56 Late Pre-Cambrian rocks 57 Introductory statement 57 Huronian 57 Introductory statement 57 Cobalt series 57 Distribution 57 Lithological character 58 General 58 Basal conglomerate 59 Greywacke and argillite 60 Arkose and quartzite 60 Upper conglomerate 60 Pebbly quartzite 60 Structure and origin 61 Post-Cobalt series intrusives (Keweenawan) 62 General 62 Lithological character 62 Palaeozoic sediments 62 Pleistocene 63 Glacial 63 Post-Glacial 64 Champlain clay and sand 64 Lacustrine clay and sand 64 «i 4 J 1 I 5 CHAPTER IV. PACE Nomenclature and correlation 65 General statement 65 Objectioni to an inter-sub-provincial nomenclature 66 Our knowledge of the succession of formations in the iub-provincet incom- plete 66 The principles of Pre-Cambrian correlation inapplicable or inadequate 67 Timiskaming region 71 Correlation of the Grenville and Timiskaming belts 73 CHAPTER V. General geology 76 General statement 76 Table of formations 76 Basal complex 77 Grenville series 78 Crystalline limestone 78 Distribution 78 Lithological character 78 Structural relations 78 Pyroxenite 79 Distributbn 79 Lithological character 79 Cyanite and garnet gneiss 79 General character and distribution 79 Lithological character 79 Age and correlation 80 Abitibi group 81 General statement 81 Distribution 81 Extrusive rocks (Abitibi volcanics) 81 General character 81 Basalt, diabase, and gabbro 82 Distribution 82 Lithological character 82 Amphibolite, hornblende schist, and chlorite rocks 83 General character and distribution 83 Lithological character 84 Andesite and diorite 84 Distribution 84 Lithological character M Chlorite-sericite schist 85 Quartz porphyry and rhyolite 85 Distribution 85 Lithological character 86 Sericite schist 86 Origin 86 Relations to other formations 87 Intrusive rocks 87 General statement 87 Peridotite and serpentine 87 DiabaK and gabbro '*°" Diorite and andeaite Quanz porphyry ?: Lamprophyre Sedimenury rocki !" General autement SUte and phyllite ' Diatribution ' Lithologtcai character „, ^Oripn ,J Conglomerate and asglomerate n. Iron formation „. Ferruginoua dolomite -, Pontiac aeries ' General autement and distribution 53 Greywacke, arlcose, and conglomerate 93 Iron formation _. Amphibolite _, Pontiac schists _- Granites and gneisses I? General statement „, Northern batholiths ~ General autement 07 Lithologkal character „ Belt of banded gneisses n. General sutement and distribution m Lithological character ^ Granite and granite gneiss m Syenite and syenite gneiss m Granodiorite and granodiorite-gneiss (qq Diorite and diorite gneiss ,qq Pegmatite and aplite ,„» Mica schist |r^ Structural features ,«, Foliation J" Bandi-g l^ Granulation |^ Folding and faulting .q, Huronikn J~ Cbbrit series J?f General sutement ,„, Distribution 1^ Lithological character jq- Basal conglomerate jq- Gr-ywacke and argillite jQg A''"*' 108 Upper conglomerate jq, Ville Marie quartsite ,r^ Relatlonahipsof theCobaltseriestothebasementcomplex! ..'.'.'.'.'..'" 109 Folding jjj Origin of the Cobalt aeries ijj PACB 89 89 89 90 90 90 91 91 91 91 92 92 92 93 93 93 9* 95 96 97 97 97 97 97 98 98 99 99 99 100 100 100 100 102 102 102 103 103 103 103 103 106 106 106 108 108 109 109 109 111 111 PAGE Post-Cobalt series intrusives 112 Introductory statement 112 Diabase "^ Distribution l'^ Lithological character * '^ Olivine diabase '" Distribution 1*^ Lithological character 1 '* Structural relations of the quartz and olivine diabase 114 Origin of diabase H* Syenite porphyry 1 1^ Distribution 1 1' Lithological character 115 Structural relations and correlation 1 IS Pala»K)ic "* O.-dovician and Silurian H* Pleistocene '^^ Glacial "^ Lacustrine clay, silt, and sand 1 1* Distribution H* Character 1** Origin "9 CHAPTER VI. Special problems of Timiskaming region 120 General statement 120 Pillow structure 120 Character *20 Origin _ J" Origin of ferruginous dolomite 1** Genera! statement 12' Lithological character and composition 124 Origin '25 Stratigraphical and structural relations of Pre-Cambrian basal complex 127 General statement 12' Timiskaming belt 127 Grenville belt *28 Ottawa gneisses belt 128 Mode of batholithic intrusion 129 Origin of banded gneisses "1 General statement "^ Metamorphism of laminated sediments "1 Lit par lit injection 1^^ Flattening out of masses of country rock included in an igneous magma 134 Deformation of a heterogeneous complex of igneous rocks long after con- solidation ; 1^^ Deformation of a heterogeneous igneous magma during or immediately following its consolidation 136 Conclusion "' Origin of Cobalt wrin '**" Introductory statement \\l Conglomerate ' Greywaclce, argillite. and arkoie '...'.'. "* Ville Marie quartzite Conclusion '^* Clay belt of northern Ontario and Quebec . . \^ Introductory statement *" Limitations '*" Character **' Origin '*• Extent of lake Barlow \*l Glacial barrier ]" Duration of lake Barlow and take Ojibway ........ \^ Change in elevation :*: 145 CHAPTER VII. Economic geology General statement History of mining in Timiskaming county ,,. Gold 1** Character '** Origin '** Prospects '** Union Abitibi J*' Sullivan "' Smith "0 Bernard *^' Silver ' ■ ' '^^ Prospects *'^ Wright mine *" Quinn Point |'^ Pontiac Mining and Milling Company ,tl Mill *** Terra Nova Mines, Limited |?1 Molybdenite '" General statement Jff Character "^ Origin '" Prospects '^^ Height of Land Mining Co. .pany. ..............,,,[ jf^ St. Maurice Syndicate ,„ Peninsular Mining Company , ?- Index 189 rACR 137 137 138 138 138 139 140 140 141 141 142 143 144 145 Illustrations. PAOL Map 1495. Timiskaming county, Quebec _ 'n pocket. PUte I. Concretionary, stratified cUy, Simon lake Frontispiece. II. A. Black spruce swamp, Trfcewon township 15' B. Banksian pine, Matchimanito lake •'' III. A. Muskeg, Senneterre township j6| B. Grove of red pine, Ogaskanan lake i*' IV. Turners chute, upper Kipawa river j63 V. Abitibi volcanics showing flow structure, Shabogama lake 165 VI. Abitibi volcanics, head of Kiask rapids, Bell river 167 VII. Glaciated surface of seamed chloritic greenstone, lake Opasatika. 169 VIII. Pontiac schist dipping northeastward, lake Opasatika, Dasserat township ~ , , , ,,, IX. Truncated anticline of banded gneiss. Hunter point, Turtle Uke . . . 173 X. Lenticular inclusions of pegmatite in granite gneiss, Grand lake Victoria - - - '" XI. Conuct of diabase dyke with granite, west shore of Shabogama take !" XII. CroM-bedded glacial drift, Courville township 1'9 XIII. Stratified post-GUcial clay in prospect pit, Kewagama river, Preissac township |*| XIV. Stratified sand overtain by boulders, Courville township 183 XV. Contemporaneous folding in stratified clay, Courville township 1 85 XVI. Broken stratified ctay, Senneterre township 187 Figure 1. Location of Timiskai.iing county 2 2. Ares in vicinity of lake Kipawa, showing the multitude of lakes 28 3. Linear valleys unretated to rock structure, Timiskaming county 35 4. Directionsof linear valleys ^ 5. Diagrammatic cross section of Timiskaming county *' 6. Ctay belt of northern Ontario and Quebec •*" Timiskaming County, Quebec. CHAPTKR I. INTRODUCTION. GENERAL STATEMENT AND ACKNOWLEDGMENTS. This memoir is a gc.ieral statement of the results of geological v,-ork carried on for several years in the northwestern part of the province of Quebec. It has special reference to a numlier of local areas studied by the writer in that region, all of which are included in the recently created county of Timiskaming (Figure 1). The discovery of important mineral deposits at Cobalt. Porcupine, Kirkland Lake, and other localities in northwestern Ontario, in recent years, seemed to indicate that similar deposits might possibly be present across the interprovincial boundary in the province of Quebec and it was for this reason that the geological explorations in Timibkaming county described in this report were undertaken. Unfortunately, throughout a large part of the county and especially in the northern part where the geological conditions are most favourable for the development of miner- al deposits the bedrock surface is largely hidden beneath post-glacial lacustrine clay so that prospecting is necessarily confined to the scattered knobs and ridges of rock, the total areal extent of which in many local- ities is less than one per cent of the total area of the bedrock surface actually present. Since the construction of the Timiskaming and Northern Ontario railway and the discovery of the silver-bearing veins at Cobalt, however, a few prospecting parties have visited the district during the summer months of each year and occurrences of gold have been found at several points, also pegmatite dykes and quartz veins carrying molybdenite; but mining operations up to the present have not been carried beyond the opening up of prospect pits. It does not follow from this that extensive deposits of valuable ore are not present in the district or may not eventually be discovered. The geo'ogical succession of formations in the northern part of the county as far as has been determined, is similar in every respect to that found in the Kirkland Lake and Porcupine districts in Ontario, so that geologically there is no apparent reason other than the presence of the overlying cover of lacustrine clay, *rhy similar deposits should not be discovered in Quebec. The dwtrict included in TimiskaminK wunty \\c* wholly within the Laurentian plateau and fornix a part of the great Pre-Cambrian shield of northeastern North America. The rocb. of the region. thu«. belong for the most part to tho«e ancient Pre-Cambrian terranes which have suffered »o many vicissitudes that their original character and relation- ships to one another have not yet fjecn wholly determined. Figure 1. Location of Timiskaming county and other areas mentioned in this memoir. In the discussion of the geology of Timiskaming county contained in the following chapters, an attempt has been made to separate the ons that are largely descriptive from those that are more or less coretical. This method of treatment was deemed advisable in that ven though it involves some repetition, it renders the material contained in the report more a ible and at the same time draws a definite line between the descri. . of the geological features observed and the hypotheses based on tncse observations. The writer desires to ucknowled|{e his iiulebted <•(« to the residents <»f the district and others for many courtesies recei\ > d during the rours<- of field work, and to his field juwistants whose efficient strvice contribute*! much to the progress of the work. The thanks of the Geological Survey are especially due to Mr. J. O. Tremblay, agent for the Department of Mines. Quebec, at Ville Marie; to Mr. Albert McKegg; to Mr. John Alger; to Mr. John Hough, mining recorder for Larder Lake mining division; to Mr. Chas. Richmond; to the officials of the National Transcontinental Railway survey; and to the officers of the Hudson's Bay Company at its various posts in the district. (iHOkaminK omnty whiro tlir RJaciattd surface of tl Pre-Cambrian b«'tlrock i» alnioi^t continuously fxfxiwd. there is little or no M>il suitable for agriculture except in a few very limited arcast; but in the northern and wcbtern p<»rts of the county extensive areas of po»t-Glacial, lacustrine clay occur, forming what is* generalU known as the clay belt. This belt is not continuous or unilorni throui-li- out the rcKion, however, for here a.nd ihere hills and knobs of r. . k and ridges of gravel and sand protrude through the clay, forming cn- ■picuous landmarks in an otherwise plain-like KU.-face. Within lire clay belt proper, there are alwi numerous large, undrained muskegs in the interstream areas, where the surface of the clay is covered with peat to a depth of several feet.' In addition to these rocky, sandy, and swampy districts in the clay Mt, there are many well drained areas of clay and these afford a good soil for the growth of ixttatocs, vegetables, hay, and the hardier cereals. The southern extension of the clay belt situated to the north and east of lake Timiskaming has U en settled for a number of years and supports a large farming commiini(>'; and at the post of the Hudson's Bay Company on lake Abilibi, potatoes, hay, and oats have been grown successfully for a numlxr of years. Potatoes have also been grown for a number of years by the Indians living along Bell river. The thick growth of vegetation, which everywhere covers the surface of the clay belt at present, kcips the soil at a lower temperature than would otherwise be the case and with the clearing of the land the summer frosts will probably be less frequent and harmful. The provincial government of Quebec has Ixgun the building of roads in the section of the clay belt adjoining the N.itininl Transaintinental railway and a number of settlers have already taken up land in that districi. CLIMATE. Climatic records have been kept for the Canad" .1 Meteorological Service for a number of years at a post of the Hudson's Bay Company on lake Abitibi, in the northern part of Timiskaming county. Then- are no records available from points in the central or southern parts of the county, but meteorological observations have been recorded at Haileybury which lies just outside its western boundary. The averajfe I Thr maxiniHin tbirknMa o( prat tA»rmd in th<- cuu along the Natiomil TranKonl'O'ntal railway •M to lect. I monthly temperatures and precipitation at Abitibi po!-t and at Haile' bury are contained in the followinfj tables prepared by Mr. R. F. Stupai director of the Dominion Meteorological Service. Meteorological Ohsenations Taken at Abitibi, Quebec. 1897-1910 Temperature. Mean I Mean i Daily hi'Kh. low. Moan rancc. January. . .1 12-5 rebruary. . March . April May June July August. SeptcnilKT October. November Decemljer 14 2 28-2 40 .? .S4 6 67 9 72 6 68 60 2 47-2 31 1 16 6 -11 1-6 21 (I .%-4 49 .^ ,S,"i 5 52 3 44-7 32 1 18 2 -1-4 6 ! 6 14 9 30-6 45-5 58-6 64 60 6 52-5 39. 6 24 6 76 33-4 23-8 25 2 26 6 19 3 18 Absolute. I No. , day? K.or S. Max. Min. 42 46 62 70 94 94 94 86 87 76 68 48 -46 -44 -42 -20 8 28 35 34 26 15 -16 -45 9 7 7 6 9 8 10 12 12 12 11 9 Rain- fall. 05 00 09 1.00 2. 64 2 67 2-77 2-85 2.60 2. 55 0-77 09 18 08 Snow- fall. 18 14 5 21 6 4 3 2 2 41 12 8 21-3 98-8 Tot I pre lip 1 1 2- 1 2-; 2i 2- 2-1 2 ( 2 < 2 1 2-: 27 •< Averase date of last frost, June 8. Average date of first frost, September 14. Summer temperature 57-2° . 3 mo. 61 1° Meteorological Observations Taken at Haileybury, Ontario. January. . February March . . . April May. . . June uiy August . , , September October. . November December . Temperature. Absolute. Mean | Mean high. I low. 17 19 32 48 61 73 7 76-7 73 65 1 51 2 35 -3 21 -4-3 -2 9 83 26-3 390 50 55 51 44 33 20 3 Daily Mean. range. Max. Min. 6-7 22 48 -40 85 22. 7 47 -38 11 9 23. 8 71 -34 37. 3 22 79 - 3 50. 3 22 6 93 17 62 23. 5 100 28 66 21 3 99 36 62 4 21. 2 93 27 .54. 7 20. 7 91 24 42 5 17 3 80 13 281 14 4 63 -25 12 1 18. 2 47 -35 No. daj's R.or S. Rain- fall. 16 12 13 16 14 12 14 13 15 14 15 17 32 024 51 126 3 14 3 03 3 91 2 63 3. 52 2-43 94 42 Snow- fall. 17. 2 17 4 17. 2 5-8 8 22 36 2 8 13 1 19 8 94 Average date last frost, June 5. Average date first frost, September Tota pre- cip. 31 7 r low- all. Total pre- tip. 8 4-5 16 4-3 2 2 4i 2-8 13 1-8S 1 45 2 25 1 43 2 86 2 67 2-77 2-85 2 60 2 96 2 05 2 22 8-8 27-96 Total lOW- pre- ill. cip. 204 1 98 2 23 184 3. 22 03 91 63 52 71 25 40 31-77 4 3 NATIVE INHABITANTS. As is stated in the section of the report in which the agricultural possibilities of the region arc discussed, the district north and east of lake Timiskaming is occupied by settlers and settlers are also taking up land in the district adjoining the National Transcontinental railway. In the remaining parts of the region, the only permanent inhabitants are the Indians and the employees at the posts of the Hudson's Bay Com- pany. The Indians who inhabit the region belong to the once powerful Algonquin tribe and speak Ojibway (Chippewa) — the common language spoken by the Indians throughout the whole of the wide territory lying along the northern border of the St. Lawrence basin. The larger part of the Indians of the region have organized themselves into bands, the members of which all assemble in the early summer of each year at one of the Hudson's Bay Company posts. With the exception of the Timis- kaming band all the Indians of the region live by trapping and have the territory of each band apportioned among the various families as hunting grounds. The native population of Timiskaming county is distributed as follows:' Population. Lake Abitibi 285 Lake Timiskaming 245 Grand lake Victoria 227 Kipawa and Grasssy lake 135 Lac des Quinze (Long Point) 105 Lake Opasatika 30 Hunters Point (lake Kipawa) It Unorganized 37 Total 1,074 FORESTS. The forest of Timiskaming county belongs to a belt intermediate between the Canadian and Hudsonian floral zones or to the subarctic rone in the classification of Professor Macoun of the Geological Survey. It is distinguished from that of the more southerly parts of Canada chiefly by the presence of a greater abundance of conifers and a corres- pondingly smaller proportion of deciduous trees. The variations in the type of forest in different parts of the region are of two classes, those that are regional and those that are local. The regional variations are chiefly related to the climatic diflference between the northern and southern parts of the district while the local variations are related to local environmental conditions such as the character of the soil and drainage. > Rtpoit of the Deputnwnt of Indian AITairt, 1914. The regional variations in the forest are indicated by the relat abundance of numerous deciduous trees in the southern part of the regi which are absent or poorly developed in the north and by the grad disappearance of white and red pine {Pinus strobus and Pinus resino from south to north. Thus, in the southern districts, basswood (T^t Americana), hard maple {Acer saccharum). ironwood (Ostrya Virginii beech {Fagus ferrugtnea), oak {Quercus macrocarpa, Quercus alba, a Quercus rubra), and white elm (Ulmus Americana), are locally commi but, with the exception of the elm, are entirely absent in the nor Red and white pine occur in abundance only in the southern part of i county, although scattered groves occur here and there almost to its nor ern boundary. Groves of pine were seen on the shore of Christophers lake, in the vicinity of Kewagama lake, near Dufault lake, on Og kanan lake (Plate IIIB) and on the islands in Duparquet lake. 7 most northerly pine seen in the whole region were a few scattered tn on some of the islands in lake Abitibi. The local variations in forest types repeat themselves throughc the region according as the conditi.r.s most favourable for the grow of particular trees are present. Thus, in the partially drained portic of the clay belt, the forest generally consists of black spruce {Picea nigr, and constitutes what is known as a black spruce swamp (Plate 11^ Exceptionally wet areas, on the other hand, are commonly occupied tamarack {Larix americana) and these are known as tamarack swami Along the margins of lakes and rivers, there is a belt, several hundr feet in width, where the drainage is good and, in these zones, popl (Populus tremtdoides), balm of gilead {Populus balsamifera), and bir {Belida papyrifera), grow large in size and in great abundance, districts where the soil is sandy or gravelly, as in some of the are underlain by glacial outwash materials, a forest of Banksian pine {Pin Banksiana) occurs. The- are known locally as jack-pine sand-plai (Plate IIB). If, however, a forest fire has swept over an area in rece years, a thick growth of small poplar and biich is generally preset In some localities, generally the more rocky areas, a mixed forest occu and there the white pine, the red pine, and the jack-pine, the popls the birch, the balsam {Abies balsamea), and the cedar {Thuya oa dentalis) grow side by side. Commercially, the most valuable trees in the region are the red ai white pine and the spruce, the latter being used in the manufacture pulpwood. Much of the original pine has been removed from the southei part of Timiskaming county by lumber companies and by forest fire although here and there some large areas of virgin pine forest still remai notably along the headwaters of Kipawa river. In the vicinity of tl upper Ottawa, little of the pine has yet been cut, but in this district tl trees are smaller and more scattered. Spruce occurs everywhere through- out the county in great abundance. It reaches its best development in the clay areas where the drainage is good and in these localities some of the trees have diameters of 2 to 3 feet. The other timber found in the district is not of much value at present. In some localities, especially in sand-plain areas (Plate IIB) banksian pine grows straight and tall with a diameter as great as 18 inches. This is useful for rough lumber or pulpwood wherever the cost of transportation is not prohibitive. There is also considerable canoe birch in the area from which logs 2 feet or more in diameter might be cut. The difficulties of transportation, however, render this valueless except where it occurs in close proximity to the railways. Tamarack was at one time abundant in the muskegs (Plate III A) of the district, but the trees were all killed by the larch sawfly about twenty-five years ago. Cedar, balm of gilead, poplar, and balsam — the remaining trees found abundantly in the region — do not grow to sufficient size to be of importance commerrially. FAUNA. fauna of Timiskaming county includes the usual species f "nd in thv -ocky wooded districts of eastern Canada. Of the larger varieties, moose (Alee americanus) are the most abundant and form one of the principal sources of food supply for the Indians of the region. Red deer ( Virgianus cariacus) though not so abundant as the moose, are common and would be much more abundant were it not for the large numbers killed by the wolves. These animals follow the deer in their migrations and are always abundant wherever the deer are found. Caribou are also present according to the Indians, although none was seen by the writer during the several field seasons spent in the county. The most valuable animals found in the region are the fur-bearing varieties. These include the fox (Vulpus vulgaris), otter (Ltitus cana- densis), beaver {Castor fibre), lynx {Lynx canadensis), fisher {Mustella americana), black bear {Ursus americana), mink {Pulorius vison), ermine {Pulorius erminea), and muskrat {Fiber zibelhictis). Large numbers of these animals are trapped each season by the Indians and, in consequence, some of the varieties whose fur is most valuable, are gradually disappearing. Other animals common in the region include the porcupine {Erethi- zon dorsatus), groundhog {Arctomys mnnax), chipmunk {Tamias striatiis), red squirrel {Sciurus hudsonius), flying squirrel {Sciuropterus volucella), and varying hare {Lepus americana). No attempt was made to study the birds of the region, but a few notes with regard to the principal varieties seen, may be of interest. 10 Among the most abundant are the gulls (Lartis argenlalus smithsoniat and Larus delau-arensis) . They nest in the numerous rocky reefs wh project from the lakes of the region and in some localities make tli home by hundreds on a single rock only a few feet in diameter. During the spring and autumn migrations large numbers of du( gather in the marshy bays of the larger lakes but at other periods of i year these birds are not abundant. The most common of the fam seen in the region during the breeding season is the black duck (Ai obscura). The old bird with her young is often met on the small lal and in other secluded spots along the waterways of the region. Wh approiiihtd by a Canoe, the old bird endeavours to attract the attenti of the intruders while the young hide in the grass and underbrush ale the shore. The young birds hidden in this way are often difficult find, but, once discovered, can be easily killed with a stick and are tl secured by the Indians during the months of July and August. The loon or great northern diver (Gavia immer) is another conim Inhabitant of the region, usually making its home in rocky clear wa lakes. There is generally at least one pair of these birds op each the small lakes of this type, and generally a pair on each separ; expansion or bay in the case of larger bodies of water. To the localities the loons return each summer with great regularity to brc< The two varieties of Canadian grouse or n ■ .jge (Bonasa tiviheh togata and Canachites canadensis) are gen' ..y common in the distr but vary greatly in relative abundance from season to season. Tl variation is probably related to climptic conditions and especially the amount of sleet which falls during the winter; for the birds ha the habit of burying themselves in the snow, ard, when a hea\'y fall sleet occurs, they are not always able to extricate themselves. Other common birds observed in the region are the followir saw-bill {Merganser awericaniis), pied-billed grebe (Podilymbus podicep bittern {Eotaurus lentiginosus), mud hen (Fulica americana), spott sandpiper (Actitis maciilaria) , owls (Syrnium varittm and Nydea nyctet woodpeckers (Diyobates pubescens mediamis, melanerpes erythrocephalt and Ccophloeus pikatus abietkola), flicker {Colaptes auratus luteti belted kingfisher (Ceryk akyon), sapsucker (Sphyrapicus variu. whip-poor-will (Antrostomus vociferns), night hawk {Chordeiks virgi iantis), and raven {Corvus corax principalis). The lakes and rivers of the region abound in fish, the species prese in different localities varying according to the ennronmental conditio which prevail. Thus in the clay belt nearly all the lakes and strear contain large amounts of suspended material during the greater part the year and for this reason afford an unsuitable environment for eith trout (Salvelinus namaycush) or bass {Micropkrus salmoides and 1 n tilhsonianus reefs which make their ;r. rs of ducks riods of the the fiimily luck {Anas small lakes on. When e attention jrush along difficult to id are thus t. pr common clear water OP each of h separate To these / to breed. sa 11 m bell us he district son. This pccially to birds have ■a\'y fall of 3. following- ' podkeps), [), spotted 'ea nyctea), roiephalus, us luieus), s variiis). ties virgin- ies present conditions id streams ter part of : for either ts and M. bolomieu). In the clear water lakes of the rocky portions of the country, on the other hand, these fish are generally common. The large deep-water lakes of the district contain whiteiish (Core- gonus clupeiformis), sturgeon {Acipenser rubicundus), freshwater herring (Gyosomus artedi), and the common eel (Anguilla rostrata). VVhitefish are especially abundant in lake Timiskaming and in the connected series of lakes forming Bell river. Sturgeon are most numerous in Grand lake Victoria. Brook trout (Salvelinas fonlinalis) although comparatively uncommon are found here and there in the clear, cold- water brooks occurring in the rocky headwaters areas. There are certain fish such as the pike (Esox lusius), maskinongt (Esox nobilios), and dort (Stizostedion vitreum), which seem to be capable of living through a great range of environment and these are found nearly everywhere in the region. Pike and maskinonge, however, are motl abundant and largest in the shallow grassy lakes of the clay belt. The other fish found in the region are of little or no value although many are very abundant. They include the sucker {Calostomus ter is). rock bass (Ambloplites rupestris), perch {Percea americana) , sunfish {L''*^omis pallidus), and several varieties of chub. EARLY EXPLORATIONS AND SURVEYS. That the principal geographical features of the Timiskaming region were known to the French at a very early date is shown by the maps of Canada or New France, published in France during the early y{'ars of the French regime. This information was largely obtained from the fur traders who, even at that early period, penetrated far into thesf northern wilds in quest of furs. It was no doubt for the protection of this traffic that forts were established by the French, about the close of the seventeenth century, on lake Timiskaming and lake Abitibi. It is probable that in going from lak^ Timi&kaming to lake Abitibi the early French voyageurs did not follow the present rouU' by way of lac des Quinze and lake Opasatika, but went by way of the east or Abitibi branch of Blanche river and Labyrinth lake, for on Del'Isle's map of Canada published in 1703 and on Bellin's map of Canada pub- lished in 1744, the route by way of Blanche river and Labyrinth (Labir- inthe) lake io indicated. The principal surveys used in the compilation of the published mafie of Timiskaming county are: surveys of lakes and rivers made by the members of the staff of the Geological Survey who have examined portions of the region from time to time; surveys of waterways, base, meridian, and township lines by the Crown Lands department of Quebec; the sur- National Transcontinental line. PREVIOUS WORK. „„,c, in Tlmfekaming county haw app..-rfJVot^>™ was an examination of he O"^^^ "^"^5,,;^^ [ ;„ 1845. This portion of the country on the Ottawa J""'^ ^j S^takc Timiskaming/' an account of >^hch appeared .^^po^^^ ^ Progress of the Geological Survey for 1872 73. Ihu po detailed description of ^he rocks occurring along t^^^^^^^^^^ j^. ,^e Timiskaming to lake Ab.tib. and abng the |ho^e^o ^^^^^^^ ,n 1887. Robert Bell -f^J'J^^f^ ^^^^ lakes Kipawa. from lake Tim.skammg to Gr^d lake V.c^ V ^^^^ ^^^^^ ,^^^ ^.^. Birch. Sassaganaga, Wolf, Grassy, anuL/ . ^ ^^^ of the Ottawa toria. Bell continued h!s ^-^'°'''''T'X)'S^^ "-^th- and thence down Gatineau river. ^^^''^ ^^J . ^^^^^^^^ to a point 10 ward across the height of land and des^ndcd Be^ r ve^^^^^ ^Po^^^^^ miles north of ^^abogama lake He hen ret^^ac^^^^ ^.^^^ ^^^ lake Victoria -^ ^^I^f p^^Va^in rTu-d fo Grand lake Victoria lac des Quinze. In 1895 Bell again ret Cochrane in 1887. and continued the explor^^^^^^^^^ ,own the Not- to Its outlet into lake ^a"ag reconnaissances were given LTKn'rSu'SU'trn *e Geo,o.ica, Survey f« .he yoa„ along .he prindpal «aterw»>Yn.h«""^r'=^ ,8„ ,„ BarloWs the Nipissing and Timiskaming map sheets^ ^^^ ^^ ^^^^ ^■:ro^t;\::^=tr.eUa-^ ."-■:. .he ».. . G«l. Surv.. Cu... Kept. oJ Prog.. 1M5-46. 1 3 13 kan and other tributaries of BcU river. The emails of these excursion* are given by Bell in the Summary Report of the Geological Survey for that year. r^ , ■ ^ In the year 1901, a paper was published m the American Geologist by W. G. Miller, on some newly discovered areas of nephclinc syenite in central Canada in which the occurrence of nepheline syenite on the Kipawa river was mentioned. In 1901, J. F. E. Johnston made a reconnaissance examination of the geology along some of the waterways of the region. These included La Sarre river. Makamik lake. Lois lake, Lois river, the canoe route from lake Duparquet to Dufrcsnoy lake, and Kinojevis river. Johnston's observations were published in the Summary Report of the Geological Survey for 1901. . . , . i. In 1904. W. A. Parks made a geological exammation of the rocks along some of the canoe routes in the country north of lake Timiskaming. including the southern part of the Timiskaming-Abitibi canoe route. Dasserat and Labyrinth lakes. His report was published in the Summary Report of the Geological Survey for that year. During the summers of 1906 and 1907. W. J. Wilson investigated the geology' along the waterways and railway survey lines adjacent to the National Transcontinental railway. The results of Wilson's work were published in the Summary Reports of the Geological Survey for 1906 and 1907, and again in greater detail in Memoir No. 4, "A geological reconnaissance along the line of the National Transcontinental railway in western Quebec." The reports of the Provincial Department of Mines for Quebec for the years 1906 and 1907, contain accounts of reconnaissance trips through this region made during the summers of those years by J. Obalhki. In 1909, in the course of the preparation of his report on the molyb- denum ores of Canada for the Mines Branch of the Department of Mines, T. L. Walker examined the occurrences of molybdenite in the vicinity of Kewagama lake. In 1911, an examination of the township of Fabre on the east side of lake Timiskaming was made by Robert Harvie for the Department of Colonization, Mines, and Fisheries, of the province of Quebec. An account of this work was pv'-'---hed by the Quebec Department of Mines, the following year. During the field seasons of 1911 and 1912, J. A. Bancroft was engaged in mapping the geology in the vicinity of Kewagama lake, the headwaters of Harricanaw river, and the Nottaway basin adjacent to lake Matta- gami. Bancroft's account of the geology of these areas was published in the reports on mining operations in the province of Quebec for 1911 and 1912. 14 BIBLIOGRAPHY. Ami, H. M., "On some Cambro-Silurian and Silurian fossils I on; lake Timiskaming, lake Nipissing and Mattawa outliers," Gcoi. Surv., Can., Ann. Rept., vol. X, pt. 1, 1897, pp. 283-287. Baker, M. B., "Lake Abitibi area," 18th Ann. Rept., Bur. of Mines. Ont., pt. 1, 1909, pp. 263-283. Bancroft, J. A., "Report on the geology and mineral resources of Keckeck and Kewagama Lakes region," Rept. of mining operations in the province of Quebec, 1911, pp. 160-207. "A report on the geology and natural resources of certain portions of the drainage basins oi the Harricanaw and Nottaway rivers, to the north of the National Transcontinental railway in northwestern Quebec," Rept. of mining operations in the province of Quebec. 1912, pp. 131-198. "Report on the geology and natural resources of an area embracing the headwaters of the Harricanaw river, northwestern Quebec," Rept. of mining operations in the province of Quebec, 1912, pp. 198-236. Barlow, A. E., Geol. Surv., Can., Ann. Rept., vol. VL pt. A, 1892, pp. 34-35; pt. AA, 1893, pp. 30-36; vol. VII, pt. A, 1894, pp. 56-57; vol. VIII, pt. A, 1895, pp. 61-63. "Rejxjrt on the geology and natural resources of the Nipissing and Timiskaming map-sheets," Geol. Surv., Can., Ann. Rept., pt. 1, 1897. "On the Quebec side of lake Timiskaming," Geol. Surv., Can., Sum. Rept., 1906, pp. 113-123. Bell, Robert, Geol. Surv., Can., Ann. Rept., vol. Ill, pt. lA, 1887-88, pp. 22-27; vol. VIII, pt. A, 1895, pp. 75-81; vol. IX, pt. A, 1896. pp. 66-67. "The basin of the Nottaway river," Geol. Surv., Can., Ann. Rept., vol. XIII, pt. K, 1900. Brock, R. W., Geol. Surv., Can., Ann. Rept., vol. IX, pt. A, 1896, p. 68. "The Larder Lake district," 16th Ann. Rept., Bur. of Mines, Ont., pt. I, 1907, pp. 202-218. Cochrane, A. S., Geol. Surv., Can., Ann. Rept., vol. Ill, pt. A, 1887-88, pp. 24-25. Harvie, R., "Geology of a portion of Fabre township, Pontiac county," Dept. of Colonization, Mines, and Fisheries, Que., 1911. Johnston, J. F. E., "Eastern part of the Abitibi region," Geol. Surv., Can.. Ann. Rept., vol. XIV, pt. A, 15»01, pp. 130-143. I 15 Logan, W. E., Geol. Surv.. Can., Ript. of Prog., 1845-46, pp. 5-98. Geology of Canada, 1863. McOuat, Walter, "Report on the examination of the country latween lake Timjskaming and Abitibi," Geol. Surv., Can., Kept, of Prog., 1872-73, pp. 113-135. Miller, W. G., "On some newly discovered areas of ncphelinc-syenite in central Canada," Am. Geol., vol. 27, 1901, pp. 21-2.S. "Lake Timiskaming to the height of land," Kept, cf Bur. of Mines, Ont., 1902, pp. 214-230. Obal;«ki, J., "Explorations on the north of the county of Pontiac," Kept, of mining operations in the province of QucIhc, 1006, pp. 2-27. "Explorations north of Pontiac," Rcpt. of mining operations in the province of Quebec, 1907, pp. 42-56. Parks, W. A., "The geology of a district from lake Tinii.-kamiiif; north- ward," Geol. Surv., Can., Sum. Rept., 1904, pp. 198-225. Walker, T. L., "Report on the molybdenum oros of Canada, Dept. of Mines, Can., Mines Branch, 1911, pp. 32-38. Wilson, W. J., "Western part of the Abitibi region," Ciol. Surv., Can., Ann. Rcpt., vol. XIV, pt. A, 1901, pp. 115-128. "Geological reconnaissance along the line of the National Trans- continental railway in northwestern Quebec," Geol. Surv., Can., Mem. 4, 1910. Wilson, M. E., "An area from lake Timiskaming eastward,' Geol. Surv., Can., Sum. Rept., 1907, pp. 59-63. "Geology of an area adjoining the east side of lake Timiskaming, 1908." Geol. Surv., Can., 1910. "Lake Opasatika and the height of land," Geol. Surv., Can., Sum. Rept., 1inj{ i>x|K)M'd by the stripping away of the ovt-rlying iicries. There arc also numcrouH other loraliticit throughout the plali-au — a* on the eaht nicle of Ilucl.ton bay', in central Labrador^, on Hamilton inlet,* on MattaKanii river,* and at a number of points in the reKion w<'»t of Hudtion biiy«— where flat-lying hedimentH wcur in which no fossils have Inrn found and which are prulhMy of Pre-Cambrian age. In these places, likewise, the ancient floor uix)n which the wdi- ments were deposited is Ining once more laid bare by the removal of the flat-lying, less ! distant covir. Although, as indicated in the previous paragraph, the present toixigra|)hy of the Laurentian plateau corresponds very closely in places to I're-Cambrian erosion surfaces, it is probable that those surfaces an merely rtmnants which have Ix-en preserved either (1) because the surface of the Pre-Cambrian (H-neplain at the points where the remnants are preserved had originally an elevation stjmewhat below the general elevation of the peneplain; or, (2) because downwarping or downfaulting has occurred in these localities since the late Pre-Cambrian sediments were deposited; or (3) because the late Pre-Cambrian sediments were originally of greater thickness or have been more resistant to erosion in the localities where they are now found. Pre-Palcto~otc Palceoplain. During the late Pre-Cambrian there was a cessation of orogenic movements throughout a large part of the Laurentian plateau — as shown by the numerous occurrences of approximately horizontal, late Pre- Cambrian rocks — which terminated finally in a prolonged perloti oi Ijse levelling preceding an early Palaeozoic marine submergence. While the geological record is too incomplete for positive conclusions with regard to the extent of this Pre Palaeozoic base level, yet the following data and inferences therefrom indicate that the whole plateau was probably reduced to a peneplain condition at that time. Palaeozoic sediments, which overlap the Pre-Cambrian along the margin of the plateau and in the interior basin of Hudson bay, rest on a surface which has all the characteristics of a well-developed pene- > B«li. R., "The Nuupoka and Manitounuck group*." Geol. Surv., Can., Rept. of Prof., pt. C 1877-78, pp. )t.|8. Low. A. P.. Geol. Surv., Can., Ann Rept , vol. XIII, pt. DD. 1900. pp. 16-31. Leith, C. K.. Econ. Geol., vol. S, 1910. pp. 227-246. • Low, A. P., Geol. Surv., Can., Ann. Rep., new ler.. vol. VIII, I89S, pp. 261-282. • Bell. J. M.. Ann. Rept., Ont. Bureau of Minet, vol. I), 1910. p. 140. Baker, M. B., Ann. Rept., Ont. Bureau of Minea, vol. 20, 1911, p. 225. •Tyrrell, J. B., Geol. Surv., Can.. Ann. Rept., vol. Vlil, pt. D, 189S, p. 17; pt. F, IS9«, p. 171. plain.' Furthermore, numeroun outlii-rs of Paljrozoic tK-dimrnts notinK en a Iww-levelird surface occur within the plateau up to j)«)int» 200 mileit front its Imrder. These outliers'. hf)wever, must obviously lie a long distance within the limit o( the I'ala-ozoic m.irine submcrKina-, ftr they consist largely of limestone, an easily eroeem evident that denudation since the I'ala-((Zoic suhnurgence h.is Incn largely engaged in stripping off the sedimentary cover and th.it il'e prt sent low relief of the Laurentian plateau in its marginal jKirtions at leaiil is pre-Pala-ozoic in its origin. One of the striking characteristics of the early PalaH)Zoic strata whi(h overlap the Laurentian plateau is the general paucity of clastic .sediments; for limestones* and even a)ral reefs* rest directly on the smoothly eroded surface of the Pre-Cambrian. If the surface over which the Palxozoic sea advanced had been deeply weathered, or had possessed a rugged topography, or if the rivers flowing into the sea from the interior of the plateau had possessed steep gradients, great thicknesses of clastic sediments would have b LawKn. A. C Bull. G«ol. Soc. Am.. 1890. p. IW. Aduiii. F. D., Jour, of G«>l., vol. t. I8«J. p. 2Jg. Bell, R., Bull. Gtol. .Soc. Am., vol. 5. 1894. pp. 3.^0-366. Van Hi». C. E.. Sdtnce, new ter., vol. ♦. 1896, pp. 57-59. Wl ion, A. W. G., Can. R«. Sc.. vol. 7, 1901. pp. U5-18«; Jour, of Geol., vol. 11, 1903. p. 65. Cu»hin«, H. P.. FalrchiW. H. L., Ruedemann. R.. Smyth. C. H.. N.Y. State Mu».. Bull. 145. 1910. pp. 54-60. • f irlch. E. O.. and Schuchert. C. Rept. N.Y. State Palaontoiogiit, 1907, p. 639. • l,a Klammt, J, O, K., Ceoi. Surv., Can., Ann, Rept.. pt. D. 188J-3-4, p, 15. Adam*, F, D. and Barlow, A. E., Geol. Surv., Can., Mem, 6, 1910, p. 342. Baker, M. B„ Ann, Rept.. Ont. Bureau of Minci, pt, I. 1911. p. 226. < Parka, W. A„ Ann. Rept., Cnt. Bureau o« Mioea. 1899. p. 188, 20 Froi.i .. study of the pre-Palseozoic floor in the central part ol southern Ontan \ ^^ G. Wilson concluded that following the pene- planation of ii > 1 n.