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The following diagrams illustrate the method: L'exomplaire fiim6 fut reproduit grdce d la g6n6rosit6 de I'dtablissement prdteur suivant : La bibliothdque des Archives publiques du Canada Les cartes ou les planches trop grandes pour dtre reproduites en un seul clichd sont filmdes A partir de Tangle sup6rieure gauche, de gauche d droite et de haut en bas, en prenant le nombre d'images ndcessaire. Le diagramnie suivant illustre la mdthode : 1 2 3 1 2 3 H 5 6 s mmm i THE LAURENTIAN AND HURONIAN SYSTEMS i3sr THE RHia-ioisr nsroRTia: of LAKE HURON BY ROBERT BELL, B.A. Sc, M.D., LL.D., Assutant Director of the Oeological ihtrvey. (FROM THE REPORT OP THE BUREAU OF MIXE5I, O.VTARIO). PRINTED BY ORDER OF THE LEGISLATIVE ASSEMBLY. TO RON TO f PRINTED BY WARWICK A SONS, 88 AND 70 FRONT STRBIST WEST. IS92. ■ --14 2 -; ,; iv'A V i^A^ . , >• Ihf iftj IM fti rf»M ifflftirtrti i'i"i-- l*V'-|?>jriW .»■ .<• ■ <?»,';'« ...J.' ,■.(^J,,,,^,;-.» ■JJ,H(i^,^.,,.■^>^_ <■,,;;'< ^5j-s,;i<fi|(i(«*,^(«*;,i^,,ij!»«^-(,(»»i5fij, '^#»*>v#- .:}>t,)s^^>,^8,.i j,^.», ./^v'j;?;s>eii(^sj,j-i. rw<»-*-,»;-v,.,vf e-?ys'. ^mm i THE LAURENTIAK MP HURONIAN SYSTEMS I3Sr TDEiE REG-IOIT ^STORO?!! OF lAKE HURON BY ROBERT BELL, B.A. Sc, M.D., LL.D., Asddaid Uirector of the Geological Survey. (FROM THE REl'ORT OF THi: BUREAU OF MINES, ONTARIO). PRINTED BY ORDER OF T H Pj LEGISLATIVE ASSEMBLY. TORONTO : Pb'Mted bt Warwiok & Sons, 68 and 70 Front Stb*bt Wkbt, Tobonto, 1892. «*1 ( ^ 9) ■yi I <:4 THE LAURILNTIAN AND HURON IAN SYSTEMS NORTH OF LAKIi HURON. liy Dr. ttobiTt Cell, Assistant Director nf tiie GtMlogical Survey ot Canada. This paper is intended to give a brief account of the geology of the country represented on the accompanying map extending from lake Huron northward to lake Temiscaming and from lake Nipissing westward to the Spanish river. It will aim at giving a summary of the various reports of the Geological Survey referring to thnt region in the light of the most recent views in regard to the rocks of the district, and will cover ground already described by the writer in the annual reports of the Survey for 1865 and 1866, 1875 to 1877 and from 1887 to 1890, by the lute Mr. Alexander Murray of the same service in the reports of 1847 to 1857, and by reports made at various times by officers of the Department of Grown Lands. The geological coloring of the map is compiled by the Director of Surveys in ihe Department of Grown Lands from the niiips and descriptions of Mr. Murray, the geological map of the Basin of Moose liivi r, 1883, and that of the Sudbury Mining District, 1890, by the writer, and also the ma])S accompanying Sir William Logan's (irology of Ganada, 1863, as well as from the descriptions contained in the various reports above referred to. As these reports and maps are not very accessible to tl;e pub- lic, and some of them are out of print, it is felt that a s'lort summary of their contents, with suitable explanations, arrangeul in convenient form tor reference and illustrated with a geological map, would be found useful at the present time. The colors used are made to harmonize with those at present adopted by the Geological Survey. The topo- graphy is compiled from the surveys of the Department of Crown Lands and of the Geological Survey. With the exception of the larger islands'on lake Huron, and possibly a tract in the Sudbury district, the area represented on this map is occupied almos*^ exclusively by rocks of the Laurentian and Huronian systems. Descriptions of these rocks in general and of their relations to each other by the writer are contained in the Section devoted to Geology in the Report of the Royal Commission on the Mineral Resources of Ontario, 1890. But it is now proposed to give a more detailed and local account of the rocks belonging to these systems which are met v/ith in the area represented on the map. THE LAURENTIAN SYSTEM. The Laurentian system may be divided into an upper and a lower formation. The latter consists almost entirely of primitive or fundamental gneiss, wiiich is supposed by many geologists to have been originally of an igneous nature, but to have undergone altera- tion which has produced its more or less foliated character. The upper Laurentian appears to consist of metamorphosed sedimentary strata to some extent at lenst, while the Huronian rock" are undoubtedly largely sedimentary, but mingled with a varying propor- tion of igneous rocks, both of which have undergone more or less metamorphism. Mbtamokphism. By this term is meant those changes in rocks which have been produced by pressure and heat, and possibly electricity, acting slowly or through a very long time, and producing molecular or chemical interchanges in their constituents, and causing them to become in a greater or less degree crystalline. The original com- position of some rocks is more favorable to metamorphism than that of others With a change of conditions, rocks may undergo a second or further metamor- phisiu. Th(3 element of time being very important in l)ringing about metamori)hism it follows that the older rockH are the more subject tliey have been to have undergone this process. The more ancient rocks have necosHarily been those most liable to disturbance from these changes wh'ch have always been going on in the crust of the earth, so that they have been moved from their original positions and have been tilted, crushed and cont'^rted more than the newer ones, almost in direct proportion to their age. The very fact of strata standing at hiqh angles to the horizon appears to be connected with the metamor- phic processes, and rocks which are locally disturbed, as in certain mountain chains, are found to be metamorphosed, while the same strata in continuation are not changed where they are found nearly horizontal. Great outflows of igneous matter have also in many instances had the etiect of altering rocks locally. A crushing and disturbing force due to the constant shrinking of the earth and act- ing horizontally at the surface has been going on in its crust from the earliest times. The effect of this force may bo seen, not only on the large scale, in the tilting, folding up and faulting of the older rocks, but also in their microscopic structure, thin sections of them vpi y often aflbrding the clearest evidence of their having been subjected to intense pressure, forcing asunder solid grains, grinding them against each other or crushing them to small particles. Another effect of the intense lateral pressure referred to has been to produce in rocks a schistose or a slaty cleavage at right angles to the direction of the force. In the crystalline schists this has been effected by the crushing force, aid<?d often by a shearing movement, causing the component particles to move slowly around till their greater diameters assumed positions at right angles to the direction of this force. In the schistose rocks the cleavage planes of such minerals as possess cleavage have been made to corre.spond with the directions of the mechanical arrangement of the other particles, so that in cro.ss section the whol- texture has a i)arallclism of its grains, giving it a lami- nated appearance. Dioritic schists have proba])ly been originally massive diorites, and have had their cleavage structure developed in the manner just indicated. Many geologists believe that some kind of gneiss have been formed out of massive granite in the same way. These | recesses involve an enormou.s lapse of time, so that a crystalline and schistose condition is prima facie evid' nee of antiquity. Indeed if we exclude those cases of local metiuuoiphism wbicli have been referred to, it may be said in a general way, the more crystalline and altered rocks h»v ; uecome the more ancient they may be presumed to be. Notwithstanding the apparent stability of the rocks in this part of the world, far removed as they are from volcanic activity, there exists nevertheless within them a state of perpetual unrest. Unceasing changes are going on in the arrangement of their con- stituents as illustrated by crystal enlargement, pseudomorphism and decomposition in a petrological sense. Besides the constant internal changes taking place in the rocks there is restless action or movement on a large scale throughout the whole body of the earth. One of the primary causes of this movement is the constant shifting of the matter on the surface by the action of air and water or ice. The earth is not a rigid solid, but obeys hydrostatic laws. When a certain weight of matter has been transferred from one part ';o another its effect is to sink down the part to which it has been transported, while there will be a tendency to rise to a corresponding degree at the point which has been relieved of this burden. These oscillations were probably more frequent and rapid in the earlier geological ages than they are now, but they will continue to go on to a greater or less extent as long as air and water exist to transport matter and disturb the equilibrium of the earth. Divisions of thk System, The lower division of the Laurentian system is characterized by monotonous uni- formity in the nature of its rocks, which consist of gray and red gneiss, usually much bent or disturbed, and having generally only a ruUely foliated structure and a solid or massive character. Its felspar is almost entirely orthoclase, whereas the other speciea arc aiiuiulaiit in tlic upin'i' (li\i,si()ii. 'riicic is u ytiicial iiliscnct! of i.roiioiiiic iiiiinrals, iiiul the nutiilier of iniiiiTal spcoifH is .small aa eoniparcd with th« lattf-r. Thtt upper diviHioii is of a more i'()iii|ilcx or (liMV'riMiti-.tcil cliarai'tcr, or coinpriHcs a f^Tcatcr vitrifdy of rocks and mini'ials. It posscHst's more rc;;uiarily in its Htratitication and incliidfs j^rr-at liandfil niassi'H of ciystaiiint! linii'stoncs, vitrcoiiH (|uart/it('.s, mica and liornhlcndo scliists, massivfi pyroxene, and l)Otli massiv(! and fi)liale(! ialiradoritu rooks. Con.sideralile areas of jjranito and syenite occur in the tbrnrition. These, as >v(!!l as the pyroxene rocks, and perliaf.,s also tlie hornlilendic hands, are evidence of iniier)us action. The dykes ot <,'reen-itono and porjihyry wliuh cut the upper Laurentian ma;/ helong to a Ir.ter jt^eological jieriud. rpvvards of sixty dilh-rent mineral spociea havo W-^n found among tlio upper Laur- entian rocks in Canada. Diey also contain a variety of economic minerMJH, amou'< which may he mentioned gi'aphite, apatite, mica, serpentine and limestone marhles, limestones suitahlo for calcining, felspar for jmrcelain, ])orphyriesand other ornamental stomas, pyrite, sulphates of harium and strontium, asbestos, crysotile, building stones, and ores of iron and othi-r metals. It is not impo.s8il)le that gneiss may havi^ h(!en formed in more than one way. Wliile some varieties, from their mioioscopical characters and other circumstances, appear to he of clastic origin, it seems to he eijually certain that others owe their foliation to pressure and internal changes which may havo taken i)lace in rocks of igneous origin. Dr. Steiry Hunt is of the opinion that we have not yet discovered any rocks which can he regarded as having formed part of the oiiginal crust of the earth, that is, if we suppose the crust to have heen first formed hy th(! m(;re ruperhcial cooling of a molten lUass, since the earliest rocks of which we have any knowledge all contain water and free silica. The lower Laurentian gneisses are the oldest rocks witli which we are acquainted. Their thickness is entirely unknown, and it may ever l)e found impossible to arrive at even an approximatinn to their volume. It must however be enormou.s. The upper Laurentian, of which some kind of measurement is possible, n.ay be roughly estimated in the Ottawa valley, wliere it has been more studied than elsewhere, at from 50,000 to IQO.OOO feet, or nearly 20 miles in tliickness, and even much more. Although tlie older Laurentian rocks may afford no mechanical proof of the per- manent existence of a sea ujion the earth, unless their foliated or stratiform character be taken as such evidence, water appears to have been present, perhaps as only temporary precipitations upon the surface, at every stage of their formation. But in the upper Laurentian the great de])osit8 of nearly [)ure carborate of lime and of tolerably pure silica in distinct bands afford strong support to the tqueous theory of their deposition, while it negatives that of their igneous origin. Ai. important feature in the general character of the Laurentian system is that its rocks, as a whole, are of an acid nature, or contain a preponderance of silica in their ultimate chemical composition. We shall see further on that in this respect they contrast with a considerable proportion of those of the Iluronian system, which are largely of a basic character. Whether we reganl tlie bulk of the Laurentian rocks as having had a clastic or an igneous origin, the general condition of the surface of the earth does not appear to have undergone any great change while they were being formed, or while the cooling process was going on to the extent of their thickness. Even in the upper Laurentian we have found no proof of the pre existence of solid rock or dry land such as might be afforded by conglomerates. A P K li 1 O 1 1 OF C H A N G E . But with the beginning of the Huronian period came a new order of things. Great volcanic activity took place, and at the same time we have distinct evidence of the per- manent abode of water on the surface of the earth and of the wear and tear of the sea on the solid rocks. Immense^ quantities of volcanic ashes, cinders or tufa, broken rock and other ejectamenta were thrown out, in some cases with explosive violence. Molten matter was poured forth in great quantities from vents and rents in the crust, forming thick sheets and large masses that became incorporated among the marine sediments which were probably accumulating rapidly. The surface of the earth would be almost *2 (M) ■■ i 4 entirely covered hy tlu; sow, wliioh would likely lie slmllow, hot and (u!I of disHolved mineral matters, the greater part of which have Hince heen eliminated. It would l)n untit to Hupport animal or plant lil'c, and it is therefore improltalile that we shall »iver lind any organic remains in this >ystem. Soun? of the (Tupted rocks remain massive and un- chan^'ed to the pre.ient day. except hy the internal or molecular action among the con- gtituenth themselves, hut the hulk ot" them had heconu! hroken up under the strong weathering iidhiencea of the period, or hy contact with water, and spread out on the V)ottoni of the sea to foini tlu; various stratified rocks of the system. The general cliar- acter of thf! Huronian rocks may therefore he said to he pyroclastic, this term signii'ying that although fiagniental they have nevertheless had an igneous origin. The lluronian rocks of lake Superior, and the coi:ntry norlli ^md west of it, c(;nsist largely of greenish Bchists wh" .. . .e, chemically speaking, hasic as distinguished from the gneiss ot the Laurentia!!, whicli, as already stated, is of an acid or silicious character. A considerahle proportion of the great Huronian lielt is made up of greenstones and allied rocks that are also hasic. Rocks soitii ok t ii k Hi iuinian Hki.t. In the country represented upon the map, tlu^ rocks lying hotwoon the great Huron- ian Iwlt and the shore of Georgian hay appear to helong to the upper Laurontian for- matio I. In the French river region the gneisses are generally oliaracterized hy much regul irity in their dips and strikes, which often maintain the same course and ahout the same angle of inclination for long distances. The dips vary from a horizontal to a vertical attitude, but in the majority of cases they are ahout intermediate between these. This region is noted for its peculiarly straight and almost parallel rocky channels, many miles in length, having a general course neaily east and west, which are intersected at large angles by othjr channels almost equally straight, the whole forming a sort of nst- work quite unique in its character. Some of these channels belonging to both sets run with the strike of the f,neiss, which v/hen mapped has a sort of zig-aag arrangement on a large scale, while Ma others follow the lines of the principal set of joints. It some- times happens that between two leading joint-planes other and parallel joints occur, un- usually close together, breaking the rock up into blocks which have been removed by glacial denudation, thus producing these channels. The angles of dip being only moder- ately steep, those channels which follow the strike occupy ditch-like notches formed along the outcrops of paiticular sets of beds which have been more easily excavated by eroding agencies than those on either side of them. It will be observed that the French river flows in two principal east-and-west channels between lake Nipissing and its rocky delta, and that about half way down they both jog to the southward at right angles. This interruption in their course is perhaps originally due as much to somo northand-south break or disturbance in the rocks as to changes in the strike. The long east-and-west channels, whether parallel with or transverse to the stratification, are also probably situated upon lines of crushing, and possibly of some dislo- cation, along which the strata have been broken up so as to permit of the deeper pene- tration of the surface waters and the conse([nent decay of the lock prior to the glacial period, during which these channels have been excavated below the general level ot the country. They are really only long and very narrow lakes, with slight falls or lapids between them, and they persist in their courses uninfluenced by the changes in the strike of the rocks they pass through. Besides the channels shown upon the older maps, there are many others in the French river country, all of which belong to the reticulating system of waters which forms so remarkable a feature in .is whole district. The curious rocky delta of the French river has a breadth across its mouths of fifteen miles. The channels, which are very numerous as we leave the coast, form three groups, the east, middle and west, each of which unites by cross channels into one at a short distance up. They are all nearly parallel and have a general northeast and