1854.] 



GEOLOGY OF WESTEKN C^^JNADA, 



Geology of Western Canada. 



In tlie August number of this Journal wg published a 

 Geological Map" of a considerable portion of Western Canada, 

 by W. E. Logan,'; Esq., P.R.S. & G.S., Provincial Geolo- 

 gist. We now propose to furnisli monthly abstracts of those 

 portions of the Geological Reports which describe the physical 

 structure of the countiy comprehended within the limits of the 

 Map. We are induced to adopt this method of disseminating 

 information respecting the Geology of Canada, not only on 

 account of its intrinsic value, but also because it is a matter of 

 extreme difficulty to meet with copies of the earlier Reports, in 

 consequence of the destruction of the reserve during those 

 disastrous conflagrations which destroyed the Parliament 

 Biiildings at Montreal and Quebec. 



Ahstraci of the Proiuncial Geoloffist's Reports, dated Montreal, 

 April 28, 1844. 



WESTERN DIVISION. — PRIMARY AND METAMOUPHIC ROCKS. 



In availing myself of the labours of the American Geologists . 

 to illustrate the general relations of the rock formations of the 

 Province, it will be convenient to divide the subject into two 

 parts, and drawing a line along the Hudson River and Lake 

 Champlain to Missisquoi Bay and thence to Quebec, to con- 

 sider the region to the west of this line separately from that 

 on the south side of the Saint L;iwrenoe to the east, there being 

 certain conditions in the one that do not prevail in the other. 



WESTERN DIVISION. 



The Western Division, as connected with the Geology of 

 Canada, may be described as a gigantic trough of fossilifcrous 

 strata, conformable from the summit of the coal to the bottom 

 of the very lowest formations containing organic remains, with 

 a transverse axis reaching from- the Wisconsin River and 

 Green Bay in Lake Michigan to the neighbourhood of Wash- 

 ington, a distance of nearly seven hundred miles; and a 

 longitudinal one extending from Quebec in a south-westerly 

 direction, to some point, with which I am unacquainted, be- 

 yond the Tenessee River in Alabama.* Contained within this 

 vast trough and resulting from gentle undulations in the strata, 

 giving origin to broad anticlinal forms, there are three important 

 subordinate' basins, in the centre of each of which spreads out 

 an enormous coal-field. One of these extends in length from 

 the County of Logan on the southern borders of Kentucky, in 

 a north-westerly direction to the Rock River in Illinois, where 

 it falls into the Mississippi, a distance of three hundred and sixty 

 miles, and in breadth from the mouth of the Missouri to the 

 County of Tippecanoe, on the Wabash in Indiana, two hundred 

 miles. Presenting an oval form intersected by the River 

 Illinois, Wabash and Ohio, and bounded by the Mississippi, 

 which sweeps along nearly the whole of its western margin, this 

 cual-field covers an area of 55,000 sc|uarc miles. The second 

 occupies the heart of the State of ]\Iichigan, and reaching 100 

 miles in an cast and west direction from within thirteen leagues 

 of the Lake of that name to Saginaw Bay in Lake Huron, and 

 150 miles in a north and soutli line from the neighbourhood of 

 the Rivers Manistee and Ausable, to the source ol" the Grand 

 River near Jackson, on the road between Detroit and St. 

 Josephs, it exhibits an irregular pentagonal shape and comprises 



* See the geological Map of the JliiUUo and AVestoru Ststos, lately 

 published by James Hall, Esq., oneof tlioStateGcologistsofNcw York. 



a superficies of 12,000 square miles. The third carboniferous 

 area stretches longitudinally about 600 mUes in a north-east- 

 erly coui'se from the state of Tenessee to the north-eastern 

 corner of Pennsylvania, where many outlying patches belong 

 to it, and 170 n)iles transversely from the north branch of the 

 Potomac in Maryland, to the south-eastern corner of Summit 

 County in Ohio, just twelve leagues south of Cleveland on I^ke 

 Erie. It possesses a sinuous subrhomboidal form and spreading 

 over a surface somewhat larger than the first named coal-field, 

 may comprise about 60,000 square miles. The Ohio and its 

 tributaries linwater nearly the whole of it, and the main tmnk 

 of this great river serpentines through the centre of the region 

 for about 400 miles of the upper part of its course. The 

 Susquehanna and its tributaries intersect the north-eastern 

 extremity of the deposit, and the vuUies of denudation in 

 which these waters flow, assisting the effect of a series of nearly 

 equidistant undulations in the strata, there break its continuity 

 into the outliers alluded to, which generally rest on sinelinal 

 mountain tops, in the interrupted prolong-ation of a number of 

 narrow subsidiary trouglw resulting from the undulation in 

 question, and giving an irregular and deeply indented contour 

 to the outcrop of the main body of the coal. The chief part of 

 the outliers, as well as the main body of the depofit, and also the 

 other two great coal-fields described, j'ield fuel of the bituminous 

 quality ; but to the eastward of the Susquehanna, there arc 

 three large outliers almost sufficiently important to deserve the 

 designation of another coal-field, in which the fuel contained is 

 of the anthracitic kind. 



The undulations which have been mentioned, constitute an 

 iinportant feature in the structure of the country between the 

 St. Lawrence and the Atlantic* Their ridges or anticlinal 

 axes presers'ing a remarkable degree of parallelism, have been 

 traced for vast distances, ranging in a sinuous south-westerly, 

 course from Lower Canada to Alabama. Crossing them from 

 north-west to south-east, those forthest from the ocean are 

 broad and gentle, but they in succession become more acute and 

 prominent; and as they do so the dips on the north-west side of 

 the axes increase in inclination in a more rapid ratio than those 

 on the south-east, giving to the undulations the form of waves 

 driven before a gale, until at length the former a.ssumo a per- 

 pendicular attitude and even present an inversion of the 

 strata. 



It is where the flexures reach the Apalachian chain of 

 mountains that the phenomena of these overtiu-n dips are ex- 

 hibited, and there the undulations, becoming identified with the 

 ridges and vallies of the chain, afford an explanation of the 

 structure of this great range of highlands. Tlie disturbances 

 which have given origin to these mountains, as they aflcct 

 the coal measures, must, of course, take their date subse(|ucnt to 

 the carboniferous era : but, as may be gathered from what has 

 been said,, it is only on the south-e:»st side of the third coal- 

 field that the measures are violently comig-ated and fractured. 

 The north-west outcrop exhibits a comparatively quiescent con- 

 dition, and it would appear from the regular contour of thg 

 lllin'ois and Michigan deposits, that the disturbing forces had 

 entirely died away before reaching them. It docs irot 

 seem improbable, however, that the broad low anticlinal arch 

 which seiiaratcs these two fi'om the other, may have some re- 

 lation to the expiring effort of tho.se forces, for althougli its axis 

 cannot be called precisely pandlcl to the Apalachian undula- 



* See Professor 11. D. Rogers' State Reports ou the Geology of 

 Peimsylvonia. 