-Cai 'jrian old land a period of dissection ensued.' Our knowlcG < i rlu . ationships of the Palaeozoic outliers occurring in the interior o. .ue plateau is not sufficiently complete, however, tc determine whether this dissection was common to the whole plateau or not. The outliers on lake Timiskaming and lake St. John lie somewhat below the level of the plateau surface in their vicinity, suggesting that these sediments may occupy pre-Palaeozoic valleys; but it is also possible that they have been lowered to their present elevation by faulting, oi were deposited originally in broad depressions in the prc-Pala»zoic peneplain surface. Post-Palaozoic Uplift. Since we know from the absence of folding, both in the Pala?ozoJc sediments which overlap the margin of the plateau and in the flat-lying outliers of rocks occurring in its interior, that no orogcnic movements have occurred anj-where in the Laurentian plateau since the early Palaeozoic, it follows that whatever regional or local relief the plateau has acquired since that time owes its origin primarily either to uplift ol the plateau, as a whole, or to faulting, or warping. The first of ihest diastrophic agencies has apparently played the most important part ir the post-Pala;ozoic history of the plateau. The Pala-ozoic strata occurring to the south of Hudson bay, on tht Arctic islands, and on the Mackenzie basin, have all widely extended outcrops indicating that they lie in a horizontal position and, therefore have not suffered differential uplift. Along the southern border of tht plateau, on the other hand, the overlapping Palaeozoic sediments dip away from the plateau showing that in this locality the uplift has been differ- ential. In some places along the southern margin of the plateau, also the pre-Palaeozoic floor descends so rapidly near the Palaeozoic contact that it has been suggested that faulting has occurred as well as differential uplift although the actual fault plane has not been discovered.'' It would thus seem probable that the uplift of the Laurentian plateau since tht early Palaeozoic submergence, while uniform in the northern and centra' jxjrtions, has been accompanied by marginal warping and possibly faulting on its southern border. There is little geological or physiographic data from which th« history of the plateau during the long interval which elapsed betweer the Palaeozoic emergence and the coming of the continental ice sheet car 'TraiM. Can. In«., vol. 7, 1901. p. 157. > Adama, F. D.. Geol. Surv., Can., Guide Book No. 31, 1913. p. 19. Kindle. E. M.. and Burling. L. D.. Geol. Surv., Can., Mus. Bull. No. 9, I91S. 21 lie (Jiductd. Sedimentary rocks overlappid its wtstern border duriiin the Cretaceous, but with this local exception it was app-irently a land area during the whole period. Probably it st(xxl so close to base level for such a large part of the time that denudation proceeded with exceeding slowness. It has l)een suggested by J. VV. Spencer that the plateau was elevated to a much higher point than at present immediately preceding the Glacial epoch, the evidence cited in s>:.iv,url- of this hypothesis being; (1) the existence of a river-like depr - :on on ihe U;'tnm of the gulf of St. Lawrence and (2) the occurrence of f.ord-Iiko inlris on the margin of the plateau such as those which C arfcterize tlie i utiets of Saguenay and Hamilton rivers.' It is proba ;'■ , ; - rK-inted out in the section on denudation by the continental ice-sheets, tha^ a large part of the detailed dissection so characteristic of the plateau at present wa.s accom- plished before the Glacial period and such an uplift might aca)iint for the wide extent and depth of this dissection. Continental Ice-sheets. The last imf)ortant modifications in the bedrock physiography of the Laurentian plateau were those eflfected through the agency of the continental glaciers. These modifications may be regarded as falling into two classes: (1) those produced by denudation and (2) those resulting from deposition. The importance of the first in the physiographic development of the plateau has been generally recognized, but the last has been equally important in its topographic effects. Denudation. That the continental glaciers were capable of consider- able denudation is evident from the general roches mouton^es contours of the plateau surface, from the gently sloping curve of the surface of rock exposures on the north as compared with their more abrupt termination on the south, and from the glacial striae and grooves which are commonly observed wherever a rock exposure has been protected from weathering agencies. Notwithstanding these evidences of the intensity of glacial denudation, however, there is other evidence indicating that the erosive action of the glacial ice sheets was largely of a superficial character and that the surface of the Pre-Cambrian bedrock which underlies the drift corresponds in its major features to the pre-Glacial topography of the plateau. In numerous localities throughout the Laurentian plateau there are deep, linear, gorge-like valleys, now partially filled with drift, which cut across all varieties of rocks regardless of their structure or age and trend in practically every direction of the compass. We know that these valleys have not been formed since the glacial epoch, because they are > Bull. G«ol. Soc. Am., vol. 1. 1890, p. M. 22 partially filled with glacial drift and because post-Glacial erosion throughout the plateau has been so insignificant that dissection has scarcely commenced even in the unconsolidatecl glacial and post-Glacial deposits. Furthermore, if the valleys had been excavated by the erosive action of the continental glaciers it might be assumed that wherever the rock was of a uniform character the valleys would trend parallel to the direction of movement of the glacial ice and that whatever divergence from parallelism occurred in localities where the rocks were not uniform would be closely related to rock structure. But the valleys are wholly unrelated to rock structure, are not parallel, and, in many cases, trend at right angles to the direction of movement of the glacial ice-sheets It follows, therefore, that the "trench" valleys of the Laurentian plateat are probably not of glacial origin and hence must be remnants of pre Glacial topography, presumably pre-Glacial river valleys. Much evidence has been cited in discussing the physiographi* history of the plateau, which indicates that its surface has not beei greatly denuded during the interval which has elapsed since the Palaeozoi< submergence, and that the present surface corresponds very closely to the pre-Palaeozoic peneplain.' This would also indicate that th« plateau has not been greatly eroded by the glacial ice-sheets. The cuesta ridges of Palaeozoic sediments which parallel the southeri margin of the plateau stand up in places with abrupt northward facinj scarpe. These pre-Glacial forms could scarcely have survived if th( glacial ice-sheets had been capable of general deep denudation. In the light of the preceding discussion, the topographic effect produced by the erosive action of the continental ice-sheets must b regarded as largely modifications of previously existing forms rathe than the production of an entirely new topography. A summarize! statement of these modifications follows: (1). Removal of the pre-Glacial soil cover of the plateau. (2). Production of "hogback" surfaces on the stoss side of the rock exposures. (3). Formation of grooves and glacial striae. (4). Excavation of undrained rock-rimmed basins. (S). oievelopment of scarps by glacial plucking. (6). Overdeepening of pre-Glacial valleys. (7). Modification of pre-Glacial valleys to U-shaped valleys. (8). Rejuvenation and partial disorganization of the pre-Glacial dramage ot th plateau. Deposition. With the final retreat of the continental glaciers fror the Laurentian plateau, glacial debris was left scattered irregularl over the plateau surface in the form of moraines, outwash plains, kames Bdl. R., Ana. }our. Sc. vx>l. 1, 1896. pp. 219-22*. Low, A. P., Bull. Gcol. Soc. Am., vol. 4. 1893. pp. 419-42J. 24 TIMISKAMING REGION. Timiskaming region lies wholly within the Laurentian piatea and pof-sesscs in part the usual rocky-lake topography which characteriz* that physiographic province; but, it departs, locally, from the chai acteristic physiography of the plateau in its flat, plain-like areas of pes Glacial lacustrine clay, forming what is generally known as the "da belt," and in its nu .lerous, linear, gorge-like valleys, incising its bedroc surface. The physiogr,->phy of Timiskaming region may thus be d( scribed in three sections: (1), rocky uplands; (2), clay belt, and (3 linear valleys. ROCKY UPLANDS. Distribution. The rocky upland country occupies the southern and southeaster parts of the Quebec portion of Timiskaming region, wheresis the clay bel covers the larger part of the northern and northwestern part of th district. Within the clay belt, however, there are numerous ar-^a which rise above the nighest point at which the lacustrine clay was a posited, and which exhibit all the typical physiographic features of th upland topography. The largest elevations of this type are the Abijevi hills, the Tenendo hills, the Smoky hills, and the group of hills (Kekek ridge. Swinging hills, etc.), which forms the St. Lawrence-Hudson Ba; divide in the region north of lake Opasatika. Since the last-mentione hills lie across the interprovincial boundary and are all part of a con tinuous area of Hurfian rock, they may be appropriately designatei collectively the Boundo , hills. i Relief. The rocky uplands, as their name implies, include most of th higher parts of the region. The dividing line between the rocky upland and the clay belt is not solely a matter of elevation, however, for portion of the district possessing typical upland topography have a much lowe elevation with respect to sea-level than parts of the clay belt. The large are:? of upland country which occupies the southern an( southeastern part of the district is the most typical example of plateai topography in the whole region. It is underlain throughout nearly it whole extent by the banded gneisses which occupy such a large part o the Laurentian plateau and exhibits the low regional relief, minuteh rugged topography, and other physiographic features cnaracteristii of the plateau, to a remarkable degree. The surface of the area has ; gentle regional slope towards the southwest, rising from a general eleva tion of 900 feet above sea-level in the vicinity of lake Timiskaming t( wmmm 25 1,150 feet at Grand lake Victoria. Unlike the upland areas in the north- ern part of the region there are no prominent hills serving as conspicuous landmarks in this belt, the highest elevations nowhere attaining altitudes greater than 300 feet above the surrounding country. The elevations of some of the principal lakes in the southern upland belt are included in the following list: Lake Elevations. Feet above sea-level. Obashing 822' Kipawa 873' Morin 892' Lavallee 974' Ostalxjining 928' Satisaganaga 1 ,02"' Ogaskanan 1 ,040' Wolf 1.025' Grassy 1,027 Trout 1 , 1 70' Old Man 1 , 146' Kawasachuan 1,116' Grand lake Victoria 1 , 103' Wapusanan 1 ,080' The upland areas forming the Abijevis, Tenendo, and Smoky hills arc alike in that they all consist of the ancient volcanics of the basal complex and are on this account of special interest since they indicate the amount of relief possessed by the ancient erosion surface upon which the Huronian Cobalt series was deposited. They arc all .situated in the northwestern part of the region, the Tenendo hills in Montbray township southwest of Tenendo lake, the Smoky hills east of the Smoky river m Uuprat township, and the Abijevis hills in the northern part of Destor, Aiguebelle, and Manneville townships. The Abijevis hills form an especially definite upland area, extending as a continuous range with a width of 5 to 6 miles for a distance of 20 miles and having an elevation of 1,630 feet above the sea and 700 to 800 feet above the surrounding country. The Boundary hills include a group of prominent elevations con- tinuous with a similar upland area occurring in the vicinity of Windego and Larder lakes, across the interprovincial boundary, in Ontario; the whole of this belt being a remnant of the Cobalt series which denudation has failed to remove from the surface of the basal complex upon which it rests. All the Boundary hills arc, therefore, composed of similar rocks and have had a similar origin and for this reason have been grouped together, although they embrace a number of separate knobs and ridges. In Ontario, the upland area is divided at th^ west end of Raven lake into two north it-southwest trending ranges, one of v ch parallels the east side of the Windego series of lakes and the other the west ' Aneroid determination. t Can a d i tn Pacific Railway survey. 26 shore of Raven lake. The latter range is terminated abruptly near the interprovincial boundary by a deep depression which cuts it off from a prominent haystack-like knob known as mount Shiminis. From this pomt the upland belt splits into three extensions, one of which trends northward to Labyrinth lake, forming what might be termed the Laby rinth hills, and the second continues northeastward terminating at th< south end of Dasserat lake in the Swinging hills (so-called ftom the Indiar name which translated literally means "the place where the spirit s-wings") the third prolongation is much longer than the two northerly extension and lies eastward, forming the prominent east-west trending ridge to thi northwest of Kekeko lake known as the Kekcko hills. The elevations^ of some of the most prominent points in the boundar; upland area are as follows: Upland Elevations. „ , , , Feet above sea-level. Mount Shiminis } '/inni Swinging hills \'^, Kekeko hiUs Vo' ' • . , ow Height of land between Ogima and Summit lakes ^^'^ Mount Shiminis. the highest knob of the group, with the possibl exception of Maple mountain in the Montreal River district of Ontario has the greatest elevation yet recorded for any point in the whole Timii learning region. The small diameter of the hill compared with its height and i peculiar haystack like form makes it, as its Indian name Shimini "big island" implies, a veritable island in the landscape. It is visib for many miles in every din-ction and is one of the best known landmarl in the whole upper Ottawa basin. The foregoing account of the upland relief of northwestern Queb indicates that there is a close relationship between the topography these areas and the lithological character of the underlying rocks. Thu the general high relief of the boundary upland area is directly related the resistant character of the firmly cemented conglomerate, arkose, eti of which the hills of this district are composed. Likewise, the southe upland belt which is underlain almost entirely by hard granitic gneiss has, on the whole, a considerably higher relief than the northern part of t region where the metamorphosed volcanics of the basal complex predon nate. On the other hand, however, owing to the greater uniformi of the gneissic rocks, the local relief is much less in the southern uplan than in the northern districts underlain by the more variable volcanics. • Aneroid determination. •OttawaRiverRegulationSurvey, Public Worlu Department. Canada. _.. . o i • Maple n:ounlain ha» an Ptevat.on of a life over 2.000 feet above .ea-level according to R. 1 Gcol. Surv.. Can., Ann. Kept., vol. X. pt. 1. 1897. P. 22. 9^m 27 Drainage. The rocky uplands, being generally higher than other portions of tiu- district, are the headwater areas in which the streams of the region originate and form the divides or heights of land between drainage basins. In this way it happens that three of the northern upland areas— the Boundary, the Smoky and the Abijevis hills— are situated on the divide between the St. Lawrence and Hudson Bay basins, dividing their drainage between the Abitibi on the north and the Ottawa on the south. The southern upland belt also forms a height of land between two basins which are wholly sep».iate except for the deep Timiskaming gorge which has been incised across the uplar.d belt, thus connecting the upper and lower Ottawa basins into one system. If this connexion were absent, the waters of the upper Ottawa basin would not find an outlet into the St. Lawrence, as at present, but would flow northward across the present height of land, to Hudson bay. River of the normal type can scarcely be said to exist anywhere in the upland districts of Timiskaming region, the drainage being effected, for the most part, through innumerable lakes connected by rapids and waterfalls. A few of these so-called rivers occupy marked depressions in the rocky surface of the plateau in parts of their courses, but the majority' are of the most fortuitous type occupying such indefinite channels, that, in many parts of their courses an obstruction a few feet in height would deflect the river in an entirely ciifTerent direction. The northern upland areas are limited in extent and on this account are drained entirely by small headwater brooks; whereas the southern upland belt, being much more extensive and continuous with a still larger area of similar upland territory to the eastward, is traversed by streams of considerable size. On its northern slope, it includes the upper Ottawa from Wapusanan lake and Giand lake Victoria eastward, also, the connected groups of lakes forming the upper portions of the basins of the Winiwiash and Spruce rivers— tributaries of the Ottawa which traverse the clay belt in the lower parts ol their courses. On its western slope the principal river is the Kipawa (Plate IV) which inclu'Ies Kipawa, Ostaboining, and other large lakes in the southwest part of the region. On the south slope, there is Maganasibi, Dumoine, Black, and Coulonge rivers — all important streams flowing southward into the lower Ottawa from the interior uplands. Of the topographic features which distinguish the Laurentian plateau from other physiographic provinces, probably the most characteristic is the remarkable number of 'akes of all shapes and sizes which, every- where, cover its surface. These are especially abundant, in those districts which like the southern upland belt of the Timiskaming region, are imderlain by granitic gneisses. A typical area in this granitic belt 28 is thown in Figure 2. In this area, 535 square miles in extent, there ai over one hundred and thirty-five lakes and approximately 27 per cent ( the surface is covered by water. . ScaJeorMilea Geolotia/ Surnf, Canada Figure t. Area in the vicinity of lake Kipawa showing the multitude of lakes; abot 17 per cent of the surface area is water. The lakes of the upland district of Timiskaming region are of thre principal types. The most common variety of lake has a form which i not controlled primarily by the underlying bedrock surface, but by th gladal drift deposit«:xi on the bedrock surface. Lakes of this class ar remarkable both for the detailed irregularity of their shore-line and th enormous number of scattered islands which they contain. The secon< wm mm 29 ^1 type of lakf occupies structural basins, that is, basins whose form is tontrolltcl primarily by the structure — foliation, licdding, etc. — of the underlying rock. The third type of lake includes those bodies of water whos-c form is controlled primarily by long, narrow, gorge-like depressions whi h have been incised in the bedrock surface regardless of its structure. These lakes, as a rule, are hemmed in by glacial drift at their ends, although, in the case of some lakes at least, we know that a rock-rimmed basin would remain even though glacial drift were absent. In some localities a lake of the linear type has been filled so full of water that it has overflowed into a larger basin thus expanding a linear basin into a i)asin of the irregular type. Lake Kipiwa and Grand lake Victoria .ippear to be basins of this sort. Lake Sassaganaga is a typical lake of the irregular, fortuitous type; Lavallee lake is an example of the second variety; and Dumoinc lake belongs to the third. One of the common characteristics of the rocky upland lanes «)f Timi.skaming region, both large and small, is the presence of two or more outlets to the same basin. Thus, Dumoine lake has its principal outlet into the Ottawa down Dumoine river but it also drains northward iito Grassy lake and thence to lake Timiskaming by way of Kipawa tiver. Likewise, the body of water known as Old Man and Old Woman lakes drains into the upper Ottawa partly eastward through Five Pon.ige lake and partly northward by Spruce lake, and Grand lake Victoiia Ka» several channels leading to Wapusanan 1 ke, l*ut these unite near the latter lake and for this reason must be regarded as simple portions of a single river, rather than separate outlets. The approximate areas of some of the principal upland lakes of the Timiskaming region are as follows : 4 3 A reas of Lakes in the Upland. Kipawa Grand lake Victoria Dumoine Ostaboining Sassaga naga Ogasl^nan Wapusanan Obashing Trout Stiuare miles. 120 40 38 20 20 14 13 11 10 CLAY BELT. The clay belt of northern Ontario and Quebec includes a wide area of country approximately 68,000 square miles in extent, throughout which post-Glacial lacustrine clays have been deposited, thereby forming a depositional or constructional plain. The thickness of clay deposited was only sufficient, however, to fill the minor inequalities of 30 the underlying Hurfuco and ainsequcntly the surface of the plain interrupted not only by extensive areas of rocky upland o)untry I also by small protruding nulcroptt of bedrock and by areati of giac drift. With the exception of a small area of country to the north of la Timiskaming, the clay belt lies wholly to the north of the St. Larwenc Hudson Bay divide in Ontario, but in Quelx'c it extends southwa across the divide and covets nearly the whole of the northern part of t Timiskaming basin, an area of 3,000 square miles. Relief. Although the surface of the lacustrine clay of the clay belt is generally uniform that it appears flat to the eye, yet, in reality, it ct forms to the slope of the underlying surface upon which the clay » deposited. At the north end of lake Timiskaming depression, it has elevation of only 600 feet above sea-level, but IS miles eastward, on I dcs Quinze, the elevation is approximately 900 feet. From lac c Quinzc, it rises gently northeastward with an average gradient cf o foot per mile, attaining an elevation of over 1,000 feet above sea-le^ on the height of land. Beyond the height of land as in the south slopes gently away from the divide northward towards Hudson bay. The following table of elevations of Toints within the clay belt h been compiled h ;.; the elevations on the National Transcontinent Canadian Patiti i-.nd Timiskaming and Northern Ontario railw-. from the levels on the upper Ottawa determined by the Ottawa Ri\ Storage branch of the Public Works Department, and from aicrt measurements by the writer. Clay Belt Elevations. Feet above sea-level. Lake Timiskaming, low water 578' Lake Timiskaming, high water 592' Haileybury, Ont., T. and N.O. railway depot 766* New Liskeard, Ont., T. and N.O. railway depot 642* Englehardt, Ont., T and N.O. railway depot 677* Lac des Qumze 852* Lake Expanse 854' Barri^re lake 867" Lake Opasatika 869* Height of land between Ogima and Summit lakes 936 Kinojev j river at its outlet 876* Caron lake (Crooked lake) 876* Lake Kinojevis 876* Roger lake 902« Kekeko lake 877 Lake Dufault (Lake of Islands) 951 Lake Dufresnoy (Kajakanikamak) 907 Height of land between Mackay and Bellefcuille lakes 950 Lake Kewagama 958* Height of land east of Robertson lake 1 ,074« Lake Dasserat (Mattawagosik) 913 >,',•,•. See footnote. [«fe 31. ...^>.i>j,4!i1Mh 31 Lake Uuparquet (AgotawcVami) Lake Abitibi, high water level Makamik lake. Loii lake I.a Mott* (Seal* Home) lake De Montigny (Kienawinik) lake Chriitophernon lake Lake Obatka Lake Shabogama Bell river, at Kanikawinika island La Sarre (Whitefi»h) rivtr, at N.T.R. eroding Loii river, at N.T.R. croMinn . Harricanaw river, at N.T.R. trosaing Peter Brown creek, at N.T.R. rioB^inn Natagagan river, at N.T.R. croiKting Su.Timit on N.T.R., west of toffee river Bell river, at N.T.R. crossint; _ Migiikan river, at wf»t cruiibing of N.l .R Feet above tea-level . Miy 9lS «»0 %ft» 968 1 ,(»<> I ,(U3 994 852 870« 915* 971« 1,(X).1« l,00()« 1 .0«4« 994« 1,07P Drainage. The drainage of the clay belt differs from that of the rocky upland country in the smaller numlxr of lakes which occupy its surface and in the rivers wliich have incised their channels in the easily transported post-Glacial stratifiid clay. If the deposition of lacustrine clay had continued for a sufficiently long period, all the irregularities of the under- lying surface would eventually have been buried, leaving a flat surface with no undrained depressions. The thickness of clay deposited was only sufficient, however, to carry this change to partial completion, so that the deeper lake basins survived. The drainage systems of the clay belt, like those of the rocky upland belts, are thus composed of both lakes and rivers; but, unlike the upland districts, the rivers are the most important and are of the normal type, having definite and graded channels wherever they ♦•■:>verse the lacustrine clay. .kes of the clay belt include all the types of basins which occur in the upland districts and, in addition, a fourth type which occupies wide shallow depressions, and which might be called the clay belt type. Lake Dufault is a typical example of the irregular, accidental class of lake, having a most irregular outline and containing an enormous number of islands; of the linear lakes occupying well defined rocky basins there are also numerous representatives, as for example lakes Opasatika, Caron, and Roger; the structural type of basin is represented by lake Dufresnoy which conforms in its trend to the strike of the folded volcanic flows in which its basin occurs. The most striking lake basin of the clay belt type is lake Abitibi having a total ■ Canadian Pacific Railway lurwy. • TimiBkaminK and Northern Ontario Railway lurvey. • National TranKontinental Raiiway lurvey. • Upper OtUws Regulation turvey. 32 ana nf m wiuare milen and a the Kinojevis which drains a very marked northerly extension of the Ottawa basin, approxini.ili ly 2,50<» s(|uare miles in area, around which the height of lanil U-nds sharply to the north for approximately 50 miles. The territory in Tiniiskaming county lielonging to the .Abitibi system on upies the northwestern part of the region extending from the Kinojout 6 miles north of the National Transcontinental railway by the Migiskan, a large river having its headwaters in the northeastern continuation of the southern upland belt, which at this point lies east of Bell river. On the west, there is also a large tributary river, the Natagagan, which, from 3* NatiiKagan lake about 3 miles south of the National Transcontine railway, in Piedmont township, flows northward for 70 miles to outlet into the Bell, at Kanikawinika island. There are also a nun of other tributary drainage channels, including CofTee river— «o-nai because of the dark brown colour of its water— Shabogama ri Kiask river, and Garden Island river, all streams of considerable but small as compared with the Migiskan and Natagagan. LINEAR VALLEYS. Among the physiographic features which characterize the Laurem plateau, in the Timiskaming region, probably the most interesting ; unique are the numerous deep, linear, trench-like valleys which maim their direction with remarkable uniformity across all its Pre-Cambi bedrocks, without regard to their variety, structure, or age. Prior the Glacial epoch, these rocky depressions were even more conspicu topographic features than at present; for, many of the valleys were, doubt, greatly modified by glacial erosion and those which survived erosive action of the continental glaciers are now partly filled m glacial drift deposited as the ice-sheets withdrew. Their existei in the region at present is indicated chiefly by numerous series of lo narrow lakes, linearly continuous with one another. Of all the linear trench-valleys of the region the depression occup by lake Timiskaming and Ottawa river between lake Timiskaming i the village of Mattawa is undoubtedly the most striking, having a leni of 100 miles and a depth in places within 100 feet of sea-level. 1 character of this depression is aptly described by the late A. E. Bar) as follows :' "The greater portion of this valley is a very steep, rocky gor fringed on either side by lofty hills or perpendicular cliffs, which i abruptly to a height of from 400 to 600 feet above the surface of the wat while the average of a large number of soundings indicates that the 1< has a depth of over 400 feet. The depression, therefore, occupied these waters would be about 1,000 feet below the level of the surround! country, and as the bottom of the lake wherever examined, consisted the deeper portions of a very fine, grey unctuous clay or silt, this dei may have been much greater before the accumulation of this materl From Mattawa to the mouth of the Montreal river, these abrupt a rocky shore-lines prevail, but about the mouth of this stream the la undergoes considerable expansion and the shores exhibit a more gradi slope towards the surface of the water. The traveller ascending t Ottawa river is thus usually impressed with the mountainous characi ■ Geo). Surv., Can., Ann. Rept., vol. X. 1897, pt. I, p. 2J. IS iscontinental miles to its so a number r — so-named igama river, iderable size ; Laurentian ^resting and ch maintain e-Cambrian e. Prior to conspicuous :ys were, no iurvived the filled with ir existence ries of long, on occupied teaming and ing a length level. The . E. Barlow 3cky gorge, which rise f the water, lat the lake iccupied by lurrounding consisted in , this depth is material, abrupt and m the lake ore gradual ending the s character of the district, but an ascent of the hills on either side at once shows that i the adjoining country is comparatively level, and that what appeared l-'ipire 3. Linear valleys unrelated to rock structure, limiskaming county. 36 as ranges of hills are in reality the enclosing walls of this great va (Figure 3). There are a number of other linear valleys in the Quebec po of the Timiskaming region which, although not so deep or long aj Timiskaming gorge, are nevertheless notable depressions. Abou miles east of lake Timiskaming, a parallel northwest-southeast tren trench extends from CampbtMl bay on lake Kipawa to Otter lak Laverlochere township; this is directly in line with another depre; farther to the northwest occupied by Long lake and the north Figure 4. Directions of linear valleys. trending portion of Riviere desQuinze; and it is probable that these val are parts of the same gorge. So much glacial drift has been deposi in the trench that it is not possible to determine its depth. In district between Otter and St. Amand lakes, however, it is hemmed ir the cast by a cliflF between 200 and 300 feet high overwhich the creek fi Silver lake descends precipitously to the valley beneath, forming a \ picturesque waterfall. In the northern and central parts of Timiskaming county ther a series of linear depressions extending in a north-south direction fi Robertson lake in Privat township to Vaudray (Long) lake in Vaud township — a distance of 50 miles— which are probably parts of a sii 37 great valley" leboc portion r long as thi i. About 12 east trending )tter lake, in L'r depresssioii le northwest these valley.' ;n de{x>site(l ith. In th( immed in on e creek from ming a vcr\ nty there i> ection from in Vaudraj' > of a single valley. This traverses all the important rock members of the basal complex and trends almost at right angles to their structure. Where it crosses the Abijevis hills, it forms a remarkable, narrow, rift-like gorge walled in on either side by vertical scarps which rise to elevations of 200 feet above the surface of Eileen and Abijevis lakes. Lake Opasatika, Caron lake, the Kekeko-Albee-Barrit^re chain of lake;, Kinojevis lake and part of Kinojevis river, Grand lake Victoria, Kipawa river between Wolf and Brcnnan lakes, and the northwest bay of lake Kipawa also lie in important linear depressions which are entirely unrc lated to the structure of the rocks in which they occur. The trenches (Kcurring in the area included in the map which accompanies this report are shown in Figure 3. It will be observed that the valleys trend in various directions and intersect one another in places thus forming basins for lak " ' ^•- '« radiating at various angles. In ordf ) ;• .1 whether there is a tendency to parallelism in the trend ol n.i ar valleys, the directions of the lines shown in Figure 3, as tabulated in the following list, were plotted through a single point as shown in Figure 4. Bearingt of Linear Valleys. Lake Namegosis N. 38 E. Grand lake Victoria N. 34 E. Ottawa river at lake Nimewaja N. 24 E. Dumoine and Antiquois lakes N. 12 E. Dumoine lake. Northwest bay N. 14 W. Kipawa river between Wolf and Brennan lakes . . N. 25 E. Lakes Robertson, Mackenzie, Abijevis, Wabaskiis, and Vaudray N. 2 E. Caron lake. Lake Kinojevis Barri^re-Obikoba lake . Barri^re and Kekeko lakes Lake Opasatika, south end. Lake Opasatika, north end. Roger lake . .N. 30E. .N. SOW. . .N. 35E. . N. 3 W. N. 17 E. .N. 3E. .N. 20E. Ottawa river, east of Roger lakt- N. 20 E. Morin lake N. 16 W. Lake Kipawa, Hay bay N. 14 W. Lake Kipawa, Taggarts bay .N. 57W". St. Amand, Gait, and Otter lakes N. 10 W. Lake Timiskaming, north end N. 33 W. Montreal river . N, 37 W. It can be seen from Figure 4 that these lines appear to occur in three systems and all fall in the north and south ouadrants. Origin. ^ Faulting. The origin of the linear valleys of Timiskaming region by erosion along fault planes was discussed at some length in a previous report' and on that account merely a summarized statement of the data on which the hypothesis is based is included here. ' Gfoi. Surv., Can., Mem. W. pp. lo-lv. 38 In favour of the faulting hypothesis the following evidence may cited : The remarkable linearity of the trench valleys and the manner in which they across all varieties of rocks regardless of their character (hardness, etc.). or struc< (foliation, bedding, etc.), are features, which while generally characteristic of fault pla: are not normal characteristics of river valleys. In the case of the Cobalt Lake depression, an actual fault plane has been foi to correspond with the longer axis of the basin. The evidences of deformation in the flat-lying Palaeozoic outlier at the north L '"''* /^^'fiskaminK. at a point in Dymond township directly in line with the » ■hore of the lake, suggest that the linear scarp which forms the west boundary of Timiskaming gorge has been developed along a fault plane. Numerous faults of small di.splacement have been found in the mine workings Cobalt mdicating that the region in that locality has been subject to faulting or. extensive scale. The manner in which some of the linear valleys lie on the contact of older ; younger formations lend' strong support to the hypothesis that the valleys in these Ci occur on a fault along which the formation on one side of the valley has been vertic displaced with respect to that on the other. In opposition to the faulting hypothesis there is the follow evidence : Up to the present time, the actual fault plane has been found along only one ol the Imear valleys of the Timiskaming region, namely Cobalt lake.' From an examination of maps of areas in the Timiskaming region on which geological formations arc shown in detail, it seems evident that, as regards the lai part of the linear valleys, there is no apparent difference in the rocks expoted on oppo sides of the valleys, an effect that would be very noticeable, in most localities, if rocks on one side bad suffered considerable vertical displacement with respect to ri'ier. If the linear valleys of the Timiskaming region have been developed by eros ailing planes of faulting, it would seem probable that the Timiskaming gorge, at lei the longest and deepest of all the linear valleys, would occur along a fault of gt displacement; yet the pre-Cobalt Series palseoplain occurs at approximately the ss elevation, throughout a considerable area, on both sides of the lake, showing that side of the lake has suffered little or no vertical displacement with respect to the otl Other Possibilities. If it be assumed for the purpose investigation that the linear valleys have not developed as a res of faulting, is there any othqr known way in which such a striki series of linear depressions could be formed ? It is pointed out the section of the report which follows that they ere not of glac origin and, as far as known to the writer, such a system of drains could only develop normally by the superposition of drainage vallc from an overlying series of rocks which have since been erod away, presumably, in this case, from Palaeozoic sediments, since, as 1 as known, these are the only overlying rocks which ever occurred in t region.' But even if the linear valleys originated on a younger Palaeozi cover we have still to explain how such a system of drainage compos of linear valleys trending in three principal directions could be initial in flat-lying sedimentary strata except by faulting or deformation. ■ f liller, W. C. and Knight, C. W., Eng. and Min. Jour., vol. 92. pp. 648, 1911. WiUiami, M. V.. Geol. Surv.. Can.. Mm Bull. No. 17. • Pirsaoo. L. v.. Am. Jour. Sc, rot. 30, 19!0, p. 30. «■ 39 nee may be rhich they cut I, or structure >f fault plane§, IS been found the north end with the west undary of the e workings at aulting on an of older and in these case» leen vertically e following >nly one of all on which the rds the larger ;d on opposite :alities, if the refpect to the ed by erosion arge, at least, Fault of great tely the same wing that one ; to the other. Jurpose of as a result a striking ted out in : of glacial •f drainage age valleys ?en eroded ince, as far rred in the r Palaeozoic ! comp)osed 3e initiated ion. I Conclusions. Having considered the various ways in which the linear valleys which characterize Timiskaming region might have beer '^rmed, can a definite conclusion be inferred from the evidence cited as to the mode of origin of these striking physiographic forms ? On the whole the evidence probably favours the hypothesis that the trend of the valleys has been determined by planes of faulting or deformation. The large number of the valleys and the manner in which they interset t one another, are features which are remarkably similar to those characteristic of fault planes in a region which has been subjected to faulting of a block type. Many of the dislocations in a region which had been shattered in this way, would, no doubt have very small displacements and thus the uniformity in the character of the rocks outcropping on either side of many of the linear valleys might be explained. That so few fault planes have been found may be partly accounted for by the fact that the depressions are generally filled with water or glacial drift so that the actual planes of dislocation are not generally exposed.' Age. It is not possible to fix the time at which the linear valleys of Timis- kaming region originated except within wide limits. They cannot pos- sibly be of post-Glacial origin because stream dissection since the Glacial epoch has been almost insignificant and the valleys are themselves occupied by glacial drift deposited b' -le-sneets. It is also very improbable that they are the result of gi. .c nudation, for they have no relationship to the character of the roc; .»ey traverse, and they trend, in some cases, at right angles to the direction of ice movement. Since the valleys are neither Glacial nor post-Glacial in their origin, it follows, a priori, that they are pre-glacial valleys. It is known that the linear valleys cut across the sills of Nipis- sing diabase which were probably intruded during the Kcwcenawan period so that the valleys are at least of post-Kev. enawan age. Further- more, if the linear valleys have been developed along fault planes — and the balance of evidence is probably in favour of this conclusion — the occurrence of a zone of deformation in the Palaeozoic rocks on a line continuous with the west boundary of the Timiskaming depression, would indicate almost conclusively that this trench and probably the other linear valleys of the region likewise, are of post-Silurian age. It would thus seem probable that the linear valleys were formed some time during the long interval which elapsed between the Palaeozoic submergence and the coming of the continental glaciers. If a Cretaceous peneplain covered the Laurentit. i plateau, however, they would neces- ' Hobtx, W. H.. Trans. Wa.. Acad. Sc.. vol. 15. ITOJ, p. 19. tinmm. L. V., Am. Jomr. Sc, vol. 30, 1910. p. 25. 40 sarily have to be post-Cretaceous in age. The fact that the val have survived to the present probably favours the assumption that t were formed during the period immediately preceding the Plcistoc possibly, as suggested by Spencer, during a pre-Glacial uplift of plateau. Overdeepening oj the Timiskaming Trevch. It was concluded in the previous discussion of the age of the lii valleys that they were pre-Glacial in their origin. From this, it w( follow presumably that they had been carved out, in the main, by normal process of stream erosion. Valleys formed in this way, howe have graded bottoms, whereas the Timiskaming trench is apparei cut off by a rock barrier in the lower part of its course. The Timiskaming trench proper extends from the north end lake Timiskaming to the village of Mattawa, Ontario, a distance of c 100 miles, and is occupied by lake Timiskaming in only its upper p Between the lower end of lake Timiskaming and Mattawa there is interval about 35 miles in length, in which numerous rapids occur, (irsi of which, known as the Long Sault, is 6 miles in length, and conni lake Timiskaming with a long stretch of almost currentless water, ab 16 miles long, called Seven League lake. Between Seven League 1 and Mattawa there are three abrupt descents in the water course knc as Mountain, Les Erable, and Cave rapids respectively. Of the lakes occupying the depression, Timiskaming has a surface elevatior approximately 580 feet above sea-level, and a maximum depth of feet,* while Seven League lake has a surface elevation of approximal 530 feet and a maxin.um depth of 397 feet' — that is the bottom of I Timiskaming has an elevation of 110 and the bottom of Seven Lea lake an elevation of 137 feet above sea-level. These elevations probably considerably higher than the actual elevation of the r bottom of the trench, however, for it has been partly filled Ixjth by p< Glacial lacustrine clay and by glacial drift. The obstruction wh separates lake Timiskaming from Seven League lake and over which Long Sault rapids* descend is composed of glacial drift so that the trei in reality maintains its great depth continuously from lake Timiskam to Seven League lake. The barrier below Seven League lake, on other hand, apparently consistsof solid rock, the river descending "throi a narrow channel, obstructed by rocky reefs and islets."