north-north- east course as we enter from Oeorgian bay. The gneiss in the whole interval covered by these channels runs parallel with them and has a uniform dip to the south-east and east- Boutheast, with an average inclination of from 40° to 60''. This general strike extends j for twenty niileH inland from (icorjjiftii l>fty, whf-n it hcconics disturbed, and a little fur ther on is cut off by a northwesterly strike in siinilar gneisNes which prevail on the upper part of the Frcp.uh river and the country to the norlliwarJ of it. In the ccmtral part of the course of the river tlie strike in dill'eient intervals runs about north and south, east and west, northwcsst and northeast, while between these groups of toliMably strai<,'ht liands it in often more oi h^ss bent or distorted. In some parts of th(f French river rej^ion. oven when- the striki's are regular, Mr. Murray consid- ered the structure to indicate a series of unticlitiul and syne' folds, in which some of the strata are repeated, and that the thickness of the gne' in con.seijuence made to appear much greater than it really is. But after making i ' unce for this partial repe- tition, the actual thii.kness must be very great. Southeastward of the mouths of French river, along the shore of (ieorgian bay, the rockw are (verywhen; well exposed, and the structure of the gneiss and associated strata or their local contiguration is well brought out by the erosion to which they have been Subjected. This fact is graphically illustrated by Iht! recent charts of Captain Boulton. Locally the run of the stratification is often imlicated by the form or direction of the points and bays, the larger islands and the chains of smaller ones. The curving; outlines of the islands, channels and inlets opi)osite to l*enetanf;uishene, the twisted appearance of Parry island and of the channel on its southeast side, as well as the sinj^iilar straiirhtness of Partridge bay. the Lonj; inlet, the points on the west side of Parry island and al)0ut Shibaishkong islaijd, all correspond with the local strike of the rocks nud are due to the effects of denudation, which lias formed cliannels along the courses of tfie more yielding strata, and left ridges or higher j^round wliere the I'ocks i-esisted decaj- and erosion. Along this shore there is however a class of channels and inlets due to another cause, namely, the existence of dykes of trap and breccia and of granite veins, and also of parallel 'oints or cracks alon^;- which the rocks l.iavo been rendered more decomposable ; or these .alter mav have acted merely as starting points or guiding lines for the action of glaciers or other denuding agencies which constantly enlai-ged and deepened the depressions, once they had been commenced. The channels and inlets of this class usually run nearly east and west and have steep sides, while those which follow the stratification have usually some other course and are not so abrui)t.* Thestj lines of rock-crushing and subsequent erosion have doubtless had a great effect in producing the river and lake features in most of the regions occupied by our upper Laurentian rocks, as well as in some other metamorphic districts of Canada. Dykes of greenstone and breccia have also played an important part in this connection, generally giving rise to river-channels and long lake-basins, but occasionally, where hard or resisting, having the opposite effect, producing ridges, or causing falls and rupids where they happen to cross streams. Near the head of Byng inlet, a short distance southeast of the mouths of French river, a brecciated rock is exposed near the edge of the water which apparently forms part of an east-and-west dyke, alo g the course of which the channel of the inlet and of Maganetawan river have been excavated. Parallel to this dyke are joints stained red by oxide of iron, giving a dry and crumbling character to the gneiss along their course, which is east and west, while the gneiss they cut runs in various direetions tra, iverse to the joints. On the lower or western north channel of French river Mr. Murray noticed a triable brick-red quartz-syenite at the Grand Recollet falls and for some miles below it. This probably belongs to aner .ive dyke-like mass, following a line of weakness in tlie course of the channel. In the French river country the gneisses are most commonly of dark reddish-grey shades, and they comprise both the mica and the hornblende varieties. Their texture is usually from medium to coarse grained. As a rule the latter are gray and darkly colored, while the finer grained varieties are generally reddish. Silicious belts, in some cases amounting to vitreous quartzites, bands of mfca schist with garnets and of hornblende schist c^cur among the gneisses, and in, some localities they are largely developed. * Dr. Robert Bell in the Report of the Geological Survey for 1876, page 195. A^cins of coarse rt'ddi.sh atid nearly wliite ijranite running' in different directions cut the l)ornl)lende and mica sciiists and sulu..tose i^neisseH about tiie nioutiis of b'rencli river, and similar veins are also met with occasionally in the interior. A few giennatone dykes were noticed along the river, but they do not appear to he verj common in this region. Quartz veins running in various directions are of frequent occurrence in the French river region, hut they are all of a " hungry " character, and none of them have been observed to carry economic minerals in promising ijuantities. The di\idin,g line between the Huronian and Ls 'rentian systems runs northeastward from the head of Shibaonaning or Killarney l)ay. "Between this locality and thi! middle of Philip Edward island, including the township of Rutherford and most ot Oarlyle, the rock is a massive red ([uartz-syenite ov liornblende-granite, which occasionally shows patches of an indistinctly foliated cliaracter ■ but this rock does not appear to extend far inland, although it occupies about twelve miles along the coast. Mr. Murray mentions the occurrence of a similar rock, which seems to have a breadth of about two miles and a length of about four miles, in a northeasterly direction between the western and middle groups of mouths of the French river. In the region covered by tlie map certain differences may easily be observed in the general characters of the Laurentian rocks on the southeast side of the great Huronian Vielt as compared with the rocks on its northwest side, whicli we have for the present classified for convenience with the same series, because we have not yet found it practi- caV)le to separate them by a definite line from the undoubted Ijaurentian still further northwest, with which they are continuous. Between the shore of Georgian bay and the Huronian l>elt, and about as far north as the line of the Canadian Pacific Railway, the gnei~ses are of the typical Laurentian varieties, all evenly stratified and regularly arrang- ed in anticlinal and synclinal forms, according to the structural laws governing strati ed rocks. The angles of dip are on an average not far from 4.")'-', although in some cases they are nearly horizontal and in others almost vertical. Except in a few localities the bedding is not contorted, but runs straight and evenly for considerable distances, and these gneisses have every appearance of lieing altered sedimentary rocks. Red and grey varieties are represented in about e(iual proportions, and they alternate with each other in both thick and thin sheets. They are mostly mica gneisses, although the mica is present in rather small proportions, but in some cases hornblende replaces the mica in whole or in part. No beds of crystalline limestone have been found among these rocks west of the longtitude of Iron island in lake Nijiissing, where this rock has been noted by Mr. Alex- ander Murray. These limestones are also associated with them jn some of the islands in the eastern part of this lake and at lake Talon on the Mattawa. Further east, in the Parry Sound district, the writer in 187G traced five distinct brands of Laurentian lime- stones running for considerable distances in a northerly direction from the shore of Geor- gian bay. The Laurentian rocks between Georgian bay and the great Huronian belt, from the characters which have. just been described, would therefore ho classified along witli those of the counties of Ottawa and Argenteuil, which belong to the upper portion of the system. R O C K S N O It T H W K S T O K I' M K H U R O N I A N B K L T . On the northwest side of the great belt the conditions are different. At some dis- tance to the northward of this belt the heavy contorted gneisses of the lower Lanrentian- cover an immense area, but there is an intermediate region in which red hornblende granites prevail, but they are mingled in some parts with gneiiii'.. The granites are largely developed along the northwest border of the Huronian belt all the way from the west side of lake Wahnapitfie soutliwestwaud to the Sable river, and probalily still further. From this geological boundary they extend northwestward out into the midst of the lower Laurentian gneisses to a variable distance, their greatest extension being un- known. Along the main line of the Canadian Pacific Railway they are fimnd all the way from the junction of the Huronian at Onaping station to Spanish Forks and west- it gai of Wiird frani the railway to the Spaniwli river, liut beyond tjiese limits tlie country has not been carefully exidored. Similar red hornblende i,'ranit(!, occasionally showinj,' j^neissoid texture;, forms an elongated area in the middh; of the Huronian bolt in the Sudbury district, extend- ing from near the South bay of lake Wahnapitae south westward to the towiishi|) of Drury. The southei'ii boundary of the main granitic area crosses the Spanish river mid- way ljet\ve< n tht; nortliern and southern lines of township 111, whence passing westwaid it sweeps round to the south and forms a promontory in the townshi))8of (Jough and May. From the nortliern part oi' the latter township the boundary botwe<!n the granite on the ncrih and the Huronimi (|uartzites, gr^ywackes and schists on the soutii runs westward parallel to the shore ot lake Huron, as far as the- townshij) of Proctor, were it turns noithwestward and the Huronian rocks occu))y a large area lying to the northward of Algoina Mills. Allliough the granites which have just been described are provisionally classed with the Laurentian, it is uncertain that they are all really pf this age. In some localities they are so intimately associated with gneis.ses of the ordinary Tjaurentian types that it would be ini|iO>sible to draw a line betwe<'n them. In such cases they may have been foinied out of jiortions of the gneiss softcnid by heat and re-crystallized alter having lost their stratiform cliaraclcr. In other places it is quite possible th<>y uiay be due to the alteration of arkose or gi-ey wacke similar to that wliich is so counnon in the adjacent Huronian series. Or it iiiav be that thest; granites are mainlv eruriti\(> ir their origin. The writer has pointed out in various reports on the Arcluean rocks of northern Canada that the conunonest situation of the granitic areas among these Tocks is at and neai' the junction of the Laurentian and Huronian series, and tlicre is perhaps no good reason yet known why they should be assigned to the one more than the other. In the legion at present under consideration, along the line of contact between these granites and the Huronian (|uarizites, schists, etc., the rocks are often much broken up and intermingled with oiH^ another, both in great iiiasses and smailt^r fragments. This effect has probably been produced when thegrc.nite was in a soft coiulition and subject to inti use pressure, coupled with more or less movement. Referring to th(i last mentioned consideration, it is not imjirobable that faiilis of considerable extent have taken place along tlie lines of junction between these two classes of rock,,, not only in this region but in otlier localities nhi re the Laurentian and Huronian rocks come into contact. This is only what we might expect to occur along the lines dividing rocks having unecpial jiowers of resisting the great strains to which the crust of the earth must have bei'ii su'oject in all ager.. These faulls may be looked f(ir more especially at those parts of tln' junction of the two sets of rocks wliich have been most e'xpused to lateral pressure, antl along rhose por- tions of the lines of contact which are tolerably straight for considerable distances. The bed-planes of the Huronian and Laurentian rocks on the opposite sides of a contact thus faulttd might show some want of parallelism, and from this accident a general un- confoiiiiity of the two series might be erroneously inferred. The few instances of apparent local want of conformity which have been observed seem to be capable of ex- planation in this way. Out of these instances may l)e seen at the Wahnapitae river where it is crossed by the Canadian I'acidc Railway. Within the area represented on the map, besides the gneissic and granitic rocks flanking the great liuronian belt, there remain to be noticed a few inliers of these rocks. One of them, consisting of gneiss, lies between the north and northeast arms of Tema- ganii lake. Another, also of gneiss, which has been described by the writer in the report of the Geological S'urvey for 1875, surround.- Paul's lake on the upper part of Sturgeon river, and appears to extend for .some distance to the soutli of it. A short distance east )f the angle formed by the junction of Prondfoot's east-and-west and north-aud- south lines an area of red hornblende granite was discovered, which ma^' extend to the northward, but its limits have not been traced out. Two belts of gneiss projecting from the north ward cross Montreal river, one at Elk lake and the otlier at the sharp turn in the r'ver about midway between this lake and the junction of the east branclt. Both of these belts appear to terminate at no great distance to the south of Montreal river. T II K GREAT II I' I! N I A N B K I- T . Sir Williiim Lofjan and his assistant, Mr. Alexander Murray, after exaininiiij? the crystalline rocks of lakes .Superior and Huron, gave the name Huronian (at the siig<,'es- tion of Dr. Sterry Hunt) to Jl those of both regions which lie above tiie granitic series which they called Laurentian. These terms, were not restricted to any particular area, but were meant to designate the two great divisions of the Archaean rocks and to be of general application in Canadian geology. IJoth sets of rocks extend into the United States and the Canadian names, having priority, were adopted there. But of late years efforts have been made to abolish the convenient and well establi.shed de.signa'ion Ifur- onian, except for one small area of these rocks lying on the north sidn of lake Huron and forming only a part of the great belt which is contii.uous from lake Superior to lake Mis- taasini, a distance of 700 miles following its axis, on the asserted grouml that the selected part alone forms what some geologists call the '' typics' Huronian." 1 cannot however understand why one particular portion of one belt (jf nicks of tlio Huronian system should now be selected for this distiuction to the exclusion of tiie remainder of the belt which is continuous widi it, and also of other areas of rocks which are mo.st naturally placed with them and which were expressly included by Logan when he classitied tliem and gave them this name. The rocks of the Huronian .'lystem as defined by Logan consist of crystalline scliisis in great variety, (juartzites, conglomerates and agglomerates, clay slates, greenstones, dolomites, etc. At the time referred to, more than forty years ago, th(! science of petrology was in a crude state compared with its present position, and the microscope was l)ut little used in determining the nature of rocks. Hence Logan did not recognize the volcanic or rather pyroclastic character of a large proportion of the Huronian loeks. Some of the rocks of the system, such as tlie quartzites and clay-slates, although tley do not themselves show a direct igneous origin, may have been derived from the products of volcanic activity through tlie intervention of water. Owing to tlie pyroclastic origin of the majority of these rocks the various memberi* in any region are not usually persistent for any great distance, but diminish in volume and are replaced by other beds which increase in thickness as the first diminish. As these rocks are usually tilted to high angles, the sections afforded by the surface of the earth are generally nearly at right angles to the bedding, and when mapped often show the inter- locking character of the different bands as they terminate in both directions. This want of persistence is exhibited on both a small and large scale, so that the general character.