[Ami] GEOLOGY OF SOME CITIES IN EASTERN CANADA 149 
said to have been struck at a depth of 1160 feet, immediately underlying 
an arkose series of beds twenty feet in thickness. 
THE ORDOVICIAN. 
The Utica, Trenton and Black River formations.—There is very little 
doubt that the surface of the Archean complex immediately underlying 
thé palzozoic sediments is an uneven surface. Wherever the Archean — 
has been completely or partially denuded or stripped of the overlying 
formations of the Ordovician system, the rounded and irregular and un- 
even surface has been noticed. Throughout Eastern Ontario, in a more 
or less direct line, joining Kingston and Lake Simcoe, the Black River 
and Trenton formations are seen to overlie the Archean unconformably 
and there is no doubt that these two formations continue to the south- 
west and overlap the Archean, covering it with a thickness of perhaps 
not less than 600 feet. In numerous localities along the line of out- 
crop of these two formations indicated, the contact between the older 
(Black River formation) and the Archean, is oftimes a clean contact. 
An intermediate or basal series occasionally intervenes, and consists of 
light yellow or greenish-white calcareous sandstones, associated in other 
localities with red marls and shales, constituting an arkose series. In 
many localities detrital matter lying on the surface of the Archean floor 
—at the time of the approach or encroachment of the Ordovician sea and 
its sediments—is found to be held and cemented in tne overlapping lime- 
stone beds of the Black River formation. These phenomena which 
characterize the lower portion of the palæozoic column in the series of 
formations between Kingston and Lake Simcoe are no doubt repeated 
along the line of contact between the surface of the Archean floor, and 
the overlying sedimentary formations of the Ordovician below the city 
of Toronto, and the surrounding district. 
Except in the more compact lithographic character of the limestones 
of the lower portion of the Black River formation, as weli as in the 
general character of the semi-crystalline more or less impure and at 
times earthy limestones of the upper half of the Black River and Trenton 
formations, no specially distinguishing characteristics have been detected 
in the drillings examined or recorded to prove the exact geological hori- 
zon of these formations underlying Toronto; but the general trend of the 
formations throughout the province leaves no doubt in the mind of the 
geologist that the Trenton and Black River formations are present and 
as well developed as along the line of outcrop in Central Ontario. 
Such also is the case with the Utica formation. Its dark-brown 
and black bituminous shales are sufficiently characteristic to distinguish 