^ Since elevation of the bedrock surface at Mountain rapids is about 425 f ' Barlow, A. E.. Geol. Surv.. Can.. Ann. Rept., vol. X, pt. 1. 1897, p. 165. « Guerin, Thot.. Ann. Rept.. Minister of Public Worlu, Cannda, 1884-85, pp. 106-10;. = Rep of Ptuu., Ottawa Ri\Tr Storage. Dcpt. of Pub. Works, 1909-10, p. 85, < Barlow, A. E., Geol. Surv., Can.. Ann. Rept,, vol. X, pt. 1, 1897, p, 170. 41 the valley.- 3n that they Pleistocene, iplift of the Df the linear lis, it would nain, by the ly, however, apparently orth end of ancc of over upper part, there is an s occur, the nd connects trater, about League lake )urse known Of the two elevation of epth of 47(1 proximately torn of lake ven Leagu« vations are )f the rock )th by post- :tion which T which the t the trench 'imiskaminy ake, on the ng "through Since the ut 425 feel •lUive sea-level, there is a roik-rinimed basin having a minimum depth of not less than 315 feet in the lK)ttuni of the Timiskaming trench. In a paper entitled "Crustal warping in the Timagimi-Timiskaming district, Ontario," published in the American Journal of Science in 1910, Dr. L. V. Pirsson pointed out that a rock-rimmed basin was present at the Ixittom of the Timiskaming trench and suggested tha* the upper portion of the trench had been over-deejiened by downwarping, the alternative possibility — glacial overdeepening — being dismis.sed as unten- able, because the trend of the Timiskaming valley (as pointed out by Dr. Barlow") was transverse to the direction of movement of the glacial ice. The warping hypothesis of Dr. Pirsson presents some physiographic difficulties in that if the northern portion of Timiskaming trench had been i lowered 300 feet below the southern portion either by transverse warping I or faulting, this would almost certainly be evident in the higher elevation of the region adjacent to the trench from Seven League Lake southward. This is apparently not the case. Furthermore, it might be pointed out with regard to the overdeepening of the trench by glacial denudation, the continental ice-sheets did not move across the valley at right angles ^ but obliquely, so that it is not impossible that a subcurrent of the ice- sheet might have been directed down Timiskaming gorge eroding out its bottom to a depth of several hundred feet. TOPOGRAPHIC HISTORY. The most important events in the physiographic history of Timis- kaming region have already been described in the section of the report on the topographic history of the Laurentian plateau. In the following I account of the physiographic development of a particular area within the plateau, however, the various events are described in greater detail than ■; was possible in the general outline of the development of the whole pliysiographic province. The physiographic history of Timiskaming region may be regarded , as commencing with the development of the great erosion plain which sep- arates the Huronian Cobalt series from the great basal complex beneath. During geological ages which preceded the develcj ment of this ancient Pre-Cambrian erosion surface, numerous plains of denudation may I have been formed in the region but these find no expression in the present i topography and the evidence of the presence of even the last of them is to be found only in the wide areas of clastic sediments and in a few doubtful rei .nants of older denuded surfaces. Although the floor which underlies the Cobalt series has been consid- erably warped and dislocated in places, during the long period which has 'Geol. Surv.. Can., Ann. Rept., vol. X, 1897, p. 25. 42 elapsed since the Cobalt series was deposited on its surface, it is possible to discover the degree of relief possessed by this ancient surf from a study of its contacts with the ovei lying sediments. In n localities, where the contact is exposed at numerous points or wl numerous small scattered remnants of the sedimentary cover occur, i seen that the surface was generally one of low relief. In a few pla however, there are hills composed of rocks belonging to the basal com] which rise to elevations of several hundred feet above outcrops of Cobalt series exposed at their base — as for example the Abijevis 1 in Dcstor township; if these hills have not been raised to their pres elevation above the Cobalt series by faulting, they must repres monadnocks which stood above the surface of the ancient plain. 1 ancient erosion surface, moreover, was developed over the territory- least 50,000 square miles in area — extending from the north shore of 1 Huron to lake Mistassini throughout which the Cobalt series is fot so that it was not merely a local base-level but a wide plain of low re with remnants of erosion rising here and there above the general 1< of its surface. This Pre-Cambrian surface of denudation, theref( represents a remnant of a peneplain once buried and later ex^ :ed ; falls into the class of land form known as a palaeoplain. In Chapter III of this report, it is pointed out that the Pre-Cambi basal complex of Timiskaming region includes parts of three great lit logical belts or zones: a southern zone extending from the east shon Georgian bay to the lower Ottawa, in which crystalline limestones ; common lithological type; a northern belt extending from lake Supci and the north shore of lake Huron to lake Mistassini, throughout wh volcanic lavas are the dominant rocks: and between these two zones intermediate belt of banded gneisses stretches from the north shore Georgian bay to the gulf of St. Lawrence. If an examination be mi of the geological maps of the territory in which these belts occur, i seen that the late Pre-Cambrian Huronian sediments which rest on truncated surface of the basal complex are limited in their distribut to the northern belt, in which the basal complex is largely composed volcanic flows — a coincidence which can scarcely be accidental. On the whole the elevation of the Laurentian plateau in the reg where the Huronian sediments occur, is but little higher than the elcvat throughout the belt underlain by the banded gneisses; so that th younger Pre-Cambrian sediments must evidently, at present, occt a depression in the Pre-Huronian peneplain surface, and it is proba that it is chiefly on this account that they have been preserved throu] out the northern gcosynclinal belt while they have been denuded aw elsewhere. To account for the occurrence of the Huronian rocks ir depression coincident with the great northern volcanic belt of the ba 43 ce, It 18 yet ient surfacr, s. In most ts or where r occur, it is 1 few places, isal complex crops of the- ibijevis hills heir present >t represent plain. This erritory — at ihore of lake ies is found, of low relief ;eneral level I, therefore, ;x^. jcd and e-Cambrian great litho- ast shore of estones is a ike Superior jhout which \o zones, an •th shore of on be made occur, it is rest on the distribution omposed of 1. 1 the region lie elevation that these •nt, occupy is probable ?d through- luded away rocks in a )f the basal complex two possibilities suggest themselves: (1) there may have been a depression in the Pre-Huronian peneplain surface throughout this belt when the Huronian sediments were laid down; or, (2) the Huronian rocks may have been downwarped or downfaulted throughout the region in which they occur, since they were deposited. The occurrence in the basal complex of a great central igneous belt of granitic gneisses flanked on either side by surface rocks — sediments and volcanic flows — would seem to indicate that the belt of banded gneisses represents the core of a great Pre-Cambrian geanticlinal mountain range and that the folded surface rocks are the remnants of geosynclinal intermontane belts. If this interpretation of the structural relationships of the rocks of the basal complex be correct, then the mountain belt even after numerous cycles of erosion owing both to the J original higher elevation and to the superior hardness of the granitic gneisses, would probably lag somewhat behind the intermontane areas in erosion and in tx>nsequence a depression might occur in the ancient peneplain surface throughout the geosynclinal areas. In discussing the origin of the linear valleys of the Timiskaming region, it was pointed out that the Cobalt series had probably been subjected to faulting and it is probable that these rocks have in places been depressed relatively to the other rocks of the region, in this manner; i furthermore, it is also possible that the deformation which has occurred I in the Huronian rocks has taken place along structural lines which par- I allel the axial trends of the great geanticlinal and geosynclinal belts " in the basal complex beneath, and, in such an event they might be downwarped or downfaulted or both downwarped and downfaulted throughout a region which would correspond to the geosynclinal belt in the basement complex. In order to establish this hypothesis, however, it would be necessary to show that the structural trend of the folds in the Huronian sediments has a northeasterly-southwesterly direction parallel to the axial trend of the folds in the older complex, and this has not yet been determined. The great erosion interval during which the pre-Huronian peneplain was developed was finally terminated in Tin.iskaming region by the deposition of the Huronian Cobalt series of sediments which are believed to be in part of glacial origin. Following the deposition of the Cobalt series a second period of denudation ensued which continued into the i early Palaeozoic when a marine submergence occurred as shown by the , presence of Ordovician and Silurian rocks at the north end of lake I Timiskaming. It is probable that the larger part of the denudation I which has occurred in the region since Pre-Cambrian time, took place I during tliis interval; for the PaIa?ozoir sediments rest, in part, on unroofed and denuded sills of Nipissing diabase, which were intruded into the (.'(ibult .lerics in the Kew enawan jwriod, and in pan on the prt-Huro floor from which the Cobalt series has be»n Mtrip|xrdanc-<- in structure which separated the Palsrozoic s-edim from the Cobalt series indicates that the foldinn which has orcnrri these sediments took place during this period and that after the fol had occurred the region was base-levelled before the Palxozoic mi Mibmergence tcx)k place. It was formerly thought from the fossils a>ntained in the Palan: outlier occurring at the north end of lake Timiskaming that the 1' ozoic sea had covered the Timiskaming region during the Silurian pe only and that these Palaeozoic sediments were deposited originally depression which lay below the general level of the surface of the l,au tian plateau. Recent investigation has shown, however, that there also fossils of Ordovician age' in the Timiskaming outlier and that Palaeozoic sediments were probably not depos.tcd originally in a depres but occupy their present depressed position as a result of faulting. Boi these conclusions have an important bearing on the history of the Lau tian plateau; since it may be inferred from the first that Timiskan region was twice submerged beneath the sea during the Palaeozoic and from the second that the Palaeozoic sediments originally cov( not only the area in which they occur but the whole region in the vicii of lake Timiskaming to a depth of at least several hundred feet. During the interval which elapsed between the withdrawal of Palaeozoic sea and the coming of the Pleistocene continental glac Timiskaming region was, as far as known, continually a land area, it is probable that the agencies of erosion were engaged during a consi able part of this period in removing the Palaeozoic cover. At some t during the interval — most probably during a period of uplift neat dose — numerous rivers cut their way into the surface of t' plal forming the peculiar trench-like valleys so conspicuous in the .'rra of the region at the present time. The effects of glacial denudation and glacial deposition ni modifj the topography were practically the same in Timiskaming region a the Lauren tian plateau as a whole (page 22). The abundance of gla striae and grooves and the general mammalated character of the bedi surface bear ample testimony to the effective erosion power of the gla ice in modifying the detailed topography of the region ; on the oi hand, the presence of numerous linear valleys, which are probably pre-Glacial origin, is an indication of the limitations of this poi Owing to the dep ts of glacial drift and post-Glacial ciay which cc the bedrock surface, it is difficult to determine the amount of gla > Wllllanu. M. V.. G«ol. Surv.. Can.. Mus. BuU. No. 17, 19IS. 45 jrt'-Hiironi.ii) •. Moreover lie M-dimont* » occiimd ill r the foldinK ozoic mariiu' he PalaHJzoii' at the Fala iuiian pori{«l riginally in .1 I the Lauren - lat there an and that the I a depression ng. Both of ' the I.aureti- rimiskaniin^ alicozuic era ally covered I the vicinity ?et. rawal of the ital glaciers, nd area, but g a consider- U some time >\i(* near its t' plateau ^'r;raph\ i ;:ouginK whii'h has actually n.-ciirred; luii. .u the Uiiintn of the Tiniis- kaniinn trench (iwge 40), there is a roek-rinimid basin MM) ti et deep which probably originated in this manner. M.iterials deposited from the continental jjlaciers, as elsewhere in the Laurentian plateau, are abundant in all the forms — moraines, kames, cskcrs, outwash plains, etc. — usually assumed by glacial and IhivW glacial deposits. The control exercised by these materials on the hydro- graphy of th • region is also very conspicuous, the linear willeys In'inn practically the only pre-Glacial forms which have survived. Thus, the Timiskaming trench, which was undoubtedly the trunk drainage channel of the region in pre-Glacial time, still serves in that capacity, although the river which occupied the channel originally has lieen replaced by a •series of lakes lying behind barriers of rock or glacial drift. The concluding event of importance in the physiographic develop- ment of Timiskaming region was the deposition of stratified lacustrine (lay from large but shallow bodies of water —lakes Barlow and Ojibway — which occupied a wide extent of country in the central and northern parts of the region thereby producing the great constructional plain known as the cl.iy belt. The disappearance of these great lakes, following the withdrawal of the continental glacier from the region, practically con- hi -li marine sediments li ,. .^nfo rusive dykes, sills, etc. ni^'-, ' ■ das late Pre-Cambrian, "I o Pala'ozoic (Upper Cambriar 1 <'8t-Glacial de|x>sits belonging to BASAL CUMPI.KX. Of the four grejir divisions to which the rocks of the Ottawa bs belong, the most widely exposed is the heterogeneous assemblage tnttamorphosed sediments, volcanic flows, granite, granite-gneiss, i other igneous mcks, generally referred to by the early geologists as basement, metamorphic, or fundamental complex and more recently geologists in United States, as Archaean. In this particular region, th basement rocks occur in three great southwesterly trending belts wh are lithologically different from one another. On the south, extend through southeastern Ontario and along the lower Ottawa, there zone in which crystalline limestone, and other altered sediments comp ing what is generally called the Grenville series, predominate and wh for this reason may be designated the Grenville bell; on the north, in vicinity of lake Timiskaming and extending westward to the north sh of lake Huron and eastward to lake Mistassini, there is a belt consist chiefly of folded volcanic flows belonging mainly to the Abitibi group wh may be referred to as the Abitibi or Timiskaming belt; and intenen between these northern and southern belts there occurs a third I consisting almost wholly of banded gneisses which may be appropriat called the belt of Ottawa gneisses. The central of these great lithologi zones is thus distinguished from those on the north and south in be composed mainly of plutonic igneous rocks, while the latter con: largely of what may be termed surface rock* — sediments and voica flows. 47 ^^5^ ided accord ly into liji.r to the latti 'ian in age, ills, etc., (if tmbrian, (3) Cambrian tf tiging to thi ttawa basin iciiililagc ot -gneiss, and gists as th( recently by cgion, thesi belts which I, extending; I, there is a nts cGmpu>- ; and which lorth, in thf north short' t consisting; ;roup which intcrv'eninsj 1 third bell )propriatcly ; lithological ith in beinj; tter consist nd volcanii. S I I a 5 §^ § I o .a 48 Grenville Belt. The principal rocks composing the southern or Grenville portion o( the I'ri-Cambrian basal complex of Ontario and Quebec have long fweii known from the works of Logan, Murray, Vennor, FZils, Adams, and other geologists employed on the staff of the Geological Survey during thi tarly period of its investigations, but the relationships of these rock types throughout the region as a whole have not yet been worked out except in a few local areas. Lithologically, the rocks of the Grenville belt belong to three prin- cipal groups: (1) metamorphosed sediments consisting of crystallini limestone, garnet gneiss, quartzite and mica schist, amphibolite, pyroxo nite, and other products resulting from the contact metamorphij-m ol limestone, and in the Madoc district, Ontario, volcanic lavas. (2) Fyroxenic gneisses, gabbros, diorites, anorthosites, and other rocks ol intermediate to basic composition. (3) Granites, syenite, nephelini syenite, pegmatite, aplite, and related rocks. With the exception of a few areas of limestone, slate, conglomerate quartzite, and mica schist occurring in the Madoc district of Ontario, whicf are believed to be infolded synclinal remnants of a younger (Hastings] series,' all of the rocks of subdivision 1, as far as known, are conformablt with one another and belong to a single group, the Grenville series Whether or not the pyroxenic rocks of subdivision 2 are all of the same ag( is not known, although they are all apparently intrusive into the Gren ville series. The acidic rocks of the Grenville belt, subdivision 3 flh far as has been observed, are all intrusive into the rocks of groups 1 and 2; but wliether they were intruded during one or several periods o hatholithic invasion has not been generally determined. In the Madoi district, however, according to Miller and Knight, of the Ontario Bureai of Mines, there are two granites, the older of which lies unconformabl) beneath the Hastings series, while the younger (Moira granite) intrude »hese sediments. Timiskaming Belt. As has been already pointed out, throughout the region extendinj from the north shore of lake Huron to lake Mistassini there is a bel in which the basal complex is composed chiefly of folded and meta morphosed volcanic flows. There is associated with these volcanic in places, however, a considerable proportion of clastic sedimentar; material, and both these sediments and the volcanics are intruded her and there by batholithic masses of granite and granite gneiss. ' Report of ttie Special International Comniitte* on Pre-C»mbrian correlation. Jour, of Geol.. vo 15. I'Xth p. I'M. Miller, W. G. and Knight. C. W., Ann. Rept.. Ont. Bureau of Minet. vol. 22, pt. 2, 1914. 49 It has become customary among most geologists engaged in field work in Timiskaming region to regard the sedimentary rocks of this gre;ti northern belt as generally younger than its volcanic members, and in accordance with this conception, the sediments are called Sudbury or Tim- iskaming series, while the volcanics are grouped together as Kecwaiin. In Chapter IV, it is pointed out, however, that, although in certain localities sediments occur resting unconformably on volcanic rocks, it has not been established that all the volcanic rocks of the district are older in age than the sediments; nor that the complex is composed of two and only two series; nor that the volcanic members of the complex are necessarily equivalent in age to the volcanic complex called Kiewatin in the region northwest of lake Superior. It is, therefore, thought to be more in accord with our actual knowledge to use the name Timiskaming group instead of Timiskaming series for all those areas of rocks which are known to be younger in age than other rocks of the Pre-Cobalt series complex with which they are associated, and to include all those rocks of the complex of which the age is in doubt or which are older than any of the series composing the Timiskaming group in a separate subdivision, the Abitibi group. ABITIBI GROUP. Igneous Rocks. Extrusive. The Abitibi group is composed mainly of a complex of lava flows ranging in composition from basalt t' rhyolitc, which for the purpose of description may be designated the Abitibi volcanira. These lavas are dark green to grey rocks having characteristically a fine-grained aphanitic texture. In the interior of the flows, however, they Ik come porphyritic or even approach the texture of plutonic rocks of similar composition. They commonly exhibit the amygdaloidal, variolitic, pillow, and other structures which usually characterize extrusive rocks. The Abitibi volcanics have been everywhere more or .jss meta- morphosed but, except in the vicinity of the intrusive granite batholiths or along local zones of deformation, the alterations have been mineralogi- cal rather than mechanical; so that in most localities it is still possible to approximately determine their original composition and texture. The metasomatic changes which have taken place are remarkably uniform everywhere even in rocks of considerable difference in composition, the feldspars bting transformed into sericite, epidote, zoisite, and carbonate and the fcrromagnesian minerals to chlorite and secondary amphibole— actinolite, tremolite, or hornblende. Except for the presence of quartz, the acid members of the group differ from the basic merely in the pro- portion of these minerals, the sericite which occurs so abundantly in the acid rocks being replaced by epidote and chlorite in the basic varniits. so Where the volcanics have been subjected to contact metamorphism in th vicinity of the granite batholith, the basic volcanics have been generall recrystailized to hornblende schist or amphibolite. The acid lava; on the other hand, have been mashed to sericite schist. In most parts of Timiskaming region owing either to the paucit of exposures, or to the absence of definite and uniform horizons such a occur in sedimentary rocks, it has not been possible to work out th detailed structural or stratigraphical relations of the volcanics; yet, i places, the attitude and trend of the lava flows can be determined from th change in texture from the centre to the margin of the flow, from th presence of amygdaloidal and other flow structures along the surface f the flows, and from the strike and dip of the associated sedimenti Wherever it has been possible to apply these criteria, it has been foun that the volcanics have generally a vertical or nearly vertical attitud and trend, for the most part, in a direction parallel to the trend of tli great Abitibi belt to which they belong. Intrusive. Here and there, throughout the Abitibi belt, mass( and dykes of qusrtz porphyrj', aplite, dio.ite, andesite porphyry, perid( tite, and lamprophyre occur in association with the Abitibi volcanic which, except for their somewhat coarser texture, differ in no respec from the coarse-grained phases of the volcanics and are probably genet cally related to them. Many of the intrusions of quartz porphyry an aplite have been partially replaced by ferruginous dolomite and chron mica; and, it is possible, as is pointed out in Chapter VI, that the man masses and bands of chromc-mica-bearing ferruginous dolomite, whic occur throughout the Abitibi belt have also originated in this way an( on this account, should be regarded as belonging to the intrusi> members of the Abitibi group. Sedimentary Rocks. The sedimentary rocks belonging to the Abitibi group generall occur as small isolated masses or long narrow bands either surrounded c all sides by the Abitibi volcanics or intervening between the volcanii and batholiths of granite or granite gneiss. They include the followir rock types: agglomerate and tuff, slate and phyllite, iron formatioi ferruginous dolomite, conglomerate, greywacke, arkose, and quartzite. Agglomerate and Tuff. Agglomerate and tuff are not extensivel developed in the Abitibi group but have been described as present in few localities. They presumably represent fragmental ejectment deposited contemporaneously with the volcanics with which they ai associated.' 'Rept. of min. odct., Qnc.. !91I. p. !82. Gcol. Sunr., Can., Sum. Kept.. 1912. p. 3t been positively determined although the occurrence of the series a long narrow belt 110 miles in length, intervening between the gr batholithic belt of gneisses and the volcanics, indicates that they have b folded up into their present position in company with the intrusion of batholith and that, just as in the vicinity of laccolithic intrusions, older strata occur adjacent to the laccolith; so the Pontiac series wl adjoins the intrusive should underlie the volcanics occurring farther to north. On the other hand, the presence of pebbles of rhyolite in conglomerate of the Pontiac series might l)e taken to indicate that Pontiac series is younger in age than the Abitibi volcanics. Thi not conclusive, however, for the pebbles of rhyolite might have b derived from lavas contempwraneous in ai^e with the Pontiac series older lavas not now represented in the area. Larder Lake Series. In a number of localities in Larder Lake dist of Ontario, areas and bands of highly metamorphosed sediments o( which are believed to be overlain unconformably by conglome belonging to the Timiskaming group, and which, therefore, must classed as a part of the Abitibi group. They consist of well bed phyllite and slate interbanded with chrome-mica-bearing ferrugir dolomite, the dolomitic bands having widths ranging from a few y^ to several hundred feet. TIMISKAMINC; GROUP. In this group are included all the areas of rtx'k belonging to Pre-Cobalt series complex which are known to be younger in age i other rocks of the complex with which they are associated. The [ oipal rock areas Ijelonging to this class, so far discovered in the Timisk ing region, are the Kirkland Lake series, with which is inckuled conglc rate on Larder lake, the Timiskaming series, and the Fabre series. Kirkland Lake Series. In the Kirkland Lake district a belt of ments about .S miles in width and 30 miles in Imglh extends all continuously from the village of Swastika t)n the Timiskaming Northern Ontario railway to the Larder Lake district. These sedini include highly deformed conglomerate, greywacke, quartzite, related rocks having generally a vertical or nearly vertical attitude east-west strike. The conglomerate memlH-r of the series contai large variety of p«-l)l)U's including various gree^^t(^^^^, diabase, qi 53 ■ml )n and one K-'bblcs and ry, rhyolite, Dlcanicb ba- the series in n the grt'.ii jy have bci n ■usion of tht fusions, liu series which irthcr to thr oolite in tht ate that tiu cs. This i^ t have bcin iac series or -ake district ments occur onglomerati re, must bt well bedded ferruginou- a few yariN porphyry, iron formations, jasper quartz, and granite, and has been 1 found to rest unconformably on greenstone and quartz porphyry.' I An area of conglomerate belonging to this series, occurring on I claim L.M.78, in the district north of Larder lake was observed to I contain pebbles of the chrome-mica-bearing dolomite which occurs inter- I banded with the slate and phyllitc found on the north shore of larder I lake. This seems to indicate that the Kirkland Lake series rests uncon- i formably on the Larder Lake series. I Timiskaming Series. In the region adjoining the north end of lake I Timiskaming (chiefly to the northwest of the town of Haileybury) highly metamorphosed sediments, conglomerate, greywacke, and slate, occur, for which the name Timiskaming series has been proposed. The conglomerate member of thir. series contains pebbles of granite, syenite, iron formation, diabase, basalt, and other rocks resembling the Abitibi volcanics. The series is, therefore, regarded as younger than both the Abitibi volcanics (Kecwatin) and the Laurentian — the name I^urentian, in the nomenclature of the Ontario Bureau of Mines, being reserved I for the hitherto undiscovered granite from which the pebbles of granite contained in the conglomerate of the Timiskaming series were derived. The Timiskaming series is intruded by a mass of granite which has been named the Lorrain batholith." Fabre Series. In the township of Fabre, in the region east of lake Timiskaming, some local areas of conglomerate, slate, and other sedi- ments having the same general lithological character and relationships as the sediments already mentioned, were described and designated the Fabre series by Robert Harvie.* Belt of Ottawa Gneisses. nging tu thi in age than The prill- le Timiskiini- L'd conglonii • eries. belt of Mill tends aim - ^kaming cale around the augen of feldspar in the augen gneiss. 56 From the study of the structure of the banded gneisses it is apparei that they have folded forms very similar to that assumed by deformc sedimentary strata. While there are no bands which can be tract continuously over wide areas like sedimentary beds, yet, all the varioi types of folds which characterize folded strata are present on a smii scale and, in places, anticlines and synclines nearly half a mile wide transverse section can be recognized (Plate IX). These anticlines ar synclines are generally pitching, but the strike of the beds is northeaster parallel to the trend of the great belt to which they belong. In describing the structure of the Laurentian gneisses occurring eastern Ontario, Adams and Barlow note that the foliation of the gnci near the border of the batholith corresponds to the strike of the su rounding sedimentary rocks and conclude that the batholiths are ani dinal in their relationship to the Grenville series, the anticlinal ax trending north 30 degrees east. They also point out that the trend of tl foliation and banding in the batholiths is commonly oval or elliptic in form, and, while no further statement is made by the authors as structure of the gneiss, it seems apparent, from the trend of the foliatif indicated on their maps, that the gneiss in that locality also has a fold* structure similar to the central belt of gneisses of the Laurentian cor plex." Structure and Relations of the Three Great Basal-Complex Belt It has been pointed out in previous sections of this report that throug! out eastern Ontario and southwestern Quebec the basal Pre-Cambrian cor plex is composed of three great northeasterly trending belts, the northei and southern of these consisting of surface rocks (volcanic flows ar sediments) and the central consisting, for the most part, of intrusi' banded orthogneisses; also, that the rocks composing these belts are i highly folded and have a structural trend parallel to the trend of tl three great zones to which they belong. Furthermore, geologic investigation throughout the world has shown that, where folded mou tains have been greatly denuded, batholithic masses of acidic rocks a generally found at their centres and, since the Laurentian banded gneiss occur in a central belt intervening between belts of folded surface rocl it seems probable that the great gneissic complex extending from Gee gian bay to the gulf of St. Lawrence originally formed the core of Pre-Cambrian mountain chain and constitutes a geanticlinal axial b' intervening between geosynclines formed by the rocks of the Abii group and the Grenville series. > G«oL Surv.. Can., Mem. 6. 19ia 57 LATE PRE-CAMBRFAN RCX-RS. Introductory Statement. Since the geology of only a very small part of the territory incliuled in the Ottawa basin has Ix-en majiped in detail, our information with regard to the rocks of late Pre-Cambrian age in this region is necessarily ini-nmplete. The known rocksof thisclass, however, include the Huronian >wliments occurring extensively in theTimiskaming region, and numerous dykes, sills, and other intrusions of diabase, quartz diabase, olivine diabase, and related rocks, believed to be approximately of Keweenawan age. Huronian. INTRODUCTORY STATEMENT. Throughout the region underlain by the Abitibi complex and along the northern border of the central belt of gneisses there are, in places, comparatively undisturbed sediments which rest on the truncated and greatly denuded surfaceof .he basal complex in most striking unconformity. Thtbc are believed to be equivalent in age to similar rocks occurring on the north shore of lake Huron which were designated Huronian by Sir William Logan. As represented in Timiskaming region the Huronian consists, as far as known, of a single groupof conformable clastic sediments, the Cobalt scries. COBALT SERIES. Distribution. The geological investigations of the Geological Survey, the Bureau i)f Mines of Ontario, and the Department of Mines for Quebec, in i recent years, have shown that the Cobalt series probably extended originally al! the way from the north shore of lake Huron to lake i Chilwugamiiu in Quebec, a distance of nearly 500 miles, and covered j an area of at least 40,000 square miles. Throughout the larger part I "f this territory, however, the series has been eroded away from the Hurfacc (1 the basal comple.v so that it now remains, for the most j part, merely as retnnantal hills and ridges or small isolated exposures. I In the Timiskaming region, outcrops of the series are known to occur as far i. north as lake Abitibi and as far south as the southern extremity of lake iTimagami. The most easterly exposure observed by the writer occurs I in Dcstor township, Quebec, approximately 25 miles east of the inter- Jprovincial boundary between Ontario and Quebec. On the west, the Iseries extends across the whole of the Timiskaming basin and beyond Ito the Sudbury district and the north shore of lake Huron. S8 Lilkological Character. General The Cobalt series in the Timiskaming region includes all the- common varieties of clastic sediments and more especially the poorly sorted types, viz.. conglomerate, greywacke. and a^>'<»e- '" »»'r localities in the district where the most complete tactions of the ser.es are present, it is generally composed of the followmg htho ogical divisions from the base upward: (1) coarse basal conglomerate. (2) greywacke and argillite. (3) arkose and quartzite. (4) coarse conglomerate Mmilar This classification holds only in a general way. however, for each of these subdivisions contains local beds similar to the other members of the scries and the contacts between the different members are generally Kradational. Nevertheless, except when the upper members have been removed by denudation, two thick beds of massive coarse conglomerate separated by fine-grained stratified sediments are generally present. A compilation of the published observations of the succession anil thickness of the various members of the Cobalt series m d.fTerent parts .. the Timiskaming region is included in the follow ng table. It is evidem that many of these sections are only partial, mcludmg m some cases tht upper and in others the lower members of the series, yet m a general way, the succession is remarkably uniform. SecHon of the Cobalt Series in Timiskaming Return, Ontario and Quebec. Rock. Thickness FRET. Quartzite, etc Argillite and greywacke. Conglomerate Unconformity Basal complex. 1,100 100 600 Quartzite Argillite Conglomerate Unconformity. Basal complex. Locality. General maximum section; Timiskam- ing region. Reterencb. Barlow. A. E. G«ol. Surv.. Can., Ann. Rept., vol. X, 1897. p. 104. Between Rabbit and Timagami lakes. Quartzite passing into con- glomerate at top Argillite Greywacke ■ • • ■ ■ •.■ • ChocoUte-coloured argillite Contact not exposed Basal complex 90 26 10 54 ? Young. G. A., Geol. Surv., Can., Sum. Rept., 1904, p 198. Windigo lake. Parks, W. A., Geol. Surv., Can., Sum. Rept., 1904, p. 215. 59 n •v.. Can., jt., 1904, p KOCK. TaiCKNEss riBT. I.OCAUTV. Rrfbibnci. CoDKloinerate Ouartxhe Greywacke Congioinerate ? ? ? ? Urder Uke. Brock, R. W., Kept. Unt. Bureau of Mines, 1907, p. 211. Unconformity Bauil complex Arko«e Arsiliite ? > > Trout lake. South Lorrain tp., Ont Burrows. A (■ . Kept. Ont. Bureau of Mines, pt. 11, 1908, p. 25. Unconformity Baial complex. Argillite ? ? ? Everett lake, Gowganda district. Quartzite Conglomerate. ... Burrows, A. G., Kept. Ont. Bureau of Mines, pt. II, 1908, pi. Unconformity Basal complex. ArkoM and quartzite Conglomerate, etc ? ? 200 Gowganda diatrict. Collins, W. H.. "Prei. Kept, on Gow- ganda dist.," Gcol. Surv., Can., 1909. pp. 26-27. Conglomerate Unconformity Basal complex. Congtomerate, greywacke, •late, and quartiite Congk>merate J 300 ? Mount Sinclair McMillan, J. G., Kept, on Geol. along T. and NO. Railway trait Gowganda to Porcupine, 1912. Contact not exposed Bafial complex Conglomerate 30 to 40 15 20 ? Little Silver Cliff mine, Cobalt, Ont. Miller, W. G., Quartzite Kept. Ont. Bureau of Mines, vol. XIX, pt. II, 4tb edit.. 1913, p. 78. Greywacke with beds of ar- gillite and quartzite Contact not exposed Basal complex Arkose and quartzite 9UU ? Maple mountain, Ont. Miller, W. G., Kept. Ont. Bureau of Mines, vr>l. XIX, pt. II, 4th edit., 1913, p. 78. Contact not exposed Basal complex. Conglomerate 90 150 250 250+ Mount Shiminit. Wilson, M. E., Arkose Greywacke and argilltte Geol. Surv., Can., Mem. 39, 1913. Contact not exposed Basal complex. Basal Conglomerate. The basal conglomerate is an exceedingly variable rock consisting largely of coarse rock fragments in some places, and in other places consisting almost entirely of matrix. The included 60 fr.iKments may be angul.r, wubangular. or round in hhape ami are t-oni inonly 2. .». or ewn 5 liet in diameter. They include every variety .. r«K;k reprcK-nted in the ba«al complex, a large number occurrinK cvii in a ninglc outcrop. The matrix varieii from a coarse arko«e to a fine grained tlate-like rock, the latter being the type described by U)gan • chlorite Mate congk)mcrate. As a rule, the bawal conglomerate n withoii stratification, but in placen a partial alignment of pebble* can be mi i The thickness* of thin «-onglomer.ite member, like that of all the otht fornwilioii^s of the Cobalt wric». i» »o variable that it i»i difficult todetei mine ili» original average thickntsw. Greywuhe and Anilltle. The Mcond formation, the Cobalt seric .-rmsisLs of finely cemented ferromagnesian sediments which range i texture from a sand to a fine-grained mud. The coarse-grained pha- of these dcpobits constitutes what ha.H been generally described as gre; waiki; the fine-grained mud phase has been generally called slai or less fre<|uently shale. The rock to which the latter names have bee applied is neither a slate nor a shale as these rocks are usually define, however, for it does not possess the slaty cleavage of slate and. on il other hand, i« much too finely cemented for a shale. Since rocks of tli class are very common in the slightly disturbed late Pre-Cambru sedimentary series of the Canadian shield, the writer has proposed th it be called argillitc. Argillite,' according to rhis definition, would thi (xxupy approximiitely the same position in the shale-slate series of set menLs that quartzite otvupics in the sand-sandstone group. In plaa the grcywacke and argillite are unstratified. but. as a rule, they a uniformly liedded. the IkiIs ranging from an eighth of an inch to half i inch in thickness, l.ikt the other members of the Cobalt series, t thickness of the greywarke and argillite is cxix-edingly variable rangii from to a ni.iximum of .^00 feet. Arkosc and QuartziU. The greywarke aiul argillite gradates upwa into iH'ds of quartzite and arkose. The rrn-ks are always stratifit although in places the stratification is not strikingly apparent. T maximum thickness recorded for this member of the Cobalt series 250 feet. Upper Conglomerate. The upper conglomerate which overlies t arkose resembles the basal conglomerate in every respect and cam be distinguished from it except where the stratigraphical succession known. The maximum thickness observed in the region examined the writer was 90 feet. Pdbbly Quartzite. On the east and west shores of lake Timiskami near its north end, a peculiar sericitic green quartzite containing str • CmL Swv.. Can., Utm. ». 