-* of wide belts of Huronian rocks differ much in different regions. In other [larts cf the world, such as Scandinavia and Scotland, where Archiean rocks are largely developed, series corresponding with our Laurentian and Huronian are met with. Nowhere have rocks of a different character been f )und to intervene between them. Ve might therefore infer that in a gem ral way the two systems are conformable to one aiiother. This inference i;^ borne out by our observations over the enormous area of Arclnean rocks which we have in the Dominion. It might be expected that in some parts of this great area a local want of conformity might be detected at the same time that the two systems were conformable on the grand scale. But in the few instances where there appeals to be a want of parallelism in the stratificat'.on on the opposite sides of the contact, this is more probably due to faulting. On the other liaml, we have observed numerous instances where there is a gradual and conformable transition from the lower into the upper series. The ))eds of passage as a general rule consist of hornblende and mica schists alternating with fine-grained gneisses, and these are followed by other crystalline schists. In the Huronian areas of lake Superior crystalline schists predominate, although representatives of all the otiier varieties of the rocks of the system are not wanting, while in the lake Huron region and to the northeastward cf it greywackes and (juartzites with clay slates are the most coi- picuous rocks, bui the various crystalline schists similar to those of the lake Superior region are likt wise to be found. An impression has got abroail in some quarters that one of the distinguishing thf 11 featurtsof thn Huronian rocks on the nortli side of lake Huron is that they usually clip at vory moderate angles. Kven if this were true, it would be a matter of no con- sequence in chronological geology. It is however only an incorrect assumption, and on the contrary as a rule the rocks of that region are highly inclined, as shown in a sec- tion by Mr. Murrny in the report of the Geological Survey for ISfiG, and in my own section across the Sudbury district juiblished in 1891. They do however dip at low angles in certain limited areas, such as the tract lying northward from St. Joseph's island and in that situated to the east of lake Wahnapitae, and again between lake Temagarai and the Montreal river. l!ut instances of equally low dips are to be seen among the np])er Laurentian gneisses, as for exam|)Ie in a large region to the northward of Mon- treal. Although in the lake Superior region and thence westward to Lake of the Woods the Huronian rocks consist so largely of crystalline schists, still there are silioious rocks among them, which may be the eciuivalents in diminished volume of the (juartzites of lake Huron , also conglomera*"s, clay-slates, serpentines, dolomites, et(;., and on the other hand tliere is an abundance of crystalliiu! schists among the Huronian rocks of the lake Huron region. Conglomerates occur at various horizons among these rocks in both regions, but any single conglomerate bed is probably only of local occurrence and cannot be held to be the eijuivalent of any particular conglomerate in another re- gion. As these conglomerates cannot be connected with one another in dirt'ercnt Huronian areas it can scarcely be said that they represent a general break in the chronological continuity of one piirt of the system with another, much less a time break between this .system an<l any other. F'rom what has been said of the nature of tlu' Huronian system we should not exp'ct even contemporaneous ])arts of it to be everywhere I'epresented by the same kind of rocks. On the contrary, great local dillerences might be looked for at the same horizon. In a given re-^ion one variety may be largely developed, and yet in another this may bi^ en- tirely replaced l)y a different rock without there being any difference in the age of the two. Rocks like those of the Lake of the Woods may be the equivalents in time of those of the north .oide of lake Huron, or of some other part of the system wliere the lithological ditl'erence is e(iually great. Still we have always admitted that perhaps the prevailing schistose series of the lake Superior region may belong to an older part of the system than the quartzite, clay slate and greywacke series of lake Huron, which appar- ently forms the newest p(jrtion of the great belt. Thus the area characterized by the great development of quartzites in the region extending from lake Huron to lake Abittibi may be somewhat newer as a whole than those portions of the series whf re the quartzites are in small amount or entirely absent. iVt the same time it is not to be forgotten that the qiuvrtzites of the region n)entione<l are associated with a variety of crystalline schists, such as may be seen on Spanish river, around Temagami lake, on Montreal river and in the region to the northward of it. The stratigraphical sequence of the various kinds of rocks found in the Huronian belt within our region has not yet been ascertained with sufficient certainty. The following descriptions of these rocks are therefore not given in the supposed order of their superposition. guishing Q r A K T Z I T K s . It is an interesting fact in connection with the origin of these rocks that the quartzites and clay slates are so often found together. The decomposition of the arkose or greywacke and the separation of the siiit^ious grains and the clayey portion would give rise to these two kinds of rock. Or they might result from the decomposition of the binary granite, from which the greywacke itself is probably derived, by the sepnration of the quartz grains from the argillaceous matter that would be produced from the felspar. Nearly all the quartzites contai'i more or less felspar, ami sometimes it is present in largo propoitions. giving the rock the general outward appearance of granite. In some instances observed by the writer this mixture had become so far metamorphosed back into granite that it required to be examined in thin slices under the microscope before ifc could be decided that it had ever been a clastic rock at all. 12 Thesi) liij»hly tolspalliic ([uartzites are ahuiulaiil aloiij^ tlus North riven- cauoo-route from lake Mattagaiiiashini; (just east of lake Wahnapitae) to the upper partof iSturyeon river, and again wi st of Laily Kvelyn lake, which lies noith of Teiiiiij^riiui lake. In other roifioiis howevei' the proportion of fekspar in these roeks is generally small, ami the texture of the nearl_y pure (juart/,it(>.s varies from compact with conchoidal fra(;tiire and composed of microscopic grains up to coarsely granular, made up of small p(d)bles closely crowded together. Some i^eds in almost every large; outcrop of these rocko are of a distinct con- glomerate charactc^r, tilt! pchhles luang well rounded and almost all of white (juartz. In the country just north of Bruce Mines, and again on the norrh side of (.4oulais bay, lake Superior, some beds and groups ot' Ixid.s of these conglomeiates contain pebhhis of red and dark jasper and lightcolort \ chalcedony, thickly scattered among oth< rs of white quartz, ail in a matrix of white (juartzite. Tliis beautiful lock has long been known as jasper conglomerate, and forms a line ornamental stone, but owing to its hardness it is expeiLsive to cut and polish. / few scattered pebbles of jasp(>r are found here and there in the (juaitzites all the way from the above localities to .Slontreal river. Light grey and nearly white quartzites form the north shore of lake Huron from the mouth of Spanish river eastward to ivillarney bay. They constitute the LaOloche moun- tains, which run as two and sometimes three parallel ridges close to the shore, and nearly due east iind west with the strike. The height of the front ridsre varies from -ICO to 755 feet above lake Huron, but tlie altitude increases in tlie continuation of these hills to the eastward, and it rises at one point to an elevation of 1,180 feet. The dip is everywhere nearly vertical. Similar quartzites, also standing nearly on edge, form the long and high points jutting out into lake Huron in a southwesterly direction between McUregor and Killarney bays. The strata terming these points are probably repetitions of those of the La- Cloche mountains, on the opposite side of a synclinal n\ nearly verti(!al strata, one extremity of which would be in the vicinity of the east et d oi lake Panache. The quurtzite of the points and islands south of Frazer bay continue^ .outhweslward, and appears on Hey wood island, and further on upon (.Ji-and Manitoulin isi <\, at the head of Sheguiandah bay, and thence past the northern sides of Bass and Pike la ^. Quartzites, mostly of light colors, constitute the prevailing rock around lake Panache und the great bend of Spanish river, and northeastward to the township of iiroder, but beyond this, for some distance on the general strike, they diminish in volunu;, and a conHiderable proportion of what remain merge into greywackes in passing through the contracted part of the belt in the Sudbury district. Still lurther on in tlie northeastward strike, or in the country to the eastward of lake Wahnapitae, the greywackes have passed into or have been replaced by clay-slates and argillites, dipping at much lower angles. Northward of lake Wahnapitae the quartzites are again met with in great abundance. Along the upper Wahnapitae river they strike north-northwestward parallel to the Laurentian boundary in that direction, and dip at high angles. On the North river chain of lakes the general strike is east of north, turning more easterly in approaching Sturgeon river, beyond which the quartzites run northeasterly towar/ls Lady Evelyn lake and Maple mountain to the west of it. These rocks are exposed in numerous places along the main Montreal river, and both its branches south of the great bend. Still further north they are largely developed in the counti'y along the height of land westward from its intersection with the north and south inter-provincial boundary line. In the region northeast of the St. Mary river the quartzites show considerable differences of color, and on this ground Mr. Ale.<and< r Murray separated them into diff<ir- ent bands. In thu southern part of the district shown on our mip they are nearly all of light shades, but near its northern border ihere are red, pink and purple varieties. These are however of local occurrence. Greenish and yellowish tinges are common in all parts of the distribution of the lighter varieties. C r, A V-S I. AT KS ANU A U U I L L 1 1' E S . The term slate should be given only to rocks formed principally from clay, in which arallel cleavage planes have been developed independent of the bedding. It is not properly pplied to those crystalline schists in which the cleavage ia mora or less imperfect and thv3 pill Clr; kill liv nor til. kk coll .slia Will al)f a hi; occ OIK for th<' or roc of 1 the As old the scr itit of oce are am in Sin Gn of nar not div nia of i son gra siz( di-si Frs por this of! wit 13 plrtnos aro not parallel to otio anotlier. Argillites are clayHtones in wliicli the slaty cleavage has not been devolopoil. Confining our remarks always to the iir';a i('{)r(^s(»nted on the map, rocks of these two kiiuls are met witli most larj^ely in the country hotwecii liike Wahmipitae and Stuff^eon river, aloni» that stream between the Maskinoii^e and Hound lake Ijranches, about the north "lid of Tcmai^ami lake*, and thenci^ liy [jiidy iCvelyn lake co .Montreal river, and on the latter ; likewise along the Matahechnwan river, which disclrMj^es into the foot of laki- 'i'emiscaming. Tlies(! slates arc^ mostly of olive or l)luisli j^rucii, purplish, drab and ,L,'t'ay colors, and are often barred across the cl(!ava<^ " with narrow parallel bands of '.litl'ereiit shades. At the northern outlet of Temagami lake a jjreenish cotupact variety is marked by thin interrupted black bars. This rock, when cut, takes a smooth surface, and was much prized by t.'io ancient Indians for ornaments and ceremonial stones. These principal acounuilations of slates and argillites appear to be in a general way about contemporaneous with thi' (luartziies, that is to say, they were l)eing depositcnl in the altove localities at th(^ same time that tlie (juartziies were forming in others. Wlnirt^ they occur in smaller vohunes they are sometimes found in proximity or ii\terstratitied with one anotlier. As already stated, they m:iy both be derived from the greywackes, which form so laig(; a proportion of the rocks of the great Huronian lielt in this region ; and till' gicywiickes in tiieir turn arts evidently iiiaih! iii> of the (M>riti of a (piartz-felspar rock or binary granite. Ur th(;y may have been formed directly from tlie decomposition of this rock and its rearrangiinent Viy water, the silica and the undecoinposed felspar, when any of the latter remained, going to make the, (juartzit(>s, wliile the tine mud resulting from the di'cay of th<; felspar was carried elsewhere, and now constitutes the slates and argillites. As far as our present knowledge goes, tlie (juartzites therefore cannot bo said to be either older or newer than the slates of this part of the Huronian series. Tlio rooting slati's found among the metainorphic rocks of the Eastern Townships in the province of Quebec are probably of somewhat newer geological age than those just de- scribed, which in some places may be found suitable for roofing purpoH(>s. Among tlie local- ities where; the argillitcis or non-clcavable varieties occur may lie mentioned the southern part of ^Mattagamashing lake, Koo-kagamiiig and Lady Evelyn lakes. Good cleavable slates occur on the Canadian Pacific Railway a short distance east of Algoma Mills. Felsitea are soinetiiins found associati-d with the slates and ([uartzites, but they are more abundant among the greywackes. Dark gray or drab and almost black clay slates are found along the .Spanish river, in the northern part of IJaldwin, and at tlie tails on lot I, fifth concession of Nairn. Similar slates are met with on the Oanadian Pacific Railway in the southwestern part of Graham, antl again just south of Geneva lake. Tiiey are alto said to occur in the township of Drury and a short distance east of Bannerman lake. G R E V \V A C K K OK A It K O S K . In some parts of our region a rock which may be described under either of the above names is met with in great abundance. It has some resemblance to sandstone, but does not usually occur in distinct beds with parallel faces, and is generally either massive or divided by joints or a rough sort of cleavage. Under the hammer it breaks readily, and may be easily bruised or scratched, thus showing the presence of a considerable proportion of ingredients softer than quartz. It has an ashy appearance, and its color is usually some shade of ash-gray. On closer examinatior, it is found to consist of comminuted granitic debris, and generally holds *juantities of pebbles and angular fragments of all sizes of the granite itself. The latter are mostly of the same character in all parts of the district, and consist of a binary granite or cpiartz-felspar rock of either a red or gray color. Fragments of gneiss and other crystalline rocks are occasionally mingled in small pro- portions with those just described. Under the inicrosco|)e the matrix or finer portion of this rock is seen to consist of somewhat rounded grains of (juartz, and more angulai ones of felspar, with a tilling of fine serecite or of some dark amorphous mineral. Rocks of this kind occur here and there in almost all parts of the Huronian belt within our region, but they are particularly abundant in the narrowed portion in the 14 Sudbury district and around Teinagami lalte and Rabhit luko to thu east of it. They are also common in tho Onapin^ anil Stniij^ht lake outlitM'.s and all alou',' the Spani.ih river, below the granite area, and thence westward as far nt MisHiHsajja river. Sometimes, us on the Montreal rlvei, ti.c; iiu-luil:'d fragint^uts of <{ranite attain tlio size of boulders, and these, as well us the smallet inciithion , nviy occasii nally be found so closely packed together that only the interiti(^es are tilled by the finer material. Th^ fragments are most common in the greywackes where the latter occur in large volume, and in these cades there is little evidence of stratification. The more uniforndy-i^rained varieties, without angular fragments, are often fo'ind interstratifying quartzites, as in the Sudbury and Whitetish lake regions, and they nay i)e seen containing every firoportion of (luartz grains II they themselves become quartzites. There wiis no doubt great volcanic activity on the earth at the time these greywackes and their associati'd rocks were being formed. The thick unstratified and brecciatfd maisses of greywackes may represent volcanic ashes or mud with stones thrown out upon the land or in shallow water, while the stratified varieties may have been similar ejectamenta thrown into deeper water and modified by the currents or waves of the yea. Some of these rocks, whether stratified or otherwise, may represent volcanic products which wei'e origi- nally poured into the sea in a molten condition and became broken up and disintegrateil. The glass breccia already referred to as forming such a thick belt in the Sudl)iiry district is direct proof of volcanic activity with explosive violence on a scale probably grander than any such action in modern times. Even without this and many other proofs v/hich might be cited from the earliest records of the rocks themselves, it would only be in ac- cordance with the general geological history of the globe to f)elieve that volcanic or igne- ous action was going on upon the surface more generally and on a greater scale in the earlier than in the later geological times. From a study of the greywackes and the rocks associated with them there would appear to be little doubt that the former constituted the crude material from which the quartzites and clay-slates were derived by the modifying action of watfr. Again by the action of time, pressure, heat, electricity, and perhaps othei metamorphosing agents upon different varieties of grey wacke, some of our granites, syenites, gneisse.s, felaites and pos- sibly other rocks were formed. Many instances were noted in the Sudbury district where the more massive greywackes exhibited a proneness to revert to granite again, while some of the stratified varieties showed different stages of their passage into gneiss, and again certain of the finer-grained and more homogeneous kinds had been altered into felsites. Slat i-C o n <; l o m k r a t e. Some of the argillaceous varieties of the grey-/acke containing pebbles of granite, and occasionally some ^ ! quartz, jasper, etc.and h.wing more or less slaty cleavage, were call- ed sla'"! conglomerates by Mr. Alexander Murray, and he even extended this term so as to include massive brecciated forms of grey wacke, which show no cleavage at all. This name was also given to certain Huronian schists containing rounded pebbles and boulders, and likewise to dioritic schists full of lens-shaped inclusions parallel to the cleavage or bedding, and which in cross-section look like elongated pebbles but which may be of a concretionary character in the majority of cases. They are often inconspicuous or diffi- cult to distinguish on dry surfaces of the rock, but when wet are quite distinct, having a lighter color than the matrix. But they do not appear to differ much in "ompositi>n from the rest of the rock. The.se rocks, which have sometimes been called dioritic schist- conglomerates, are very common in the lake Superior region, hut they appear to be scarce in our present district. Imperfect Gneisses. Imperfect gneisses are met with in most of the Huronian areas in both the lake Superior and lake Huron regions, but they always occur in limited quantities. They difler from the Laurentian gneisses in being usually finer grained and less perfectly crys- talline. Under the microscope they sometimes show traces of clastic origin. In all of the numerous cases tried by tho writer it was founa that they invariably contained carbonate All l.i lu! lake . They tly crvs- lII of the r*)omite of lime, 'horeas the Lanrentian gneisHeH are Hpldoni calcareous. Where their crystalliza- tion has lieen coarse enoiif»h to observe their felspars easily these have sometimes proved to be of triclinic species, while the felspurs of the Laureiitiaii j,'neiH8e8 are ehielly ortho- clase. G It K K N H T O N K S . Within that portion of the great Huronian belt which imvcrses our district are numerous areas of greenstone, varying in dimensions from masses too small ro di'Hnc on the map up to others many miles in length. The word greenstone is used in this [lap-r to include ii variety of (rappeaii rocks which cannot always be distinguished fr()m imo another in ilie field. These crystalline masses have often undergone metamorphism as well as the sedimentary rocks, and it sometimes happens that even a microscopic and chemical study of them in the laboratory fails to prove what their original condition has been. The term greenstone, which includes them all, is therefore a very convenient tield-iia:iie In the Sudbury district they consist of diabises, dioriles and gal)b os. The hst niiiiH'd constitute some of the dykes, while the others shadt into each other, and as a cl iss may be divided geologically into three groups. The first of these consists of masses of highly crystalline dark green d'orite (some- times passing into diabase) of medium texture and hoUling disseminated specks and sp.)t8 of pyrite, pyrrhotite and clialcopyrite. These masses occur principally among the grey- waokes, quartzites and clay-slates, and with few exceptions their gi'eatest lengths are in the direction of the general strike ot the surrounding rocks. They may have been origi- nally laid down as molten sheets in nearly horizontal positions with the enclosing strata, and hiibst quently tilted to the present high angles of iiiciinatiun. fn a i't'W cases the lower suiface of a ^reenstoni* moss may be seen tilling inequalities which seemed to have been worn in the underlying rock prior ti the advent of t\w greenstone. As these masses appear to have become incorporated with the strata before the la'ter had assumed thijir present positions it becomes uncertain that they are all intrusive, although some of them probably are so, but their original positions with regaidto the horizon have be.