: » i 8. Hunt on the Geology of Southwestern ; ek ¢ 9357 
4s just defined, including twenty feet of black shale at its base, 
‘is only 224 feet, which are represented in Ontario by 200 feet 
om the Sydenham river, and by 213 feet at Corunna on the St. 
Clair. Yet Prof. Winchell, for some reason, doubts the exist- 
ence of the Portage formation in Ontario. 
The Hamilton shale, which in some parts of New York at- 
tainsa thickness of 1,000 feet, but is reduced to 200 feet in 
le western part of the state, consists in Ontario chiefly of 
_ Soft gray marls, called soapstone by the well-borers, but in- 
cludes at its base a few feet of black beds, probably represent- 
the Marcellus shale. It contains, moreover, in some parts, 
beds of from two to five feet of solid gray limestone, holding 
silicified fossils, and in one instance impregnated with petrole- 
syne which, but for the nature of the organic remains, 
the 
the underlying marls, would lead to the conclusion that 
Lower Devonian had been reached. The thickness of the 
=e 
shale above, varies from 275 to 230 feet, while along the 
of Lake Erie it is not more than 200 feet. Further 
the base of the black shales. It thus appears that 
milton shale (including the insignificant representative 
the Marcellus shale at its base) augments in volume, from 
200 feet on Lake Erie to about 400 feet near to Lake Huron. 
Such a change in an essentially calcareous formation, 1s 1m 
Scordance with the thickening of the Corniferous limestone 
™ the same direction, : 
The Lower Devonian in Ontario is represented by the Cor: 
>on limestone, for the so-called Onondaga limestone has 
Bi 
bin 
h have-been sunk through this lime: 
paration 
Met with nothing distinctive to mark the se 