1*11. »■ U. 6t w.ll-r«»undcd pebble* of quartx and iM\nr in lenticular aRgnjjatcH, in expoMd. Wherever ihe reUtionHhipit of this quartzite were oliMrvwl it either rested directly on granite or psumed imperctptibly downwaril into greywackc: and ihu« apparently occupied a rjtratijjraphical p«v,ition »imilur to the urknst-quar'zitf memU r of the Cobalt r«erie» occurring in ihe adjacent districts l.itholoRically. this pebbly quartzite diffent from the typical arkosc and quartzite. however, in its more highly sorted character, in llw rouridnrss of itH grains, and in the |k Miles t>f quartz and jasper whirh it a»ntains Moreover, in the reRion west of the TimiNkaminK district, a rock, litholngically similar to th»>* quartzite. is reported tooctu y a much higher position in the Cobalt series oo- zoic sediments ranging from the Potsdam to the Quecnston in age, extend almost continuously from the outlet of the Ottawa at Montreal to Quyon, a point 25 miles west of Ottawa. Beyond Quyon, numerous outliers continue as far west as Allumette island, a distance of 50 miles. In these remnants, however, an overlap seems to have occurred, for the Potsdam sandstone is absent and the Boekmantown or higher formation rest directly on the surface of the Pre-Cambrian complex. m In the upper part of the Ottawa basin, a few small outliers of sand- stone and limestone containing fossils which have been identified as be- longing to the Black River and Trenton formations occur in the bed of the river,' a few miles east of Mattawa, Ontario. At the north end of lake Timiskaming there are a number of Palaeozoic outliers, some of which are several square miles in extent and several hundred feet in thickness. It was formerly supposed that these occurrences contained only Silurian fossils (Clinton and Niagara)', but recently it has been discovered that some of these outliers contain fossils characteristic of the Ordovician.* PLEISTOCENE. The Pleistocene deposits occurring in the Ottawa basin are of two classes: unsorted glacial till, and stratified clay and sand. The latter occurs in two localities: along the lower Ottawa (Champlain), and north of lake Timiskaming (lakes Barlow and Ojibway). Glacial. The Pre-Cambrian and later rocks previously described in this chap- ter, are now largely covered by boulders, gravel, sand, and boulder clay. This unconsolidated material is believed to have been laid down from a huge continental glacier which covered the eastern part of Canada and the adjacent parts of United States during a considerable portion of the I C«>l. Surv.. Can.. Rept. of Prof., 1845, pp. 64-<>«, Gfol. Surv.. Can . Ann. Rrpt., vol. X. pt. I, 1897, p. 120. •G«)l. Surv., C«n., Kept, of Prog., 1845, pp. ft"). 70. Geoloriy of Canada, p. 334. r*ol. Surv., Can.. Ann. Rept., vol. X, pt. I, tWl. pp. 121-127. ' Wllliama. M. V., Gtol. Surv., Can., Mua. Bull. No. 17, 1915. n i 64 Pleistocene epoch. Up to the present time evidence of the presence < only one of these continental glaciers has been found within the Ottaw basin proper; but in tlie southern part of the territory covered h the Labradorean glacier and along Mattauami river, to the south i James bay in Ontario, glacial till sheets separated by interglacial deposii have been found, indicating that there were in reality several continent, ice-sheets. The thickness of the glacial deposits is generally not vir great, the average for the whole region being certainly less than 50 fe< They occur in all the common forms assumed by such glacial debri: kames and outwash plains being especially common ip the northern pat of the region. The direction of movement of the ice-sheet throughoii the Ottawa basin indicated by the glacial strite was generally from norl to south. Post-Glacial. CHAMPLAIN CLAY iND SAND. Throughout the lower part of the Ottawa basin and along the lowc St. Lawrence, the glacial and older formations are hidden beneath . thick mantle of stratified clay and sand containing marine shells. Whili these deposits vary somewhat in different localities, on the whole tli. clay is the dominant member, the sand occurring only in local areas am generally as the topmost beds. In those portions of the region wher. river di.ssection has not removed the Champlain clay and sand, the elev.i tion of their surface is generally between 300 and 400 feet above se.i level, but local flats occur above this level up to 700 feet. LACISTRINE CLAY AND SAND. Deposits of this class are found in the Ottawa basin along the inter provincial boundary north of lake Timiskaming, and northeastwani from this point through the province of Quebec to the St. Lawren.. Hudson Bay divide, where it joins a still more extensive area of simil.ii deposits occurring in the James Bay basin to the north of the divid. The larger part of these deposits consists of stratified clav constituting what is generally called the clay belt of northern Ontario and Quelx-. They are believea to have been laid down in huge post-glacial lak<- which cowred this territory following the retreat of the last I.abradorc.in ice-sheet. '^'-•'"'^iMai m 65 CHAPTER IV. NOMENCLATURE AND CORRELATION. GliNERAL STATEMENT. The detailed geological work carrif\i on in recent years throughout I the southern part of the Canadian Pre-Cambrian shield has shown that I the geological succession in the ancient terranes of this territory is ngion- lally less uniform and includes a greater number of rock series than wa.-. I formerly supposed. Moreover, it has become evident that the wide- I spread correlations implied by the use of the .same nr>menclatun-, nii/rly I verywhere throughout this great Pre-Cambrian provinct- , assumes jnuich more with regard to the regional suix-esjiiiin in these ancient rocks I than is actually known. Although it is not possible generally to dt-monstrate with math* - [matical conclusiveness that geok)gical formatiuas occiirrinp in different [localities are equivalent, nevertheless the premature use of the samt- I name for formations, the correlatioo of whick is t^»en to question, or 1 the continued use of the same name for the formations after it hiis r»e- jcome evident that their correlation is in d<3ttbt, is misleading, ar.J in [obstacle rather than an aid in geological investigation. Hypotbetical I correlations of groups of rocks occurring in widely separated districtii I may serve for comparison or as a stimulus to investigation,' but all the I advantages of such tentative correlations may be attained by using a jgeneral terminology (Proterozoic. Archapozoic, etc.) and thereby avoid- jing the definite correlations implied in the use of names of local origin. j In the Pre-Cambrian province which occupies the n«M-thern part I of St. Lawrence River basin, there are four geographically and geok)- I gically separate sub-provinces: (1) the region northwest of lake Superior, j (2) the region south of lake Superior, (3) the region extending northeast- Iward from lake Superior and lake Huron to lake Timiskaming and lake iMistassini, and (4) eastern Ontario and the lower St. Lawrence, with fwhich might be included the Adirondack region. With the possible Itxception of the south shore of lake Superior and the lake Huron-lake i Timiskaming sub-provinces, the available data upon which the rocks ol i these separate regions can be correlated, are exceedingly meagre; and, jfor the present, at least, the only logical course would seem to be to ihuild up a st>paratp nomenrlature for each sub-province by using ^hi Inames originally defined in each sub-pro\inci' supplcnu nted i)y surfi Inc w local names as geological investigaiifin requires. 'Uwmi.A I I niv. a«r«lifoniw. nerit ii( (iio . Hull vdl to I'llo p i 66 In the present report and in several previous publications in whic the geology of districts occurring in the Timiskaming region is describee a local nomenclature, in accordance with the principle stated in th previous paragraph, has been adopted by the writer, and ^he followin discussion is mainly a re-statement of the reasons why this terminolog was found necessary. OBJECTIONS TO AN INTER-SUB-PROVINCIAL NOHENCLATURE. The widespread correlations implied in the use of a common nomer clature throughout all the Pre-Cambrian sub-province of the St. Law rence basin has been based on the assunpcion that the succession of fo mations within the various sub-provinces has been worked out to practical completeness and, on the application of certain principles b which the correlation of the various formations in these widely separate areas are presumed to be established. The purpose of the followir discussion is to point out that the assumption that our knowledge of tl succession of formations in any of the sub-provinces is comfilete is opt to question, and that the principles by which Frc-Cambrian rocks ai generally correlated are in part inapplicable and as a whole quite inadi (]uate for the establishment of a Pre-Cambrian romenclature embracir all the territory in the St. Lawrence bann in which Pre-Caiabrian roci occur. Our Knowledge of the Successiom of Formatmns in the Sub-prmmcei Incam^eU. The numeroas regional class*ficatior» oi the Pre-Cambrian wk-I of the St. Lawreace basin, which have appeared from tiwe to tiae recent years, and the lise of such ttrms as Kaewatin, Laarentiaa, ai Huronian nearly everywhere throughout this gfeat Pre-Caaifartaa pai ince and at points hundreds of mies from thcae in whidi tteae wmm were originally defmed, wouW see^ to imply tiat oin- knowledge rf "! succession of formations within thit vast territery was much more am plete than is actually the caae. 0*r a very saull part of tte territor in the St. Lawrence basin in which Pre-Caadbran rocks occur, has \xf actually mapped in detail, and even in those localities which have be mapped in considerable detail and which have been reganled in the pa iis type areas, the succession of formadons formerly supposed to be pn cnt has in many cases been considerably mo di i td by more recent inv< ligation.' iLawMin. A. C.Gcol. Suiv.. Can.. Mem. 1%. IQU. and M«m 40, I«t3 p 4 Mlfcr, W. G. mnd Knight, C. W.. Ann. Kep«. Ont. Buwaw '/ Mima, '-ol. XXII. ft- 1. 1'U- ABm. R. C, and Barrett, U P.. Jour. Grot., vol. 21. »•» ColMna, W. H., Geol. Surv.. Can.. Sum. Krpt.. I<>l«. f 1*4 67 Tkf Principlfs of Pre-Cambrian Correlation Inapplicable or Inadequate. Continuity or Approximate Continuity of Outcrop. The principle I .,1 (ontinuity or approximate continuity of outcrop i>, the most conclusive i of all the nH>ans by which the relationship of rocks can he r more points on the earth's surface to-day. As a consequence of this I uBBcientific method of correlation, the name Keewatin while presumed I to represent a definite formation, in reality is now applied in the Cana- iMliam Pre-Cambrian sub-provinces to any metamorphosed volcanic rock i without regard to age. f Simihr Stratigraphical Succession of Beds. The larger part of the I Hre-Cambrian surface rocks of the region under oonskleration are vol- Hanic flows or clastic sediments, in which a regular sequence of strau ■ uncommon, and this criterion is, therefore, inapplicable except to the |l.ite Pre-Cambrian rocks. It has been especially useful in the mapping '-^\ 68 of the Huronian series in Timiskaming sub-province, the Lower Mar quette in the region south of lake Superior, and the Animikie sediments in the region northwest of lake Superior. Similar Serial Succession. The widespread correlations implid in the nomenclature applied to the Pre-Cambrian rocks of the St. Law rence basin has been based to a considerable extent on this principle although the apparent similarity in the serial succession may very frc quently be explained in other ways. The principal objection to the list of this criteiion is that it neglects to consider the possibility of overlap Sedimentary rock series are not generally deposited continuously oi uniformly over wide areas and where they have been deposited they art very commonly swept away in part by later erosion, before succeedinj series are laid down. Moreover, the Pre-Cambrian surface rocks are tt a large extent volcanic flows or land sediments and on this account an much more discontinuous than sediments of marine origm. Mode of Origin of Formations. This criterion is of limited applic.i tion ; for, sediments originating in the same way may be deposited durinj different geological epochs and likewise sediments originating in differcn ways may be deposited contemporaneously in adjoining localities. I might be of value in the correlation of certain uncommon types as glacia deposits which generally occur only at long intervals in geological time Relationship to Batholithic Intrusions. The relationship of thi Pre-Cambrian surface rocks to the great epochs of batholithic inva,sioi is of great assistance in correlation and may possibly eventually prov to be the most important of all the criteria used in the classification c the Pre-Cambrian rock series into major groups; for geological invest! gation throughout the world has shown that batholithic intrusions ar an accompaniment of mountain building movements in the earth' crust and are thus directly related to the great regional changes in rocl structure, to regional metamorphism, and to the uplifts which give ris to the great erosion intervals which form the dividing lines betweci the great Pre-Cambrian terranes. Some of the applications am limitations of batholithic invasion in rock correlation are included ii the following- Batholithic masxifs are exteiwive with the mountains they underlie and sim mountains are generally extensive and linear, the mauif should also be extensive an linear. The extent of the outcrop of the massif will depend, of course, on the extent i *hich unroofinK has been carried. In the Rocky mountains, for example, unroofiji has apparently only begun; in the Coast Range batholith of the Pacific coas^t, on tr other hand, unroofing is almost complete; and in some of the Pre-Cambrian batholi;! of the Canadian shield, the unroofing is not only largely completed but the batholii has also bevn reduced to base level. If two batholithic massifs have been intruded in a given region, the younger ma displace the first. Hence the conspicuous structural feature* of the region wouUI 1 those of the younger massif and all evidence of the former presence of the older batholit might be destroyed except for such remnants as happened to remain in association wii the roof rock.-* \a the ge.-synclinal belts. 'mm 69 Mountain building periods and hence alw periods of batholithii' intniRion occur at iociK interval* separated by erosion periotl* and the development of peneplain*. Iht rock* in the vicinity of un intrunive l>atholithic malt* are ^'encrally highly folded and metamorphoKed; hence if in a given area in the vicinity uf a balhoTith, flat-lying rock* occur which have not been greatly metamorphoseatholith. BatholithK are compcnile and their intrusionH continue during lung intcrvnln of time to that their various part* are only approximately of the same age. Hatholithic loclu are lithoiogically bO similar that it i» generally iinixaiillile to di«- tinguish between batholithr of difTcrt-nt ages except by nieanK uf their rclationnhips to other rocks uf which the age is known. Rfitntly A. C. Lawson has contributttl an interesting (wper to the rfiscussion on the "C't^rrelation of the Prc-Cambrian rocks of tho region { of the Great Lakes," in which he formulates the hypothesis that through- out the region extending from the Adirondacks to northwestern Ontario there were in Pre-Cambrian time, "two and only two periods in which Kriat granitic batholiths were developed in the earth's crust." On tlie liasis of this hypothesis he correlates all the Prc-Cambrian rocks «>ccurring in the territory to whirn his hypothesis is applied.' This hyjjothesis. if true, would undoubtedly greatly simplify the problems of Prc-Cambrian nomenclature and correlation in the legion under discussion; but, an examination of the hypothesis from either a deductive or inductive standpoint seems to indicate that it is an unwarranted assumption. The principal fact on which Lawson's hypothesis of two and only two peritxls of granitic batholithic intru.sion was based, was that, at the time the hypothesis was formulated, only two jieriods of batholithic intrusion had been recognized in most of the Pre-Cambrian siib-jirovinci-s of ♦he St. Lawrence basin. There is a very apparent rea5«)n, however, why two and only two batholithic intrusions can be recognized in a sinjile locality, namely, that if a ihird batholith were intruded in a district whfre two batholiths were already present, the evidence of the former presence of one or other of the older batholiths would probably di.-^appear.* If it be assumed that batholithic intrusions represent the interior jxirtions of mountain chains, it is obvious that the prolon^'eti irosimi, which generally follows an orogenic uplift, must inevitably result in the ^tripping cflf of the roof rocks from the underlying massif and the replaci- runt of surface rocks by plutonic type^ in the district where the uplift has occurred; als<:» that successive crustal movements of the orogenic tyiM- ill the same or adjoining localities must eventually bring alxiui the (ii-.appe;irance of all trace of r(>cks originally pre^-nt in such .'.ones of (listiirhance. It is pn^hable that within tht' liiise-levened Pri-C.nnbrian conpltx which underlies the larger part of the ("anadiaii shield evidence "f the presence of more than tvvo separate periinls of batholithic intrii.siori wonlil not generally survive in .1 single locality If. liowcvcr. the sue cosion of formations can ^K' determined over an c.xtcitdcd ari-,i. .1-- where ■ i nivpnijtv at Califomin Fubt. Alums, vol, lo. mu.. du l X'l 'iMX. A. I . Am. Jout St. via. 4.! 1';17. ji 4.i. 70 let* metamorphosed late Pre-Cambriau sediments cn-cur, the number of batholithic intnisionii which can he recognized might be increased. Thus, as a result of the more extended arcal geolDKical studies t)f recent years, evideni-e is accumulating that at least three definite iM-riodsi of batholithic invasion arc represented in several of the Pre-Cambrian i*ub-pmvinces of the St. I^wrence basin. The folded and metamorphosed Pre-Cambrian rocks occurring aloni; the ftOLthern margin of the Canadian «hi(ltribulion ha-s lieen diterminrd. arc distributed in norih- eahterly trending loi^s; thus the region (a()proximat(ly 1,(M)0 niiks in length) extentiing from the Adirondacks to lake of the Wootls, to which Ijwson's hypothesis has Iteen applied, lies almo.-.t ir.irisvcrse to the regional trend of Pre-Cambrian folding, mountain building, and batholithic invasion. Moreover, mountain systems throughout llir world are generally n.)* row and linear and where zones of crustal disturli- ancp a)mposed of several mountain systems, such rts the cordillera f)f North America, .iccur, the systems composing the /one are generally of varying age. Hence, if granitic nvissifs represent the interior of mountain systems exposed by denudation, it is more probable that the •«uthwesterly trending Pre-Cambrian batholithic zones of the St Lawrence basin instead of belonging to two and only two periods ol batholithic intrusion in reality represent several periotis of batholithic «pvelopnient. Relatumship to Igneous Intrusions other than Batholiths. Igneous intrusions ather than batholiths, especially if they are com|)osed of unique rock t\pesi. can likewise f)e employed for purposes of correlation, but generally only within a single sub-province. The principle has bern used for inter-sub-provincial correlation in the case of the late Prt- ( ambrian diabase intrusions, however, all of which have been generailv rt^arded as Keweenawan in age. FMing and Metamorphism. Since folding and metamorphism an accompaniments of mountain building and batholithic invasion, thi-c mteria are in reality included under the head, "Relationship 'n Batholithic Intrusions." It can be generally inferred that in the s.mit district those rocks which are most highly folded and metamorphoMtl are the oidest in age. This does not follow in the case of widily separated regions, however; for it has been found that rocks which are Hat-lying and slightly metamorphosed in one district may be highh folded, metamorphosed, and intruded by granite batholiths in anothti locality. 7! TIMISKAMINU REGION. The investigations ot ihe Ontario Bureau of Mines ami the Geolo- gical Surviy in recent years throughout the territory extending from the Timisk.iming region to the north shore of lake Huron have shown that the rocks known in the Timiskaming region as the Cobalt seri»s are approximately continuous from lake Timiskaming to the north shore of lake Huron, and that this series corresponds to the upper portion of the Drininal Ilurtjnian; the lower of the two scries present in the original Hurunian a:ea apparently disappears when traced northeastward towards Tin^i^kaming region, that is the time during which the lower of the original Huronian series was deposited is represented in the Timiskaming region by an erosion interval.' Furthermore, in the vicinity of lake Chibougiimau near lake Mistassini, a basal complex similar to that occur- ring in the Timiskaming region i.', overlain by a series of flat lying sedi- ments which structurally, lithologically, and in the sequence of its members corresponds in every respect to the Cobalt series, m> that it seems evident that the Huronian is represented in the Lake Chibougamau district also. The extent and stratigraphical relationships of the Huronian, as originally defined, has, therefore, 1 1 'n approximately determined throughout the whole of the great Timiskaming lK?lt, more than 40,000 square miles in area, and it is now known that with a few isolated exceptions, all the late Fre-Cambrian (for the most part undisturbed) sediments in this wide territory belong to the Huronian system. As regards the ba.sal complex which underlies the Huronian, the regional succession of formations has not been fully determined. The succession of formations assumed to be present by the geologists of the Ontario Bureau of Mines is that included in column I of the following table; the classification used by the writer is indicated in column H. * t Lorrain granite Ifneovs conlatt Timiskaming (cries Unconformity Banded gneisses (I.aurentian) Keewatiii n. Pre-Cotalt .scries granites and gneissex Igneous contact Timiskaming group Unconformity in part Abitibi group In the classification outlined in column I. it is assumed that the -surface rocks (volcanic flows and sediments) of the Timiskaming region are everywhere divisible stratigraphically into two .separate jjroups of nx-ks, the Timiskaming series, to which nearly all the sedimentary rocks > Uilld. W. C and Knight. C. W., Ann. Kept.. Ont. Burenu ot Mines, vol. XXIIl. pt. 1, t«l4. CoUiiu. W. H.. Gcol. Surv., Can., Mu«. Bull. No. S. IVU. 72 belong and the Kerwatin HericH whirh inrlu(i< h all the vulcuni(>; that th« Pre-Hurunian tiatholithic nxrlut urv uf two ag* ^<, tht- In It of banded gncis- MS rcprettcnting the older of the»e batholithic intru ives (Laurintian); and that the volcaniu rocka of the biu>al mmplex in the Timihkaming region are equivalent in age to the rucks classed as Keewntin in the region northwest ui lake Superior. The objection to all these assumptions is that they are hypotheses not yet established liy detailed investigation in the field. While the presenceof unmiiformable contacts here and there * i thin the basal aimplex indicates that at least two series of rocks arc pr >bably represented, the actual succession of formations present hcis nowhere been worked out to sufhcient completeness to determine that two and only two series of rocks are present or that all the volc.inics are older than the sediments. From an examination of the region.il m.ip which ;>nipanies this re|X)rt it may be obser\'e(i that the Pontiac M-nes, which I'ls U-m |)laced provi- ionally in the Abitibi group, intervenes In'twcen thi handid nnei».ses and the volcanics of the Pre-Huronian complex in a narrow Ixrlt almost continuously from the Ontario boundary to lake Matuhimanito, a distance of tlO miles. The position of the Poii ( lac series in this fxcition as a narrow belt extending along the margin of an intrusive m.issif. suggests that, just as in the case uf an intrusive laccolith the older fi !• mations adjoin the intrusive, so in this case liu Pon'iac series is oUh r than the volcanics which adjoin it on the north. On the other hand, if the Pontiac series lielongs to the younger group of sediments clasMd as Tiniiskaniing, the belt of banded gneisses which intrude the Pontiac series must be post-Timiskiiming and not pre-Timiskaming in a^e; so that cither the first or second of the assumptions cited is false. Further- more, in those portionsof Timiskaming county studied by the writer it was found that owing to the absence of well-defined beds in the basal complex which could serve as definite horizons in working out the geolo^jical strut - ture: to the predominance of volcanic rocks which generally do m.t oecur in such uniform beds as sedimentary rocks ; to the highly metamorphosed and (lefornied condition of the rocks of the complex; and lo the paucity of exposures, a large part of the basal complex Ix-'ing hidden from vi( w beneath the overlapping Huronian formation and jwst-Glacial lacustrine clays; it was not possible to work out the regional, structural, and strati- graphical relationships of the various formations composing the pre- Huronian complex. For these reasons it was deemed advisable to adopt a classification for the rocks of the basal complex which would 1h', as far as possible, a statement of what was actually known, and the pre-Huronian has accordingly Ix^en divided into three divisions: the Abitibi group, the Timiskaming group, ar. uxually callc«l Krewatin in the Timifkaming rcKion, If ha. term was oriKinally defini-d, m a hypothetical aswuniption. Theoritic.illy there is a basal Abitibi neries reprew nted in the pre-Huronian t-ompkx of the TimiskaminK region, but, in most localitii^ it is not possible to ixisitivcly (lifTerentiale this series in the fuki an«l for this reason the name Abitibi loup has bt'en used instead of Abitibi series. The Timiskaming group inciudcb all those surface rocks included in the pre-Huronian which are known to Ix- younger than other |)ortion« of the complex with whi( h they are associated. It has not been est,iblished however, that all these rocks are part of a single series and, on that acn)unt, the term group has Ihi n sul)^titufe(l for series. Although the presence of pebbles of granite in the conglomerate mcmlx-rs of the Timiskaming group and the Pontiac series indicate* that there was a granite older than the sediments at one time, if not at present, in the region, the surface rocks of the complex are intrudeil by the batholithic masses wherever they have been observed in contact with the latter. There is no positive evidence, therefore, that the batho- lithic rocks of the basal complex fwund in the Timiskaming region are of »PPLIED IM/CF '653 Eoal Uoin Street r?f^,"'l'' "*' "o"' '♦•■■■9 US* ("6) 462 - 0300 - Phone ("6) 288- 5989 -Fo. 74 Grenville series are not present in the Timiskaming region; and that the Grenville series is equivalent in age to the Abitibi or Timiskaming groups. Evidence that might be cited in favour of the first of these pos- sibilities is: that the Grenville series .. much more highly metamorphosed than any of the rocks of the Timiskaming belt; that the Grenville series is intruded almost everywhere by rocks of intermediate composition which might be equivalent in age to part or all of the volcanics of the northern complex; and that the central massif of banded gneisses, almost to its northern margin, contains bands of garnet gneisses and amphibolite which might represent recrystallized inclusions of Grenville series. The second possibility, that rocks equivalent in age to the Grenville series are not represented in the Timiskaming region, implies that the Grenville series was never deposited in the Timiskaming region or after its deposition was removed by erosion. This hypothesis is supported by the following observations: the rocks composing the Grenville series originally consisted of interstratified beds of shale, sandstone, and limestone, a typically marine succession of sediments, whereas the rocks of the Abitibi and Timiskaming groups consist mainly of volcanic flows and poorly sorted clastic sediments ; since Pre-Cambrian time, the Lauren- tian plateau has been almost continuously a land area and it is probable that this positive tendency was characteristic of the plateau even in Pre-Cambrian time, and that just as in the Palaeozoic so in the Grenville era marine sediments were mainly deposited on the margin of the plateau. The third possibility, that the Grenville series is equivalent in age to part or all of the Abitibi group or the Timiskaming group, implies that the conditions of deposition in these two sub-provinces were different in theGrenville era; for the abundance of unassorted sediments in the Abitibi and Timiskaming groups indicates that terrestrial conditions probably prevailed in the Timiskaming belt at the time these rock groups were laid down. It may be possible, therefore, that either the Abitibi or the Timiskaming group represents land deposits laid down contempor- aneously with marine sediments in the Grenville region. In recent inter-sub-provincial classifications it has been assumed thai the Grenville series was approximately equivalent in age to the Abitibi group (Keewatin). The principal evidence upon which this assumption is based is the apparent presence of two separate series of rocks in the basal complexes of both sub-provinces and the presence of areas ol ellipsoidal greenstones in the Madoc district of eastern Ontario which art said to underlie the Grenville series without evidence of unconformity It is assumed that the greenstones of the Madoc district are of the sam( age as the Keewatin volcanics of the Timiskaming sub-province and thus it is inferred that the Keewatin (Abitibi group) of the Timiskaming sub 75 province is older, but directly underlies the Grenville series. The object- ions that might be raised to this conclusion are: that it has not yet been established that there are two and only two series of rocks present in the basal complex of the Grenville and T miskaming sub-provinces; that even if there are only two series in each sub-province, these are not necessarily equivalent in age; and that the presence of lava flows in conformable contact with the Grenville sediments has little of age significance since volcanic extravasations are common phenomena in earth history. It is concluded, therefore, with regard to the relationships of the Grenville series to the surface rocks of the Timiskaming belt, that there are several possible relationships betwetn the rocks represented in these two great sub-provinces. Conclusive evidence in support of any of these possibilities is wanting. All that can be positively stated is that the rocks in both belts are apparently older than the belt of banded gneisses and that typical marine sediments such as characterize the Grenville series are either not represented in the Timiskaming belt or are buried beneath the accumulations of lava which occur so extensively in the northern terrain. ■I 76 CHAPTER V. GENERAL GEOLOGY. GENERAL STATEMENT. The rocks occurring ii Timiskamiiig county, like those of the Timi> Warning region generally, fall into four great divisions: the basal comple> the Cobalt series and associated Keweenawan ? intrusives, the Palaeozoi sediments, and the Quaternary Glacial and post-Glacial gravels, sand; and clays. Of the first three groups, the basal complex is geographicail by far the most extensive. TABLE OF FORMATIONS. The succession of formations arranged with respect to age in descend inji order, is as follows : Post-Glacial Stratified lacustrine clay and sand. Glacial Gravel, sand, boulders, boulder clay. Unconformity Paleozoic Silurian Niagara Calcareous sandstone and limestone. Unconformity ? Ordovician Black River Limestone. Unconformity Pre-Cambrian ? ...,,. Keweenawan Diabase, olivine diabase, olivine gabbro, syenit porphyry. Igneous contact Pre-Cambrian Huronian Cobalt series. Conglomerate. Arkose. Greywacke and argillite. Conglomerate. Unconformity Basat complex Pre-Huronian batholithic intrusives Granite, granite-gneiss. Syenite, syenite-gneiss. Granodiorite, granodiorite-gneiss. Diorite, diorite-gneiss. A[)lite, pegmatite. Mica .schist. 77 :he Timi>- I complex. Palaeozoic els, sands, raphically 1 desccnri- Abitibi group. Grenville series . Igneous contact . Sedimentary: Pont lac series: Mica schist, hornblende schist, staurolite schist, etc. AmphiboUte. Iron formation. Greywacke, arkose, conglomerate. Ferruginous dolomite ( ?) Iron formation. Conglomerate and agglomerate. Slate and phyllite. Igneous: Intrusive Lamprophyre. Ferruginous dolomite ( ?) Quartz porph>;ry. Diorite, andesite porphyry. Diabase, gabbro. Peridotite, serpentine. Extrusive Sericite schist. Quartz porjihyry, rhyolitc. Chlorite-sericite schist. Andesite, andesite porphyry, diorite. Amphibolile, hornblende schist, chlorite rock. Basalt, gabbro, diabase. . . Garnet gneiss. Pyroxenite. Crystalline limestone. bro, syenite BASAL COMPLEX. As was pointed out in the outline of the geology of the Ottawa basin, the surface rocks of the basal complex (volcanic flows and sediments) occurring throughout southwestern Quebec and the adjacent portions of Ontario, may be divided lithologically into two sub-provinces: a southern belt, in which crystalline limestone and other sediments belonging to the Grenville series predominate, and a northern belt in which volcanic flows and clastic sediments art t'le dominant members. Between the Grenville sub-province and the Timiskaming belt intervenes the central belt of banded gneisses. If a geological section be made, proceeding northward from the region where the rocks of the Grenville series are abundant, across the central belt of gneisses to the northern volcanic belt, it will be observed that along the southern border of the gneissic belt, tb-- gneisses intrude and include masses and bands of crystalline limestone and other metamorphosed sediments belonging to the Gren- ville series and that these masses and bands gradually decrease in size and numbers towards the north ' replaced almost entirely by the banded orthogneisses ; and that, ... A'ise, a similar relationship holds on the north, the rocks of the Abitibi group being intruded by the gneisses and gradually disappearing when traced (st)uthward) towards the gneissic belt. 78 Grenville Series. Timiskaming county, Quebec, can scarcely be said to include an; part of the great Grenville belt, the Grenville series being represcntic only in the southern part of the country by a few scattered masses oi bands of crystalline limestone, by mai^ses of pyroxenite or relatcc ferromagnesian rocks, which have probably resulted from the meta morphism of crystalline limestone, and by bands of garnet gneiss, whirl may also represent metamorphosed (argillaceous) portions of the Grcn ville series. The distribution, lithological character, and relationship' of these various rock types are described in the following sections. CRYSTALLINE LIMESTONE. Distributton. Crystalline limestone was observed by the writer in only one localiij in Timiskaming county, namely, on the northwest shore of Brennai r- Sairs lake — one of the series of bkes which together constitute tht ujjper Kipawa river — at the point whe/e the southern east-west trending portion of the lake bends northward. In the region east of Brennar lake, which was not examined, limestone was reported to be present bj the loc.ll inhabitants, but, throughout the territory north of Brennar lake, no limestone was seen and it is probable that the Brennan Laki occurrence marks the approximate northern limit of the Grenvillt limestone in Timiskaming county. Lithological Character. The Grenville limestone occurring on the shore of Brennan lake is i coarse, white variety, consisting of calcium carbonate t'-aversed bj numerous seams or zones of tremolite. Along the contact of the lin.estoni and the gneiss, a lime silicate zone has developed which, when examinee under the microscope, was found to consist of tremolite and diopside. Structural Relations. The Brennan Lake limestone occurs in two lenticular masses aboui 10 feet long and from 2 to 3 feet in thickness. These have almor.t i horizontal attitude conforming to the foliation of the enclosing gneis-s which, at this f)oint, lies almost flat. From the contorted and lenticulai forms of the limestone masses and the conformity of the lenses lo thi foliation of the gneiss, it is evident that the limestone has been subjectcc to intense deformation, and from the occurrence of lime silicates on theii margin, it is also evident that considerable contact action between tht gneiss and the limestone has taken place. 