^ii chang- ed owing to the subsequent folding which has taken place in Lhe c. ust of the earth. Greenstone masses of tiiis kind are lound in the Huronian belt all the way from the shore of lake Huron northward to the border of our sheet, and thence for a great distance towards James bay. They are nunierous atid often large in the Sudbury district, where upwards of fifty occur, and also around lake Tamagami and in the v.'Ury of the Montreal river, but towards lake Huron they become smaller and do not form so prominent a feature in the geology of the region as they do further north. Our second variety of these rocks has a grayer color and more coarsely crystalline texture, while the disseminated specks of metallic sulphides are not by any means so abundant as in the first. Its composition appears to be always that of a diabase. This rock forms three distinct belts among the granites and gneisses of the Sudbury district, and they appear to cut through them as intrusive masses. They all run northeast and southwest. Windy lake on the main line of the Canadian Pacific Railway lies upon the central portion of the most northwesterly belt, which has there a breadth of about one luili-, but narrows to a point in the northeastern part of LH\ack on the one hand and in Trill on the other, the total length being about eighteen miles. The second belt runs northeast- ward through Morgan towards Sagi-tchi-wai-aga-mog lake, while the third runs from lhe township of Creighton to the vicinity of Whitson lake. The third variety differs from the first mainly in being schistose in some parts, ami in frequently containing rounded and angular pebbles and masses of all sizes and of various kinds of rocks, but especially of quartzites, other varieties of greenstone.s, gran- ites and greywackes, Lhus constituting agglomerates and breccias. These portions appear to run in ill-dtfined bands about parallel with the longest diameters of the i.iasses. The greenstone belt which extends from Garsou to Graham belongs to this class, as do also the areas of this rock in the fourth and fifth concessions of Denison. All these lie against the southeast side of a long granitic are-i, and it miy be that they IG have 811 fTcn'tJ more from Intcral |)rPH8urc cniiiinij frnin tho Houtlu'iiHtwanl tlmn tlic dioiitic JiiassrsdcBi rilicd under tlic first div ision, wliicli iimy Imvc hccii pri)t<'ctcd liy the iimrt' yicld- i!i<; roiks w itli which they are Hurroundcd. Examiilcs of th(! f^rceiistoiic aL'iiloiiicin'cH mid lirccfiiis rcfcrrcil to may li<^ hcimi in'ar the lUt-ziird, .Stuhic, Copipcr dill', < 'n an and Vcrmihon miiif's, and also where tho main lino of tho Canadian Paiilic Railway croHsea lot S ill the fourth rani;(! of Mclvim, and aijuin wlieii- it oiohscs lot .') in the liftli ooiiccHsion ol .Mqncricn. D I A II A S K I) ^ K KS. Dykes form an int(>rPHtiiig feature ainonj^ the rocks of our district, and th"y may also piovo to have some, hearins^ upon Us cconoiiiic f,'eoloyy. 'I'hey consist of fjaliltro and oliv- ine iiahaso, and are of rather freijuent occunenw! in Home sections. As far as direction is coneerneil they may lie saiil to licloni,' to t\vf)sets, the course ot one varyimj; from went- northwest to northwest, and of tiie oilier I'rom north to norih-noriheast. MosLofthem dei (impose more rajiiiUy than tlie containiiiE; rocks, and their posilions may li(> reco^'nized li\ the depressions they form on the land and tin? ciianm^ls in the lak'-s. On tln^ shore of lake Huron some of those lielnii^iiii,' to the northwesterly set may he seen in the viiinitv ot Shiliaoiianiiii); or Killarney, and around Krazer hay. Many dykes of liotii sets are shown un the yeolojiical map ol' Sudbury district by the writ(;r. Around Ministi..' lake in Krmatinjier and Cascaden, where a number of them cut the gneiss, their {general coarse is norihwest. Almost in continuation of these, a larye dyke at tin- j'unciion of Ai^nes river with the Spanish in townsliip lOS cuts ilie granite there in the same direction. Dykes belonging to the northwesterly set may be setm here and there along tlie main line of the ('anadian Pacitic Railway between Sudbury .function and Straight lake, lietween Sudbury a:id tlic Murray mine and again beiwtjen Windy lak(^ and Cartier station they have facilitate^ the building of the line by tlie depressions whicli now niark their courses through, the rocky hills wlios', general course lies across that of the railway. In the granitic region l)etweeii the Onaping and upper Vermilion river dykes lielonging to both sets are met with. A large dyke running north-northeast crosses the Vermilion river near the middle of the east line of township GO. The basin of Onaping lake appears to be excavated along the course of parallel dyke.s cutting the granite and gneiss in a northerly direction. The lake is about twenty-six miles long, and except towards the south end is very narrow. In some parts the shores are formed by tin; dyke walls, to wliich patches of greenstone are still adhering. A large dyke running a little west of south is traceabh; along the east side of the .'southern part of the lake. A dyke which may be a continuation of this occurs also on lot t in the third concession of JMoncrietl". A short di.stance north of the head of Onaping lake we pass over the height-of-land and come to the head-waters of the Mattagami river, which flows northward in nearly the same longitude and falls into the western side of the lake of the same name. Mattagami lake has about the same length as Onaping, and is a';;o narrow. Its outlet flows north- ■ward in the continuation of the valley, and at aliout seven miles falls into the head of Kinogamissc' lake, another long narrow sheet of water, also running north and south and ha\ ing a length of twenlytwr- .ailes. On the course of the riv r connecting Mattagami with Kinogamisse lake a great north-and-south dyke makes its appeaiance, and below the latter lake large dykes, cut- ting the Hnronian and Laurentian J ^cks and all having a northerly course, are met with at intervals along the Mattagami river until it enters upon the Silurian and Devonian ba.^in extending to James bay. Several of these occurrences may brt only diflPerent sections of one great dyke. Some of them are 300 to 400 feet wide. They are more com- pact near the walls than along the centre, which has been more easily eroded and in some parts forms the channel of the riv.er. The head waters of Moose river, from tJie Missinaibi to the Abittibi, covering a hre.adth of 120 miles in the lattitude of Abittibi lake, comprise upwards of a dozen nearly parallel north-flowing branches which afterwards converge to form the main jiver. The Montreal river is remarkable for drawing its waters from several nearly parallel augi striK pale refr,'( dish zone fillin dorit one ol 17 |t-of-land larly the .ttiitjami north- heiid of lUth and a j^reat [rkes, cut- met with )evonian J (lifferont liore coni- \{ in some covering a dozen lain -iver. parallel strcivniH, also tlowin'^ north, hut tlicy full into n viiUcy in which they arc immcdiati'lj turned round to th(! eastward throu^li nion' than a riyht ans^'le and pursue almost a straight line southeast to the Ottawa. The north and south valleys of those streums lieloiio, as far as their orif^in is ooncerned, to th(i samo set as the extraordiniiry parallel valleys of the; l)iisi!» of Moose* river. Dykes and elont^ated masses of greenstone with a general north aiid-south course were found ak)ng hoth tlii; east and west hranchos of the Alontieal river, and it may he assuux'd that they also exist along the other parallel tributary streairs and lakes of tliis system. As far &a our present knowledge goes, this parallelism of the water-courses in hoth th<i hydrogiuphic basins which have just been named is due to the guiding inlluence on eroding agents of the large ;,'reenston(* dykes with wliicli the whole region is seamed. There is no doubt that dykes like these have played an imp )rtant p^irt in determining th(! present topographical features of this part of th<! country, Previous to the glacial period tlie dykes probably decomposed to a greater depth than the enclosing rocks, and when the ice passed over the land the trenches which would soon be excavated along tliem under this powerful denuding agent would act as guiding lines for further erosion, and the depressions along them would become deepiMied and enlarged until they had formed tlie various lake basins and river valleys that lie ui)on th^'ir courses. In the uppijr parts of th(! .Moose and the .Montreal river basiins the general direction of the glaciation was siiliicicsntly near that of the great dykes which have been mentioned for it to adjust itself locally to tiiem.* These dykes, whether of diabase or gabbro, when undergoing decomposition at the surface weather into rounded boulder-like ma.sses, the result of the disintegration and crumbling away of their angles and *;dges along the joints which had originally divided thtmi into blocks. After they have been reduced to the rounded form they scale otf in conc(mtric layers, and this giv(!S them a concretionary appearance. This is a common characteristic of sucli dyk(*s everywliere, and often causes their outcrops to resfMnble rows or ridges of boulders. When fresh, both of the above-named dyke-rocks are very tough or difHcult to break. The gabliros are as a rule of a lighter color, and resemble granites more than tlie diabases do ; but they are generally deeply penetrated by the eU'ecta of the weather, which gives them a brownish discoloration, and it is only when deep-seated or completely unexposed portions are broken that the true color is seen. One of the principal ditforences between the two rocks is that in the gabbros the augite or pyroxene takes the form of diallage. Micuoscoric Ch.vracteristics. Samples from both tlieae varieties of the dykes of the region liave lately been examined microscopically for the writer by Professor George H. Williams, lithologist of Johns Hopkins University, and in order to convey a correct idea of their structure, composition, etc., we cannot do better than (juote a description of each by this distinguished authority. On the Spanish river, opposite the foot of the 5th portage, or just below the junction of the Agnes river, in township 108, there is to be seen a dyke of medium-grained gray olivine diabase 240 feet in width, running north -tO*^ west, from which a specimen was submitted to Prof. Williams. He says : The niiorosco|ic shows this specimen to be a fresh ae;grey;ate of olivine, reddish augite, pla'.jioclase and iluienitc. with accessory apatite and biotite- Its diabase or ophitic structure is very typical. The olivine in tills rock is remarkably fr«rsh. It is in small pale yellow jjrains. which rarely show e.xteinal c.ry^tal bo\indari«-s. It has a very Ir'gh I'efraotive index, no pI(!ochroism and contains {i;lass inclusions. The au>i;itc is of the red- dish and slightly pleochroic variety common in diabase. It not uncommonly sliows zones of growth, liavinu; different shades of color. In form the anjjite is allotriinorphic, filling the interstices between the laths of plaR'Oclase. The felspar (probably labro- dorite) is idiomorphic, and forms an interlacing net-work of lath-shaped crystals. It is * Th J a;<ency of dyke< in foriniiii; a river v illi'\- is sulticieiitly clear in the case of the Mattap;aini river, one of the parallel branches of the Moose, ani which han been alrea'iy described. IM the only constitiu'iit that shows iiiiy alteriitioii, anil this i: comparatively slight. 'I'hti opa(|ii(i irou oxido is [nolnihly ilmenite. It is without distinctivo foini or alteration, and is Kometimes siirroundud hy a narrow rim of hiotito. Apatitu is abundant. At the Dominion Mineral (Company's miiiH on lot 4, sfcond rantje of Mle/uid, there is a dyke from .50 to ."jO ftiet wide, running north ;$.")" cast, a wp ■oiinen from wh ' Ih deserihod hy IVof. Williams as a (juartz liyperstheno >j;ahl»ro with aocesHory l>iotit«). He says : The microscope shows this to he an eruptive rock of (|uite except ioriiil character and interest. Ii helon^s to the nenoral type of ^'ahhros. hut has tiici's of a diahiiscdike struc- ture in its lonn idiomorphic- felspars : is related to theiH)rit»s hy the ahuiKJaiice of its hyperstheue, and contains what is excejitioiuil for nil of these' n ck-types an ahundance of oriKimvl M"'"''''" The rock is miite fresh, hut shows the elTcict if (lynamic action in the bendin;; of felspar crystals and the uralitization of the pyroxene, 'f'he felspar is in stout lath-shujied crystals of cood size which pr'^duce a coarse ophitic or diahaso structures as in many of the well known Scandinavian K'll'hros. They i)resent a brownish color in the thin si;C,tion from an iihundance of ultra- microscopic dust-like inidusioiis They exhibit, in a beautiful nuiiiner the effect of striiin, in the bending of the crystals and the (iroduc- tion of secondary- twinning lamelhe. The i yroxene is both monoclinic (dialla^jo) and orthorhcmbic (hypersthene) in about equal amounts, iioth are underKoinj^ alteration into compact ),crcen hornblende. The mica is an intensely pleochroic biotlte. It is abundantly j)re.sent in lar>;o tlakes of irre^jular size and has all the projierties of an ori^imil constituent- t^Uiartz is also quite abundant in larj^c clear Ki'fiins of irregular shape, and was apparently the last mineral to crystallize. ,\patite. zircon and majjnetite are also present in consid- erable amount. This rook, althoiif^h a typical fi'il'lJi'O. is unusually acid and approaciies in its quartz and zircon to the auj. ite granites. L INKS OK Cms K I N(i. In '.he region we are considering the etFecta of cleavage and beddin<,', tissures and joints, rock-crushing, intrusive dykes, etc., on the topography are so well marked that it is worth directing attention to some points in connection with the subject. The joints, fissurer and dislocations of the rocks in any given district generally run in two sets, those of each one being nearly parallel to one another. One set is usually more strongly marked than the other and exercises an important influence in the decay and disintegration of the rocks, and this in its turn affects the contours and other topographical features of the district. Greenstone dykes, even wh.en thin, are often remarkable for persistence in length. They are also oft*"! parallel, or nearly so, and transverse to the strike or cleavage, and in these respects au allied to both joints and dislocations. This is only what might have been expected, for the igneous matter could not have come up from below to form tiiem unless the rocks had first been rent. The forcing asunder of the walls of the original fissure or joint may have been due to the hydrostatic pressure of the molten matter itself, V hich must have been very great on such extended surfaces. In the various processes of decay, denudation and erosion of dykes, joints — fissures and dislocations have co-operated to produce j)aralleli8m in the natural features of many parts of our district, as well as in other regions underlaid by crystalline rocks. Among Archiean rooks evidence of intense pressure is ilmost universal, which is not the case with regard to the newer and undisturbed strata. When thin slices of these rocks are made, so that their elementary structure ruay be examined under the micro- Fcope, it is found that in some parts they are crushed, while in others there is evidence that they have been slowly stretched, proving that they have been subjected to great and long continued strain. In this process the patches and grains of rock had time to con- stantly adjust themselves, ana tliey lave been kept firmly cemented together by