112 ROYAL SOCIETY OF CANADA 
these places the development is not complete since the rocks are affected 
by faults and low anticlines. 
The thickness of the Black River formation, largely limestone and 
now including what was once styled the Bird’s Eye, has been given at a 
number of points. This formation has been separated as far as possible 
from the Trenton which succeeds it upward without apparent break, 
and forms, over a wide area, a very extensive series of strata between 
the Black River and the Utica shales. The beds of the former differ, 
however, from those of the Trenton in lithological aspect and also in 
the presence of certain fossils which have a somewhat limited range. 
Like the preceding formations the thickness of the Black River 
limestone varies in different parts of the basin. Thus at Montreal it 
is found to measure only thirty-eight feet. At Joliette to the east, it 
is placed at fifty feet; at Ottawa about the same, while in the area to the 
west, in the vicinity of the great lakes, as at the Moira river, the 
thickness is placed at sixty-five feet, at lake Couchiching, which is a 
short distance north of lake Simcoe, it is 150 feet and at St. Joseph’s 
island it is about 150 feet. 
Along the upper Ottawa, escarpments of these limestones are seen 
at several places. ‘Thus on the Bonnechère near Eganville the apparent 
thickness of the formation is not far from eighty to one hundred feet, 
but the overlying Trenton beds are rarely seen, so that the exact thick- 
ness cannot be determined. 
The limestones of the Trenton formation present a much greater 
volume. The thickness may be safely assumed to be not far from 600 
feet. Measurements have been made at a number of points, the results 
of which are stated in the Geology of Canada, 1863. Thus at Montreal 
the thickness was found to be about 540 feet with local thickening at 
several places. At Joliette it was ascertained to be 430 feet. In the 
vicinity of Quebec city not far from 600 feet, and at Ottawa about the 
same volume. In the area east of Ottawa city, in Cumberland, the 
thickness ranges apparently between 650 and 700 feet. 
Further west, on the Moira river, the Trenton has a thickness of 
614 feet; on the Trent river about 750 feet, at lake Couchiching from 
500 to 600 feet, and at Collingwood about 750 feet. 
The Utica formation, consisting almost entirely in Canada of black 
or dark brown bituminous shales does not present, in the Ottawa basin, 
sufficient data from rock outcrops to furnish reliable figures as to thick- 
ness. There are numerous outcrops and the contact with the Trenton 
can be seen at a number of points, but no continuous section is avail- 
able. On the lower St. Lawrence, however, near the falls of the Mont- 
morenci river below Quebec city, a fairly good section is seen. At this 