79 PYROXr.NITE. Distribution. Pyroxcnite was seen at several points on the southwest short of Sassaganaga lake, outcropping in elongated masses, about 10 'cct in width and trending in a southeasterly direction parallel to the strike oi the adjacent ^ i^iss. At the southeast end of Birch lake a small island i occurs which is composed of a rock, consisting of a carbonate, antli<)[)hyl- lite, and a green mica. The similarity in composition and mode of occur- rence of this rock to the pyroxenite indicates that the two rock types are related in origin and for this reason they have been described together. Lithological Character. The pyroxenite occurring on Sassaganaga lake is a massive greenish grey to resinous-looking rock which, under the microscope, was found to cont^ist of a colourless pyroxene, partly altered to yellow green serjKntine, carbonate, and pale green lamellar talc. The mass of rock composing the island in Birch lake, in the hand specimen, is a rusty yellow to white, fibrous rock containing scattered flakes of a dark green lamellar mineral. In thin section under the microscope, the rock is seen to consist of arithophyllite, partly massive and partly fibrous, carbonate, and a colourless lamellar hydromica. CYANITE AND GARNET GNEISS. General Character and Distribution. In numerous localities throughout the belt of banded gneisses, especially in its southern part, bands of biotite and hornblende gneiss were observed which contained garnet, also in two localities — on the north shore of Birch lake and on the north shore of Hunters bay, lake Kipawa — these beds of garnet j'neiss were observed to conty'.i cyanite. The relationships of these bands differed in no apparent way from those of the other portions of vhe gneissic complex; but the peculiar mintralogi- cal composition of the bands points to the possibility that they may represent metamorphosed remnants of Grenville sediments, and for that reason they have been included, for the purpose of discussion, in this section of the report. Lithological Character. The rocks belonging to this group are so variable in character that it is scarcely possible to adequarely describe all the difTercnt types collectively. The hornblendic varieties are generally dark uniform 80 rorks having the appearance of a diorite or amphilxilite. The biotit varieties, on the other hand, are light coloured and variegated in app( a ance, the minerals occurring in aggregates, biotite in one portion of t\ rock and quartz and feldspar in another. Throughout the whole roi srattertd red garnets occur, some of which have a diameter as great , J of an inch. In one band of this type occurring on Brul6 lake, a f( flakes of molybdenite were obser\Td. The cyanitic garnet gnci occurring on Turtle lake, except for the pale blue cyanite which it contain resembles the f)rclinary garnet gneiss, but that on Hunters bay, lal Kipawa, uIm) contains muscovite. The hornblende-garnet gneiss, when examined under the microsrnpi except for the presence of the garnet difTered in no respect from tli ordinary dioritic bands of the gneissic complex, the usual minerals pres-cr being oligoclase, blue green hornblende, biotite in variable quantitin and magnetite. The biotite types are granular rocks with a considcrabi variation in the size of the mineral grains and consist chiefly of quart; orthoclase, acid plagioclasc (largely oligoclase), garnet, and apatite A muscovite variety occurring on lake Kipawa, when examined under th microscope, was found to consist essentially of quartz in irregula grains showing undulatory extinction, garnet, deep brown biotite, an muscovite. AGE AND CORRELATION. The Grenville series, as has been already stated, is the name applie to highly deformed and crumpled masses of crystalline limestone, game gneiss, vitreous quartzites, and related ancient metamorphosed sedi ments occurring along the southern border of the Laurentian highland: These ocks are lithologically similar wherever they occur and, as fa as known, are in conformable succession and hence are assumed t constitute a single series. The crystalline limestone occurring on Bren nan lake has been correlated with the Grenville series because it i lithologically similar to a characteristic member of the series, it is !ocate( in the same geological province, and like the rocks of the Grenville series it is a part of the basal complex. The cyanite and garnet gneisses hav also been placed provisionally in the Grenville series because tiici mineralogical and chemical composition suggests that they are possibi; metamorphosed sediments and in that case are similar in origin and rcla tionships to the sillimanite-garnet gneisses of the original Grenville area The mode of origin of these rocks is discussed at greater length in th( section on the banded gneisses in Chapter VI. 81 Abitibi Group. GENERAL STATEMENT. It has been previously explained (Chapter IV) that the surtace rocks of the basal complex occurring in the Timiskaming region have been clasi-ifitd for the purpose of description into two divisions: the Timis- kaming group, which includes all the rocks which are known to be younger in age than other rocks of the complex with which they are associated; and the Abitibi group which includes those rocks which are known to be older than the Timiskaming group or of which the age is in doubt. Rocks of the first class, while present in the region directly to the west of the district, are not positively known to Ix; present in Timiskaming county, the relationships of the Pontiac series which constitutes the largest single belt of sediments in the pre-Huronian complex of the Timiskaming region, being in doubt. The surface rocks of the basal complex as ^presented in the nortiiern part of Timiskaming county are, therefore, all classified as belonging to the Abitibi group. DISTRIBUTION. Local intrusive masses of granite are so common throughout the region in which the rocks of the Abitibi group occur, that it is impractic- able to outline the areal extent of the group in detail. Except, however, for the areas underlain by granite and the narrow east-west trending belt of Cobalt series which overlaps the basal complex in Dasserat and Boischatel townshijjs, all the rocks occurring in the northern part of the region belong to the Abitibi group. The contact with the belt of gneisses, which limits the Abitibi group on the south in Timiskaming county, trends in an east-west direction from tho north end of Grand lake Victoria to lake Opasatika; but at the interprovincial boundary it turns abruptly to the south and continues in this dir«- tiop to a point about 16 miles below the upper end of lake Timiskf. ^ • » • it again trends westerly to the north shore of lake Huron. EXTRUSIVE ROCKS (, VOLCAMCS). "i General Character. -i The larger part of the Abitibi group is composed of a series of more or less metamorphosed volcanic flows ranging in composition from basalt to rhyolite. These are on the whole fine-grained aphanitic rocks, but locally in the interior of the flows they become coarse-grained and possess the textures of intrusive rocks. Their structure is exceedingly complex and unlike normal series of stratified sediments they contain no sharply defined, uniform, and easily recognized beds which might be used as 82 horizon markers; furthermore the bedrock surface throughout the n^;i in which they occur is, for the most part, hidden beneath the post-Gl.ic stratified clay deposited from lake Barlow. P'or these rei sons, it hii> i been pf)8sible to work out the structural relationships of the various pk tf) one another. They are all lava flows, however, and on this accm have been grouped together as the Abitibi volcanics. although tl may [xwsibiy represent rocks of widely different ages. The distribution given for the rocks of the Aibtibi group in gene applies equally well to the Abitibi volcanics except tii.K along ihesoiithi border of the territory occupied by the Abitibi group and adjoining i l)elt of gneisses, the Abitibi volcanics an- replaced by th»- belt of setlinu i composini; the Pontiac series. In the- description which follows, the Abitibi volcanics have In divided into three principal classes: (1) (a) basalt, diabase, and g ii)t) (b) amphibMallinc nilcM cuiiiti^tini; uf Minall phi-tiDcrysU of oliKiN'laHc-.iixloim' (nrlovcd in a Kruumtmasti of minute lath-likr rrytttulM of plagimlaM^' fpiloi.ixitii' tcxtitrt'); t'hluriti', and tt|XTktt of iron ore are uIm) commonly prtMiit. The '.iteration prcxtuctM usually ol>MTV«'d are epidote, jteririte. «()i>iH', chlorite, and carbonate. The feldcpiir phenocrynti* are seen in xotni thin sections to Ik broken and strunjj out linearly, a condition which ha.t evidently U-en hrounht alK)ut by the Howage of the lava after ihf ftkl»i>ar had crystallized. The diorites as a rule are com|x)se much decomposeil for mi( roscopic determination. When •ul'ti' irntly unaltered for the albite twinning to bv recognized, the maxi- mum extinction angle is generally found to be alwut 7 degrees, indicating' th.it the feldspar is an oligocla.se-andesine. Oth» r original minerals which commonly occur in the thorite are ilmcnite, titanite. and magnetite. The minerals of secondary origin generally present arc > >ritc, s»'ricite, zoisite, cpidote, and carbonate. Of these minerals, the chlorite results fron. the alteration of the ferromagncsian cfinstituents, while the sericite, ipi(li)t>, zoisitc, and carbonate replace 'he feldspar. In some Im'.dities, the r. idesites and diorites contain quartz in micrographic intergrowth *•'•'. feldspar and thus pe were not studied by the writer but are described by Dr. J. A. Bancroft in his report on this district published by the Mines Branch of the Department of Colonization, Mines, and Fisheries of Quebec. Th( peridotite which occurs in the vicinity of Kewagama lake is describid by Bancroft as follows. "Intrusions of peridotite are especially numerous in the vicinity of East Kewagama lake, west of Poirier lake, and on the northwest part of Indian peninsula. In places the peridotites arc nimmonly altered to talc, a light greenish mica, and a carbonate probably rich in magnesia and particles of black iron ore." The occurrences of peridotite found in the vicinity of De Montigny and La Motte lakes are described by Bancroft in the following quoUtioa "The most interesting Keewatin rocks within the area, are the peridotites and their scrpentinous equivalents. Fine-grained serpentine rocks, the relations of which are obscure, occur at a few points on Kienawisik (De Montigny) lake, and at two of the three outcrops on the river leading from this lake to La Motte lake. On the eastern shore of the latter lake and especially on the long narrow peninsula just to the west of the mouth of the river from Kienawisik lake, and upon the large island northwestward from this peninsula, they are especially well developed. Upon the other shores and upon some of the islands of this lake, partly talcose or serpen- tinous peridotites are exposed in numerous localities. In the eastern and central portions of La Motte township, some of the low hills arc composed of this interesting group of rocks. "Upon the long peninsula which has been mentioned, the peridotite i? fresh and displays a great variety in petrographical character. Upon the end of this point, where it is traversed by two small veins of asbestos. the rock is quite coarsely crystalline and displays beautiful lustre-mottling or poicilitic structure. Under the microscope it was found to be composed of olivine, biotite, hornblende, and augite with particles of black iron ore and pyrite." 89 Diabase and Gabbro. Rocks of this class which could be positively identified as intrusive in their relationships were not observed by the writer, but they are stated to occur both in the De Montigny (Kienawisik) Lake and Kewagama Lake areas, by Bancroft. In the Kewagama Lake district, according to Bancroft, diabase of this class intrudes the peridotite previously described. Diorite and Andesite. Although diorite belonging to the Abitibi group was not seen any- where in intrusive contact with the Abitibi volcanics, outcrops of diorite having the coarse texture which usually belongs to intrusive rocks were observed in several localities. The most coarsely crystallized occurrences of diorite observed were those seen on the north shore of the south- eastern bay of Labyrinth lake and on the eastern shore of Dufault lake. In both of these outcrops the rock differs only in texture from the ordinary diorite occurring in the lava flows and like the rocks of the lava flows has been subjected to intense metasomatic action. The rocks of these t\^o outcrops consist mainly of secondary hornblende, chlorite, and epidote. Andesite porphyr>' was observed in numerous small dykes intruding the mass of ferruginous dolomite occurring to the north of the Cascade rapids on the Kinojevis river. This rock is a fine-grained aphanitic type containing small feldspar phenocrysts embedded in an aphanitic matrix. Under the microscope it is seen that the feldspar phenocrysts are altered to sericite and epidote and are enclosed in a groundmass of small feldspar rods and epidote. I Quartz Porphyry. . Only a few dykes of quartz porphyry were observed which were I positively determined to be intrusive in their relationships. Intrusive I quartz porphyry is extensively developed, however, in the region adjacent 1 to Kewagama and De Montigny lakes' and it is possible that part, I at least, of the quartz porphyry occurring in the region east of lake I Timiskaming is intrusive in its relationships. Lithologicaily the intrusive I quartz porphyry is similar to the extrusive variety, except that in some I localities, as in the case of the porphyry dykes occurring on the shore of I Fortune lake to the northeast of lake Opasatika, it contains ferruginous I dolomite and chrome mica in addition to the usual metasomatic alteration I products. In Chapter VI much evidence is cited which indicates that 1 ^^'^'■'°"^ occurrences of chrome mica bearing ferruginous dolomite S 'Bancroft.!. A., "Min.oiwr. in the prov. of Qaebec." Ill 2, p. 20*; toil, p. 17J. 90 found in Timiskaniing county and the adjacent region have all possilih originated by the replacement of quartz porphyry or related intrusive: in a manner similar to that observed in the dykes on Fortune lako; i these dolomite rocks have been formed in this manner, they pron< rl\ belong to the intrusive rather than the sedimentary members of ih( Abitibi group and should be described in this section of the report Tin y have been classed among the sediments, however, for the puriion of description, not because the evidence is more favourable to this niodt of origin but because the evidence pointing to their igneous origin is not in all cases, conclusive. Lamprophyre. A dyke of lamprophyre was observed to intrude the Abitibi volcanic occurring on the southwest shore of lake Dufault and a dyke of siniiln rock was observed by Mr. Stewart J. Lloyd in the interior of the peninMil; which projects into Dufresnoy lake. Examined under the microsinfH this rock was found to be a minette, consisting essentially of crthod.iM plagioclase, biotite, and carbonate with chlorite, sericite, sphene, and iroi oxide as secondary constituents. The result of a chemical analysis of the minette from lake Dufresnov made by Mr. Lloyd, is given in column 1. The analyses of similar rock from other portions of the Timiskaming region have been inserted ii columns 2 and 3 for the purpose of comparison. Analyses c; tlinttte. SiOs . Al,Oj , Fe,0,. FeO CaO MgO Na,0 KiO TiO, H,0- H,0+ CO, 100 09 100 59 Nos. 2 and 3. Ann. Kept., Ont. Bur. of Mines, vol. 23, pt. 2, 1914, p. 12. SEDIMENTARY ROCKS. General Statement. The sedimentary rocks of the Abitibi group may be convcnicntl divided, for the purpose of geological description, into two chisse: these which occur as scattered local bands or masses in association witi 91 rK i 52 29 19 38 4 40 6 (H) 7 79 3 54 2 12 4 12 95 ■1 the Abitibi volcanics and those which bclopi; to the great band of sedi- ments known as the Pontiac series. The rocks of these two classes are in part lithologically similar, but their age relationships to one another are unknown and they are, therefore, separately described. Slate and Phyllite. Distribution. Slate and phyllite were observed in association with the volcanics of the Abitibi group on the north shore of lake Duparquet and at Clay rapids on Kinojevis river. The last mentioned occur- rence is, however, continuous with an area of greywacke similar to that of the Pontiac series, occurring on Clericy lake, and has been included provisionally in that series. Rocks of this class also occur in the township of Fabre' and it is possible that the fine-grained fissile sericitic schists occurring on the south shore of Chauvigny lake, on the Lacroix claim to the north of Beauchamp lake, on the south shore of Boundary bay on lake Abitibi, and on the property of the Union Abitibi Mining Com- pany to the north of Renauld lake, are metamorphosed sediments and, • I that case, to be classed with the slate and phyllite. Lithological Character. The slate and phyllite are fine-grained, grey to black, bedded rocks which, on microscopic examination, are seen to consist of chlorite, sericite, carbonate, quartz, feldspar, and pyrite, the proportion of these minerals present varying in the different types. The grey varieties generally contain an abundance of sericite and carbon- ate, the green an abundance of chlorite, and the black types contain graphite. Origin. The slate and phyllite wherever they occur have generally a vertical or nearly vertical attitude and are enclosed on all sides by the Abitibi volcanics. Whether they were deposited contemporaneously with the volcanics and folded up into their present position in company with them, or were laid down after the volcanics were extruded and later infolded into their present position was not determined; although their limited thickness, their uniformity of strike and dip, and the absence of evidence of a synclinal structure might be possibly regarded as indi- cating that they were deposited in conformable succession with the volcanics. They are all uniformly stratified rocks and were evidently deposited from a standing body of water. Their composition is approxi- mately the same as that of the volcanics, so that they might be materials derived from the volcanics by denudation of fine-grained volcanic ejectmcnta, the original characteristics of which have been destroyed by mt tamorphism. These generalizations include all that is positively I Harvie, R. "Geology of a portion of Fabre townihip," Mines Branch. Dept. of ColonizaUon, Mines, and Fisheries. Que. 92 known with regard to the origin and relationships of the slate ; phyliite. Conglomerate and Agglomerate. Several small elongated patches of squeezed conglomerate contain pebbles of greenstone and iron formations were observed in assoriai with the Abitibi volcanics, in Laverlochire township to the soiiili Lac Clair, and similar squeezed conglomerate is reported to occur in eastern part of Fabrc township.' Agglomerate was seen in only i locality in the whole region, namely on the shore and adjacent i>la of Duparquet lake, near the outlet of the Magusi river. This r consis ed of fragments of dark amygdaloidal greenstone enclosed ii chloritic matrix which in places contained considerable pyrite. Iron Formation. Iron formation was seen in association with the Abitibi volcai in three localities in Timiskaming county: to the south of Lac Claii Laverlochire township, on the portage from Riviere des Quinze Kakake lake, and on Bell river below Kiask rapids. The iron formation found in the Ltic Clair district is included in belt of Abitibi greenstone which extends from Lac Clair eastw.i It occurs as a number of exposures a few feet in length outcropping intervals for 2 miles, the maximum width of the exposures being feet and their strike 6 degrees south of east. It consists of bands siliceous magnetite and vitreou.j quartz having an average width of ah half an inch. It contains considerable pyrite in places, has been gre;: faulted and brecciated, and is cut by porphyry dykes. The iro.i-bearing rock observed on the Kakake portage occurs i band about 30 feet wide and 100 yards in length and is composed bands of siliceous magnetite interlaminated with layers of white, r and grey quartz. The strike of the formation is north 20 degrees i and the dip 70 degrees northwest. The third occurrence of iron formation observed in association w the volcanics of the basement complex, is merely a small exposur few feet in diameter outcropping near the north end of the portage Kiask rapid on Bell river. It consists of siliceous magnetite ini banded with chlorite. Ferruginous Dolomite. In almost all districts in Timiskaming region where the Abi volcanics have been mapped in detail, scattered masses and bands c chrome mica ferruginous dolomite have been found in association w ■ Harvie, R., "Geology of a portion of Fabre townthip," Minet Branch, Dept. of Coloni»tioa, M and Fisheries, Que. 93 ihf volcanics. All tlie occurrences of this rock in Timiskaming county, yutbcc, are of very limited extent: it was obsfrvo (olour due to the presence of disseminated chromiferous mica. When examined in thin section under the microscope, the rock is seen to consist ' of pyrite, chrome mica, sericite, quartz, and feldspar, the proportion of I these minerals present, varying greatly in diflFerent localities. I Further details with regard to the character and relationships of i ihis inte'-esting rock are presented in the discussion of the origin of the 4 ferruginous dolomite in Chapter VI. Pontiac Series. General Statement and Distribution. The Pontiac series embraces in assemblage of rocks which have been separately designated, not because it has been definitely established that they are of diflFerent age to other portions of the Abitibi group, but because they are lithologically different from the Abitibi volcanics and associated rocks, because they occur in a single great belt, and because they were apparently laid down fluring a continuous period of deposition. The rocks composing the series may be grouped, for the purpose of description, into four classes: grey- wacke, arkose, and conglomerate; iron formation; amphibolite; and mica schists, hornblende schist, and staurolite schist. All the rocks occur in an east-west belt averaging about 10 miles in width and extending continuously across the central part of Timis- kaming county from the interprovincial boundary and the north end of lake Opasatika to Grand lake Victoria and lake Matchimanito, a distance of 110 miles. The limitations of the belt are sharply defined, on the north, in Dasserat and Boischatel townships, by its contact with the over- lying Cobalt series and from thes- townships eastward by its junction with the Abitibi volcanics. On the oCJth, on the other hand, the boundary is indefinite because of the wid*" Intruded zone which marks its contact with the belt of banded gneiss. Greywacke, Arkose, and Conglomerate. The belt of sediments compos- ing the Pontiac series has been so greatly metamorphosed by the intrusion of the great belt of gneisses which adjoins it on the south that it is only 94 along the northern border of the Ix-lt that the sediments retain any trace ot their original clastic character. Throughout the region north of Kekeko, Kinojevis, and Kiekkiek lakes, there is a marginal zone about 1 miles wide, consisting of greywacke and arkose which, here and thirc, contains aggregates of squeezed granite and rhyolite pebbles. On tht northeast shore of Garden Island lake, there are also two small outcnip- of mashed conglomerate similar to that on Kinojevis river and Kiekkiik lake. In this locality some of the softer and less resistant pebbles hav( l)ecn so flattened by deformation that they are now represented hy ttiin platos embedded in a mica schist matrix. In thin section under ihi microscope the greywacke, arkose, and the conglomerate matrix are seen tii consist of fragments of feldspar and quartz, generally more or less cornidi li and granulated on their margin, embedded in a fine-grained matrix ol the same minerals along with varying amounts of chlorite, sericiic, carbonate, and iron oxide. The arkose differs from the greywacki' merely in the smaller ptirportion of ferromagnesian material which it contains. It is only in a few localities that the original characteri.-iio of the greywacke, arkose, and conglomerate of the Pontiac series Ii.i\t been sufficiently well preserved to afford definite information with regard to the manner ip which these rocks originated. Their stratified char- acter and their occurrence in a belt 110 miles in length would indicate that they were laid down from a body of water of large extent: tht- coarseness, angularity, and unsorted character of the material a)mpo!-itij; them, on the other hand, point to shallow water deposition. Other features such as cross-bedding and ripple-marks, which might have aided in determining their original character, were not observed, possibly because they had been destroyed by deformation. All that can be said with regard to the mode of origin of the greywacke, arkose, and con- glomerate is that these rocks are characterized by features which might belong to sediments deposited on the flood-plain of a river, on a delta, in a large lake, or in a shallow sea. Iron Formation. Iron formation is known to occur in association with the Pontiac series in Cadillac township to the south of Newagama lake, and on the east shore of lake Matchimanito. The former occurrence is described by Bancroft as consisting of slates rich in magnetite inter- banded with foliated, grey quartz, slate, and schists, the whole having a vertical attitude and a strike a few degrees south of east. The zone throughout which the magnetite lamina; are present has a maximum width of 1,300 feet and length along the strike of 2 miles. The iron formation occurring on the east shore of Matchimanito lake is very similar in cliaracter to that occurring in Cadillac township, but the Pontiac series in its vicinity is represented by a garnctiferous and stau- rolitic .schist. The iron-bearing rock outcrops throughout a zone 30(1 9S yards in width and half a mile in length and consists of a laminated, magnetite-bearing, mica bchist having a vertical attitude and a strike of north 60 degrees east. Microscopically, the rock is seen to consist chittly of granular quartz and magnetite and parallel flakes of mica, with epidote, chlorite, sillimanite, and apatite as accessory constituents. The alternating laminx all a)ntain the same mineral constituents, but the proportion of the constituents present is variable, some bands nmtaining more magnetite and correspondingly less quartz and biotife than others. These iron-bearing rocks are stratified deposits and are undoubtedly M'dimintary in origin; but, whether they were originally laid down in their present form, or as hematite, or, as in the case of some of tin- iron- Ixaring formations to the south of lake Superior, as iron carl^onate or iron silicate, cannot now be positively determined. If iron carbonate or iron silicate were ever present, these minerals were long ago destroyed ; on the other hand, it is significant that whereas the Pontiac series as a whole is composed of unsorted rocks and in only a few localities, as far as known, consists of slate or staurolitic schist — rocks generally regarded as repn;senting the ultimate products of weathering — it is in association with these rocks that the iron formation is found. Furthermore, the iron formation, except for the magnetite which it contains, is similar in mincralogical composition to the ordinary mica schist of the Pontiac series, a feature which indicates that the iron was deposited originally as iron oxide rather than as a silicate or carbonate. Amphibolite. At a number of points within the belt in which the Pontiac series occurs, outcrops of amphibolite were observed, which have been included in the Pontiac series because of their geographical associ- ation although lithologically they are similar to the Abitibi volcanics. These rocks are exceedingly variable in texture, colour, and structure, but are alike in being composed for the most part of amphibole. When examined under the microscope, the light green varieties are seen to be composed chiefly of tremolite, or actinolite, whereas the dark green varieties contain an abundance of blue green hornblende. Some thin sections of the rock contained considerable magnetite, some contained garnet, and one contained diopside. The most typical amphibolite consisted of hori.olende, alkalic feldspar, quartz, biotite, magnetite, titanite, and carbonate. The amphibolites of the Pontiac series were not observed in direct contact with the other members of the series and neither their mode of origin nor their relationship to the other rocks of the Abitibi group were determined. In some localities, as on Kinojevis river, outcrops of the amphibolite occur which have a botryoidal appearance on the weath- erid surface somewhat similar to the pillow structure of the Abitibi 96 volcanics — a feature which indicatett that in this locality the ampl bolite may represent a volcanic flow preHUtnably ctjntempurnncnus age with the Pontiac scries. In other localities, the aniphibf regards the origin of thi- Pontiur ttchistx it i" Itclitvid tli ihiir I beddid character, their mmpuhitiun, especially where they ontain I highly aluminous minerals such as staurolite and K^rnet, their cryst.d- I lobla»tic texture, and tlie transition from the schist to greywai ke, arkose, J and conglomerate,' on passing northward awiiy from the great Ix-lt of J intrusive gneisses, indicate that they weie originally sediments which ■ haw been metamorphosed into schif-t by the great batholithic massif i which adjoins them on the south. Granites and Gneiues. i ; r.ENEPAL STATKMENT. A large part of Timiskaming county, Quebec, in common with th» Laurcntian plateau generally, is underlain by granites and gneisses I which in this report, for reasons explained in Chapter IV, arc referred t<> collectively as the pre-Huronian batholithic intrusives. For the I purpose of description these rocks may be conveniently divided accordin); V to their distribution into two great classes: the granites and granodiorite^ occurring as isolated batholiths here and there throughout the belt of : sediments and lavas composing thr Abitibi group, and the grt^t belt composed largely of banded gneisses which occupies nearly the whole of the southern part of Timiskaming region. NORTHERN 3ATHOLITHS. General Statement. The rocks composing the no**hern batholiths are chiefly granite , or gneissoid granite passing locally into granodiorite, and occur as irregular * masses ranging from a few hundred feet to several miles in diameter. ■; These have intruded their way through the rocks of the Abitibi belt ; with which they are in contact. It may be observed from an examina- tion of the map which accompanies this report, that only a part of the batholithic masses have been outlined in detail, but all the masses seem , to be remarkably similar in character and belong to the class of rocks generally described as subalkalio. Lilhological Character. The northern batholiths are chiefly composed of medium to coarse- grained, granular rocks, having the mincralogical cximposition of a hornblende or biotitc granite. In the hand specimen the prevailing typi' is fresh-looking pink, white, or grey rock having a more or less ^!«ck!ed appearance due to the scattered crystals of hornblende or mica ■Crtol. Surv.. Can.. Mem. 39. 1«I3, Platea XVI, XVII, and XVIII which it containx. Very i-ommcinly the ferrumaKncxian mineraU h.ii a piirallfl arranKfmcnt, but a gni-iiiiMiid ntrufture in the most of tl batholithst in not c(>n»picuoui*. One of the striking peculiaritio of ti northern batholithH i» the great heteroReneity which prevails mar everywhere. Very commonly a granite containing very little liiuti may be >ecn to have broken through a granite in which this mineral more abundant or more finely diHseminatetl, or a hornblende granii may Ix- cut by a biotite granite in a similar manner. In some pl.in long schlieren of granite containing a larger proportion of biotite ilia the surrounding rock are present, and in other localities masses of hon blendite are common. These, however, arc very probably masKo i the Abitibi volcanics which have lx>en broken off from the walls of \\ magma chamber durin^ the intrusion of the batholith. Pegmatite an aplite dykes and quartz veins are abundant in all the batholiths. The microscopic examination of these batholithic rocks shows thci to be largely granites consisting essentially of hornblende or biotii or both of the"" minerals with orthoclase, microcline, soda plagioclas (albite to oligoclase), and quartz as salic constituents. In a few localitie the hornblende granites pass into granodiorites, quartz diorites, or eve diorite, by the loss of potash feldspar and quartz, but these occurreiia are of limited extent. In the Kcwagama Lake batholith, which i some respects more closely resembles portions of the great southi-r batholith than the other northern batholiths, muscovite is also a abundant constituent. The less common minerals occurring in this Dcks are apatite, titanite, muscovite, epidotc, allanite, magmtin ilmenite, calcite, pyritc, and chlorite, the latter being always of sccoiular origin after hornblende or biotite. In those places where the feldspar have undergone metabomatic alteration, they are largely transfornip ii. io sericitc or to sericitc, zoisite, and epidote. The aplite and pegniatit when examined microscopically were found to consist chiefly of quart; orthoclase, and microcline, with muscovite in subordinate quantity Aci-cssory minerals observed were magnetite, biotite, calcite, and garnci BELT OK BANDED GNEISSES. General Statement and Distribution. Practically, the whole of the southern part of Timiskaming county Quebec, is occupied by the L It of banded gneisses, which, as has tieei previously explained, extends continuously irom Georgian bay on thi west to the gulf of St. Lawrence on the east. The junction line betr eei the Timiskaming belt and the belt of gneisses crosses lake '^im":'tamin| al a point about 30 mites from its north end, and east of the lake turn almost directly north continuing for 60 miles to lake Opasatika, fron 99 I I which jxiint it ttinlinuoit iipprnximati-ly t-axtwarcl acr»»ii the cinmty to the north end of (irand lake Victoria. With thi- t-xrt-ptiun of a few liKiil .man orcupiecl l)y thi- limcNtone and pyroxiniti* of the Grenville xrit' ihi region not"' of thin htu' of junction itt underlain almost wholly liy liaiidi'd RneiHMH. Lilholonical Character. The rcK-lcH of the Ix-lt Kneiiwcd differ from the northern hatholithH nd. only in pottsewinR chararteristirally a foliated structurc but also in the l).mded and foldeegmatite, and belongs to the pegmatite and aplite division described below. The common accessory minerals found in these rocks are cpidote, titanite, garnet, zircon, and apatite. The minerals arfved- ^onite and aegerine are also present in some thin sections of granite yniisis occurring in the district to the north of the upper Kipawa river. From the microscopic examination of thin sections of the granite and granite gneiss it is seen that, in some places, the constituent minerals art' remarkably fresh, whereas in otiiers the feldspars are largely replaced Ijy sericite and the hornblende and biotite by chlorite. Between those two extremes an intermediate rock type is also common in which seri- citizcd feldspar occurs enclosed in a matrix of fresh, granular, quartz and microcline. In some sections, too, the minerals show by their undulatory extinction and granulated character that they have been -ubjccted to intense mechanical deformation. In others, however, all these evidences of deformation are entirely w.inting. Syenite and Syenite Gneiss. The syenite and syenite gneiss are com- monly a grey to rusty red rock, which in most localities shows a remark- able tendency to disaggregate into its constituent mineral grains on the weathered surface. Examined under the microscope, the syenite and ^^ycnitc-gneiss are seen to consist essentially of orthoclase, albite, micro- P*"rthitc, aegerinc, and dark brown biotite. The accessory constituents 100 observed arc titanite, apatite, zircon, epiciote, and magnetite, llnd the microscope, it can also be seen that the disaggregation on tl weathered surface arises from irregular fractures which traverse the ro( along the contacts of the mineral grains. The cause of the fractures not apparent, but they are possibly related in their origin to tl pressure which no doubt accompanied the slight decomptjsition whic has occurred in the aegerine. The syenite and syenite gneiss lia\ their greatest extent in the region adjacent to the upper Kipawa rive a few miles east of lake Kipawa. Granodiorile and Granodiorite Gneiss. The granodiorite and grin: diorite gneiss are rocks of similar appearance to the granite and grani gneiss, but their mineralogical comp)osition shows them to occu()y a intermediate position between diorite and granite. They contain nuu less quartz and orthoclase than the granite and corresfwndingly nioi plagioclase,and biotite is replaced by hornblende as thedominantferruma nesian constituent. The accessory mineral constituents, mineral alter, tions, and evidences of mineral deformation are the same in the gram diorite as in the granite and granite-gneiss. Diorite and Diorite Gneiss. The diorite and diorite gneiss are dai rocks containing an abundance of glistening crystals of hornblend Examination under the microscope shows most of the rocks of this clai to consist essentially of blue green hornblende and plagioclase (eithi albite, oligoclase, or andesine), but in some thin sections the proportit of plagioclase becomes so small that the rock might be more appropriate! called a hornblendite. The common accessory minerals observed ui garnet, magnetite, biotite, titanite, epidote, and zircon. The hornblem and biotite are commonly more or less altered to chlorite and the plagii clase in some sections is entirely replaced by sericite and epidote. Pegmatite and Aplite. The rocks of this class occur in i\ gneiciic complex partly as parallel bands, partly as included leii.-e and partly as crumpled dykes intruded transverse to the banding an foliation. They consist largely of quartz, orthoclase, microclinc, an albite, the names pegmatite and aplite being used according as the rot is coarse or fine-grained. In addition to the quartz and feldspars alread mentioned, numerous accessory minerals were ofeerved in the pcgniatii and aplite, of which the following are the most abundant: muscxniti biotite, apatite, garnet, allanite, graphite, molybdenite, epidote, tiiaiiit. and cyanite. Mica Schist. Within the belt of banded gneisses, there are sever, occurrences of mica schist which are possibly, in some cases at lca.> altered sediments; but, because their mode of origin is in doubt an because they are closely associated with the gneisses, they have Kt- included in the belt of banded gneisses. One common tyi e of nik 101 schists occurring in the gneiss is a fine-grained aphanitic rock containing broken and rounded fragments of feldspar which give the rock a por- phyritic appearance. This was observed in four widely separated local- ities; on the south shore of Hunters lake, on lake Ostaboining, at the north end of Trout lake, and near Mink narrows on Twenty-one-mile bay, Grand lake Victoria. Under the microscope, this schist is seen to consist of fragments of biotite, quartz, and feldspar enclosed in a fine- grained matrix of the same minerals. In some of the thin sections examined, the rock has an appearance closely resembling that of an arkose, but the abundant evidence of fragmentation in other sections suggests that it is in reality of igneous origin, and has assumed thi«. clastic appearance as a result of deformation. Mica schists resembling the Pontiac schist were also observed in several localities within the central belt of gneisses. These are hnc- grained rocks consisting of biotite, quartz, orthoclase, and albite, and possess the mosaic-like, crystalloblastic texture so characteristic o! iiie paragncisses. On Grand lake Victoria, there is an area of these rocks several square miles in extent, which contains a very large proportion of pink garnet. The presence of such a large proportion of this highly aluminous mineral indicates that the schist has the chemical composition of a sedimentary rather than an igneous rock and is probably a paragneiss. In the following table are included the chemical analyses of five rock specimens collected by A. E. Barlow from the belt of banded gneisses.' A nutyses of Gneisses. i ' i 2 69 .?9 17 46 . 3 ! 4 1 i 5 Silica .Alumina. . . Ferric oxidp Ferrous, oxide .M.innanoiis oxide 71 69 1 . 1 14.84 tr. i. 103 37 67. 74 16 13 1 .50 1 96 tr. 4 41 1 36 1 M) 4 92 10 86 . 67 ,S0 IS 23 ; 2 39 :' 1-8^ 1 -56 4 25 3 79 , 0(18 90 1 44 92 i 18. 8S 2. 73 13 76 ' 26 9 07 538 053 2 94 20 1 62 l.itiie- . . .Mafjne-i.i ... 2 14 52 2 77 5. IS 06 47 l'0t,ls.«il Soda Water at IOO°C " above 100°t'. . . . I 7.09 ..; 3.13 ..i 010 49 Totals 99 9<> j 99. 37 ! 1(K) 2.S KKI 55 100 29 , 1 (.raniie Knei.ss from the weM shore of TaREarts bay, lake Kipawa -I , ';'■•'"!"-' 8"'^'.*'* from the south shore of .McLaren bav, lake Kipawa I n„r *'"""' gneiss from west shore of lake Timiskamiiig, at north end of Opinaka 1- 4. (.ranite gneiss from the northwe.st shore of Leonard inlet, Wiiksiml lake X yuartz-mica dioritc pneiss from Ottertail creek, lower end il ilie second ixjrtace i above the junction with the north branch. 'Util. ."^urv.. Can., .Ann. Kept., pt. t, I8y7, p. jj. 102 Structural Features. Foliation. Everywhere throughout that portion of the great ctnti bi-lt of gneisses studied by the writer the rocks, as the term j;ne implies, were ail highly foliated. This foliation arises for the most p; from the (larallel orientation of biotite plates and hornblende prisn but also, in some cases, from the flattening of the feldspar and qiui in the same plane. Very commonly the biotite of the biotite gnc i^s seen to "eye" around small lens-shaped fragments of feldspar, j;ivi rise to the characteristic augen structure, which results from deformatic The trend of the foliation, like that of the banding, indicates that it li the form of anticlines and synclines simulating the structure of fold sedimentary rocks in every respect. Banding,. The most striking and the most characteristic struitm feature of the central belt of gneisses is the banding which is everywiu developed (Plate IX). The extreme complexity of the strurtiii exhibited by these bands and the heterogeneity of the rocks which th contain even in a singk rock outcrop are scarc( iv capable of descriptic yet when examined over broad areas, this complexity and heteroj;* lui is so uniform that it beaimes monotonous. The banding of the giu is: may arise either from a variation in the proportion of minerals prcsc in the same rock or by the alteration of bands of different rock. Thi one of the most common types of banding is brought about by t alternation of bands of biotite gneiss containing varying proportions biotite so that a light band, in which little biotite is present, alternat with a dark band c"ontaining a large proportion of biotite. In a simi manner, variations in the proportion of hon.blcnde in the hornhlcii granite gneiss, the granodiorite gneiss, or the diorite gneiss result in banded structure. The second type of banded structure, in whirli t alternate bands are composed of diP ent rocks, may also be ronibin with bands of the first types, and in this way an almost infinite vari.iti in the composition of the bands may occur. The commonest nxk the banded gneiss is the biotite or biotite-hornblende granite gnci^^: li pegmatite and aplite are also important, composing not less than 1.^ r rent of the whole. The proportion of other rocks is small, so that t central belt of gneis^ses, considered as a whole, is granitic rather th dioritic in composition. The width of the bands may vary fnmi fraction of an inch to hundreds of feet. When followed along the stri they are commonly found to pinch out as though they were in nali thin lenses. This lenticular character is particularly evident in the ca of the pegmatite, which commonly occurs as a succession of Icii; (Plate X) around which the foliation in the surrounding gneiss hen in a manner very similar to that which occurs on a small scale aroui the augen of feldspar in the augen gneiss. 103 Granulation. That granulation has occurred to a large extent in the landed gneisses is apparent from the abundance of augen gneisses and from the evidence of strain and fragmentation seen in some thin sections. Rccrystallization has followed granulation in many cases, however; for in many rocks which have very evidently suffered granulation, the granular quartz and feldspar which surround the lens of the augen contain a large proportion of microcline and are much fresher in appearance than the central core. Folding and Faulting. The study of the structure of the banded gneisses indicates that they have been folded in a manner very similar to that exhibited by deformed sedimentary rocks. Though the bands are not continuous over wide areas like sedimentary beds, yet all the various types of folds are present on a small scale and, in places, anticlines and synclines, nearly a half-mile in cross section, can be recognized. These folds are generally pitching and, since the strike of the bands is dominantly in a southwesterly direction, it is inferred that the banded gneiss has been folded into pitc' -ig anticlines and synclines having a southwesterly trend. In some pieces the biotite has been smeared out along the contacts of the bands, giving a slickensided appearance which has, evidently, Ited from differential movements accompanying the folding. On the whole, faulting has been subordinate to folding in the gneisses, but faults of both the overthrust and normal types are present. The pegmatite and aplite dykes which are transverse to the banding of the gneiss have been very commonly intruded along fault planes, for the bands on opposite sides of many of the dykes have been relatively displaced. HURONIAN. Cobalt Series. GENERAL STATEMENT. The second great division of the Pre-Cambrian in the Timiskaming region is represented by a group of approximately flat-lying clastic sediments (conglomerate, greywacke, argillite, arkose, and quartzite) which, as far as has been determined, are in conformable succession and thus constitute a single series. These rocks are not sharply defined members occurring everywhere in the same definite succession, nor are all the members pr-sent in every locality. Nevertheless, as shown in the following table, in those localities where the most complete sections of the series are present, there is commonly a basal and upper conglomerate with greywacke or argillite and arkose or quartzite as intermediate members. 