the con- tiguous mineral matter, so that tlie strength and outward firmness of the rock have not been affected by this internal rearrangement of its component particles, and therefore when lithologists speak of a rock as "crushed" they do not mean that its present strength is weakened. But this latter state has been produced along certain lines of more recent movements affecting only the present outward condition. This phenomenon will be more fully described further on. Although the textural crushing just described may be detected so generally among the ancient orystallire rocks, it is particularly manifest at points unusually exposed to has proac| horizq remov case ol and df 19 Ulil \^ re iuii :rilje<l \r iind struc- of its ini't^ of in tho 1 stout ire, as in tho xhiliit, iioiUic- ;o) and on into idantly tituent. larontly consitl- iroaches urea and 1 that it le joints, its, those marked )n of the !8 of the length, and in it have m them original ter itself, processes operated well as in \vhich is 8 of these le micro- evidence great and me to con- the con- have not therefore strength ore recent 1 be more lly among xposed to tho action of thf forces which produced it. One of tliese occurs o the west side of lake Wahiiapitat', whereii [>rouiont()iy of tht! granitic rockn projoLts into ulie Iluronian belt at its narrowest point. Tiie HpaccH wliich have been h'ft by tlie inecpinliticH tiloni; lines of fracture after dis- location in certain Archii-an rocks havt! sometiineM lieeii lillcd by the debris ground oil the walls, and which ntiw forms dykes of breccia. An example of tliese may be seen at tho first rapid in tiie .Maganetawan river, eastward of tlm head of Hyng inltjt. The breccia dykt' runs eastwiiKl witli the couise of th<» stieani. Its matrix is aiiiorphotis and very brittle. .Some of the fragments coi'sist of a dark riMl<liHh lirown (ipa([ue clierty rock, and others of a d'.rk variety of syenite. The muM holds a little calcspar and specks of iron pyrites. IJut thcs.! Ion/ -iieH of fracture are not often marked by any consolidated tilling. The conditioMb i ear t.ie surfacn may not have been favoralile to the formation of such a tilling, and many of tliese fractures are perhaps too recent to have allowed of sntlicient time for this process to liave taken place. Close to thfse lines the rock all along is broken intosuiall |)ieces, which however have been only sliglitly moved Irom tlfir ptiginal sit(\s ; but p • we recedt from tlm lines of crushing tho angular pieces l)ecorae larg(«. and larger till tne whole rock has resumed its normal solidity. This broken condition has p(!ruiitted the percolation of the surface waters to great depths, which has been followed by the decay of the fractured rocks more or less rapidly in proportion to the fineness of the pieces into which they have been crushed. The joints for some distance on either side of those lines are stained with the oxide of iron, resulting from the general decomposition. The disintegration of the rock on such lines, as well as that of the greenstone dykes» has caused valleys to be formed along them as the result of glacial and other eroding agencies. In the district under consideration the writer in referring to this subject in 1870 said : " Between the mouth of the MaTranetavvan river and the first fall, especially along the north side, the pneiss, whicli runs in various directions, is of a dry, cruraolinK char- acter along a set of joints which run parallel to the stream and are lined with oxide of iron. The course of Bynj? inlet and of the .Maganetawan river (in continuation of it) is remarkable for being comparatively straight and crossing tho general course of the gneiss and mica and hornblende schists, as well as that of the lakes and the numerous smaller streams of the district. This would appear to indicate tliat the formation of this channel has had something to do with the existence of the brecciated dykes or the joints above de.scr;bed."* Lines of crushing in the Laurentian rocks were seen by the writer in some of the precipices in Hudson strait, where they were observed traversing walls of gneiss, and were well marked by the crumbled gneiss, still quite fresh. Transverse depressions or gaps in crystalline rocks have also been formed in the fol- lowing manner : The parallel joints which so frequently traverse granite, gneiss, quartzite, etc., are apt at intervals to occur in groups closer together than usual, or two or three may run side by side, which are stronger and more persistent than the single ones and comparatively distant from the nearest of them. The narrow walls of rock between such joints have suffered decay or injury from the surface influences in pre-glacial times, and, yielding to erosion more easily than the rest, have formed the starting lines of depressions and valleys. This phenomenon was referred to in connection with the erosion of water- channels in the French river region, and it may also be observed in various rocks in other parts of our district. Two sets of nearly vertical joints often traverse crystalline rocku at angles ap- proaching 80'' or 90" to each other. When such rocks are cut by a third set almost horizontally they are then divided into rhombohedral blocks, and are much more easily removed by aljrading and disintegrating forces. It not unfreqnently happens, as in the case of some granites, that there may be four sets of joints, t. Ickly penetrating the rock and dividing it into comparatively small triangular pieces. This imparts a shattered *Report of the Geological Survey for 1876-7, p. 202. •JO chiiracter to tho whole niasw, ivnd rendois it useless iov l)uildiiig or nioiiunientai ^ ^joses. Some masses of granite have heen saved from the foiees >^hich produ(;ed tliese numerous joints or cracks, apparently by the protection afforded by yielding; belts of schist. At all events tiie n>ore solid and serviceable "ranites are often thus sheltered. C li Y s T A I, r. I N E Schist s. The Huronian system comprises a j/reat variety of crystalline schists In botli the lake Huron and lake Sujierior regions. In the latter the older portions of the series are to a great extent formed of mica, hornVdende, diovite and chlorite schists, while these and other varieties of schists are interstratified with different rocks higher up in the scale. In the Sudbury district the northwestern border of the Huronian belt in the townships of Waters, McKini and Hlezard is largely made up of crystalline schists, of which dioritic, hornblendic, silicious and felsitic are the most abundant. Further to the northeast similar schists are abundant on lake Temagami. Silicious and felsit'c schists are largely developed between lake Wahnapitae and the line of the Canadian Pacific Railway. Coarsely crystalline hornblende rock, such as is found among the ITuronian strata of lake Superior, has been met with just east of the Stobie mine in Blezard, in the fifth conjession of McKim, and near the McConnell mine in the fourth concession of Snider ; also at the southwest bend of Spanish river and at Lamorandiere bay in the northwest corner of Rutherford. Green schists, schistose grey wacke and gueissoid schist, the latter enclosing boulders, occur among the rocks of the Straight lake Huronian outlier. In illustration of the mode of occurrence of crystalline schists among the Huronian rocks of the lake Huron region, the following examples on the Spanish river are selected from the descriptions in the report of the writer for 1888-90. Half a mile up the west brunch of this river a rock was met with which consisted of a mixture of gi een schist and fragments of granite. At the bend of this branch, four niiles from the main stream, there was found what Professor Williams describes as a " pinkish to brownish crypto-crystalline banded rock, which might be macroscopically described as a banded jasper or felsite. The microscope shows that it is a clastic rock, consisting mostly of quartz which has been whoU re-oi-ystallized under the influence of intense pressure, and that it has thus had the parallel structure developed in it by an elongation of its grains in one direction that is commonly known as stretched." Oil lot 1, sixth concession of Baldwin, just bf low a large island in Spanish river, the rocks in the bed of the stream consist of fine-grained pink quartzite in thin layers, inter- stratified with rough surfaced black slute, dipping southward at a high angle, while at a greater elevation there is exposed a heavy band of dark green mica-schist formimg the top of a long ridge. At the narrows of the river, on the east side of lot 12, first concession of Hyman, there is a coarse gray glistening schist and a sm-ill quantity of a dark greenstone. Below the narrows, on the next lot (11 in the same concession) a glossy dark bluish grey schist and a slaty grey wacke strike northeast along the flank of i mass of diabase which has a length of more than a mile in a northeasterly direction. .V fine-grained hornblende rock also occurs at this lo.ality. In the same vicinity, where the line between lots 10 and 11 intersects the north bank of the river, quartzite occurs dipping south at an ai.gle of 55°. In the northwest corner of lot 8, first concession of Hyman, there is a chute in the Spanish river with a fall of 15 feet. At this locality there is an extensive exposure of rather tine-grained silver-gray mica-schist with crystals of staurolite, thickly scattered over the cleavage surfaces. In the middle of lot 5, second concession of Hyman, the river passes through a canon or narrows, with gray schist en the northern side, and the northern flank of a ridge of fine- grained splintery greenstone running north 70" east on the southern. At a rapid in the north half of lot 3 in the same concession, a bluish gray satiny schist striken due north and south, the dip being east at an angle of 45". This sudden change in the strika is accomi)anied by an equally sudden turn in the course of the river. tai ,j()ses. (se numerous hist. At all i in both the series are to a ese and other cale. In the townships of hich dioritic, le northeast ts are largely ^ay. Coarsely [ike Superior, )n of McKim, ;he southwest Rutherford. )ulders, occur he Haronian r are selected 1 consisted of branch, four escribes as a croscopically L clastic rock, ! influence of d in it by an id." lish river, the layers, inter- e, while at a forinimg the n of Hyman, ione. Below h grey schist i which has a rnblende rock 3ta 10 and 11 u.gleof 55°. , chute in the 3 exposure of scattered over igh a canon or ridge of firie- 1 rapid in the iei due north the strika is 8 f- 81 R e 8 1< b V P o a 1 tl c< ti T S( oi tl tj ]V f( tl S] 'fi 8l ai h ii ai q' M re tc cr n( th oi Hi oi 21 The rocks at Kettle falls, on lot 2, second concesHion of Flyman, are gniy and satiny schists with a tiiree feet band of nearly black hornblende schist, all striking north 7G^ east, with a southerly dip of 75". On the line between lots 2 and 1, first concession of the same township, and opposite the west end of an island in the river, the rock is a glossy gray, tinely-arenaccous schist nearly on ed^'e and striking north 85'^ west. A gray gli.st- ening schist, standing vertically and striking north To*^ east, occurs at the falls on the south side of the island. A soft bluish-grHy schist striking eastward with the course of the river is found on lot 11, first concr-ssion ; and on the northeast corner of lot 1) there is a glossy green schist, but without strong cleavage. A gray hydro-mica schist running southwest occurs where the Canadian Pacific Railway crosses the Spanish river, in the centre ol lot 11, second concession of jVairn. •S ER 1' KN r IN K, Steatite and Dolomite. These three kinds of rocks may be mentioned among thoee which occur in minor volume in the Huronian system. Serpentine has not yet been found at all within onr present region, but some ex])osure8 of it were met with at Pigeon lake on the west l)ranch of Montreal river, a short ilistance to the northward. The serpentine occurs by itself, or associated with calcspar, or pa.ssing into limestone, on some small islands in this lake. On the shores ii' the vicinity are fine-grained and massive reddish-gray quartzite, gre^ -.ish-gray clay-slate, fine-grained "ddish-gray syenite, light greenish-gray finely crys- ,' e diorite, with disseminated grains of iron pyrites and gray porphyry very thickly ■>, .vied with opa(|ue-white crystals of felspar and a few of shining black hornblende. 1.... serpentine on fresh fracture shows different shades of green, and is somewhat mot tied. Under the weather the natural surface becomes rough and of a rusty color. It contains oxide of chromium, both in the form of small grains and in chemical combina- tion with the rest of the rock, and thus resembles the serjjentines of the Eastern Townships in the province of Quebec. The writer has been shown speciinons of serpentine said to have been collected among the Huronian rocks some miles north of Pigeon lake. On the point about the middle of the west shore of Abittibi lake the late Mr. Walter McOuat of the Geological Survey met with dark green serpen- tine, weathering dull white, strongly magnetic and containing grains of chromic iron. M r. E. B. Borron informed the writer that he had heard of serpentine having been found in the country lying north of the west end of Abittibi lake. On the Mattagami river, tHrty chains below the junction of the Muskoota branch, there is an exposure of massive gray semi-crystalline steatitic rock, holding grains of specular iron and cut by small veins of whitish bitter spar. Although this locality, as veil as those for sorpentine which have been mentioned, are outside of the limits of our sheet, both of the rocks referred to above may be looked for wherever similar rock associations exist within this area. The greenstone of the Evans mine, near Sudbury, has changed in some parts into a vaiiety of steatite or soapstone. Dolomites or magnesian limestones, having ceitain characters in common, occur spar- ingly in th(i Huronian system in the most widi'ly separated areas of these rocks. They are usually fine grained to compact, silitaous and marked by strings and fine threads of quartz and sometimes of calcspar, which have commonly a reticulating arrangement. Most of them are ferruginous, jind the weathered surface is generally yellow, brown or red, but sometimes gray or black. The iron is often present in large enough proportion to form a spongy crust of the oxide. Oi-casicnally these dolomites become rather finely crystalline, like saccharoidal marble, and nearly white. In our present region they have never been traced far on the strike, although they attain from 100 to 300 feet in thickness. Midway up the northeast side of Pigeon lake, already mentioned, on the west branch of Montreal river, there is a blufi' thirty feet high of semi-crystalline, yellowish gray limestone, mottliHl with green and reddish-brown patches and full of reticulating strings of white calcspar. The weathered surface has a ferruginous crust, from one-half to one *3 (M.) 22 incli tliick, showiiit; th» rock to contain a lar'o proportion of iron. A thickness of upwards of one luindred feet of the litnestono is exposed at this place, and it continues north- ward along the sliore for a qn irter of a mile oi mo-e. The other rocks in th(! vicinity of tliis diilouiite cons'st of syenite, diorite, serpentine, porphyry and different varielieH of quartzite. On the eastern side of South l)ay, lake Wahnapitae, and thence round the promontoiy towards Outlet hay, .Mr. Ale.xunder Muu'ay desc ibed a calcareous breccia associated with quartzites and greenstones.* In (ieneva lake, about a niil<! and a-half northeast of the on let, there is an islet entirely composed of tliinly l)edded light gray, dove-colored r xd nearly whit(! dolomite, fc.riking north 35" easi., and dipping to the westward side at an angh^ of 80^'. It is com- jiact and has a conchoidal fnictun^, but is traversed l>y fine threads of quartz, which pre- v( nt it from tak'Tg a good p)lish, otherwise it might be suitable for maibl.). The same rock is exposed on the east side of the lake on the point Just southward of the above islet, but the l)and could not be found on thi' northern side of I'le lake, towards which it strikes in the opposite direction. On thi- railway track threequa _'rs of a mile south of the outlet of Geneva lake there is a liftet'ii-fi ^t b^d ot' gray to dove colored tine-grained dolo- mite, weathering d irk brown. It strikes north 4.)" easu, and the bedding is about vertical. This dolomite br.nd is separated from hornblende granite to the southeast by about three hundred feet of ash-gray greywacke. The g/ani d towards its contact with the If ter becomes mixed with coa^.se breccia and conglomerate. Ou the other side, or to the r >rthwe:-ttward, the doloniile is followed by coar.se felspathic sandstone and silicious grey- wacke-conglomeiate or brec(5ia. At the outlet of Oisn-iva lake the rock is a greywacke passing into granite, and it includes some black slate and a patch thirty feet thick of impure dolomite. A band of magnesian limestone occurs at Island Portage on Wahnapitae river, about four miles below the outlet of tlie lake of the same name. Ic has a width of at least 300 feet across its general strike, but owing to the undulation of the strata the true thickness of the band could not be determined. On fresh fracture it is mostly light greenish-gray in color, tine grained, soft, somewhat impure, and weatii^rs to a brown color. The weathered i irface in Kome parts is marked by small co. rugated ridges, like that of the Huroiiian limestone of Echo lake, which result from the weathering ou.- of minute silicious streaks following the bedding. An exposure of tlie limestone at the head of Island Portage shows a more massive variety with a brownish gray color on fresh fracture, t Referring to the magnesian limestones of lake Panache Mr. Alexander Murray says : On the north shore of lake Panacho, about midway between the inlet from lake Lavase and its western extremity, a hand of limestone occurs which when first observed ap|.ear.s to be l;otli underlaid iiiid overlaid by syenitic slate con^iilomerate. The mass of this limestone, wliicli measures aliout sixty yards across and may be about 150 feet thick, is of a pale gray color on fracture, weathi'rint; to a bhii.ih ij;ray. with thin layers which have ttie appearance of chert, but are in i-eality only harder portions of the limestone, weather- int; quite black. About the base of the calcareous strata some of the beds are blue, holding more silicious matter than tlie Ki'^^y beds, while ott'.ers are of a brecciatcnl I'haracter. The beds are all more or less intersected by small veins of fine greenish jaspery-looking trap whi"h wcath'>rs brown or yellowish. To the eastwaril of this exposure the onl.v indications oljservedof the presence of lime- stone were on the east side of the large island at the entrance of the south bay. and in the peninsula on the north side at the entrance of the eastern arm ; in both of these localities small exposures of a black-weatherintc brecciated r(jck, which proved co be calcareous, came uji in one or two jiarts just over the surface of the water. On the island the cal- careous rock is overlaid by a bbuk-weatherinu; slate whicli, though without pebbles, resembles the matrix of portions of the slate-conglomerate. On the peninsula at the eastern arm the brecciated rook comes directly in contact with greenstone. At the head of the lower south expansion of 'ake Panache the limestones are again seen on both sides, and also on the two islands near the middle, striking about east by * Rf'tiort of (he <J<'"]'){;ical Survey for 186<), p. 177. tHeixirt of tlif' (ieologiciil Survey for 1876, p. 29(J. •?:{ licktK'ss of nuH9 noi'th- vicinity of variotieH of promontory ciated with is an islot ; dolomite, It is com- which pre- Tlic same above islet, li it strikes (utli of the ained dolo- t is about utheast, by ct with the !, or to the cious grey- grey wacke et thick of itae river, I width of the strfv^a dure it is [ weathers small CO. esult from exposure 3ty with a Murray ke Lavase d apiiears ss of tills liick, is of hich have weather- e. holding cter. The >kinp; trap c,c of lime- uul in tlie localities iilcareous, 1 the cal- t pebbles, ila at the are a(<;ain It east by norfli and west by soiiMi. and sliowinu; a southerly 'lip on the north siilo of the exposures • but the slate (^on^jlonicrato with which it seemed to he associated at other parts onl ■ ajipears on the soutli side of the Ur^e island lyint< iit the entrance to the nortli(u-n army' and between this island and the exposure of liiuesroiie on the west side of the bay there jj* a fioint to the northeast of the limestonedisplayini;- liue-irrained ^,n'een slate which, tliouj^h very much disturbed and intersected by ipiartz veins, appears to show r. K^'ieral dip to the northwest.* Mr. Muri-ay thinks that some of the above strata niii^ht yiehl good stone for burnin<' into lime. A specimen from the section on the north side of lake "anache was analysed by Dr. T. Sterry Hunt, and yavc in 100 pirts .oj. 10 carbonate of lime, (i.oO carbonate of magnesia, .'58.40 insoluble sand and a trace of iron. A specimen of the limestone at the lower end of lake Panache, analysed by the same chejnist, gave 41.97 per cent, carbonate of lime, 2.40 carbonate of magnesia and T^v)^V.^ insoluble nssidue ; and a specimen from tlie lower lake near the outlet, lying between the two ridges of the mountain range gave 36.50 per cent, carbonate of lime witli a little niagnesia.t Along tlie northern arm of the larger La Cloche lake calcareous rocks or impure lime- stones occur at several places passing below a considerable thickness of slate onglomer- ate, and tliey are again met with on the smaller lake to the northwest. High ridges of quartzite, standing nearly on edge and forming part of the La Cloche mountains, rise on either side of the southern arm of the larger lake, while greenstone and quartzite are found on the northern side of the smaller one. It would tlierefore appear that in this part of the great Iluronian btdt tlie inagnesian limestones occur among the quartzites, and are sometimes more inimcidiately associated with slate-conglomerate. A band of finely crystalline limestone occurs among the Huronian rocks in the northern part of the township of Rutherford. The locality is near the boundary line between red granite to the southward and a great thickness of quartzites to the north ward. The junction of the granite to tlie soutlieast with the Huronian quartzite and hornblende schists to the northwest occurs at the .south side of a rather elevated rocky island in a cove almut one mile north of the western entrance to " the passage " or channel, on the north side of which Killarney village is built. The geology of this locality and tlie relatioi"' of the limestone referred to can best be given ijy (juoting the description in the Geological Survey report by the writer for 1876, page 209 : On the west side of the township of Rutherford, from the nortliern limit of the granite (at the elevated rocky island above mentioned) quartzites and hornbleiiQo scdiists hold the shore as far US Lamorandiere bay. in the northwest cornei' of the township. A blackish groi n massive and rather coarsely crystalline hornblende-iock. having an exceedingly rough or irreurularly i)itted surface, is exposed on either side of the narrow entrance to tliig bay. Upon the sloi)e of the hill, about 100 yards in from the north shore of the bay, at a point about half-a-inile from the above-named narrows, a band of finely-crystalline lime- stone occurs among the Huronian rocks. It has a vertical attitude and runs about north 70' west at the part examined. Its total thickness is about 7.o feet, of which the 2.5 feet along the northern side consist of a single solid hand of nearly white finely-crystalline limestone, clouiled with light greenish and grayish patches. The remaining .")() feet are mixed with shaly patches of hornblende, together with a lirtle shining granular magnetic iron ore. Adjoining the limestone on the north side is a ])and, only a few f»et in thickne«s, of dark smoke-colored chert-rock. ril)bonod with streaks of a dull red color. It breaks easily with a fine conchoidal fracture, and ajipears to be identical with a rock which was used by the mound-builders for making some o.' their arrow-heads. This is followed to th". northward by a dark-colored dioritic conglomerate, in whicli the pebbles are mostly small and generally widely scattered, and farther on by a very dark gray, soft massive- looking micaceous schist, most of which is full of small i)ebbles. Measured fro.ii the limestone band, a thickness of between loo and 200 fi'ot of these rocks is exposed. On the north shore of Lamorandiere bay. a few hundred yards eastward from the outcrop of limestone above described, are two exposures of very tough massive hornblende rock, and bHtween the two arms of the bay is a more fissile variety, interstratiiied with a reddish gray quartzite. which also overlies the mixed rocks. The dip is here northwest- ward at an angle of 00" to 70 . and the series is underlain by granitoid gneiss. •Report Geological Survey for 1856, pp. 181-183. ill. p. 190. 24 I N r K r S I V K (J R A N 1 T K S . The red grHiiito of George island and the township of Rutherford may he of intruaive ori<rin, notwithstanding that it shows an approach to lamination towards tlie odges of the mass. " Its position is along the junction of th(' Laurcntian with the lluronian series, and it appears to belong to the latter rather than the former, ft has a medium texture, and is composed of reddish felspar and bluish-white quartz with a little hornblendes, which however is often wanting. Excepting at the sides it has a massive homogeneous structure, but in a few instances a single reddi.sh or yel- lowish green shaly streak, an incli or two in thickness, was observed running in a northeasterly direction with a dip to the southeastward of about 50". Towards each side the grain of the rock begins to assume a sort of parallelism or a gnessoid structure. "* Reference has already been made to an area of red granite measuring about four miles in length by two in breadth between the western and middle outlets of French river, and also to a brick-red granite or syenito along the upper ])art of the lower north channel of that river just l)elow (irand Recol let falls. Red granitic rocks border the newer ones which lio to tlie south of them all the way from the township of Cascaden to lake Wahnapitae. Althou'.^h the macroscopic appearance of thete rocks is that of a red granite, yet in some parts, as on the east side of Windy lake, the textural arrangement of the component minerals is more like that of a quartzdiorite, and they are certainly of eruptive origin. Professor (ieorge H. Williams examined under the microscojie a thin slice of a fine grained variety of these locks from Ivin-ni-wabik lake in the township of fjovack. He pronounced it raicropegmatite, and stated that it was an undoubted eruptive. Towards lake Wahnapitae similar rocks continue to be fine grained, but in that direction they become dark grayish-red in color. Around Washai-gamog or Fairbank lake the rocks have a similar color and te.vture to the last, and their appear- ance is the same except that they are distinctly stratified aiid occur in vary even Ijeds. The granitoid rocks above described merge into gneiss at varying but not great distances to the northward. Al)Out a mile east of the angle formed by the intersectiv^n of Proudfoot's east-and-west with his north-and-south line red hornblende granite was found. Its extent has not been ascertained, but it may continue a considerable distance northward. A Laurentian inlier has been mentioned as occurring around Paul's lake on the upper part of Sturgeon river. Where first entered upon in ascending the river at four miles below the lake the rock of this inlier con.sists of a rather coarse dull red quartz-syenite, or hornblende granite, but this passes into gneiss before the lake is reached. An area of coarse red granite crosses lake Temi.^caming about the middle. (Jenkuai, Xai'vkk ok tmk Hiudnian Rockh. While the greater portion of the Huronian rocks show the agency of water in their formation, there is also abundant evidence of widespread contemporaneous volcanic action. These detrital oi- clastic sediments were largely derived from igneous matter which had been more or less recently erupted, and hence they may be called pyroclastic, aa indicating both phases of their nature, liesides rocks of this character, we have seen that tlie Huronian system contains large igneous or crystalline masses. The whole series having been considerably metamorphosed, the true origin of some portions may not be at first apparent. JJut our study of them on a large scale in the field as w ;ll as the microscopic examination of hand specimens go to show that the above is the general nature of the lluronian rocks in all the areas which have been explored. The pebbles and i)ouldi ("s of the conglomerates rf the Huronian system consist of l)inary-granite, scliist;s,quartzitt; white quartz and red jaspar, grei nstoue, gneiss and other rocks derived from older parts of tlie same series or from the underlying Laurentian. The pre.ojnce of these conglomerates and the ripple-marks which are sometinu>s ])lainly seen <m ^he surfaces of beds of quartzite prove the existence in tl;ose days of either dry land or of seas which were very shalbw in some places. The limestones or dolomites are *l)r. Bell in Report of Geological Survpy for 1S76, p. fc,{s» ';r;!?jj 25 rimy he of n towards itian with be former, lite quartz he sides it iah or yel- ning in a varda eacli Tuoturo."* about four 3nch river, th channel i way from ^arance of 'indy lake, tz-diorite, ned under vahik lake it was an e grained, i-gainog or ir appear- ^ven I)eil8. ; distances t-and-west s not been the upper Four niilos z-s3'enite, In area of in their volcanic IS matter clastic, as seen that PS having )e at tiist croscopic re of the )uldt '•s of tc. white •ts of the 3 plainly ither dry uites are only of local extent. They are sonietinies nearly pure, or, as we hav(! seen, th(!y may be largely mixed with insoluble matter, or they may i)e brecciated with silit-ioiis fragments. The lime and magnesia may have been derived from the decomposition of the pyroxene and hornblende of the grtumstones. Some of the masses may be of a segn.'gated or a concretionary character, while others were precipitated from wattT. Nkwkst Rocks oi' t ii k !■. f n ii r k y DisruK t. The newest rocks of the Sudbury district form a distinct basin extending from near the west side of lakt* Wahnapitae southw('st to about the centre of the township of Trill, a distance of thirty six miles, with a l)readth of eight miles in the centre. This l)asin con- stitutes a prominent feature in the g(!ology of the district, and it. iiiiy prove to be of lower (,'ambrian age. Along its iiortluirn side it is iiounded by the ^'raiiitoid rocks already described, and on its southern by a belt of Huroniim schists and greywacke. The rocks of the basin con.sist of two principal divisions, — (1) the lowest being ii Irind, probably tliree or four thousand feet thick, of dark colored or almo.st black siiicious volcanic breccia or vitrophyre tuif, most strongly developed along the northern side and passing into black slate and black slate-conglomerate along the soutliern ; and (2) drab and ilark gray argillaceous and nearly black gi'itly sandstones with ahaly bands which vary in color tr.im greenish dral) to black. At the itasc; of the volcanic breccia a conglomerate consisting of a grey silicious matrix with rounded white <iuartz pebbles is seen in .some places, l>ut this may belong to the underlying series. The area of this geological basin corresponds in a striking manner with certain well markeil physical and geographical features. The volcanic breccia f rms a range of hills more conspicuous and rugged than any others in the district, whi..; the Hand.stones and shales constitute a low and nearly level tract from which likes, elsewhere so common, are absent. The Vermilion river Hows southwestward with the strike all along the northern side of this division, and Whitson creek flows in the same direction along the southern side. The silicitied glass-breccia or vitrophyre tuff maintains the same character and apparently^about the same thickness all the way from the vicinity of lake Wahnapitae to the township of Trill. It occurs in massive form and falls from cliffs or ridges in large blocks. It breaks with a conchoidal fracture, and when fresh is seen to be made up of angul.ir fragments, mostly small and closely crowded together and flei-ked with irregular white spots. Tlie fragments are not .so dark as the matrix, and present various shades. When examined with a lens many of the fragments show a distinct vesicular structure. Prof. George H. Williams has examined this breccia carefully both in hand specimens and under the microscope, and says that it is " composed of sharply angular fragments of vol- canic glass and pumice, which, in spite of almost complete silicification, still preserve every detail of their original form and microlithic flow-structure with a distinctn(!ss not to be e.xceeded by the most recent productions of this kind . . The fragments even down to those of the smallest dimensions have the angular form characteristic of glass shreds produced by explosive eruptions. The ilow-structure is as perfectly marked by sinuous lines of globu- lites and niicrolites, which terminate abruptly against th'^ broken edges of the glass particles as in the most recent vitrophyre. Minut<i spots of opaque pyrrhotite are scattered through the section. The groundmass is of a dark color, owing to the massing in it of minute black globulites, to whose nature the highest magnifying power gives no clue . . . After a careful study of this rock I find it possible only to interpret it as a remarkable instance of a very ancient volcanic glass breccia, preserved through the lucky accident of silicification. Nor did this process go on as is usual through devitrification and loss of structure, but rather lik' the gradual replacement of many silicilied woods, whose every minute detail oi structure is preserved. The rarity of such rocks in the earth's oldest formations is readily intelligible ; but, for this very reason, the exceptional preservation of a rock like this is all the more welcome proof that explosive volcanic activity took place at tlie surface then as now, and on a scale if possible even greater than that with which we are familiar."* "BuUetinH of the Geological Society of America, 1890, \>\i. 1^^-40, A fri'tih s(!otion of this rock Ih t'.\[)OH(itl in a ciitliiii{ on tlic! Ctinadian Pivcitic Railway at the liij;li falls of Onafiinf; river, twenty niileH nortliwfstof Su ll>ury Junction. An anaiysin of an aveiaj,'e s|teuinif ii from this jiiae(^ was made liy .Mr. Ilollinann of tiio (i(^olo- fjieal Survey, and it was t'oinid to uontaiu liU.L'ii per cfiit. of .silica. A siiieothed surfnoe of this iliirl ': has a handsome ap|i(>aranc(.', hut it is incapahh; of a hi^li pulish. The da. K ar^^illaccoua sandstones and drah and tiark sliales of the lii;,dier division of the rocks of this newer hasin may In- s-en at all tlii southward hends of the Vermilion river from Unwatin lake ntariy t<» Vermilion lake. Tho .strike corresponds with the fjeneral course of the river, and tht) dip is soutiieastward at rather hii,'h angles. Tho sand.stont s are characterized iiy dissendnated "grains of transparent ([Uart/, and they often holil rounded or ovate spots from an inch or two up to three feet in di.imeler, of a li^^hter color than the re t of the rock. On exposed surfacoa these spots W(;ather into depression.s. 8e\('ral parallel ridijes of tins smulstone with a northi'asteriy course cross the Canadian Pacilij Railway line diagonally hetween Liuchwood and Clielmsford. It appears to lit* well suited for l)uilding purjioues. This sandstoiii', Imtii as rej^ards the spots Just described and its dark color and massive character, hears a .stron;^ resemliltiice to the, silicious rocks whicli, in the form of houlders and smaller pieces, are .siiattered so ahundantly around the sliores of James hay and over the country lb r a threat distanee to the south- west of it. A similar rock is found in place on Lout,' island on the east coast, and at Clniichill on the west coast of Hudson Ixy, and there are reasons for believing that it is very e.\te':siveiy developed on the lloor of that sea. 1. O »V K 11 .S 1 L I' li I A .