104 Sections of Cobalt Series. Locality. Rock member. Thickness FEET. Contact Basai COMTLE Kekeko hills Cross-bedded, pebbly ar- kose and conglomerate 5.50 l.SO 50 + Not exposed Pontiac schiat Conglomerate 750+ North end lake Arkosc 220 Opasatika Conglomerate 80 Gradational Pontiac schist 300 Swinging hills Arkose 250 365 70 Not exposed Abitihi ? Conglomerate 685 Mount Shiminis Pebbly greywacke Arkosc 90 ISO 250 ? Not exposed Pontine 8chibt*< Greywacke and argillitc. 490+ Labyrinth hills Coarse conglomerate . . . Arkose ? 65 165 175 ^' .Aposed Abitibi volcani 405 Lavallee bay, lake Timiskaming Arkose Greywacke and argillitc Conglomerate ? ? ? Not exposed > 350 Little river, east shore Arkose ? ? Not exposed lake Timiskaming f ireywacke . Conglomerate ? !» Bale des Peres, lake Timiskaming Quartzite containing pebbles of jasper and ? ? Gradational Arkose Conglomerate Joaiine bay, lake Timiskaming Quartzite containing pebbles of jasper and quartz . . ? 35 Not exposed Conglomerate > East shore lake Timiskaming, north of Wright mine Pebbly quartzite Red argillite and grey- wacke Congloincraif ? ? 30 Not exposed ; 105 Basal Complex, Locality. West shore of Antler lake Rock member. Lot 40, range IV, Duhamel tp. Coarse conglomerate . . .Argillite Thickness FEET. Contact 75 Basal COMFLBX. Not exposed Pebbly quartzite . Arkose Conglomerate. . . 250 Gradational Granite In the preceding table it may be observed: that in every locality where the base of the series is exposed, the basal beds consist of coarse : unsorted conglomerate; that in most localities the basal conglomerate i is overlain by ^reywacke or argillite followed by arkose or quartzite, or . the grcywackc and argillite are absent and the arkose or quartzite rests directly on the conglomerate; and that in several localities the arkose- j quartzite member is overlain by an upper conglomerate. There are, I however, some .(j parent variations from the usual succession as well as striking changes in the character of the different members in different localities. Thus the Kekeko hills, in the whole of their upper parts are 3 composed of rudely sorted arkose and conglomerate; and, though uni- : formly stratified greywacke and arkose occur in the vicinity of the base ) of the hills, these members were not seen in the hills proper and may be , entirely absent. If this is the case then the whole Kekeko ridge, 750 feet = in height, might be regarded as simply an upward continuation of the ; basal conglomerate. Another example of a variation from the usual I succession of the members occurs in the Antler Lake section where the - upper conglomerate rests on argillite, the arkose-quartzite member ; b(ing absent. The marked variations which occur in *he character of the same member even in adjoining localities is illustrated by the upper J conglomerate which occurs at the top of the Labyrinth hills and Mount Shiminis. In the first of these localities the conglomerate is an exceedingly coarse variety containing boulders up to 2 feet in diameter; that on mount ^ bhmims, on the other hand, is a fine-grained greywacke in which small I iir'^'^'f ^"^ disseminated. In the region adjoining the cast side of iake < limiskaming, the Huronian is represented by great ridges of pebbly I quartzite which differs from the arkose-quartzite members of the Cobalt : Hnes found elsewhere in its more highly sorted character and in the sixbbles of quartz and jasper which it contains. As far as could be I determined, this rock apparently occupies the same stratigraphir position ;a. l,e arkose member of the Cobalt series, resting on gr ywacke or 106 argillite in places and in otiicr localities passing gradually downward in arkose-con glomerate developed in situ on the surface of the basal complt> In the region to the west of lake Timiskaming, however, a similar p a partial alignment of its pebbles and boulders. If classified according u> the character of the matrix the basal conglomerate would fall naturally into two groups: a greywacke conglomerate in which the matrix is com- p-wd of greywacke and an arkose variety in which the pebbles and bouUkrs are enclosed in arkose. Of these two varieties, the latter is much more common in Timiskaming county, although the greywacke conKlomerate is also extensively developed in some localities notablv along the cast shore of lake Timiskaming. It was to this rock that the name chlorite slate conglomerate was applied by Sir William Logan in 1«47. The pebbles and boulders of the conglomerate incluntent or by an alternation of fn-dji of the tw(» I riH-ks. This member is a stratified, firmly cemented feldspathic sand \ which, when examined microscopically, is found to consist of rounded, i angular, or subangular fragments of quartz and feldspar with small' quantities of calcite, sericite, cpidote, and pyrite. In places, as in the .irkose occurrinff along the east shore of lake Timiskaming, ripple-marks ran be seen on the surface of the arkose beds. Upper Conglomerate. I Where an upper conglomerate was seen overlying the greywackc- ' argillite or arkose members of the Cobalt scries, it was found to difTcr in no respect from the basal member of the series, exhibiting the same httirogeneity, in the variety, size, and angularity of its pebbles and iiouldirs and in the composition and texture of its matrix. Ville Marie Quartzite i In portions of the region east of Lake Timiskaming and notably in the vicinity of the village of Ville Marie, a quartzite occurs consisting . of well-rounded grains of quartz and minute flakes of green sericite. As : has been previously explained, this rock is lithologically similar to a quartzite found in other parts of Timiskaming region occupying a strati- graphical position above the other members of the Cobalt series. On this account it is here separately described as the Ville Marie quartzite. i RELATIONSHIPS OF THE COBALT SERIES TO THE BASEMENT COMPLEX. It was explained in the discussion of the physiographic history of : Timiskaming county, that the Cobalt series was laid down at the termin- ation of a prolonged period of denudation during which the crumpled and metamorphosed rocks of the older complex were worn down to base level; so that the pre-Huronian surface must be regarded as a buried peneplain or palaeoplain. At those points in Timiskaming county where :. the basal conglomerate can be seen resting on the older basement, the I contacts are of two strikingly different types; in one, the line of contact I is exceedingly well defined, and, in the other, the basal conglomerate j passes gradually downward into unbroken rock, no definite line of junction B being visible. I Contacts of the first type can be seen on the east shore of lake I Timiskaming in lot 18, range I, Fabre township, at a point about one I mile south of Kennedy lake, in Dufay township, on the east side of the I large island of Dufay (Rest) lake, and on the south shore of Dufay lake. I In the lake Timiskaming locality the conglomerate rests on sjr.nnitc with I an irregular but definite contact, the conglomerate filling in the inequal- no itics of the K^'nitc surface. Where the TOiitact ii« expoKed on the isl in Dufay lake the i-onglomerate lies on a flat surface of Pontiar sc into which dykes of granite have U-en injected piirallcl to the schinio^ In both the other localities the conglomerate rests on smoothly im granite, the surface exposed on the south shore of Dufay lake h.i> a slope towards the north. Contacts of the transitional variety were seen in numerous loialii on the shore of lake Timiskaming at V'ille Marie, and opposite Drun island, at several points in Laverloch^re township, on lot 5, ranKi Guigues township, in the northern piirt of range IV', Duhamel t<)wn>l at the north end of lake Upasatika, on the south shore of Nissaki h and at the northwest end of Renauld lake. The contact between the Huronian and the older granites ex(H) on the east shore of lake Timiskaming at Baie des Pires exhibits transitional relationship in a most interesting manner.' The first st in the transition observed is a gradual change in the rc.lour of the uiir lying granite from pink to pale green — a transformation which is w u.: Icr the microscope to be due to the alteration of the feldspar of granite to sericite. Above this zone of sericitized granite, masse^ which the sericitization has been less intense are indicated by faint dif] ences in ailour on the weathered surface. These differences become ni and more evident at points more remote from the contact until transition to typical conglomerate with an arkose matrix is compN Accompanying the change in colour of the rocks there is a grad increase in evidences of mechanical disintegration and sorting, the arkr conglomerate finally giving place to arkose and the arkose to peb quartzite. In the northern part of range IV, Duhamel township similar degradation of the granite surface is shown in a section 200 I in thickness, consisting of boulders and fragments of granite cnclo; in an arkose matrix. In this locality the feldspar of the underly rock is white in colour, and has not undergone decomposition to serii to such an extent as that on the lake shore; in consequence, there is so lii contrast between the two rocks that the line of junction cannot fixed within wide limits. The slight mechanical action to which disintegrated feldspar and quartz have been subjected also makes exceedingly difficult to distinguish the matrix from the enclosed f ragmen masses. Junctions between granite and conglomerate of a transilio type were observed in two other localities in the region, namely, the shore of lake Timiskaming opposite Drunken island, and at the e end of lot 30, range I, Laverlochdrc. In the first locality, the grnn surface is merely covered by a thin layer of arkose which is followed ' Barlow, A. E., Gtol. Surv., Can . Ann. Kept., vol. X. pt. S. t»97, p. \>)i. Ill (iinglumcrau- containing the usual atiiiortincnt of |H-bbli>:s. thf whole IxifiK encioM'd in a red culoured matrix. In thf tifc-ujul locality, the rocks arc associated in the usual transitional way. the b.isf of the nxiglo- merate consisting of closely a)mpactcd pebble* and boulders of the undcrlyintf granite (wrphyry. Since this porphyritic variation in the . uiirts on the district. It may. therefore, be merely stated here that there is much 112 iviclinro inclicaliiig that the whitk- ncrics iit ckmcly rtlatwl in ..r to ointincntal glacial comliiionN, the conglomorate mcmborN haviiiu I haraitfristicH of glacial till Khcrts. Poat-Cobalt Series Intrutivet. INTRODUCTORY STATKMKNT. With the exception of the areas of diabase occurring in 1 .1 township on the cast sic j of lake Timiskaming, thrre are no ext. n. occurrencts of post-Cobalt scries intrusives in Timiskaming com although numerous small masses and dykes occur throughout ihf uf region. Lithologically the post-Cobalt series intrusives indudi- tli rwk types: diabase, olivine diabase, and syenite porphyry, Thi f iwt) arc common, but the syenite porphyry is found in only one hx.il niABASK. Distribution. The occurrences of diabase in Timiskaming county are too numin for separate description so that only the most important areas geoloKica examined are here described. In the district east of lake Timiskaming, the principal arras diabase are to be found m the township ol Fabre. These, while not connected at present, were, without doubt, originally portions ..f single iihcct injected into the Cobalt series near its contact with 1 underlying basement complex. In addition to the Fabre areas of d base, several dykes of diabase were noted in the townships east of l.i Timiskaming. one northeast of Otter lake in range XII of LaverUx hi and the others in the vicinity of Lac des Quinze. In that portion of the region east of lake Abitibi, seventeen orci rences of the olivine free variety of diabase were seen' and in the flistr adjoining Kewagama, La Motte, and De Montigny lakes in the eastc part of the same region, several other occurrences were encounter by J. A. Bancroft. There are no large masses or dykes in this t(Trii( t however, the most extensive being a dyke 400 feet in width and st vii miles in length which parallels the western margin of the peninsul.i lyii lietwecn Kewagama and Poiricr lakes.' In the eastern part of Timiskaming county, along Bell river, a nur ber of occurrences of diabase were seen, the longest dyke beinR th outcropping at intervals along the west shore of Shabogama lake. 1 the s outheastern part of the county along the canoe route from l.il ' Geol. Surv., Can., Map WA, IVIS. '"Mlikoper. in the prov. of Qiiebcr," IVII. p. 181. Ill in iirimii 113 Kipawa to the hcadwati-rit lA Bell rivir, only a Kinglo outcrop of diatwM- waf tttn. Thi« orcurrtd ait a small rnasi* on the point of the peninhula proji-rtioK into Grand lake Victoria between its southwest and (toutheast bays. The absence of diabase in this territory would weni to iidicate that the intrusions of diabase were lew* common throughout ti.e In-lt of bunded gneisses. Lithological CharacJer. The olivine free, or quartz diabase as it is commonly (k^ignated throuKh Timiskaming county, is a rock of remarkably uniform c.imjx.si tion aUhough somewhat variable in texture and colour accordinK to the conditions under which the rock solidified. In the smaller dykes and aldiiK the margins of the larger intrusives the rcx;k is g«-n»rally black and aphanitic; elsewhere it is generally dark green or grey green or, in a few l (t : .nerally fresher and in the Bludx Island dyke in lake Kt^ ^ contains phenocrysts of dark labrado up to one inch in length. Microscopically, the olivine diabase is s to consist of olivine and labradorite enclosed in augite. The oli\ generally has a rounded outline v hen it comes in contact witii augite and in some parts of the section has the same relationship to plagioclase, but is more commonly cut off sharply by the feldspar iai A dark brown mica is usually present in the olivine diabase and in su sections is associated with the ilmenite. The accessory constituc of the olivine diabase are similar to those of the ordinary type, I the secondary minerals were entirely absent in all the sections txj i .ed, the rock having suffered practically no mineralogical alteratio STRUCTURAL RKLATIONS OF THE QUARTZ AND OLIVINE DIABASK. With the exception of the areas of diabase in Fabrc towsnhip, wh are probably remnants of a sill,' all the diabase in the region occurs dykes having vertical or nearly vertical attitudes, or as small isolai bosses. It is possible that some of these isolated masses are also re nants of sills, although the only evidence for this conclusion is th lack of linearity. Wherever the contacts of the dykes with the couni rock were observed, the junction was sharp (Plate XI), the effect on t country rock was apparently unimportant, and the dyke itself suffer no apparent change other than the change to a finer texture as the marj was approached. In the dykes occurring in the vicinity of Kewagai lake, however, inclusions of granite were found by J. A. Bancroft alo the margin of a dyke. In places also impregnations of pyrite, arser pyrite, and copper pyrite were seen along the margin and in the w rock of the dykes.^ With regard to the relationship of the olivi diabase to the olivine free variety, no positive evidence was found oth than the fact that the olivine variety is the fresher of the two rod In the region west of Lake Timiskaming, however, dykes of the olivi diabase have been found to penetrate the sills of the quartz diabase. ORIGIN OF DIABASE. The mode of origin of the quartz and olivine diabase has alreac been implied in previous sections of the report, but may be here brief restated. Both varieties of diabase are believed to have been derivf ' Hanrie, R., "Geology of a portion of Fabre township. Pontiac county." Dept. of ColomjiW Minei, and Fiahrrin. Qurbrr, 1911. p. 22 ' "Min. opei. iti the prov. of Qut'bec," ivi I. p. I iv. I apptarancr le BIucIkw : labraddritt base is >tir The olivine ct Willi tht nship to the Idspar lath- and in sorat const it uini- ■y type, liu: tions exam- alterations. DIABASK. inhip, whid m occurs ,i> nail isolated re also rt>ra- lion is their the countn ffcct on the self sufferd the marpc Kewagama ncroft alone 'itc, arseno- in the wa!! the olivim found other two rocb the olivine j liabase. ! has already here briefly | cen derived i of ColonioUA 115 i from a continuous mass of basic magma which underlay a large part of I the Canadian shield in late Pre-Cambrian (Keweenawan) time. It is ■ also IK-Iieved that differentiation took place in this magma, as a result of i which acid and basic types of diabase were intruded , the basic, olivine var- iety being developed last. In the small dykes and on the margins of the I intrusions where the rock cooled rapidly, the aphori • tevturc was i formed; but in the centres of the larger masses, wh r .soliuifu ation vas i slow, ophitic structure and micropegmatite were de loptd. SYENITE PORPHYRY. Distribution. Between Oilier and Renauld lakes to the northeast of lake Opasatika, the Cobalt series is intruded by a mass of syenite porphyry, alxjut one- fourth of a mile wide and half a mile or more long. This intrusion is apparently unique, for this rock was not observed anywhere else in the region. Lithological Character. The syenite porphyry is a massive rock consisting of large pheno- rrysts of feldspar an inch or more in length enilK-dded in a pink to grey matrix in which chalcopyrite is abundantly disseminated. The rock maintains the same character throughout the whole mass even up to within a few inches of its contact. It was found on examining the syenite porphyry under the micro- scope that it consisted of phenocrysts of albite enclosed in a granular groundmass of feldspar and quartz, with sphene, chlorite, carlxmate, epidote, and chalcopyrite as accessory constituents. The plagioclases contain an abundance of inclusions of .sericite and epidote which have resulted from their alteration. The outline of the chlorite is such as lo suggest that this mineral has been derived from biotite, but no trace ol the original mineral could be found. Structural Relations and Correlation. The syenite porphyry forms a rock mass of oblong shape having somewhat irregular but vertical walls. As the diabase is the only other I' trusive in the region known to cut the Cobalt series, and since the yenite is similar in composition to the aplitic differentiates which are associated with the diabase in other parts of the Timiskaming region. It may be possible that this mass is also a difTerentiate from the diabase. The junction of the syenite porphyry and the basal conglomerate i of the Cobalt series shows distinct evidences of the contact effects of the mtrusive. On the north side of the syenite porphyry mass, the conglom- 116 erate is mashed in the vicinity of the contact and on the south is travii by innumerable joints, both of these effects being clearly due to contact action of the porphyry. PALvEOZOIC. ORDOVICIAN AND SILURIAN. The outliers of Palaeozoic sediments which occur at the north ( of lake Timiskaming are of exceptional interest to geologists btca of their isolated position, nearly 100 miles farther north than anyoi known occurrences of Paltcozoic sediments in the Ottawa basin. Tl .vere first described by Sir William Logan in the Report of Progress of Geological Survey for 1845 and more fully in the Geology of Canai published in 1863. The names of thirteen species collected from i outliers and identified by Mr. E. Billings are mentioned in the l.it publication. Additional collections of fossils made by Robert [Bill 1887, and by A. E. Barlow in 1892-4, were identified by H. M. Ami a L. M. Lambe. From the determination of these fossils Ami cone kid that the outliers belonged to the Clinton or Niagara formatioiN. i species being for the most part referable to the Niagara, although a niinil present belonged to rocks generally assigned to the Clinton. In i autumn of 1914, however, M. Y. Williams visited the district and d covered that dolomite containing Black River fossils occurred in t district north and west of Haileybury on the Ontario side of the lake, a that fossils belonging to both the Niagara and the Trenton formatio were present on Chief island. The areas of Palaeozoic sediments which occur on the Qiiebc r >i of the interprovincial boundary are limited to Chief, Mann, Ost( Brisseau, and Bryson islands in lake Timiskaming and a numhir small scattered remnants which, with the exception of a single oiitm in range 1 1 of Guigues township, lie along the east shore of the lake. T! outer' ..s of Palaeozoic rocks on Chief island occur as scattered patch of limestone and conglomerate with a calcareous matrix resting on tl irregular surface of the quartzite member of the Cobalt scriis number of fossils representing the lower portion of the Niagara forniaik were obtained from these by Barlow and in one small remnant h)\ Niagara and lower Trenton fossils were found by Williams. The coi ditions which have brought about these peculiar relationships have m yet been determined.' On Mann, Oster, Brisseau, and the north shoi of Bryson island there is a light yellow almost flat-lying limestone whici like the larger part of that on Chief island, contains lower Niagara fossils, over forty species belonging to this horizon having been foun 'Gtul. Surv., Liiu.. Muf., Hull. No. Ij. l'/15. 117 on Mann island. On the east shore of lake Timiskaming, the Fal£Eozoir occurs merely as basal remnants fringing the margin of the lake. Thas ; on the shore directly east of Bryson island, . n the north side of Joanne bay. and on the shore of the bay north of the Wright mine, small areas of an arenaceous well-bedded limestone occur dipping 5 to 10 degrees to the southwest The shore of the lake between Pich^!- point and Chief islam! is al.o bordered by a fringe of conglomerate and calcareous sandstone in which the wave action of the lake has formed a terrace about 3 feet in : h(ii;l The rock exposed between this terrace and the water of the i lake at its lowest stage consists of fragments and hummocks of the jHuronuin quartzitc enclosed in a calcareous matrix in which are jfraginental fossiliferous remains. In the district inland from the icnstcrn shore of lake Timiskaming only a single outcrop of the Pala-ozoic sediments was seen. This was found at the east end of lot 19, range II, Guigues township, and consists of a small knob of J calcareous sandstone 10 feet in thickness and dipping aporoximatelv : 5 degrees southwesterly. PLEISTOCENE. GLACIAL. The bedrock surface throughout the whole of Timiskaming county ns more or less hidden from view by a thin mantle of boulders, grave! I sand, and boulder clay-debris laid down from the Labradorean continen- tal glacier. In the clay belt portion of the region, owing to the presence -of the overlying lacustrine clay, the glacial drift is a'-ost entirelv hidden jfrom view, except on the shores of lakes, or w ^ intersected by |str<^ms which have cut their way through t. ocene deposits M bedrock, or where it has been exposed by t ..nations along the |J«ational Transcontinental railway. In the rocky upland districts IhoweN-er, it is hidden merely by the vegetable cover and its character |can be more easily determined. The glacial materials are geneti-ally *t two types; those which are unstratified and are, therefore, believed to ^nve been deposited from the glacier directly, and those which are strati- f'.l and on this account are believed to have been deposited from the |lac.er indirectly l^ the action of water. The deposits of the una.ssorted f M)e occur scattered irregularly over the surface of xY Icr bedrocks p m moraines. These are composed for the most part of the coarse pantiles of glacial debris, not a single occurrence of boulder clay being »fn in any of the cuts along the National Transcontinental railway Boulders are scattered everywhere throughout the region, but are more rnnspicuous in the upland areas from which the finer-grained material " . Dcen ^wcpt away. The gravelly type of moraine is the most common 118 unassorted placial deposit in the resion. two of the largest forini barriers across the Timiskaming trench, at the narrows and at the l.c Sault rapitls. Boulder clay was not observed in many iotalities, hut w nol((i at the north end of the Heiglu of Land portage from Oy.inii Suniniit lakes, at a number of points on the shores of Duparfiuei .1 Lois lakes, at the north en'' of Brennan lake, and at Young's farm Wolf lake. The fluvioglacial deposits of the region (Pl-te XII) are foiiiK! ellipiical-shaped hiiis (kames), or spread out broadly over a wide ,11 (outwahh plains), or in long serpentine ridges (e?kers). One of the hi examples of a kame seen in the region, is the elliptical-shaped ma.-^ w an esker-likc prolongation at its southern end, intersected by the Natini Transcontinental railway, westof the crossing of LaSarre(\Vhitefisli) nv A typical example of the widespread type of fluvioglacial deposits. 1 outwash plain, occurs in the central part of Tr^cesson township. T best illustration of an esker observed extends along the west shore i,( \ southern bay of Trout lake — one of the principal lakes on the (.11 route from lake Kipawa to Grand lake Victoria. There ate also o isolated masses of gravel and sand in this district which are pnjhil kame.s. lacujTrine clay, silt, and sand. Distribution. Throughout the northern part of Timiskaming county, the k't and fluvioglacial deposits are . lain by stratified clay and sand \vh have filled in the minor inequalities of the drift surface, thereby form load plains. These deposits (Figure 6) lie approximately norili line drawn from the north end of lake Timiskaming to the north tnd Grand lake Victoria. They are not continuous throughout the whnlc the northern part of the county, however, for numerous knobs and rid of bedrock as well as areas of glacial drift project through the day and sand, so that the latter in reality occur only in the lower depnssii of the region. Character. These stratified materials consist for the most part of alteniat beds of clay and silt or clay and sand, the beds ranging in thickness fr half an inch to 3 inches (Plates I, XIV, XV). In a few localities (chit in the vicinity of deposits of glacial drift) the stratified clay ar ' .-.I overlain by sand. This sand is nowhere of great extent, however, ; is generally not more than 4 or 5 feet in thickness. The bedding of deposits near their contact with the underlying drift, or Pre-Cambr rock surfan" parallels the slope of the surface upon wliich they w 119 'St forming It till- l.dng ies, hiil w.i. 1 O.ijcinii I.J larciia-t ,ii;ii ij's farm nn ; fciund in J wi(ic .irta of tlu' lu-i 1 mas^ with he National tefish ) rivtr. cposits, thr iship. The ihort' (if the 1 the caiiw e alMi -I mil re pnjh.itily deposited: but these undulations, for the most part, disappear within a fiw feet, the overlying beds assuming the flat-lying attitude which gives the surface of the clay belt its characteristic plain-like appearance.' The total thickness of the deposits nowhere was observed to exceed 25 feet. Origin. The origin and character of the stratified post-Glacial deposits of the clay belt are discussed at greater length in Chapter VI, so that it may merely be stated here that it is believed that they were laid down from a large post-Glacial lake which covered the northern part of Ontario and Quebec following the withdrawal of the last Labradorean ice sheet. For this body of water the name lake Barlow is proposed. the i:,hai\ sand which eby forniir.j north nf J north (.nd u: the whiile of IS and ridgt* the day sil: ■ depression> ' alterntitiitf ickness frnir. litics (rhii'tiy ,y ar : ,-.liij owever, atio 'dding of tkt re-Camhrijr h they werr (ieol. Surv., Can.. Mem. 39, Plate XXV. ■» t^m " ii'BW " 120 chapter vi. spe::ial problems of timiskaming region. GENERAL STATEMENT. In this report, as stated in the introductory section of Chaptir 1 an attempt has been made as far as possible to separate those section which are largely theoretical from those which are either largely cici criptive or include only those theoretical assumptions which are gent rail accepted by geologists the world over; and, in accordance with ihi arrangement, the theoretical geological problems presented by th Timiskaming region (with the exception of those having reference to th physiography and nomenclature discussed in Chapters II and IV) liav been included in this chapter. Many of these problems, howevti have been discussed at some length in former reports on the region an in such cases merely an outline of the previous discussion is included. PILLOW STRUCTURE. Among the structural features exhibited by the ancient volcanic which form the dominant part of the Pre-Cambrian basal complex in th Timiskaming region, one of the most common and interesting is th ellipsoidal or pillow structure, a form formerly supposed to be uncommo but now known to occur in volcanic rocks in all parts of the world, an especially in those volcanics whose geological relationships indicai that they were extruded under water. The structure is of sped; interest in the Pre-Cambrian volcanics of Timiskaming region, betau> it can be used in places to determine the upper and lower side of a lav flow and thus aid in working out the complex geological structure i these ancient lavas. Charactsr. The pillow structure, as it occurs in the volcanics of the Timiskamin region, consists of round to pillow-shaped, more or less irregular massi of basalt or basic andesite ranging from a few inches to 5 or 6 feet i diameter. Very commonly these masses are tiner-grained along the margin than in the interior and in a few localities are amygdaloid; along the margin of the ellipsoids. Between the pillows there are p nf! ally numerous triangular spaces which have been filled in with carbonali quartz, or, in some cases, with fine aphanitic material which has betn • much altered that its original character cannot be determined. Thi might be volcanic ejectmenta deposited Ijetween the ellipsoids or merd 121 fine lava. As a result of differential weathering the forms of the pillows arc much :noie sharply outlined on the exposed surface than in the interior of the flows, the interstitial material weathering out entirely or assuming a rusty colour strikingly different in appearance to the masses enclosed. The pillows of the lava are not perfect ellipsoids or spheroids but irregular in form, the surface of each pillow having apparently adjusted its ^hape to fit the irregularities of the pillows upon which it was laid down In pines, the pillows can be seen to be flattened on one side so that a bun-like form is produced.' This flattr- :.g has been observed by numer- ous geologists in more recent pillow lavas and in every case is stated to occur on the under side.' This feature is, therefore, of assistance in working out the structure of the Abitibi volcanics, since, where the bun- shaped pillows are present, the upper and lower sides of the lava flow at that particular point, can be determined. Thus in Plate XI of Memoir 39 the lava flow has a vertical attitude and the top of the flow is on the right. Origin. The numerous hypotheses suggested in geological literature to account for the development of the pillow, ellipsoidal, or spheroidal structure in Igneous rocks would seem to indicate that the mode of origin of this feature presented an exceedingly difficult geological problem It is probable, however, that the multiplicity of these hypotheses l.as arisen in part, because the terms pillow, ellipsoidal, and spheroidal structure have been applied to wholly different phenomena. Thus, in the Bucking- ham district, Quebec, recently studied by the writer, ellipsoidal structure remarkably similar to the typical pillow structure was seen in intrusive gahbro; and the so-called leopard rock, found in pegmatite in the same region, is likewise remarkably similar to pillow st-ucturc on a small siaie. In both of these cases ellipsoidal forms have been developed in intrusive rocks as a result of deformation. It is probable also that jointage, concentric structure, and other forms found in intrusive and : extrusive rocks have been frequently described as ellipsoidal or spheroidal structure, and thus confused with pillow structure. In discussing the "rigin of the pillow structure it may be stated, therefore, at the outset , that the structure under consideration is a flow phenomenon characteris- tically developed in extrusive lavas only. In Memoir 39 it was concluded that the ellipsoidal or pillow structure . originated in a manner similar to that of tlie pahoehoe lavas of the I Hawaiian volcanoes, that is by the successive ejection of lava under ' Geol. Surv., Can.. Mem. 39, 1913, Plate XI. J ' Daiy, R. A., Am. Geoi.. vol. 33. 1902. pp. 65-78. I Kaotome, F. L.. Bull. Dept. of Geol., Univ. of Cal.. 1893, pp. 75-85 ^ """"U. I. C. U.S.Geol. 3urv., BuU. 199, 1902. p. 113. ■ I 122 pressure through fractures along the margin of major lava flows, but t "whereas under subacrial conditions the lava ejected from fradi in the surface of a flow, spreads out into pahoehoe, under subaciui conditions it would immediately become viscous owing to its om with water, so that masses of lava would be developed which w( stretch out into an ellipsoidal form as they detached themselves at t point of ejection." Since the publication of the above memoir, several papers,' in wl the origin of pillow structure is discussed, have appeared, among il an exhausti\e treatise on the subject by J. Volney Lewis." L concludes that not only does the ellipsoidal structure originate in same way as the pahoehoe structure but that the two structures are same and that "neither the presence nor the absence of water p(\ can be predicted as favourable to the formation of this structure." l.i conclusion that extrusion under water is not essential for the iUw ment of the pillow structure is largely based on the observalii.r Green and Day in Hawaii. In some of the photographs of the Haw: lavas taken by Day and Shepard the pahoehoe appears to approach closely to pillow lavas in form but in Dutton's description of pahoelim stated that "the superficial crust of cooled lava undergoes rupiiir numberless points and little rivulets of lava are shot out under pro; Preserving their liquidity for a short time they spread out very thin an very quickly cooled forming pahoehoe." Thus according to Dutton pahoehoe laVc»3 more closely resemble the form taken by overl ir plates or pancakes rather than pillows. The explanation of the app; difference between the forms described by Dutton and the photogr of Day and Shepard may be that both are pahoehoe forms divd according to the temperature of the lava in difleient extrusions or di different eruptions. It is conceivable that under subaerial conditions, if the temper of a highly fluid type of iava were not too high, small extru-ioi lava throut' fractures might become viscous on the outside. 1 would retain their fluidity in their interior and thus develop a pi like form, but such conditions on the whole would be exci-pii On the other hand, if a lava were extruded, under wate into water, no matter how high the temperature, the absorbeu in converting the water into steam would almo!^t f cool the surface of the small ejections of lava quickly, thi producing an outside viscous meniscus which, filling with tluitl > Sundius. N., Foren Forhandl.. vol. J4. 1912, pp. 317-332. Capli. S. K.. Jour, of Gcol.. vol. 23. 1915. VV- 4.^-5!. > Bull. Geol. Sec. Am., vol. 25. 1914. pp. 591-654. • U.S. Gtoi. Surv.. 4th Ann. Rept., 1882-3. p. 96. 123 iws, but tha' »tn fra( lurt. sub.Kiuiou; » its OMitac ivhich uiiuW .'Ivcs at ihrir •rs,' in whirt among thtii ;wis." Liwi- jinatt in \h turcs .III' tht water per j? urc." I.i\\i> the (l( \r!(ii servalinns i the Hawaiiar, ppronch \\n jahoeluii, ii ■ ;s rupture s. ider pro^uu y thin am!,'. oDultdll'tt; / overl.ippir; ' the appmbed with channels along which the lava has flowed; yet, when these flow into the sea, typical pillow structure is developed as described in t'le folK wing quotation: "Where the lava was flowing in smaller quantity, explosions were much less noticeable, and the lava extended itself into buds or lobes. The proass was as follows: an ovoid mass of lava, still in communication with its source of supply and having its surface, though still red hot, reduced to a pasty condition by cooling, would be seen to swell, or crack, into a sort of bud, like a prickly pear on a cactus, and this would rapidly increase in heat, mobility, ami size, till it either became a lobe as large as a sack or pillow, like the others, or perhaps stopped short at the size of an Indian club or large florencc flask. Sometimes the neck supplying a new lobe would be several feet long and as thick as a man's arm, before it expanded into a full sized lofw; more commonly it would be shorter, so that the freshly formed lobes wcdd be h-apcd together The whole surface seemed to be chilled at once as the waves rolled off and on, and examination of cooled specimens iRtween high and low water mark confirmed this. The surface at and below the water level was roughly granular like that of air chilled Iwn.bs while higher up the ordinary corded or pahoehoe structure wassr.n."' In conclusion, it maybe pointed out that observations, in numerous localities throughout the world, have shown that piliuw lavas, in most of their occurrences, are found in such relationships as lO indicate that they have been extended under or into water; and furthermore, in order that the structure may develop under subaerial conditions, it is necessary that the lava be extruded at a definite temperature not far above its freezing point, whereas under subaqueous conditions the lava may be extruded either at this limiting temperature or any temperature above this limiting temperature. Thus it may be inferred boih from observa- tional data and from theoretical considerations that the pillow or ellipsoidal structure so commonly observed in lavas throughout the world is '0-srt. jour. Groi. Soc. Lond., 1910. pp. oJt-JJ. CrtMR. Jour., vol. 39, 1912, p. 129. 124 charactemtically developed under subaqueous rather than subati conditions of extrusion. ORIGIN OF FERRUGINOITS DOLOMITE. General Statement. In numerous localities throughout Timiskaming region, masses a bimds of ferruginous dolomite occur in association with ihc volcaiiii? the basal complex which are of interest not only because of th»ir \vi spread occurrence and peculiar composition but because of the i;nu»« dolomite as it occurs in the nortlurn part of Timiskaming region are included in the followinL; t..l.lc. Annlyses o} Ferrutinous Pnlomit,\ SiO,. AM*,. Fi)(»i KcO MgO. CaO Na,0 M) TiO, MnO (0, Hfi S. Uorun Insol. "l" 83 4 28 U 10 53 7.17 3. 83 I 10 58 j 3 68 13 70 27 23 16 % 17 60 36 18 51 82 58 63 I 11 72 30 63 1 66 2 78 12 98 26 02 03 20 10 (» 'trace 24 31 I 17 58 014 1 20 41 ! II trace j tttrong test 36 90 7 47 6 56 3 12 18 47 8 02 02 16 19 44 00 7 45 7 48 007 15 10 24 45 92 9 38 50 5 71 7 98 6 78 3 58 2 22 27 15 94 2 20 Total . 99 45 ; 100 06 100 48 I'^l'n..'*^*'."?^ •'• Poreiipine district. Ann. Kept., Ont. Bureau of Mine!., vol. 20. pi. 2, 1911, p. 13. ' No. 4, Keddick cLiini, L.irdci lake, Jour. I an. Min. InM., vol. 14, 1911, pp. 672-689. No. 5, Night Hawk lake, idem. No. 6, Harris Maxwell claim, Larder lake, idem. No. 7. Harris Maxwell claim. Larder lake,an..lysis hy M. F. Connor, .Mines Branch. Uept. of Mines, C anada. Origin. From study of the iiUioloKicul character, the chemical and tnitieral- oKical composition, and the gcolojjical ri-lationship of the ferruginous (lolomite, it is evident that certain features presented by these de[X)sits point to a sedimentary origin, while others indicate that they have been formed by the action of thermal replacement of certain acidic rocks of the Kranite and syenite family and especially of those types in which .soda feldspar is abundant. The evidence in favour of the latter conclusion may be briefly sum- marized as follows : The chromiferoiis mica which occurs so abundantly in the dolomite is not usually mund in normal seditnentary rocks, but, on the other hand, is common in association »ith minerals believed to have been deposited from deep seated thermal solutions. in numerous localities throufthout Timiskaming region quartz porphyry «yenite- rfKv*" A n^ '°^^ \™ f"""^' *^''=*' ^^"^ •*«" partially altered to ferruginous aoiomite and all stages in the transformation can be obser\ed. In order to obtain more 126 drftnitp information an to the rharacfrr of thin trannformation.two «pninifriM)f (urti altFrc It 2 5« 3 (IN .» ,n 5 4(> .) 87 N 11 (1 44 (K> (1 .n 7 72 45 <).' 5') 5 -,1 7 ')s 6 7'* 2 .'2 i ■ .