\ o It O K I) 1 V I C I A .N S Y .S T K .M. The islamls of ilu; lia Cloche j^roup and the peninsula of the same name in the south- westein corner of our sh(;et condst of lltt-lying fossiliferous rocks of the? Lower Silurian or Ordivician system, witii some ridges and knobs of Huroaian quart/ite protruding through them. The middh; portion, which constitutes the bulk of this group, is made up princi- pally of ratlier thinly-bedded, lumpy and uneven surfaced gray limestones, with many thin, shaly l)(;ds and partings int(;rstratifying them. I5nt underlying these measures are from 50 to 100 feet, or perliaps more, of reddish and chocolate colored calcareous marls \dth greenish hiyers and mottlings, together witli some beds of fine grained white and redilish sandstones, while overlying them and interstralifying the upper portit)n are beds of hard, coiiipa(;t, dark gray magnesian limestone, which weathers to various yellowish and redtlish shades. The lower or marly and arenaceous portion of the series has yielded no fossils by which its age can be identified, but it is believed to represent some formation older than tlie Trenton group, and it was thought by Logan that it might be the equivalent of the jSault Ste. Marie sandstones, which he considered to be Chazy, but which are referred to the I'otsdam formation by the United .States geologists. The, upper beds of the Trenton group are seen at the north end of >Strawl)erry island, and in the nortii-facing bank at Little Current at the northern extremity of llanitoulin island. At these localities they are overlaid by the black bituminous shales of the U tica formation. The breadth across tho strike from the north side of La Cloche island to the commencement of the Utica shales on Strawberry island is eight miles. The aver.tge dip to the south is assuuied to be 40 feet in the mile, so that the total thick- ness of the Trenton group would he about 320 feet. Che fossils which have been collected among these rocks from the summit of the marly and arenaceous portion up to the highest beds on La Cloche island, and also from the islands just west of the latter, belong to the Birdseye and Black River divisions of this group, so that the Trenton foiiiiation proper in this region is confined to a strip bordering the shore for six miles in the neighborhood of Little Out rent and thence round into West V)ay, tlie northern part of Strawberry island and the peninsula between Manitowaning and Snntli bays. On Heywood or Rat island, along with a little Utica shale there is some limestone which Appears to belong to the Trenton formation. Patches and margin.s of tossiliferous gray ill of liiiiHHtuneH resting on the quiut/.iio aiicl ili|i|iiiig into tlie lake are found here and tliere uloiif^ tht) lii;,'li j.dint which luns IVoni Killiirncy Ixiv InwardH Mi-ywood isliiiid iin<l on tin* ihUmdH juat nouth of it. Tlics*- roclis appear to In- idcnticiil with those forininj; thr i.ciitral part of La Clo<;h») island, and they woulil thorefon; l)(!lon;^ to the Birdseye or Black Kiver formation. Ah ain-ady stated, tin; Idack shales of the Utica formation re.st upon the to)> of the Trenton liiiic'^torK's in the viilaj^'c of Little Current and covir the yreater i)ait <>f Straw- l)erry island. Tiiey arc? found near the (luart-ite ritii.'f at She^uiundidi vilhi;,'c, al.so at the base of the Hudson Kiver formalinn lictwccn Manitowaninj^ antl Suiith hiiys, and in a similar position at cape Smith. ssils by ■ than of the red to wl)erry inity of shales Clocha miles. thick- been 1 up to latter, renton ales in n part . On which IS gray K U O N O M I CJ .Ml .\ ;■; II A L .s . Only 11 small part of the district represented on the accorapanyin;,' map has yet bnen explored lor useful luineral.s, but the discoveries already nuide are sullicicntly nuuierous and import.iiit to lead to the belief that a promisin,^ fiiturti is in sturo for thi^ part of Canada as a miniut,' rej^don. The metallic ores appear to i)e confined to the Murouian rocks, which are here so e.xtensiveiy deveiopeil. The, Sudbury district has becoiin> well known for its txtensive nickeliferousdi posits, and prospejtiufj has been as yet conhiied chiefly to that region. Ores of several other meta'^ have also been found in the district, and the iruiications are in favor of imieling witii souk^ of them in payiiiij i|uantities. NN'liat has lieen a(coiiiplish(d in the Sudbui'i district may be repeatetl in \aiious parts of the great unexplored Ihironian belt to the northeastward. But the us(iul luinerals of our present rei,'ion do not consist entirely of metallic ores. The non-metallic mineral products, such as building and oraanuMital stontjs, rock for lime and glass-making, etc., are also important. Some of these occur amontf the Lmirentian and others among thelluronian rocks. As the district is only beginning to tie inhal)ited, and the need of such materials has scarcely been felt, little or no effort to lind tiiem has jet been made; but as soon as there is any demand they will no doubt be found in many iiew localitit s. The possibility of discovering workable deposits of phosphate of lime among the Laurentian rocks ot the district, and of asbestos along with the lluronian sfrpentines, is well as of other substances usually found among these rocks, should be Lome in mind. Iron. Among the (juartzites of Llie La Cloche region small isolated deposits of ma.ijnetite and one or two of hematite have been found, but none of those yet discovered appear to bo sutliciently extensive to justify mining operations. From analyses reported to have been made of the ores from two or three o*' the.se deposits they would appear to be sutiiciently free from titanium, phosphorus anu sulphur to constitute lirst.-class ores. It is to be hoped that further explorations among these rocks may bring to light larger masses of iron ore. Tliin veins of good magnetite, accom])anied by (juartz, occur in the red hornblende- granite two miles north-northwest of Oaitier station, and again in the same rock on the Soanish river a short distance below The Elbow. api)ear to be promising for the ores of iron. The existence of iron ore on Iron island in lake Nipissing is oidy known to most of those interested in the minerals of the district by vague report. It may therefore be wntli while to quote the description of it given l)y the late Alexander Murray of the Oeological Survey. Small masses of specular iron ore are common to nxost of the rook in'the island, and in the crystalline limestone there is a very ijreat di.-jjlay of it. For a breadth of about forty yards ixlon^ the clijT on the east sid(! tlie rock holds masses of the ore of various sizes, somet imes running in strings of an inch thick or upwards and at otlier times accumulating? in huj^e lumps, some of which probal)l\' wei^h over half a ton. Tlie beach near the out- crop is strewn with masses of all siz-'s, from great boulders weighing several humlred pounds to small rounded pebbles not bigger than marbles. The limestone with which the But the granitic districts do not 28 ore is as.sociatetl is frequently cavernous, and tiie crevices and small fissures are thickly lined with crystals of blue fluor-spar and rod sulphate of baryta or cocksconih-sr ir- Crystalline limestone crops out on the opposite or west side of the island and. judf^inp by the strike on tlie north siiU-, it must correspond with that holding the iron ore on the east. The same minerals were found disseminated through thfj ro(^k and sti-ewn upon the beach. At the extreme southwest point of the island the rock is attain crj'stalline lime- stone, and a lonjf beach running out from it to the westward is perfectly covered with boulders of specular iron ore. Iron ore occurs also at the southeast point of the is'and, although not in such Kfeat abundance and only in detached masses strewn upon the beach.* In the Fluronian iron-bearing region of lake Superior the ores have two diflerent sets of asBociations or modes of occurrence. In the one case they are associated with hornblendic or cliloritic schists which appear to belong near the base of tlie system, and in tlie other they occur with fine grained silicioim and Jaspery rocks. The magnetite of the Atik-okan region is an example of the first, and that of Hunter's island and Kamini8ti(iuia river of the second. N I C K K L , The comjiaratively recent discovery of workable deposits of mixed copper pyrites and nickeliferous jjyrrbotite over a large area in the Sudi)ury district is one of the most im- portant events in the history of mining in Canada. Although masses of pyrrhotite are known to cxi.st in other parts of the Dominion, there is no ;)ther region where they are so numeious and in such proximity to one another, and with the exception of one near .St. Stephen in New Brunswick they do not appear to be nickeliferous to an economic degree, whereas in Sudbury district all the deposits so far tested are com])at'atively rich in nickel. The pyrrhotite of this region is found in the midst of rocks of diflerent characters and belong- ing to diflferent horizons, but it is always more immediately accompanied by greenstone. Indeed this rock may be regarded as the parent of the ore. These facts would seeni to indicate that in the Sudbury region the greenstone had a common and deep seated origin. The area over which the ore has been discovered is of an eliptical form, and measures about 70 miles from southwest to northeast and r)0 miles from southeast to northwest. The first discovery of nickel in this region was made about 1846, at the Wallace mine in Bay of Islands on the north shore of lake Huror., about a mile west of the mouth of Whitetish river. This mine was opened in 1847 and was visited in 1848 by the late Alexander Murray of the Geological Survey, but at that time mining operations had been temporarily suspended. The ore consists of chalcopyrite with magnetic and arseni- cal pyrites rich in nickel, occurring in chloritic and quartzose schists close to a mass of greenstone. The extent of the deposit cannot at present be seen on account of the debris on the surface and the shaft being full of water. Mr. Murray in his report says : The temporary condition of the mine at the period of our visit rendered it impossible to obtain such specimens as might be considered an average sample of the material exca- vated from the shaft ; but with a view of ascertaining the quality of the nickeiiferoui por- tion ot the ore a specimen of it, as free as possible from the copper pyrites, was submitted to analysis by Mr. Hunt, who found it to contain 8.26 per cent, of nickel with a trace of cobalt; hut as nearly two-fifths of the specimen consisted of earthy materials which might readily be separated by dressing, the quantity of nickel in the pure ore which this would represent would equal nearly 14 per cent.f The existence of nickel and copper in the greenstones of what is now the Sudbury district was Hr.st made known by Dr.T. S. Hunt and Mr. Alexander Murray of the Geological Survey in 18.')6. In that year Mr. Murray explored Salter's base line, running north- ward from Whitetish lake, and in what is now the township of Waters he found a mass of magnetic trap which proved to contain disseminated nickel and copper. He says : Sptcimens of this trap have been given to Mr. Hunt for analysis and the result of his investigation shows that it contains magnetic iron ore and magnetic iron pyrites generally disseminated through the rock, the former in very small grains; titanif-^rous iron was found associated with the magnetic ore and a small quantity of nickel and copper with the pyrites. J *Ue]iort of Progrpss for 18.')4, page 12.3. +(je(>l(>Kical Survey Report for 1848, i>. 44. ^Report of the Geological Survey for 1860, p. 180. nis if •JO Again referring to this Hubjnct Mr. Murray says : The maj^netic trai) liisrovored on Mr. Salter's tnorMian lino north of Whitefisli laki' was obsorvod to hold yellow siilphuret of copper oci'asionally ; and .Nlr. Hunt's atialysis of a hand-spociniiMi of tho rock. \veip;luni.' ten ounces, gave twenty grains of motallifcrous material, of which eleven wore m'VKn(Uic and consisted of iua|.;netii' iron oro, with a little titaniferous iron ore and miKnotic iron pyrites containing; traces of nickel. 'Phi nine ,?rains of non-magnetic mineral consisted of iron pyrites, oontalnintc from two to throe per cent, of copper and about one per (^ent. of nickel. Many larije i|uartz veins oci'-ur on the lower lakes of the Wl.itolish river, hut iron pyrites was the only nK'talliferous sub- stance which they were observed to contain.* fn constructing the ('anadian Pacillc Railway line in 1882 the mass of oro which is now beinj; developed as tlu .Murray mine, three miles and a lialf northwt^st of Sudbury Junction, was out through at the surface. This discovery was followed in 1881) by the fitu'ing of or(! at wliat are now the Stoltie, Clipper clitr, .McCJonnell and otli(>r mines in the neighborhood. These occurrences were at first regarded as of velue only for the cop- per which they might contain, and, notwithstanding that tho existence of nickel among the associated rocks of the region had been pointed out by Murray and Hunt so long be- fore, it was not till three or four years after the above discoveries had been mvde ami a thousand tons of dressed ore had been sent to England from the Ooppr>r-olifl' mine tiiat the value of *;he ores for nickel was recognized. The ore is very much the same at all the occurrencos in the Sudbury districc. It consists of a mixture of nickelif rous pyrrhotite or magnetic pyrites, witii more or less chalcopyrite or copper pyrites. The larger itre-masses generally approach lenticular forms, with their longer diameters parallel to the strike or to the line of junction of the enclosing rocks. Their attitude is usually nearly perpendicular, the dip or undtudie being sometimes ap- parently at higiier angles than those of the adjacent rocks. Each of the larger ore bodies is made up of a hrecciated or a conglomerate-like nii.\ture of the above-mentioned sulphides and the country rocks next to it, the fraguients of the latter varying in dimensions from n)ere grains and very small pieces up to immense boul- ders, but the average size is a few inches in diameter. In some cases the stony fragments constitute .so large a proportion of the upiss that they come aln ost into contact with each other, the interspaces being filled with the sulphides, while in others there are consider- able bodies of nearly pure ore with only occasiojial rocky fragments scattered through them. In a few instances a granitoid filling between the fragments takes the place of the sulphides. A good e.vample of this may l)e sren at an opening in one of these ore-masses on lot 3, fifth concession in the township of Levack. The usual site of the.se ore bodies is at the junction of greenstone with some other rock, especially granite, gneiss or felsite. Another circumstance which appears to have influenced the localization of the ore is the intersection of the ore-bearing planes by one of the dykes which have been described, or by a throw, or a number of minor dislocations. The existence of one or other of these conditions has been noticed at or near most of the larger ore-bodies of the district. These deposits ha e not yet been worked to a surii ;ient extent to prove much in regard to their persistence or otherwise, in depth. The Copper-cliff mine however has been already wrought to a depth considerably greater than the horizontal length of the ore- ma.ss, either on the surface or in any of the levels. Oro deposits of a similar character in other parts of the world have sometimes proved on working to possess a much greater depth than horizontal measurement. In the r.osence of any indications to the contrary, it may therefore be e.xpected that the nickeliferous deposits of the Sudbury region will prove equal in depth to their horizontal extensions. As to the genesis of the ore bodies, the evidence points to their origin from a state of fusion. The fact that the ores always accompany the greenstone (itself of igneous origin) is a strong proof of this supposition. The.se sulphides fuse at ab)utthe same temp'^rature as the greenstone, and in the cooling of the latter they would naturally tend to oalesco in small and large masses. The dissemination of both the chalcopyrite and the Report of the Geological Survey for 1880, p. 189. pyrrliotite sn generally tliroughout the wliole mass of tlie coiniiiotier varieties of the green- stones, and the lich iiiipregniition of these rouks witli the sitnie sulpliides in the vicinity of the ore bodies, arc luldi'.ional evidence in the same direction In the isolated liernels of ore, often scattered so tliickly througli tiie greenstone in the vicinity cf the workable deposits, we tind groups consisting of either of the sulphides, separately or intermingled, and often the indi\idiial kernels will be made U]) of the two kinds mixed to'j^ether. These kernels, together wiih larger patcli(!S of the ores, constitute t!very pi oportion of the rock, from a su)ail percentage up to halt'lhc! total weight or more, when the mass has become SM(Hci( utiy rich to put upon the roast heaps, In tl e mixed Hulphides of th e ore bodies the pyi ihotite generally cuntains a certain proportion of disseminated grains of quartz and other stony matter, while tli(^ chalcopyrite is usually tolerably pure. This may be owing to the manner in wln'cli th<! latter separated itself from the former, whether in a state of fusion or by some subt'equent process. Although most of these ores appear to have .seoaratod themselves from a cooling magina, we lind occasionally evidence of subse<iuent modifying processes. Still there can ))e little doubt that the larj.'er ore bodies of this dis- trict were no', originally deposited from aqueous solution like the gangue and ore of ordi- nary metalliferous veins. The above ores do not contain a veiy hi /.i ))ercentage of nickel or copper, their value depending more on their abundance and the facility with whicli they can be mined than on their richness. The Canadian (.'opper Company, after having smelted thousands of tons of the ores irom the Coj)perclili', Evans iind Stobie mines, found the average yield of nickel for tlie year 1890, to have been 3..")l' per cent, ard of copper ■i.32 per cent. The ore smel'.ed at the Blezard mine up to March, 1891, averaged 4 per cent, of nickel and 2 per cent, of copper ; that smelted at the Murray mine up to the same period averaged 1.5 per cent, of nickel and 7a per cent, of copper. Mr. F. L. Speriy, late chemist to the tJanadian Copper Company, found the average of nine assays of ores from the mines of his company to be 2.38 per cent, of nickel and G.44 of copp>-r. Assays of eleven samples of the ores of the district made under the supervision of ^Ir. Hoffmann, chemist to the Geolog- ical Survey, gave an average of 1.6'J per cent, of nickel. The average of all the above smeltings and assays givis us 2.G2 percent, jf nickel, which may be taken as the general average of the ores of the Sudbury district. Exceptionally rich ores however have been found in smaller quan^'ties, especially at the Worthington mine in Drury and the Ver- milion mine in Denison. C O li .