>.s 2 *NI 1) Jil .'7 15 <)t 101 11 2 7S IIKI 4>* 2 Si 2 >' SiO, Al,« >. Ke,< '1 Fet) MkO C'.i< > K|() Na,( ) ll,f)- H,() TiO: CO, Total Specific Kfavity (powdered) " * (maskive) No. 1 coiiHislMii.iinly of alliitewith a few scattered flakes of biotilc, loiti rl bohfdr.il Kr.iins of carlionate. and here and there granular aRKrepiites of ni.i^.ii The ro I by the undulatory extinction in the feldspar and the presence of Kt.iru. zones. A lomiiarison of the mineraloKical composition of the two siMiimen^ » seem to indicate that the transformation has consisted in a decrease in the pro|'< of albite, biotite, and maenctile cop'ained in the rmk and an increase or entire .I'.A of quartz, ferruginous dolomite, scricite, chrome mica, and pyrite. If it be assimi ■! the alteration process has not been accompanied by an appreciable change in Mil then the character of the metasomatic action can be determined by a dircit coiii|m of the analyses of the two specimens, the latter of which is much more re ilie -ilu from which the quartz was de|X)sited. Moreover, the occuirencc of tourni,;liii€ related minerals of pegmatitic association in the quartz veins indicates that tli< -c tions were thermal. In some places the ferruginous dolomite occurs in the form of dykes ixTuir and in luding fragments of the adjoining rock. Thf principal evidence indicatinK that the (i n uRinmii- di.li mi possibly of sedimentary origin is as follows: Cherry iron carljonalcs of a -uiiiefthal -imil.-ir chsracter are ("isnd ^jr.r.r.y >.h Pre-Cambrian rocks of the Lake Superior region, which are undoubtedly of setlinic: origin. 127 45 ''J ,ts (1 C.J 5 ". 1 7 'I'. (> Ts i 1 » ,( •*s 2 INI 1) JU (1 J 7 15 ')( t(HI 4>' I V } 2 y> In (ilacr* thr frrruKinoim ilolomitr* (xcur in auMX-iation with grrywarkr, alatr, fif , .i» if it wrrr .i miriiiiil .rdimiiii Tliiu in tlii' i|i»trii I north of l.inltr lakf in Onlirio, >rverut ImikN of fcrriiKiiioiio iloloniilf, up to MX) feet in wiilth, .irc .i|i|i.irt'ntly inter»tr,ilili(-)lc unifiirmity in width for Mvrral niilr*. In conclusion, it may In- pointed out that ulthout{h it U not pcissililo to dru-y a positive cone lusion fr:)tn the conflicting; » \ idt im- cited ill the previous summary with regard to the mode of origin of the ferruginous dolomite; yet on the whole the balance of eviileiic*" at present ^■cms to he mtwt favourable to the hyjxuhe-is that these jx-tuliar rocks h.ivi (irininated by thermal r»'pl.icement of syenite aplite, f|iMit/ (xir- (ihyr>, rhyiilite, and related roeks.' STKATrr.RAPHICAL AND STRl'CTLRAl. Ria.ATIONS OF PRF.-CAMIIKIAN BASAI. (OMI'l.ItX. Grncral Slalcment. In Mveral places in this report, it has been pointed out that the I'rt-C anilirian basal complex of the Ottawa basin falls naturally int.) three great -diithwesterly trending; belts or zones, the northern and sntujiern of which consist in the main of surface rocks, while the central belt is larm ly comjMised of plutonic banrled Kneis>es. In the secti<'n-» which (dill w, the principal straii^raphical and structural relationships of lhe^e Hre.it basal Ix'lts are described and hyixitheses suggested to explain these rei.itionships. Timiskaminz Belt. The most northerly belt of the I're-Cambrian txjmplex is composed of highly folded and more or less metamorphosed volcanic lavas and clastic K'diments which here and there have been intruded by small hathdiiihs of granite or granixliorite. These intruded ruck masses, while iitlii)l(ij>ically similar to the great central lx.'lt of banded gneisses, differ from the latter in that they are not generally banded and otdy partially foliated. Whenever the contact of the balholiths with the adjoining surface rocks has been observed, their intrusive relationships are indicated hy the recrystallization which has occurred in the intruded rock near the margin of the intrus've, by the foliated character of the intnuletl rocks aldiij; the contact with the intrusive, by dykes penetrating the rocks adjoining the batholiths, and by the presence of numerous iticUisions of the intruded rocks within the batholith. As regards the relationships of the surf.icc rocks of the Timiskaining belt to one another, little is positively known. In [)laces conglomerate nunilurs cemtaining pebbles of granite and volcanic rocks al belong to a single period of batholilhic invasion, for their relationsliip have been studied in detail in only a few localities throughout the whol Grenville belt. Ottawa Gneisses Belt. The central belt of gneisses is largely composed of granite, syenit granodiorite and related rocks, with some associated sediments, all o which are highly folded and generally banded and like normal deforme( 129 sediments have been folded into pitching anticlines and synclines. Along the southern margin of the belt, the gneisses include small lenticular, partially (jr completely silicated masses of crystalline limestone elongated in a direction parallel to the trend of the enclosing gneiss. The relation- ships of these inclusions of the surface rocks belonging to the Grenville cielt suggest that they are detached fragments or thin infolded bands which have become involved in the central massif during its intrusion or at the time the banded structure of the massif was developed. The junction of the banded gneiss with the Fontiac series on the north is marked by a contact zone throughout which the mica schist phase of that series is intimately injected and intruded by dykes of granite and pegmatite. On procefding northward from this zone, the intrusions become less numerous and the mica schist is gradually replaced by conglomerate, greywacke.and arkose. Towards the south, on the other hand, the mica schist becomes less and less common and the gnmite and pegmatite more and more abundant until all trace of the Pontiac series has finally disappeared. In the region most remote from the intrusive, the rocks of the Pontiac series have generally a vertical attitude, but nearer the belt of gneisses and in the contact zone, the foliation and bedding planes have a general dip of approximately 45 degrees towards the north and away from the intrusive— a relationship which maintains itself even in the most southerly inclusions within the central massif. Mode of Balholithic Intrusion. The preceding description of the regional structural relationship of the Pre-Cambrian basal complex in northwestern Quebec indicates that the two great belts of surface rocks which occur in this region have a structural trend parallel to that of the great central massif of banded gneisses. Moreover, geological investigation throughout the world has shown that wherever mountain chains are greatly denuded batholithic massifs are generally found at their centres. It is concluded, therefore, that the belt of banded gneisses represents the interior of a great Pre- Cambrian mountain chain laid bare by prolonged denudation. The structural relationships of the basal complex in this region should, there- fore, afford some information with regard to the process by which this Rreat massif was intruded. Did it make room for itself by marginal assimilation, or by stopinganddeep-seated assimilation, or was it intruded as an accompaniment of a great crustal upheaval ? The geanticlinal re- lationship of the ma.ssif, the manner in which the adjt.ining sedimentsof the Pontiac series dip away from the belt of bonded gneisses, and the highly foliated character of the surface rocks parallel to the margin of the iintral batholithic zone, all point to the conclusion that the roof rocks which originally overlay the massif, were thrust aside and elevated as 130 the latter was intruded. On the other hand, the central batholith zone is in igneous contact, on the south, with a great series of norm marine sediments and, on the north, with normal clastic sediments, tl conglomerate member of which contains granite pebbles. In ntiili case has any trace of the floor upon which these sediments were h down been found; yet the occurrence of the belt of orthogneisses in th relationship can scarcely be explained on any other hypothesis than ihf not only the floor, but the lower portions of the series of surface rod flanking the belt of orthogneisses have undergone assimilation or nieltin The contact of the small batholiths which occur here and the throughout the northern geosynclinal belt are in part gradational at in part definite. At the points where the first type of contact is see the adjoining volcanics have been generally transformed into anifil bolite which, when traced towards the batholith, passes indefinitely in granite by a gradual loss of ferromagnesian constituents and a cc responding increase in its feldspar and quartz content. In the localiti where the definite contacts are found, the margin of the batholith filled with inclusions of the intruded rock which, towards the inter! of the intrusive mass, lose their original character and pass into ai phibolite. Along the northern margin of the belt of banded gneisses, as pr viously described, there is a contact zone several miles in width composi of mica schist injected and intruded transversely by dykes of granite ai pegmatite. In a few places, along the inner margin of this zone there apparently a complete transition from mica schist to granite, as if tl former rock had been granitized in the manner described by Sederholm the case of the rocks intruded by Rapakivi granite in Finland. Mo commonly, however, the transition from mica schist to granite takes pia by a gradual increase in the proportion of intruded material and ixjrresponding decrease in the proportion of mica schist to a point whe only widely separated inclusions of mica schist occur in the granil As indicated in Figure 5, throughout the whole contact zone, even to tl inclusions most remote fr'~m the margin of the massif, the mica schi maintains the same attitude. This relationship indicates that at su points the magma was intruded under such conditions that not on were the inclusions of the mica schist prevented from sinking in t magma, but were held in their original position. In such localitif therefore, subcrustal stoping and deep-seated assimilation were certain not in progress. Nevertheless, throughout the interior portion of t belt of banded gneisses, as jwinted out in the section of the report whii follows, there are areas of gneiss, in places, having a chemical and miner; ogical composition such as would probably result from the partial assin lation of sedimentary rocks. Unless these occurrences are remnants L^iMOHHi l.M r(K)( pendants they indicate that deep-seated assimilation was in active protx-< within the belt of gneisses, in places at least, during the time of nmi^olidation. Tlie conclusions which may be inferred from the preceding dis- cu>>iiin arc twofold; that the contact relationships of the central belt of banded gneisses indicate that either during or preceding this batho- lithic invasion a considerable thickness of solid rock must have undergone assimilation or melting; on the contrary, that the regional relationships of the belt adjoining, indicate that the massif has attained its present position as an accompaniment of a great crustal upheaval and this alone would be quite sufficient to account for the intrusion of the mass without the assistance of additional processes such as assimilation or subcrustal fusion. ORIGP •" D GNEISSES. .utement. The most striking of the structural features characterizing the great central massif of gneisses which intervenes between the Abitibian geosyncline and the Grenville belt of sediments is the banding which everywhere prevails. This structure, moreover, is not limited to the single belt described in this report but is characteristically developed through- out extended areas of gneiss in various parts of the Canadian Pre- ( ambrian shield and is, therefore, of special interest in Canadian geology. The most probable ways in which a banded structure in gneisses might be developed, are the following: By the metamorphism of laminated sediments. By the lit par lit injection of (a) an igneous magma into bedded sediments; (b) an igneous magma into older foliated igneous rocks (either volcanic or plutonic) ; or (c) an igneous magma into its consolidated portions during its intrusion. By the flattening out of masses of country rock included in an igneous magma. By the regional deformation of a heterogeneous complex of igneous rocks long after consolidation. By the deformation of a heterogeneous igneous magma during or immediately following its consolidation. In the following sections the possible importance of these various proa'sses in the development of the banded gneisses of the central massif is discussed. Melamorphism of Laminated Sediments. The early Canadian geologists, in accordance with the prevailing ronceptions of the period in which they carried on their work, generally regarded all the banded gneisses which they encountered to be of sedimentary origin. This error was easily made since a large part of the banded gneisses of the region in which they worked were actually metamorphosed sediments and a considerable part of those of igneous 132 origin had a bedded-Iike character and a folded structure similar to th usually exhibited by deformed sedimentary strata. With the int? duction of pctrographical and chemical methods of investigation, ho ever, it was discovered that a considerable part of the banded gneiss of the Laurentian highlands had the chemical and mineralogical coi position and textural character of igneous rocks, and the sedimt'iita hypothesis was forthwith abandoned for the igneous hypothesis regards the larger part of the banded gneisses of the Laurentiiin pl;iiwi It is probable, however, that a greater part of the banded gneisses nt t Laurentian complex is of sedimentary origin than is generally supixisi Thus, in the region studied by the writer, there are considerable arc of banded garnet gneiss, mica -chist, cyanite gneiss, and other mc which have mineralogical compositions such as usually result fnnn t metamorphism of sedimentary formations. Chemical analysis «( specimen of cyanite gneiss from a point on the east shore of the ()Ua\ river about one-half mile north of the outlet of Snake creek and thai ol similar rock from the belt of banded gneisses occurring south of Su bury, Ontario, are given in columns 1 and 2 respectively, of the followii table. Analyses of specimens of garnet gneiss belonging to the Gre ville series as represented in the Buckingham district, are given in wliim 3 and 4 for th'- purpose of comparison. In both of the analyses of cyani gneiss the a! nnina content is greatly in excess of the 1 to 1 ratio nea sary to satisf;/ the lime and alkalis, and the potash is in excess of soda ; b unlike the analyses of garnet gneiss in columns 3 and 4, the magnesia not in excess over the lime. Nevertheless, the small relative propfjrtii of magnesia in analysis 1 and the high alumina content in analysis indicate that both of these rocks are probably of sedimentary origin. Analyses of Gneisses. 1 I 1 2 3 4 SiO. 66-94 57- 30 60 33 49 .')! A1,0» 17 84 1 26 03 17 17 22 0(1 Fe.a 1 39 3 93 1 y3 FeO 4 30 ! 5 24 6 5S 9 .S5 CaO t 86 i 3-35 90 ,^6 MgO 1-82 1 2 03 3. 35 6 33 .Na,0 1-85 ! 1 07 73 140 K,0 3 36 1 3-21 4.57 3SS TiO, 1 52 04 2 (Kl PjO. f i4 ()6 MnO 1 09 0.S H,0 1 90 i 38 1 00 2 2U Total 99. 87 i i 100. 14 lOOlK OQ.37 ■iS^Bn 49 61 22 tK) 1 93 9 55 Mt 6 ,it 1 40 ,? SS 2 (XI 06 OS 1 2U OQ 37 133 by f'o. Wak*' ^' ^' ^^^' ^'"^' ^'"■' ^""- ^''^^•' ''°'- ^' '*'^' P' '• P •"• Analysis . ?■ ■ ^uKv^'b ^, ''v' N,""- '^'■P*- *^"*- ^"^^'>" °f ^^'ne*. vol. 23, pt. 1, 1914, p. 209. Analysis by VV. K. McNeill. *^ "^ J. Garnet gneiss, lot 12, range I, Portland East township. Quebec. AnaK-sis by M. r. Connor. ' Analysis by M^fU^or. '"''"• '°* '"' """^^ "'"' «-'^"«'>am township, Quebec. Lit par Lit Injection. By means of the process known as lit par lit injection,' a banded structure may be developed in any rock having a bedded or foliated structure by the intimate injection of an igneous magma, or of solutions emanating from an igneous magma, along the parallel planes of weaknes.s. Lit par lit injection may take the form of cither an actual magmatic in- tru.sion or a slow infiltration'' of highly fluid magma or of solutions emanating from a magma, accompanied by crystal growth along the planes of foliation or bedding of the intruded rock. A process of injection also probably occurs where a magmatic mass consolidates under differen- tial pressure, for very commonly in Jie banded gneisses of the Laurcntian highland.s an interlamination of thin aplitic lamina; with less salic bands of rock occurs, the relationships suggesting that the banding is of primary origin, the magma having diflferentiated during its consolidation. Such ditTcrintiation might presumably occur wherever a primary foliation was being developed in a con.solidating magma, eith v injection or slow infiltration of residual aplitic material along the . -^f foliation or, possibly, also by the crystallization of salic constitue ilong the planes of foliation, the material necessary for crystal growth being drawn by diffusion from the adjoining partially consolidated bands. It may be observed that the various types of lit par lit injection cliscribed in the preceding paragraph, fall naturally into three classes am.rding as the injection takes place into bedded sediments, older filiated igneous rocks, or into consolidated portions of the same mag- malic mass. The first and third are represented in the belt of banded gneisses, but evidence of the presence of the third is wanted in the region studied by the writer. Lit par lit injection of igneous material into sediments can be seen throughout the contact zone, approximately 10 miles in width, which ixu-nd^ along the junction of the belt of banded gneisses and the Pontiac ;-Ln(s. Throughout this area the magmatic material has been intimately injcctt'd into the mica schist member of the sedimentary series, in places vol. s'lIJij.gf *"'■ ^""' ^- ^' ''"™- ^"'- '"■■ ™'- "*• '**'-•**• P' '"2-1 13. Carte Geol. Fra. No. 36, 'Stnl.rholm. J. J.. Trans. Inter. Cn-r.! CnnE . Stockholm. 1910. p. .-i?.! i'>.nner, Clarence N.. Jour. CkkjI.. vol. 22. 1«15. pp. 5«4-612. (.V4-702 Barren. J.. V.S. Geol. Surv., Prof. Paper, No. 57. 1006, p. 144 134 cutting across the bedding of the schist but generally conforming to tl stratification, the relationships leaving little doubt as to the method intrusion. The possibility that the second type of injection, into older igneo rocks, might have occurred in the central massif is suggested by the fn that the sedimentary rocks intruded by the massif contain granite ptl)l)l indicating that an older granite was originally present in the rti,'io also by the fact that in the region north of lake Huron, post-Huroni, bathr^liths of granite occur which are younger than the belt of gneisse so that granitic batholiths of at least three different ages are or wc originally present in Timiskaming region. In that portion of the ccnti massif studied by ihe writer, however, the only rocks observed whirh wc not intensely deformed were dykes of aplitc and pegmatite and nf the there appeared to be a complete series from those with no trace of dcforir tion to those most intricately plicated; and, while it might be possil that these dykes were derived from a younger batholith, it seems mc probable that they were merely emanations from the interior pontic of the massif intruded at intervals, while the massif was undergni deformation. On the other hand, if the belt of banded gneisses wi composed of granitic rocks of different age intruded prior to the deforn tions, the younger of the two intrusives would undoubtedly occur bosses or batholiths in places, and, despite the effects of deformatit would almost certainly be recognized as a younger intrusive; yet such masses were observed. As far as was observed, therefore, the o tral massif is composed of a «ingle batholithic mass. The third type of injection, iniection of unconsolidated magma it its consolidated portions, was probably the most important of ;ill p cesses by which the banding of the gneisses of the central massif v developed. It was in this manner that all the minute, less defin banding and that formed by the intrusion of the dykes of pegmatite a aplite parallel to the banding or foliation while deformation was progress were produced. But, throughout the belt of gneisses a? whole, intense deformation has obliterated most of the evidence liavi a bearing on the relative importance of this type of injection as co pared with other processes in developing the banded structure of i great central complex originally present. Flattening Out of Masses of Country Rock Included in an Igneous Magf The theory, that the development of a banded structure along i contact of the Pre-Cambrian granite batholiths of the Canadian »hv was caused by the flattening: nut nf xenoliths, has been advocated b) ■CoUiDi, W. H., G«ol. Surv.. Can.. Mua. Bull. No. 8. 1916. i^^^aa. 135 number of Canadian geologists.' This is undoubtedly an important process in the development of the structure in some places ; but. so long as the process was confined to the margin of a batholith, it would necessarily be limited in area and could nowhere result in the development of ex- tended belts of banded gneisses such as occur throughout the Laurentian plateau. If, however, the xenoliths sank in the magma mass or were carried out into the interior of the magma mass, they would be found throughout the whole batholith in all stagesof assimilation, and, if flattened out by deformation, would form a banded complex of great hetero- geneity. Is it possible that the banded gneisses of the Laurentian plateau have originated in part or wholly in this manner ? and, if so, is there any evidence in the character or composition of the gneisses by which the relative importance of the process can be determined ? In the case of the belt of banded gneisses under consideration, whatever roof rocks be- came engulfed in the magma would presumably be similar in com- position to the surface rocks intruded by the massif along its northern and southern margin. These consist, in the main, of basic to inter- mediate volcanics or metamorphosed sediments of the well sortcJ types, namely, crystalline limestone, quartzite, and garnet gneiss. Furthermore, if these rock types underwent partial assimilation in a granitic magma, the resultant rock type would necessarily be of a composition inter- mediate between that of the magma and the rock undergoing assimila- tion; that is, the volcanics would result in amphibolite or hornblende gneiss, the limestone in rocks containing lime-silicate minerals, the quartzite in highly siliceous rocks, and the garnet gneiss in rocks contain- ing a relatively high proportion of alumina, potash, or magnesia. It so happens that all of these intermediate rock types are represented among the banded gneisses of the central massif. While some of these rock types might be formed as a result of differentiation from an igneous magma, it is probable that the larger part are the products of partial assimilation, as in the case of the band of lime silicate rocks (pyroxenite and amphibolite) which occur along the southern margin of the belt in proximity to inclusions of Grenville limestone. As regards th^- larger part of the banded gneisses, however, this process was evidently . ?z the major factor in the development of the banded structure; for the domin- ant rocks of the belt are not these intermediate types resulting from assimilation but pegmatite and biotite granite gneis.ses. •Uwson, A. C. GeoL Surv.. Can., Ann. Rept., vol. HI, 18117, pt. I, p. U8F. Adamj, F. D.. and Barlow. A. E.. G«ol. Si:rv.,Can., Mem. 6, 1910. Miller, W. G., and Knight, C, Rept. Ont. Bureau of Minei, vol. XX. 1911, pp. 280-284. 136 Deformation of a Heterogeneous Complex of Igneous Rocks Long AJt Consolidation. A heterogeneous complex of igneous rocks formed either by su cessive intrusions of igneous rocks, or by differentiation in a single igiii(, mass, or by a combination of these two processes, might be transform! into banded gneisses by the flattening out of its heterogeneous parts as result of deformation. The evidence cited in previous sections and the section which follows, indicates, however, that the central massif banded gneisses was in a magmatic condition at the time the bandi structure was being developed, and this mode of origin need not, lliei fore, be considered. Deformation of a Heterogeneous Igneous Magma During or Immediatt Following its Consolidation. Igneous magmas very commonly differentiate themselves into roc of different ccjmposition during their intrusion, and, if such a hctti gcneous magma were deformed during or following its consolidatio a banded complex might result. It has been pointed out in previous sections of this report, that t belt of banded gneisses has a geanticlinal relationship to the adjoin! belts of surface rocks and apparently represents the core of a Pre-t'ai brian mountain chain; that the gneissic bandsof the belt have bet n fold into pitching anticlines and synclines trending in a southwesterly dir'ctii parallel to the trend of the whole massif; that in the region sUidit as far as could be determined, the whole belt of gneisses btlon^s to single batholithic massif; and that the presence of dykes of aplitr ai pegmatite in all stages of deformation, cutting across the gneissic ham indicates that the interior portion of the massif was in the niagmai condition at the time the banding was being developed. If these n servations and deductions are correct, then it seems evident that t rocks composing the belt of gneisses were subjected to nioiintai building stresses during their consolidation, and such conditions won necessarily result in the development of a banded structure proxid the magma were heterogeneous. Moreover, it is probable that m(HiiUai building stresses acting on a consolidating magma would in thenisilv bring alxjut difTerentiation both by breaking up the consolidated jxirtio of the massif and by squeezing out the magma of slightly different (oi position from the interior. Just as soon as a foliated or banded ."tructii developed, however, the intrusions of magma would tend to follow tlie planes of weakness and the dilierentiation would take the form of lit par injection. C^ 137 Conclusion, In the preceding discussion of the origin of the banded gneisses of the great central massif which separates the Grcnville Inlt of sedi- ments from the Abitibian geosyncline. it is pointed out that, while these have l)ten formed, in part, either by the metamorphism of laminated adiments, or by the injection of igneous material into bedded sediments, or by the deformation of xenoiiths of intruded rock included in an igneous magma, they are in the main igneous rocks and owe their banded strucUire to deformation during their consolidation. In supjjort of this ronclusion evidence is cited which indicates that the belt of gneisses represents the core of a Pre-Cambrian mountain chain and was subjected to mountain-building stresses during its solidification. As a result of this action, the solidified portions of the magmatic mass would pre- sumably be broken up and the residual fluid magma of slightly diflferent composition squeezed out to fill the fractures around the broken frag- ments and the variations in the complex produced in this way would •hen be flattened out by deformation into banded gneiss. During the later stages of deformation the intrusions of igneous material from the interior of the massif, would probably follow the planes of foliation and banding and thus further develop a banded structure by lil par lit in- jection. As deformation continued, the banded gneisses produced in these various ways would no doubt behave very much like sedimentary strata and crumple into anticlinal and synclinal forms. Thus by the action of mountain-building stresses on a magmatic axial mass, a folded, banded, and granulated gneissic complex, such as that occurring in this great belt, might be developed. ORIGIN OF COBALT SERIES. Introductory Statement. The group of clastic sediments composing the Cobalt serie- presents one of the most interesting geological problems of the Canadian Pre- Cambrian, the characteristics of the various formations composing the series being such as to indicate that these were laid down during an epoch of continental glaciation. The evidence upon which this conclusion is based, has been dis- cussed at considerable length in previous publications,' however, and ■T'ercly a summary of former discussions of the problem will, therefore, be included in this report. 'Jour. GmI.. vol. 19, 1913. pp. 121-141. Gtol. Surv.. Can., Mem. 39, 1913. 138 Conglomerate. The following data may be cited as evidence indicating that t conglomerate members of the Cobalt series were deposited from a ic tinental ice-sheet: The enormous extent and great thickneu of the conglomerate. The great variety of rock types repretented in the pebbles and boulder* ol conglomerate. The unsorted character of the conglomerate. The great variability in the texture and composition of the confjlomerate, nnd pecially the presence of phases in which fine-grained greywacke or nrgillite conipri>e larger part of the rock, the pebbles and l)ouldcrs being sparsely ..isseminated. The subangular form of the pebbles and boulders contamed m the conglonier; The presence of scratched and faceted pebbles in the conglomerate. The enormous siie of the boulders contained in the conglomerate and the act rence of these at points several mile* distant from the nearest occurrence of uni rocks in the underlying basement. .... • . i The extremely low relief of the surface ufion which the conglomerate was I down, thus precluding the possibility of a fluviatile origin. In objection to the glacial hyoothesis, it has been pointed out tl no striated surfaces have been found beneath the basal congionu r, member of the series; and on the contrary the contact with the und lying floor is generally gradational, the typical heterogeneous a glomerate being gradually replaced by a rock composed entirely of M derived in situ from the adjacent floor'. In reply to this objection has been noted, however, that the presence of an ancient regolitli neath the Cobalt series does not preclude the possibility of Hurf)n glaciation ; for, near the margin of continental glaciers, the ice comnio: moves for miles over unconsolidated material without anywhere reach the underlying rock surface.' Creywacke, Argillite, and Arkose. The greywacke, argillite, and arkose members of the Cobalt sei are believed to be of lacustrine or'gin for the following reasons: They pass gradationally into conglomerate which possesses all the typical c acteristics of a continental glacial deposit. , j . ■ The uniformity in their stratification and the absence of mud cracks, rain pn or other evidence of exposure to the air shows that they were deposited from a permai body of water. ... . j l t. j t • The discontinuity and variability of the deposits, and the abundance ol nf marks indicates that they were laid down in a shallow, discontinuous body of w.ite The incompletely sorted character of the deposits, as shown by their mincraloi and chemical compositions, are features characteristic of terrestrial rather than ms formations. Ville Marie Quartz Ue. The Ville Marie quartzit- as previously explained, is a local pt: of the Huronian occurring ii. le vicinity of Ville Marie, on the < shore of lake Timiskaming. It differs from the typical arkose ni.m > Ann. Rep.. Ont. Bureau of Mines, vol. J9, pt. 2. 1913, p. 87. • Jour, of Geol., vol. U. 1908, p. 155. HMfia 139 of the Cobalt xTiih, in its more liiKhly sorti'd charactci, in thi- more rouiidtd character of its grains, and in the prcM'nce of lenticular aggrcgateA of quartz and jasper pebbles; lithologically it is similar to the Lorrain formation which apparently forms the topmost memlier of the Cobalt nrii's throughout a wide area in the region west of lake Timislcaming. Thi- well sorted and uniformly stratified character of this formation would sctm to indicate that it wa» deposited in a standing bo that the wrii-s was bid do * n t the outtr zone of an an.i (X)ntini'ntal glariation, that tho undt mi ^ surfari- lR*' points gctu ra! makfs an examination for --'na' inipr 'li . ! . i'igure 6. Clay lielt of northern Ontario and Quebec. CLAV BKLT OF NORTHERN ONTARIO AND QUEBEC. Introductory Statement. Throughout a wide extent of territory in northern Ontario and Oi bee, the glacial and older rocks are hidden beneath a mantle of str.ititi clay, silt, and sand which has filled in the minor inequalities of the undiT ing surface so that an extended plain, interrupted here and there by ridj and knobs of rock, has been formed. This wide depositional or con^trui ional plain approximately 68,000 square miles in extent, constitutes wli HaoiMii 141 1, m furally callcil tht- day U-lt of the north and in iKlicved t which o(TU|iiftl basins htmrnt-d in, in jwrt, by the front of the rctrctfng coiuint-ntul gliuii T. Limitations. ( insidsrabff informal! iti with rv^ard to thi' clay ImIi is contained in till- various npfirtH ha\ ing rifcrnui- to tht- Riiil'igy of this rtnion, which have Ikth piibhshcd from tiinc to lime by ihf Canadian (itoloRiral Surv(\, ihc Ontario Bureau of Minis, and the Mines Hr.mch of the f)<(Mrtm< nt of Colonization, Mines, and Fisheries fur Qii< Inc.' In most of these f>\d>li(ations, the poim, at wliirh the cl.iy terminates are not definitely stated so that only the approximate Hmitations of tht hilt arc known. With the i>xcepti,>n of a small area lying n(»rth of lake Timiskaming all of the clay I dt of northern Ontario lies tmrth of the height 1 I land Ix-tween the St. Lawn n(X> and Hudson Bay basins, the southi rn Ixjundary King generally only a few miles north of the divide. In Qiit Iht, however, a bnad embayment extends south across the height of land to the north end of I ke Timiskaming. The north« rn margin of the freshwater, lacustrine portion of the clay belt in Ontario is appar- ently continuous with stratified clay and sand of marine origin lying •-outh of James bay. In QucU-c, however, the northern margin of the clay belt is delimited by glacial drift.' Character. The greater part of the deposits composing the clay bell consist of interlaminated beds of clay and silt ranging from one-quarter inch to three-quarters of an inch in thickness (Plate I). Locally, the silt is absent and the ileposit consists entirely of clay or of clay inter- laminated with thin layers of calcium carbonate. In the vicinity of large masses of glacial drift, on the other hand, clay beds may be entirely absent, the deposit consisting of beds of silt and sand or of sand entirely. In such localities, the beds are generally from 1 to 3 inches thick and Im.s sharply defined (Plate XIV). Extensive areas underlain by strati- fied sands are uncommon in the clay belt, however, and, where present, Bell, R., Gfol. Surv.. Can.. Ann. Rcpt.. 1870-71. p. J50. MrOuat. W.. G«il Surv.. Can.. Ann. Rfpt.. 1X72-73. p. 134. Wjison, W. J.. "Report on a portion of Algoma and Thiimli-r Bay diiMrict»." GmI Sec aluo Plate XXV. Meu. 39. 'Ann, Rrpt., Ont Bumu o( Mine*, 19tl, p. 23a • Pub, W. A., Ann. Kept.. Ont. Bureau o( Minca. vol. Vltl. pt. 2, 1899. p. 175. 143 graphic basin, these also were presumably laid down in a lake or lakes formed in front of this glacial barrier during a later stage in its retreat. Coleman' suggested that a body of water connected with lake Algonquin (the most widespread of the glacial lakes occupying the upper part of the St. Lawrence basin) exte.nded from the Timiskaming region aCToss the St. Lawrence-Hudson Bay divide and that with the continued withdrawal of the ice-sheet, this lake was finally drained off and a separate body of water formed north of the divide for which the name Ojibway was proposed. At the time Coleman's paper was written, the full extent of the stratified clays south of the height of land in northwestern Quebec had not been determined and much of the evidence pointing to the existence of a large glacial lake preceding lake Ojibway was at that time unknown. It has since been discovered, however, that, in northwestern Quebec, the clay belt extends continuously across the St. Lawrence- Hudson Bay divide showing that the stratified deposits of James Bay basin were laid down, in part at least, from the same body of water as those of Timiskaming region. Furthermore, since the stratified deposits of the clay belt are nowhere continuous with the stratified deposits of lake Algonquin occurring in the vicinity of lakes Huron and Superior, it is evident that this body of water, during the greater part of its history, was not a part of lake Algonquin but a sepai ate lake. It is, therefore, suggested that this body of water be separately designated and that the name lake Barlow be used. Extent of Lake Barlow. As regards the extent of lake Barlow very little is positively known. It certainly covered all the territory underlain by stratified clay in the Timiskaming basin and in addition, all that part of the clay belt north of the height of land not covered by lake Ojibway. It is possible also that it covered portions of the region occupied by lake Obijway, for the basins of the two lakes may have overlapped. If this were the case, lake Ojibway would probably form beach terraces in the Lake Barlow deposits and thus afford evidence from which the approximate extent of the two lakes might be determined. Glacial Barrier. Since the bottom of the lower part of the Timiskaming trench has an elevation of only 425 feet above sea-level and is over one mile in width, it is obvious that a glacial lake covering a large part of the Timiskaming basin could not have existed unless the relative elevations of the northern and southern parts of the Timiskaming basin have changed ■Ana. Kept., OntBiuMtt of MiMi, vol. XVIII.pt. 1. 1909. pp. 2M-29]. P.. 144 several hundred feet since the lacustrine deposits were laid down; r unless a glacial ice-lobe projected from the front of the Labradorean ici sheet acrotiseither the lower part of the Timiskaming trench, or the Otiiw valley below the Timiskaming trench. Of these two major hypoihise the latter seems the more probable for two reasons, namely: from \\ distribution of the glacial lakes in the upper St. Lawrence bat.in it believed that a glacial ice-lobe projected across central Ontario btiwet Lake Huron and Lake Ontario basins; and at a number of points alor the southeastern margin of the clay belt in northwestern Quebec, thedii disappears abruptly without regard to topographic elevation. A basin would be created in the upper Timiskaming valley by a ice barrier lying across either the Timiskaming trench or the Ottaw valley below the Timiskaming trench (that is east of the town of Mattawa! but in the latter case, a body of water occupying the Timiskaming basi would be connected with the upper St. Lawrence basin by a nario strait extending along the Timiskaming trench and the Mattawa vallci A search for possible lacustrine deposits along the Mattawa and th lower Timiskaming valleys was made by Taylor in 1896, howeve without finding positive evidence of the existence of a glacial lake cor necting the Lake Huron and Lake Timiskaming basins.' No stratifie deposits such as form the clay belt were observed and possible btac deposits were seen at only two points. It is probable, therefore, thj if such a connexion existed, it was only temporary (possibly during lal stages in the withdrawal of the ice-lobe from the Ottawa basin) and tha lake Barlow was cut off during the greater part of its history by a ice-lobe lying across the lower part of the Timiskaming trench. The preceding conclusions would indicate that lake Barlow and lak Ojibway occupied embayments between the Ontario ice-lobe and th main front of the Labradorean ice-sheet. As long as the lower Ottaw was barred by the Ontario ice-lobe the basin of lake Barlow, presumably extended itself farther and farther northward, following the retreatin ice front. When the ice-lobe withdrew from the lower Ottawa, howevfi the whole lake, with the exception of the part north of the height of Ian having an elevation below the lowest point in the divide (930 feet abov sea-level at present) would necessarily be drained off. With the furthe retreat of the continental glacier, lake Ojibway would also, presumably extend northward and fall to lower levels until James Bay basin wa free of ice, when it would also be drained off. Duration of Lake Barlow and Lake Ojibway. It is probable that in those localities in the clay belt where th stratified clay alternates with beds of silt or thin laminae of calciur ' Taylor, F. B., Am. G«>1., vol. 18, 1896, pp. 108-120. ■■1 145 carbonate, that each pair of beds represents an annual deposit, the fine- grained layer being defxjsitcd during the winter and the coarse during the summer. If it be assumed, therefore, that one pair of these beds was laid down each year, then by counting the number of beds an exact estimate of the length of time the lake or lakes covered a particular point can be obtained.' The maximum number of such pairs of beds counted by the writer in the cuts along the National Transcontinental railway in northwestern Quebec was two hundred and fifty. In the region traversed by the National Transcontinental railway west of Cochrane, in Ontario, the post-glacial lacustrine deposits are described by M. B. Baker as consisting of alternating layers of clay and sand usually half an inch but in places reaching 3 inches in thickness, the total thickness in the deepest cut observed being 25 feet.- Assuming that a layer of sand and clay together represents an annual deposit and has an average thickness of IJ inches, the maximum number of beds in that locality would be two hundred and forty-five which is approximately equivalent to the number observed by the writer in the region farther eastward. The preceding estimate of 250 years would, of course, represent the duration of the lake or lakes at only a single point; but, even if the migrations of the lake basins in company with the retreat of the ice front be taken into consideration, it is apparent that these glacial lakes were comparatively short lived. Change in Elevation. At the present time, the surface of the clay belt varies in elevation from nearly 1,100 feet above sea-le'-el throughout a considerable area adjacent to the height of land in northwestern Quebec to 600 feet abfjve ?ca-k'vel in the vicinity of lake Timiskaming. It is probable that this difference in elevation is due, m part, to the difference in elevation of the surface upon which the clay was deposited; but it is also possible that changes in elevation have occurred in the surface of the clay belt since the clay was depxjsited. From a series of levels taken on the kachcs of lake Algonquin in southwestern Ontario, Goldthwait has found that that region has been tilted 1 to 4 feet per mile towartis the southwest. It is possible that a similar movement has oco.irred in Timiskaming region; but, in '; Company and, later, by the Union Abitibi Mining Company. Both of these companies carried on development work, but in 1912, operations were discontinued and have not since been resumed. In 1901, J. F. E. Johnston of the Geological Survey, in the course of a reconnaissance along Kinojcvis river and its tributaries, noted the occurrence of molybdenite and bismuthinite in quartz veins on the shore of Indian peninsula in Kewagama lake. A specimen of the quartz, assayed by G. C. Hoffmann, was also found to contain 0- 1 17 of an ounce of gold to the ton.' This information attracted no special attention at the time, but in August 1906, Mr. C. S. Richmond discovered another occurrence of molybdenite in pegmatite on Kewagama river, about 2 miles below the outlet of Kewagama lake, and, following this discovery, numerous other occurrences of this mineral were located in that district. A number of companies were organized to develop these properties and for several years active development work has been earned on, but up to the present, actual mining has not been attempted. In the autumn of 1910, it was reported that gold had been discovered near Kiekkiek lake — a point in the central part of Timiskaming county nearly 70 miles northeast of lake Timiskaming and 8 miles southwest of lake Kewagama. As this report became known, a rush to the region Ix'gan and before sp'-ing over four hundred claims' had been staked in the vicinity of Kiekkiek and Wabaskus lakes; but when these various claims were examined the following season it was found that, while the rocks of the Pontiac series adjoining Kiekkiek and Wabaskus lakes contained numerous small quartz veins, the veins contained no gold. Most of the claims were consequently abandoned and all development work came to an end. The last and most important discovery of gold in Timiskaming county was that made by Messrs. Sullivan and Authier, in July 1911, on the east shore of Kienawisik or De Montigny lake in Dubuisson township. When tiie report of this discovery became known numerous pros[)ectorf. were attracted to the district and a large number of claims were staked in the vicinity of the original discovery. Development work has since shown that there are small quartz veins car.ying gold on several of these claims, but mining operations have not yet been at- tempted on any of them iG«)!. Surv., Can.. Sum. Rept.. 1<)0i. p. 138. ' Bancroft. J. A.. "Mln. oper. in the prov. of Que.", 191 I. pp. 83-186. Jil 148 In addition to the localities mentioned in the previous paragruf development work for gold and silver has been carried on at s«vt points in the district, but the results in every case have beendisappoiiiti GOLD. Character. Up to the present time gold has been discovered in only two loc:ili in Timiskaming county, namely on Fortune lake near the north inc lake Opasatika and on several claims in the vicinity of De Montij (Kienawisik) lake. In the Fortune Lake locality, the gold occurs irregular veins of quartz and ferruginous dolomite intersecting dykci altered quartz porphyry. The maximum width of the outcrop of tt: veins is about 2 feet. In the vicinity of De Montigny lake, the k'I' found in irregular quartz veins, traversing either the Abitibi volc-ai or Laurentian granodiorite. In addition to gold, the quartz in th veins usually carries some pyrite, calcite, chalcopyrite, and an abund.i of tourmaline. Considerable metasomatic action has occurred in vicinity of the veins both in the Fortune Lake locality and in the Ki( wisik district; but in the Fortune Lake veins, the porphyry adjoining deposit has been replaced by ferruginous dolomite, pyrite, and chali-o rite, whereas in the De Montigny area, the adjoining rocks have b altered tosericite, chlorite.and calcite, and impregnated with tourniali Origin. The origin of the auriferous deposits of northwestern Quebec and adjoining portions of Ontario was discussed at some length in pnvi reports so that merely a few general conclusions need be mentioncci h The conclusions briefly stated are the following:' The veinsinwhichthe gold occurs are, in some places, arranged in systems trpnt obliquely to the foliation oT the country rock and have l)een drag folded and In in a uniform direction. These features suggest that the veins owe their oriKin i" i prcssive stresses acting in the same direction as the stresses which foliated the r of the region. As regards the source of the gold it has been generally concluded that it h.s I derived from granite, quartz porphyry, albite syenite aplite, or other acidic nK-k;. » intrude the Abitibi group. The reason for regarding the gold as genetic,ill> rii to these intru.sions is the presence of minerals such as tourmaline, schcelite, Milr and other minerals of the pegmatitic association in the deposits. The geology of the region has not yet been worked out in sufficient detail to drtin determine the age of the deposits, other than that they are older than the Hiiro ' Bancroft. J. A.. "Min. oper. in the prov. of Que.", 1912. p 219. •G«>l. Surv., Can.. Menu. 17 and .W; "Min. oper. in the prov. of Que. '. 1<>I2. pp. 199-2.16. • The n;ost striking example of thest* fi-aturt-s in the whole TimiakaminK reaion may be ob^'rv'.4] i veins of the llolhnKer mine at Porcupine. The veins on tins property are dra« folded and faultr.l i weat. and in consequence in following a vein, the continuation of tlie lode is aiways found, on ttie tc tbc point of dislocation. 149 and that the rocks in which thev occur had been considerably foliated before the Tciaa vert formed. Whether all the depoaits were formed during a tingle epoch of laineralua- (ion or not is as yet unknown. Prospects. Union Abitibi. The claims of the Union Abitibi Mining Company are located about 2 miles northeast of lake Opasatika on the north shore of Renauld lake. There is a small remnant of the basal conglomerate of the Cobalt series exposed on the road which borders the northeast shore of Renauld lake, but elsewhere on the property all the rocks exposed belong to the Abitibi group and consist largely of ellipsoidal basalt intruded in places by dykes and irregular masses of quartz porphyry. Numerous veinlets of quartz and calcite are exposed in prospect pits on the property, but the larger part of these carry, at moet, only a trace of goW and, even if more highly mineralized, are too limited in extent to be of commercial importance. The most important of these deposits lies on the south shore of Fortune lake, at the point where Messrs. Oilier and Renauld made the original discovery of gold. In this locality veinlets of quartz carrying coarse gold and gold telluride occur traversing two very irregular dykes of altered quartz porphyry. The larger of the two dykes has a maximum width of about 2^ feet and a length of, approximately, 70 feet. At the time the property was examined in 1911 a pit 10 feet in depth had been sunk at the western end of the larger dyke. The discovery of gold in this locality was made by Messrs. Oilier and Renauld in the summer of 1906, and during the following winter the Pontiac and Abitibi Mining Company was formed to take over the property. During 1907, a few test pits were sunk on some snmll cakrite and quartz veins but no further development work was done until 1910, when a saw-mill, engine, boiler, and compressor were installed. At the time the property was visited by the writer, in October 1911, an inclined shaft (55 degrees) had been sunk to a depth of 155 feet and drifts were being driven towards the northeast and southwest, at a depth of 130 feet on the shaft. The total amount of drifting amounted to about 300 feet. With the exception of part of the northeast drift which was being extended into the adjacent basalt, all of this work had been done in the band of barren dolomitic sericite schist at a point about 150 yards east of the occurrence of gold in the quartz veinlets on the shore of Fortune lake. The buildings on the property consisted of an engine house, camp building, office, shaft house, and a building to cover the saw-mill. ^ A mill was in course of construction. During the winter of 1912 I work on the property was stopped, however, and since that time has ~ not been resumed. ISO Sullivan. This claim, situated on the east shore of De Montigp (Kicnawisik) lake about 4 miles from its outlet, was the property up which the first discovery of gold in the Kienawisik district was mai Messrs. Sullivan and Authier found the deposit in July 1911. The gold on the property occurs in small irregular veins of qua traversing a knob of gneissoid granodiorite which protrudes throuRli i post-Glacial stratified clay.' The veins encountered in developmi work on the claim up to the summer of 1912 are described by Baiur as follows: "The widest vein on the property was that where tiu- fi discovery was made. This vein strikes nearly east and west, with a vi steep dip towards the north. At the bottom of a shaft, about 10 f deep, which had been sunk so close to the margin of the lake that i flooded during high water, the dip becomes very nearly vertical. was on June 21 that the water of the lake had subsided sufficiently permit an examination of this shaft. The vein has a maximum wii of 18 inches where it appeared from the water at that time. The sh is about 8 feet farther eastward. On the west wall of the shaft thi- \ is about 16 inches wide; on the east wall, 6 inches; but at the boti another stringer of quartz, 4 inches in width, appears toward the north face. By stripping, the vein has been exposed for 50 feet eastward fi the shore, where it tapers into a crack which is black with tourmal Eastward from the shaft, it varies from 3 to 10 inches in width. 1 well mineralized with pyrite, a little rhalcopyrite, galena and : blende, and a few specks of native gold. In places, the quartz is d in colour because of the abundance of tourmaline. An assay of a pic sample, showing no free gold upc>! its surface, which was taken from dump, yielded $1 18 per ton in gold. An assay of fragments, reprcs^cn the complete width of the vein at the bottom on the western wall of shaft, yielded $15.80 per ton in gold. A sample, representinR complete width of quartz on the eastern wall of and at the bottom oi shaft, returned $6.20 per ton in gold. A large sample of the com rock immediately adjacent to the vein did not yield a trace of gold. "About 250 feet southward from this vein another quartz striking nearly west to east, had been exposed for a distance of al 25 feet, where it displayed a maximum width of 10 inches. IrrcKula width and tapering to a small stringer at the eastern em. of the expos this vein contains more tourmaline than the one just described and a specks of pyrite and chalcopyrite. The marginal portions of the \ are, in places, very nearly pure tourmaline. For a few feet, the enclr diorite has been brecciated in small fragments, which are now distrib through a matrix of quartz anti lourmaline, the latter mineral predoi « AcconliiK to J. A. Bancroft. "Min. oper. in the prov. of Que.". I'tJ. p. 220. 151 ating. Adjacent to the vein, the granodiorite is much sheared, and up to a distance of 3 feet from the vein, contains a few large cubical crystals of pyrite. One of these crystals was observed to be 2 inches across the tide. Some of them contain a little quartz irregularly disseminated through the pyrite. Two of these crystals, when assayed, returned $33 per ton in gold. Eastward about 200 feet and in direct line of strike with this vein, where a low bluiT of granodiorite rises, a quartz vein is exposed, starting towards the top of the outcrop as a mere fracture lined with tourmaline and widening to 6 inches where it passes beneath the overburden. Very rich in tourmaline, a few specks of native gold were found within this vein. "In many other places, the granodiorite was observed to be trav- ersed by small veins of similar character, none of which possessed a width greater than 10 inches. In most instances it was plain that they were mere stringers appearing and dying out within a few feet or yards." In the summer of 1914 this property was examined by T. L. Tanton of the Geological Survey, who reports* that an average sample taken throughout a width of 6 feet from a prospect pit on the claim was found to contain 3 • 52 ounces per ton in goid when assayed by H. A. Leverin of the Mines Branch. Smith. This claim lies about a quarter of a mile to the southeast of DeMontigny (Kienawisik) lake, where a ridge of the Abitibi complex rises above the stratified lacustrine clays of the clay belt. The following brief summary description of the property has been compiled from Bancroft's report on the region: The rocks on the property ccusist of greenstones partially altered to chlorite schist intersected by dykes of porphyry. At the time Dr. Bancroft visited the district in 1912, a quartz vein varying from 3 to 14 inches in width had been laid bare at intervals for several hundred feet across the claim. Iricgularlv distributed within the quartz of this vein were numerous grains of pyrite, a little chalcopyrite, black tour- maline, calcite, epidote, and a few specks of gold. "A comprehensive sample composed of bmall fragments taken across the vein at intervals of every 2 feet, yielded 20 cents per t<.n in gold. Samples similarly taken along the best mineralized portion of the vein yielded Si. 20 per ton in Rold." Bernard. The quartz vein n\>on which the Bernard claim was staked outf OS on the east shore of Do Montigny lake about 2 miles south of Its ■ t. At the time the property was examined by Bancroft, a width of 1; ■ et of quartz was exposed, only the southern wall of the vein being visible above the water of the lake. The wall rock of the vein ■ Penonal communicatioa. m 152 consisU of albite syenite containing scattered crystals of pyritr, a s|H'( men of which when assayed returned $1.40 per ton in gold. The quar of the vein is a milk white variety containing numerous needles of tnu maline, disseminated grains of pyrite, some chalcopyrite, and a liii iron carbonate. "A sample of the vein containing all its compone minerals and especially rich in pyrite yielded a mere trace of gold." SILVEB. The proximity of the east side of lake Timiskaming to the kIIvc bearing district of Ontario has directed the attention of a large numb of prospectors to this area during recent years, but, so far, the rcsul have been largely disappointing. Since the diabase, with whii the silver-cobalt ores of the Timiskaming area are associated, h its largest extent in the township of Fabre, these minerals are more like to occur in that district. The diabase occurring in Fabre townshi however, is so poorly exposed that prospecting is rendered very difiicu and although a number of minerals have been found in association wi these rocks, no deposits of commercial importance have as yet he discovered. Prospects. Wright Mine. The most important and interesting ore deposit the district east of lake Timiskaming is that on the property known the Wright mine, which comprises the western part of lots 61, 62, ai 63, range I, Duhamel township, shown on the maps as blocks A and B. The rock exposed in the neighbourhood of the deposit is Huroni conglomerate, but of that peculiar gradational type found where t conglomerate has apparently been formed in place from debris deriv from the immediately underlying basement complex. At this particul point, the underlying rock is evidently the porphyry member of t Abitibi complex, for the conglomerate is composed entirely of mas: of this material. The ore-body is exposed for a width of approximati 50 feet on the waterworn rock surface bordering on the lake shore a consists of a breccia of the conglomerate cemented by calcite contain! galena, iron, and copper pyrites. Operations on this deposit were first begun in 1886, by Mr. C. Wright, of Ottawa, but no extensive work was carried on until 18' when the property was acquired by the Mattawa Mining and Smelt! Company. A very complete plant was installed and mining activt prosecuted until March, 1891, when work was suspended. From IS to 1902 the mine was operated in a small way, first by the Petroleum < Trust and later by the British Canadian Lead Company, both of th( corporations representing English capital. In 1906 the property « purchased by the La Rose Mining Company, of Cobalt, the prese LskBHii 1» owners. Active mining, however, has not been resumed. At the time of the suspensbn of work in 1902, a tiepth of 250 feet had been reached in the main shaft, while short drifts had been made at the 65, 100, 200, and 250-foot levels. A number of assays of the ore from this mine have been made, both in the Department of Mines and by private assayers. The galena entirely free from gangue is found to yield from 13 to 26 ounces of silver to the ton, with about 18 ounces as a mean value. It is also found to have a lead content of about 52 per cent, and usually yields traces of gold. The average value of the ore was diminished many times, however, by (he large amount of rock which had to be mined and the consequent rruahing and concentrating which this involved. During the earlier part of its history the lack of transportation facilities was also a difficulty. Quinn Point. At the time the writer examined the geology of the region east of lake Timiskaming in 1906, prospecting had only begun in that district and most of the development work since carried on was undertaken subsequent to that investigation. An account of the work in the township of Fabre up to the year 1910 has beet) given, however, in a report on Fabre township by Robert Harvie, published by the Mines Branch of the Department of Colonization, Mines, and Fisheries for the province of Quebec. The results of development work on the Quinn Point claim up to that time are described by Harvie as follows: "The diabase of the lake shore in the vicinity of Quinn point, on lots 35 to 41 of range II, con- tains numerous veins. On lot 35 on the slope overlooking Lavaliee bay, a shaft 20 feet deep has been sunk on a calcite vein 2 inches wide traceable for several chains, and showing very abundant cobalt bloom. On the west side of the same hill there are two shafts, one of them 50 feet deep, on an aplite dyke 2 inches wide showing cobalt and nickel blooms, pyrite, and smaltite; the other on a calcite vein also showing pyritc and smaltite, had reached a depth of 40 feet when visited. On lot 36 an aplite dyke averaging nearly 18 inches wide is exposed on the lake shore for at>out a chain in length. It shows segregations of calcite and carried disseminated pyrite and chalcopyrite. On lot 37 a shaft 70 feet deep has been opened on a calcite vein 5 inches wide in places and showing small amounts of pyrite, chalcopyrite, and smaltite. On lot 41, an adit has been driven for 20 feet on an aplite dyke 5 inches wide, and various other pits sunk on other smaller veins and dykes. "Most of this work mentioned above has been done by La Cic Mi- niire de la Valine du St-Maurice." On the lake shore at the end of Fabre w^harf, and cutting the diabase, there is a calcite vein 10 inches wide in places, but not showing any M IM metallic mineraln. Nearby, Hmall ^ vin» of quarti and calcite carry hnw anuiuiitH of pyrite and trace* of a cobalt mineral. Pontiac Mining, and Millini Company. A mineral deposit ocrurrii on lot 5, range V, in the towmthip of Fabre, the property of the Ponti Mining and Milling Company, is of interest because of its itimilnrity aplitic (lykeK or vein* associated with the post-Cobalt teries diabase the Gowganda district of Ontario. The deposit consists of ^ptrul.iri and Mulphidc!) of iron and copper on the surface; but, on the walls ol t shaft beneath, it can be observed that these minerals represent nun the weathered outcrop of a dyke or vein consisting of red orthoclaw' .u calcitf through which are diiteminated galena, pyrite, and chalc pyrite. The calcite and orthoclase are very irregularly distributu-d the deposit, calcite predominating at one point and orthoclase at anoitht The whole deposit is traversed by irregular anastomosing veink ts white calcite ranging from a fraction of an inch to 6 inches in widi The proportion of metallic minerals in the deposit is exceedingly mti; and whatever silver is present is probably limited to that contaiiud the galena; for an average sample of the vein material asttayed by M. Connor contained only 3 12 ounces of silver per ton. A shaft approximately 50 feet in depth was excavated on the pi perty by the Pontiac Mining and Milling Company, dunng the .siinim of 1907, the maximum width of the deposit exposed on the walls of t shaft in that depth being 3 feet. No further developmem work has I* attempted on the deposit since that time. Mill. On the Mill claim, lot 44, range IV, in the township Fabre, there are a number of veins intersecting diabase and Abiti greenstone, which consist of calcite carrying a considerable amount smaltite and cobalt bloom.' When the property was examinwl 1 Harvie in 1910 a prospect pit 27 feet deep had been excavated on a \\ of calcite 2 inches wide. Terra Nova Mines Limited. A large amount of prospecting I possible silver-bearing veins both on the surface and underground w done on lot 3, range V north, Fabre township, by the Terra Nova Mir Limited during the years 1909 and 1910. The main vein on which development work was attempted was shatter zone 4 to 5 inches wide composed of fragments >! aplite inclos in calcite, chalcopyrite, hematite, and smaltite. A number of oih small calcite veins carrying hematite and small quantities of sulphic were also opened up.* ' Accordins to R. Harvie. > Harvie R., "Geology at • portion of Uw townihip of Fibre, OucfNC," Dept. Coioai>atU>n, Mii and Fiaherie*, Que., 1910. ISS MOI YBDKMTU. Genftul Slaument. Since the prcsc-ncf of molvbdeniti in a quartz vein travx-rsinK granite on Indian peninsula in Krwagama lakr was firtit noted by J. F. E. Johnston of the Geological Survey in 1901 numcroiw uccurrmces of this mineral have been discovrreti in the rtKion adjoining the original dii«- covery, and a considerable amount of development work has been under- taken for the purpose of determining the commercial value of these deposits. In the following ^-ctions the character and origin of the deposits arc briefly discutaed and the principal prospects of the distrif' described. Character. On Indian peninsula in Kewagama lake and in the region northr.ist of Kcwagama lake the rocks of the Abitibi group (chiefly Pontiac schist) arc intruded by small batholiths of a light coloured, coar^r-urairwrl biotite — muscovite granite. These masses along with the rock.- whu li adjoin them are intersected by .numerous veins of quartz and clvkoh of pegmatite, both of which have evidently emanated from the baiholiihic masses. In these veins and dykes the molybdenite is found as ill - seminated flakes or crystals along with bismuthinite, native bismuth, chalcopyrite, and other minerals. In a rough way the deposits may thus be regarded as belonging to two types according as the molybdenite occurs in quartz veins or in pegmatite. The molybdenite-bearing quartz veins which traverse the granite batholiths and adjoining rocks, although generally irregular and dis- continuous, are exceedingly numerous and in some cases maintain a width of 10 to 15 feet for several hundred feet. The quartz composing the veins is generally a translucent variety and, in addition to the dis- seminated flakes and crystals of molybdenite, contains disseminated pyrite, chalcopyrite, bismuthinite, fluorite, feldspar, and muscovite. The amounts of molybdenite contained in the quartz are exceedingly variable, both in different veins and in different parts of the same vein; but in general, the percentage of the mineral is small. Assays of large quan- tities of the average type of ore available have not been made, but it is certain that the average percentage of molybdenite contained in most of the quartz veins in the region, is less than one-half of one per cent. The pegmatite type of deposit is generally a coarse variety rich in muscovite and containing scattered crystals of molybdenite, some of wliich are 2 inches or more in diameter. Other iiiinerala pre&ent in these deposits are beryl, garnet, bismuthinite, native bismuth, fluorite, pyrite, i 156 pyroxene,' phenacitc,' chalcopyrite, and zinc blende.' In places larg aggregates of muscovite in which crystals of molybdenite are cmbedde occur within the pegmatite, but all of these masses, so far disclosed i development operations, have been small. Origin. Following the preceding description of the character of the deposiL it is scarcely necessary to state that the molybdenite deposits occurrin in the vicinity of Kewagama lake are pegmatitic in origin, the occurrtnc of the mineral in pegmatite, the association of both the pegmatite and th quartz veins with granite batholithic masses, and the mineral assoc ation found both in the veins and in the ptegmatite all pointing to thi conclusion. Prospects. The following descriptions of properties have been compiled in [m from the observations of the writer made during a brief visit to th district, in the autumn of 1910, but mainly from the reports of J. / Bancroft* and T. L Walker,* both of whom examined the prospects i the district in some detail. Height of Land Mining Company. The property of the Height ( Land Mining Company is situated in the township of Villemontel, o the west side of Kewagama river about 2 miles north of Kewagama luki The rocks outcropping on this claim are pegmatite and mica srhis' similar to the Pontiac schist, but, directly eastward across KcwuKiim river, a granite batholith occurs; so that the rocks at the point whir the deposits of molybdenite occur, lie on the contact zone of the grnnit batholith and the mica schist, the latter trending in a southwcsterl direction parallel to the granite contact and dipping to the norihwo away from the intrusive mass. The molybdenite deposits arc of th pegmatitic variety, occurring in dykes of pegmatite outcropping withi a few feet of the west bank of Kewagama river. The development work includes two shafts 50 and 74 feet deep an two drifts driven from the bottom of tlie 74-foot shaft in oppositi' dirui tions, one extending south 60 degrees east for 60 feet, and the othi north 60 degrees west for 27 feet. Near the northern end of th property some pits have been excavated near the margin of a |h^ matite dyke where some masses of muscovite in which nunitrini crystals of molybdenite were eml)edde(l, were encountered. "A siiiiipl ' Accordinc to T. L. Walker. * Arcordinv to J. A. Hunrroft. ■ Bancroft, J. A., "Min. oprr. in thr prov. of Uur.," IQll. •Walker, T. L., "Molybdenum am of Canada." Mlne« Branch, Dept. of Minei, Can., I<)ll 117 from the Height of Land Mining Company's workings — such as might readily be selected for concentration — was assayed in the laboratory of the Mines Branch, Department of Mines, with the following result:' Molybdenum 2 39 percent. Bumuth nil Tungsten '..'..'.'.'.'.'.'.'.'.'. nil ^'°PP" 3 10 per cent." St. Maurice Syndicate. A number of claims were staked on Indian peninsula in Kewagama lake by the St. Maurice Syndicate. These are kndwn as the O'Brien, Hervey. Sweezy, Doucet, and Huestis claims. The O'Brien claim i.s situated on the southeast shore of Indian peninsula, some of the quartz veins on the property outcropping at the water's edge. The rock exposed on the claims is a muscovite granite passing into pegmatite in places. The rock is traversed by numerous irregular quartz veins, ranging from a few inches to 10 feet in width. All these veins are composed of translucent quartz carrying disseminated molybdenite, muscovite, bismuthinite, fluoritc, pyrite, chalcopyrite, and feldspar. The prospect work accomplished on the property consists of surface stripping, prospect pits, and open rock cuts a few feet in depth. The Sweezy, Doucet, and Huestis claims are located on the northern -lop<- of Burnt mountain, on the western side of Indian peninsula, and near the northern edge of the granite batholith which occupies the (intral part of this land mass. The contact between the granite and ihc' batholith crosses the northeast corner of the Sweezy claim, the strike 111 the adjoining schists conforming to the margin of the granite mass. Numerous quartz veins, striking in a northwesterly direction and dipping u> the northeast, traverse the granite on Burnt moimtain and quart/ veins and pegmatite also occur in the schist in the northeastern part of ihe Sweezy claim. The veins range in width from a few inches to 12 krt. The minerals present include the usual varieties: molybdenite, lH>nuithinite, muscovite, feldspjir, pyrite, and fluorite. On the whole. lilt molylxienite content in these veins is not great, but a sample collected trom a vein on the Sweezy by Walker and assayed in the laboratories •>l the Mines Branch was found to contain 2-60 [mt ivnt of iiKilvbdenum. Prospect work on thes*- clainw consiNts of numerous .-.iirf.ice openinKS and pit.s a few feet in depth. I'minsular Mining Company. The claints of this company are all itaated in the iTntral part of Indian jHMiinsula In-tween the northern tnd southern claims of the St. Maurice Syndicate. The dejiosit* are 158 of thf same type iu^ thow exposed on the claims of the St. Muur Syndicate, the granite as elsewhere, Iwing traversed by numerous vc of quart/. Near the southern border of the Smith claim, a diixi (if the pegmatitic type is also present in one locality. A number ol i>\n cuts and prospect pits have Iwen opened up on the claims. Recently a siimpling mill has lieen erected and additional dtvili nu-nt work performed by the St. Maurice Syndicate, according to inl mat ion given the writer by Mr. W. E. Simpson. 159 am IMMiili ■■■■■ 161 I'LUh III. A. Miiskt'K, Sfiinctirrf lowiisliip. (I'agf S.) H. ( .rove ol it^;.i^k.lni\ll l.ikf. U'ugc .*>.) m 163 165 ? 167 MKaocorr rbowtion tbt chart (ANSI and ISO TEST CHART No. 2) ISil2£ ■ 2.5 li£ ^ ■■1 Uj gM ■ 2.2 iiri^ Mb ■■■ 1.8 1.6 ^ APPLIED IN/HGE '653 Eost Uoin Street Rochester. Ne* York 14609 USA ( 7 ' 6) 482 - O.WO - Phone (716) 288- 5989 - Fo« , ■ *'"'' ')^ 169 171 173 I'l All; l.\. Iriiniatcd anticline of liiinilcd nm'i>s. litintcr point, Tiirtlf liikf. (Pasji- 102.) Ml 175 177 i;«» 3 u ISl 1S,< ^^•r 185 3 i«; 1S9 INDEX. Abijevia hill* _•; lake Abitibi etoud • Gke .,'.';.■.■.■.■.•;;■• • ' river • ^folc»lua ...'.'.'.'.','[]] . ' *nalyiee of. . Accees, means of . . . . Acknowledgmenu. . .'. Actinolite Adams, F. D iGgerine Aggk>merate Asricultural poMibilities . . Aliier, John Alhimette isbnd. Ami, H. M Amphibolite described . Analyses, Abitibi vokanics. ' , ferruginous dokimite . gneisses minette Anderson, Tempest . . Andesite described Antler Lake section. . . , Aphte Archaean Arfvedaonite. ... . Areillite Arkose Assays, gold. . ..!..' l.' .' molybdenite. . . silver Authier, H... Baby tp Baie des P^res Baker, M.B... Bancroft, J. A. . . Barlow, A. E. I lake.;,'.;;'.'.;;;;;;;;; * * duration of .. .. n .... extent of Bamere lake Basal complex .... * , conglomerate. . . ] . Basalt described.. Batholiths, northern, desaibed. Deekmantown Bell river. „' Robert...:; Bellefeuille river. . Bellin, — Bernard claim. ........ Bibliography IT .13, 88, Paoi H 25, 27. 42, 84 «. 73, 81, 87, 149 31, S7, 82, M 32, 33 91 83 3 1 9S 56 99 SO, 92 5 3 63 116 83 83 125, 126 101, 132 90 123 84, 89 89 105 100 46 99 eO, 108. 138 60,93, 108, 138 151 157 153 147, 150 82. 86 107. 110 142 89,94, 112, 114, 150, 156 ••12.34.41,56, 101, 116 45,119 144 143 % •42, 46. 56. 77, 109, 127 59 82 97 63 •5.33,84.85,92, 112 12.116 33 11 151 14 190 fiUBiiM,E '*"■ BifchT«kt >'* Bbmuth, native ,;; BiKk river '♦^« '25 Blueberry itUnd ,?! BoMchatel Ip »" Boundary hJv^ ^ ^ " : : ! i : i i i i i ! ! ! ! ! 1 ! ! ! ! ! ! ! ] ! ! ! ! ! ! ! ! ! ! ! ! ! 9j. 93 Brennan UkT ,....•..•.■•. V "' "' ^V?S' IS Briaicau bland J7, 78, Il« Brittah CanadiuLwul C^piuy. ii« Brock. R.W TT.^^ *?i Brul* Uke •• Bryion UUnd ,fj Burnt mt "S a Cadillac tp «. Cameron lake , J? CamobeUbay »" Canadian Pkcific ry S Caron Uke ,,5 Cave rapid *•• *J Chak»pyrite ,., ,„ ChampUin cUy and Mnd IM, l» Chauvigny lake oi o» Chibougamau lake ' ? i Chief iJand , Ji Cliteritfc rocka deacribed ,5 ChriatopherKin lake '2 Chrome mica ;,. ,,f CUy, Champlaln '2 ■ lacuatrine, deacribed iTi ;; poet-Glacial, lacuatrine "f • SSda:::::;:::;;: :...:::»: io: a: h. m Clericylake »} Chmate *i cob.it.., :.:::::::::::::::::::::::::;;::;::;;;;;: ,J . "^d^iij 44, 57, 61, 104, 109. 111. 137, 138 ■ « •-- 103 Cochrane. A. s"""";;; ». »?* Coffee river -r Coleman, A. P .zz congtemerate. ba«j •••':::::::;::::::;::;;:::;:■::,■:::.■.■;.■.•.• .v.M. 106 Connor. M.F. ."!"*'; ^' ]f. Correlation '^€ t.t it Coulonm river 65, 67. 73 CourviTIe tp ,fi Cyanite deacribed *i Dacite -, Oaaserat lake g De 1'i.ie, d.; .■.■.■.■; 'f D^'2r%''."''.'".'". .■.■.■..■ .v. ■.■.sY.m; uY. itt. ISO, 151 in Diabue dcKribcd . * oliviiw * Quarti. Diorite dMcHbcd ..'.'. Dolomite, feiTugiiioiM. Doucet ekim Dninagi Drunken bland Dufault lake Dufay lair*. . , ' < ....'■.'.■." DitfrewHiy lake Duhamel tp Diimoine lake „ • river Duparquet lake Dutton, — ■wilytii. Eileen Uke Ell^ R. W Eakert Exploratbna and Mrveyt, early! Extruuve rocka , Ftbre aeriea > • tp Fauna Femiginoua dolomite. .....'.'..' Fly nver Foreats Fortune lake. .... Foadia Fraaer lake Gabbro deicribed Galena Garden Itland lake. . . _ " " river Garnet, pink General geology " lUtement Geographical poaitwn of area Geology, general 1 Ottawa baain Glacial barrier • drift „, ' ?t"« V.V.'.V Olaciation Gneiss, analyses of . . . . ^ ..• banded Gold " assay of from SuUivaii claim character of origin " prospects .'.■.■.■;; ; ; r^u,uK''^,''^iM"^*' Lake. Ont. Ooldthwait, I. W Grand lake Victoria . . Paoi »J. lU 114 44,114 84 SI, 92, 124 12« isr 27, 31 110 1,31,89,90 109 109 31 84 «, 107, 110, 'l52 29 3, 27 .8,33,84,83,91,92,118 122 37 48 118 11 81 Grassy lake. 91, «; 108,109, 112, 1S3, !S4 9 31, 92 33 7 89, 93, 148 44. 63, 116 93 82 146 94 34 101 76 76 3 76 46 143 141 • 21,44,64 21.44, 63, 117. 138 101. 132 98, 102. 103. 131 146, 147, 148 ISO 148 148 149 126 ;•, 145 3, 27, 29, 37. 93, 101 29 192 Grmvillebek. GuiguM tp combliofi of. Pagi 4a, 12« 7$ 7a, ao 86, no Hamilton initt HairicaiMw river Harrij-Mrnwell cUim, Larder la kti 6m. . Ilarvic, Kobrrt Heleht oJ Land Mining Cbiiipany • portac* Hervey claim Hornblende ichitt dctcribed Hough, Ichn Hudwn bay Hudion's Bay Company ..... . Hue«(i» claim Hunter* bay " lake Huronian lce-«hcetR, continental. Indian peninaula. . . . Indians Inhabitant!, native. ] . Iron formation Jamet bay Joanne bay Johnitor, J. F. E KakakeUlce ' Kamalc ridge Kame« Kanasuta river Kanikawiniica island ..... Keewr.tin Kekeico liilU. . . " lake Kennedyt'k^:^'^*"='«'"«'''-ke.:::. Kc»-igama lake Lake batholitli '.'.'.'..'.'. Keweenawan Kiask rapid. . .'*''.'.^°'*" ^^ intrusive.. " river Kiekkiek lake King lake Kinojevis lake ............ Kinojevis river. . . Kipawa lake ' river Kirkland Lake series Labyrinth hills *" lake la 3i.U,»7 126 t J, 5J, ISJ IS6 lit IS7 IM 147 aj J «8, 2.1 3 157 79, 80 .42,43,S7,7i;iOJ,ios,}s2 ■■■•■■.• 21 1". 147, 155.157 7 7 51,92,94 33 117 . 13, 147, 155 92 82 118 33 34 4«;, 67 24, 26, 105, 107 94 37 109 8,87,89, 147 98 44 62 92 .M 94,96, 147 93 37. 94 33,37.93,147 27, 29, 36, 37 8.27,37 52 .26,105 89 193 UCl.^Ml„tt,,d.UV.IM.d«!!..M.«rie. " *• UuiiiM Ucto<« claim. ... Laket. Umbe.'L. M.','.'. U Motic tp Lamprophyrt L« P«uw tp. . . Unter lakr. ... U Rcine ;p 1^ £?*• • "'"« •^"«mp«ny. La S«rrc river . ' Laurvntun plateau. . « I Prt-Cambrian hi«ti>ry UvalMe cr-ek '*'•*«"«*'« «. W, M, 106, m 69 40 ISl 122 19. 78 .• 85, 90 12.48, 107, 116 118 33 40 106. 139 53 ■ ■■ 7 27 33. 92 33 87 116 93 26 84 64 93.94,96 18, 64 34, 40 1S2 3 12 32 6 6 33 154 13 90 90 146 10! 71 194 Molybdenite j47 ' atMty of ...[.....[..... [.[[ 157 * detcribed 155 u .k . I*o«Pe«« 156 Montbray tp ai Mooae bay ......'........'.'...].. 84 Mountain rapid ^ Murr&y, A !!!!!!!!!!!]!!]!!!!!! 48 MuKoviie !!!!!!!!!!!!!!!!]] 98 Mufkegs '.'! 1 !!!!!!!!!!!!!!!!!]!!!!!!!.! ! 5 Natagagan lalce 34 " river ..'.......[............... 33 National Transcontinental ry 3 30 113 Nepawa island ' ' 83 Newagama lake 94 Night Hawk lake 142 Nissaki lake j 10 Nomenclature 6S 06 Obalski, J jj Obaska lake 33 O'Brien claim 157 Ogami lake 118 O^skanan lake ...■■..............[.......[..] 8 Ojibway lake 45 " * duration of ......]....[[.......' 144 Old Man lake 29 " Woman lake 29 Olivine diabase .....................'. 114 * " described 113 Oilier, Alphonae ...ii6, 149 lake. 115 ^Asatika lake '. . . . .3l/37, 93. MJ 110. 113, 146 Ordovician 43 jjg Oster island .......................'..'. ' 116 Ostaboining lake .27 101 Ottawa basm, geology of ' 45 ' gneisses belt ....'..'..'.'.'.'.'.'..'.'.'.'.".'.". .'.'.'.'.'.'.53. 128 r^/ , "ver 8,27.32.33 Otter "ake 36. 1 12 Pahoehoe lavas Palaeoplain, pre-Palieocoic. Pakeozoic. sediments. Parks, W. A Peat. .43, Pegmatite Peneplains Peninsular Mining Company. Peridotite. Petroleum Oil Trust Phyllite '■'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.['. ' described .................'. Physiography .............[............... Pichi point ...............................'. Pillow structure described . [ Pirsson, L. V ........................['. Pleistocene .............................' .63 121 18 116 62 13 5 100 17 157 87 1S2 51 91 16 117 120 41 117 195 Page 147 157 155 156 84 84 40 48 98 5 34 33 10, 113 83 94 142 110 65, 06 13 33 157 118 8 45 144 29 29 114 113 6,149 115 3, 146 3,116 116 7,101 46 3, 128 32,33 6, 112 121 18 3,116 62 13 S 100 17 157 87 152 51 91 16 117 120 41 }, 117 Poirier bke Pontiac lerie* " and Abitibi MJiiiiig Company Po.t.Co.]^Si»ffl!^Co«pa„y.-' -Glacial * n .' ■*?"«"« epoch. .'..'.'.'.■ -ralseozotc uplift . . Pre-Cambrian baaal corapii.V. ^ -Huronian batholithic intnuivet -ralaeozoic palcoplaiii Prenaac tp Previous work. . . Privat tp. . Pyrite Pyroxenite deacribid. .' Pyrrhotite Quartz diabaae I porphyry......... _ • . • detcribed. Quartzite 8.' „ . Ville Marie. ...' uinn Point claim, uyon Raven lake Renauld, Auguste. . _, " lake Rhyolite described. Richmond, Chas. Ripple-marks Rivi^ des Quinze Robertson lake Roger lake Rousselet lake. . St. Amand lake St. lohnlake l!" if'^"'*-Hud8on Bay di^de ' 3t. Maurice Syndicate Sand, Champlain "^ lucustrine, deacritod.'. , . . and clay Saasaganaga lake Savu, Samoa Sections, Cobalt aerie*. Sederholm, — Senneterre tp. . . , Serpentine. . . .' Seven League lake. ....... Shabogama lake Shiminis, mt Sifton lake Silt, lacustrine, described. '. Silurian R. Pace ■ 51". ■ 72,' 93, -94;;^^ ,jj 147. 149 154 62,112 64 23 20 42, 127 73, 97 18 87 12 93 96,148 79 96 114 89 85 60 109, 138 153 63 25 146, 149 110, 115, 149 as 3, 147 109, 139 36, 84 36 31 88 36 20 .24,32, 106 157 64 118 64 29, 79 123 58, 104 130 142 87 40 33,112 • ■ • • 34 ... .26, 105 85 118 . ...43, 116 196 Silver. M«y« of from Wright mine, lake Pack 146, 152 1S3 Slate r... 152 • described 51 Smith claim 91 Smoky hilk 151, 158 " river 24, 25, 27 Spencer, j. W 33 Spruce lake 21 " river 29 Stupart, R. F 27 Sudbury or Timiskaming leries / Sulhvan claim 49 J.J 150 Summit lake 147, 150 Surveys and explorations, early "8 Swastika 11 Sweezy claim ,'.,', 52 Swingmg hills 157 Syenite porphyry described. 24, 26 Table of formations. . Tanton, T. L. . . Taylor, F. B Tenendo hills Terra Nova Mines Limited. Terraces Tjmaeami lake Timiskaming belt 76 151 144 24, 25 154 117 57 ' ET" ■:;:::::::,:,,::::::::'*;'V?I : and Northern bnuriory-... ! . . ^' 2°' ^'^ ^2. 34. 60. 108 region ,V , • ** • ^' °°*- *"'• 0"«-' "ertion of Cobalt seriM in ...... . ' ''s« ocncs .,.., _. * . . trench, overdeepening of ... 1 .! ; 5^ Topographic history 40 Tourmaline 41 Tremblay, J. O 148 Tremolite 3 Trout lake. 95 Tuff 101, 118 Turtle lake 50 Twenty-one-mile bay. . ! ! 80 101 Union Abitibi claim. . . Upl^ds. ". . ^'"'"* '^'"'^' ' ■'•■'■■■•■'••■•'■■■•'■■■■■.•/ }« Uplift, post-PaUeozoic ^4, 25, 26. 27, 29 20 Valleys. linear • • 21 Varsan tp 34, 37, 39 Vaudray lake. . 87 Vennor, H. G. . . 36 Ville Marie. . . 48 quartzite 106, 109. 110 Villemontel tp. . 106, 109, 138 156 197 W. Wabaskus lake Walker, T.L. Wapuaanan lake Willianu, M. Y Wilson, A. W. G " W.J Windego lake . , Winiwiaih river Wolf lake Wright, C.V\ assayp of silver from Young's farm V. Pac* 147 .13. 156 27.29,32 116 20 13 25 27 37 146. 152 108, U6, 152 153 118 1 ^-'' Hds.l LEGEND O gj ORDOVICIAN SILuillAM 1 RCWCCNAWANT ' OS HURONIAN f ^ f i i Mfawn 1*1 , m rt mm. PRC-HURONIAN ■«TNOLirt*lC l*|tll|/«iv|* Acgeriae aadl ^iiraMi ait >ji ■in n-1 anrf AiMdv <•«■ aariW S^ TIMiaHAMIKKi GROUP Ttlalifc— iiU wrlM KirJtiaHa.I.ahe aariBa 0.1 /■4/ ABITISI GROUP dmfeMMiiiife Hepaitmrntofiftmrs OeOLOOlCAL SURVEY W'.i *M M'lNNT^ DmtOT'Nf. CirOLOGiS* OUTLINK MAP ■^ AMria#«gMat ■ — ■■ * ttmovr ASiTiai anotp •RCNviLLC semes CTju*maia» Symbols -»* DE] Oanal 1 -« iBvn. y r jssteii TIlXABa • M^l ^!^ 47 Bdrikl IT / "" .v^4 ^ ^ ^ V te < r^ ^*S ?* 1 ■ — ' ^^^JjjC^^^C; / sk ^ E#W-. r\ •* I >■ WTSS A, r^*- OLl 79W 79W caaenrfaa. X'XCa TIMI a ■ w <» n yi|i .ifcm