\ L 1 . Cobalt amounting to little more than a trace has been detected in many of the Sud- bury ores. In connection with the Wallace mine it has been mentioned that in 1848 Dr. Hunt ascertained the presence of cobalt in the ore which Mr. Murray had brought f»'om this locality. C o P P K K . Reference has already been made to the copper always contained in the ores of the Sudbury district. The result of smelting several thousand tons of the ores from the three mines worked by the Canadian Cop[)er Company was a yield of 4.32 per cent, of copper from these ores as placed on the roast heaps. It has been mentioned that the roasting ores smelted at the Blezard mine yielded 2 per cent., and at the Murray mine 0.75 per cent, of copper. In the ores of all the mines the chalco|)yrite or copper pyrites is gener- ally so intimately mixed with the pyrihotite as to make it almost impossible to separate it by any mechanical process. But at the Stobie mine masses of several tons of almost pure copper pyritt s are occasionally encountered, and the Copper-clifi mine when tirst opened showed a large body of the .same ore near the surface. At the Vermilion mine on lot 6 in the fourth concession of Denison copper has been, found in paying quan'itics. The ore consists of clialeopyrite, which however is remark- able for having a dei p purplisii-blue tarnish, causing it to rt emble bornite or purple copper ore. It occurs as a streak about four feet wide in greenstone, but it has no distinct walls like a vein, nor any gangue except a mixture of the country rock. A shaft had been sunk on this deposit to a depth of twenty feet when it was visited by the writer in 1888. ;u of the three copper •oasting ).7r) per gener- ieparate iihuost eu tirst las beeu remark- purple distinct lad been 11 1888. The upper ten feet was decomposed to a loose gossan, mixed with fragments of rock, whirh had probably been held in the ore streak before its dccomjio.sitinn. The r<;c'ently discovered mineral sperrylite, whicii is an arsenides of platinum with a little tin, and whidi occui.-) in tine crystalline grains, was found by washing this gossan. (Jopper pyrites has l)een found on almost every lot in the iifth concession nf Ucnison, along the southern border of a belt of gr^'jnstone that runs nearly east and west tlirough tliis concession. A short distance north of the region under description tht; writer in 1S75 met witlia group ot eojjper-bearing quartz seins running north 70 west, and south 70 ea.-,t, crossing the east branch of tlie .Montn al river ten miles and a half before it falls into the main stream. Tliis gioup of veins is about a quarter of a mile wide. Tli<!y vary in thickness from nu're strings to thirty or forty feet, and contain a good deal ot specular iron, ;'.nd in some places promising indications of copper in the form of pyrites. IMr. Hoffmann found a samph; of tJie specular iron to contain 39.41 per cent, of the metal. The country rock liere consists of i.ia.ssive beds of (juartzite and greenstone, both holding large bunches or " clouds " of fragments of syenite, (juartzite and Huronian schists, and all interstratitied with sandstone and clay-slate On the north shor(^ of Xarrow bay or liaie Fine, and two miles east of its entrance, a small vein cutting the {juartzite contains gray copper ore. This V)ay lies between Frazcr and McUrei^or bays, and the above-mentioned occurrence of copper on'. has been described by Mr. James T. B, Ives in the Tranaactions of the American Institute of Mining Engineers for 1889- 'JO. The most productive co))per mines ever worked in Canada were those of the West Canada Mining Company, wliich included the Bruce on the east, the Wellington in the centie and the Huron Copper liay mines on the west. These mines are situated at the western extremity of the north sliore of lake Huron, and although they are outside of our piesent sheet they deserve a brief notice as affording the best examples of the occurrence of copper in the Huronian greenstones. These mines were opened in 184 (J and worked till 1875, a peiiod of thirty years. The actual workings extended for a distance of over two miles east and west. The ore occurs principally as the yellow sulphide in veins of white quartz, cutting a dark grayisli-green diabase. But when the veins on the Bruce location were first opened a good deal of the purple sulphide was found near the surface. On this location several nearly parallel veins running about east and west were worked, the thicker ones being about four feet wide. But on the other two locations work was carried on chiefly on two master veins called the Main lod( , which varied from three to fifteen feet in thickness, and tlie New or Fire-lode, a branch of the latter, and about equal to it in breadth. On the Bruce location the veins were worked to a depth of only about thirty fathoms, but on the other two locations the average deptli was from forty to sixty fathoms. Between the latter levels an almost barren floor was generally encountered, although in some place profitable mining extended to seventy fathoms in depth. The vein-matter as mined contained an average of five per cent, of copper, but it was concentrated by crushing and jigging to a\)out twenty per cent, before shipping to England, which was the chief market. At different times in the history of these mines both smelting and cementation had been tried upon the ground, and abandoned. From information supplied by Captain Benjamin Plimimer and other reliable authorities the writer ascertained that copper ore, preci]ii;ates, ingots and slags amounting to 40,515 tons, and realizing about .$3,300,000, had been shipped from these mines in the thirty years •luring which they had been worked. Lead a x i > Zinc. Small quantities ot galena and zincblende have been found in veins in the belt of black volcanic breccia and slate, which lias been described as occurring in the Sudbury district, and they are worth mentioning as possible indications that these ores may be dikcm ered in greater abundance in these rocks. One of the localities is on Pawatik river, about a mile and a quarter northward of the Vermilion, in township (15 ; a second is just below Oiiaping falls, and a third on the south side of Vermilion lake, near the outlet. Vein-iik(> ma ssts of blende mixed with pyrite occur at Stobie falls on lot 10, sixth con 32 cession of Creif»hton. Cialena has been detected with the pyrrhotite in the Copper-cliflT mine, and on lot 6, third concession of Graham. It is also associated with this mineral on Moore's location on lots 2 and 3 in the tilth concession of Craig. It occurs in small quartz veins in dioritic schist on lot fi, fovirth concession of Denison. (lOLT). In 1 887 a rich auriferous V)unch was found in a vein of light gray Hnely granular quartz about two feet thick on lot G, fourth concession of Denison. Theopening made on this vein came known as shaft No. 2 of the Vermilion mine. The gold was mostly in the form of small nuggets scattered rather plentifully through the quartz. It is said tliat several thousand dollars worth were mined, but the gold did not appear to hold out in depth. The country rock on this part of the lot reseml)les a Hne grained greenish gray greywacke, bu*^ on critical examination it is found to be an altered greenstone full of very small grains of iron pyrites. Prof. George H. Williams, who examined thin slices from two specimens of this rock under the microscope, describes it as an extremely changed basic eruptive, probably originally a gal)bro or a diabase — most likely the former. Its present composi- tion is H confused aggregate of chlorite, biotite, epidote, sericite, quartz, yrite, opaque iron oxide, leucoxene, calcite and apatite needles. Among the quartzites and greenstones on the south side of lake Wahnapitae a dis- covery of gold in visil)le specks Wiis made in 1888. It occurs associated with mispickel in some thin veins of qisartz following a belt of quartzite, boulder conglomerates and reddish felspathic quartzite having i-omewhat the appearance of granite. A sam|)le of the quartz from one of these small veins, which also contained mispickel and pyritc, was assayed by Mr. HotTmann of the (Jf^ological Survey and found to contain •"> 1 '_'•") ounces of gold and 0.233 of an ounce of silver to the ton of 2,000 pounds, but the quartz trom an- other of these small veins contained neither gold nor silver. A band of tine grained dark colored greenstone runs . irallel to and at no great distance from either side of this gold- bearing l)elt of quartzite. It is not unlikely that gold may be found among the rocks of the western part of lake Wahnapitae, which, as already mentioned, have been subject to much crushing in past ages. Gold is reported to have been found liy Prof, hfeys and others in quartz from veins in the northwestern part of Creighton and the eastern i)art of Fairbank. Out of a considerable number of samples of ([Uartz from the Sudbury dis- trict assayed for the precious metals by Mr. Hoffmann of the (Geological Survey, the following results were obtained : From vein No. 1 on mining location W. R. 3, township 40 (southeast of lake Wahnapitae), the property of Mr. Donald McLaren, 0. 117 oz. of gold per 2,000 pounds ; from location M. 3, at the south extremity of lake Mattagamash- ing, a short distance ea.st oi lake Wahnapitae, owned by Donald McLaren, 1.167 oz. of gold and 0.233 oz. of silver per 2,000 pounds; from Simpson's mine, lot 11, second concession of Graham, near Whitetish station on the Canadian Pacific Railway, 0.350 oz. of gold per 2,000 pounds Some distance to the west of our district, or in the western part of the township of Galbraith and about fifteen miles north of Bruce Mines, a large vein of auriferous quartz occurs in a country rock of greenstone. The vein runs about west-northwest, is of a mottled gray color, contains a considerable sprinkling of various sulphides, and is tolerably rich in gold. Of three assays made by Mr. Hoffmann, the highest result was .583 oz of gold per 2,000 pounds. I'LATINI M. Sperrylite, already referred to as occurring at shaft No. 1 of the Vermilion mine in l)enison, was first determined to be a distinct mineral species, containing 52 57 per cent, of platinum, by Prof. H. L. Wells of Yale College early in 188i). Some months pre- viously however Mr. Robert Hedley had ascertained the presence of plitinum in the ore of this shaft, the proportion in one assay amounting to about five ounces to the ton It is unlikely that the occurrence of platinum at the Vermilion mine will prove to he the only one in the district ; it is more probable that intelligent research will show the ex- istence of this valuable metal in other places among the lluronian rocks. It is reported to have been detected in small quantities at one of the mines on Lake of the Wo ids. 33 mine m per cent, tnths pre- in the ore ton lb to lie the w the ex- reported Old'*. BuiLDINfi AND OkNAMKNTAI. S T O V K S. The red granite of George island and vicinity would make an excellent stone for massive strncturcs and monnnients, as well as for ordinary buildings, Nfany of the evenly and somewhat thinly beddf d gneisse,-. of the French river region and of the shore of Georgian bay from I"'rench river to Parry Sound would serve a& very substantial and tolerably easily wrought biiilding rtones. The nearly horizontal beds of limestone of the Trenton group on the isliinds in the North channel, at Little Current and on Strawberry island are well adapted for ordinary building purposes and are very conveniently situated for transportation by water. They are mostly tine grained or compact, ajid of dark bluish and grayisli colors. The dolomites of the Niagara formation further south on the Grand Manitouliu ifland are more heavily bedded, soft(;r or more porous and iiiuch lighter in color. The light gray and cream-colored dolomites of the Guelph formation are found on the southeastern extremity of Grand Manitoulin island and the south end of Fitzwilliam island, but in tliese localities tliey aie coarsely spongy or full of small cavities. On the shores of the high jioiiits and islands to the no.-th and west of Killarney the light gray and whitish ([uartzites in many places would make very serviceable building stones. The bed-planes are generally very even and parallel, and layers can lie found of almost any thickness desired. Some varieties of the greywackes, so common among the Iluronian rocks, split readily in any direction, and as they are tolerably easily dressed they may be found suit- able for purposes of heavy construction. The argillaceous sandstones of the supposed Cambrian basin of the Sudbury district also afford ^'ood building stones and tiiey have been quarried to a small extent on the line of the Canadian Pacitic Railway between LarchwGod and Chelmsford. In regard to ornan\entai stones, the dolomites of the Huronian system when cut often show good colors for marbles, but as already stated they generally contain silica in scattered grains and as strings and threads running in all directions through the mass, which prevent.s them from taking a good even polisli. Exceptions to this general rule may however be found in such cases, for example, a.s the finely crystallint; and nearly white variety found on the north side of Lamorandiere bay in the township of Kutherfonl, which has not yet been tested as marble. The olive and greenish argillites barred with black, such as occur at tlie northern outlet of Temagami lake, and which were so highly prizeil for ornamental stones by the ancient Indians, may be found serviceable for the manufacture of a variety of artistic objects. The brecciated green chalcedony, which occurs in abundance at the outlet of White Beavt-r lake, at the head of the east branch of Montreal river, would form a hamlsome stone for fine ornamental purposes. ROO K 1 N li S I, A T K . It sometimes happens that clay-slates show a good cleavage in natural exposures resulting from the long continued action of surface influence.s, while t'le same rock, when freshly quarried deeper down, will not split readily under artificial treatment. It is there- fore ditiicult to pronounce upon the value of such slates without practical experiment. In our district slates showing fair natural have been observ(Mi in various localities, among which may be mentioned the banks of the Matabechawan river which dischargis Ral)bit lake into lake T<Mniscauiing, Maskinongewaganiing lake and the lower part of Matlagamashing lake and Spanish river both above? and below the (Jreat Bend. It has be( n already mentioned that a good chavable slate occurs on the line of the Canadian Pacific Railway within a mile or two east of Algoina Mills. While these slati-s may not lie as good as those of Mflbourne and Shipton in the province ( f Quebec, they are bettei- than the slates used for roofing purposes in many paits of Great Hritaiii, and it IS considered worth while to call attention to ihem among the mineral products of economic value occuring in this region. :h L I M K , The limoHtones and dolomites which make up the hulk of the rocks of the vnrious Silurian formations of the islands of the La Cloche group and of (Irand Minitoulm island are well adapted tor lJurnin^' into lime, the calcin.Kl dolomite passin;,' under this name. Stone suitable for burning into lime and also for metallurgical purposes inay be found among Mie Huronian magnosian liiiiestonea already described at Limorandiere bay, lake Panache, on Wahnapitae river, near Oartier station and on Geneva lake. StONK vnn frI,ASS-M AKINn. Suitable material for glass-making may be found almost anywhere among the Huroa- ian quartzites near lake Huron, where thev are nearly all of light colors. In addition to their occurrence in the La Cloche mountains and on the high points and islands towards Killarney, these quartzites are met with on the north lide of La Cloche island, at the Bouthern extremity of La Cloche peninsula and in a ridge which runs into Manitoulin island from the head of Sheguiandab bay. Al'ATITK OK PHOSPIIATK OK L I M K. This mineral has not yet been found in economic (luantities within our district. Tt exists however as a constituent of all the greenstones of the region which have been examined under th« microscope, and large crystals of it have been met with among the ores of the Copper-cittand some of the other mines in the district. Numerous crystals of apatite were found in a vein near Nasl)onsing station on the Canadian Pacitic Rail- way, east of lake Nipissing, As this mineral may be looked for among the Ujjper Laurentian rocks generally, it would not be surprising if it should be discovered in com- mercial quantities in the Nii)issing or Parry Sound districts. It occurs in various localities in other parts of the province among the Upper Laurentian crystalline lime- stones, but elsewhere it is found in larger masses in association with pyroxene rock an\oiig gneisses and quartzites, as in the countj of Ottawa. Five bands of crystalline limestones among the Upper Laurentian rocks were traced through the Parry Sound district by the writer in 187G, but th. region northward of Georgian bay has not yet been sutticiently examined to determine whether pyroxene rocks exist there or not. Should they be met with in sulKcient abundance the finding of apatite in economic ouantities would be pretty sure to follow. M I vurious litoulin icT this nay be re hay, Huroa- ition to ;owar(ls at the litouliii let. Tt ,'e been )nsf the crystals c Rail- Upper in cora- various LH litne- c an\oiig lestones by the [iciently be met e pretty