STRUCTURE OP THE HYDROCARBON FIELDS. 



227 



Devonian 



Silurian 



Cambro-Silurian 



Formations. 



Approximate A mk _ 



thickness m ■' r . 



* i ncss inject. 



r 



Portage and Chemung 



Hamilton, about 



Corniferous 



Oriskany 



Lower Helderberg \ 

 Onondaga J 



Guelph 140 



Niagara 



Clinton 



Medina 



Hudson Liver 



Utica 



I Trenton \ Rnn 



I Black Liver / uuu 



Total. 



4,125 



The geologic Formations involved. ,, 



« 

 Detailed Description essential. — To meet the requirements of this paper 



it is perhaps 1 tetter to describe, so Car as is known, the various formations 



in descending order. 



Portage. — The Portage in Ontario consists of a series of fissile Mack 

 bituminous shales and is developed almost altogether in the county of 

 Lambton, where it acquires, according to Dr T. Sterry Hunt, a thickness 

 of 213 feet, as shown in a boring made at Corunna* These shales in a 

 well bored at Sarnia show a thickness of 80 feet, and again, in a well 

 sunk on lot 12, concession 10, Bosanquet township, they are seen to have 

 a total thickness of 95 feet. In both of these instances it lies immedi- 

 ately over the upper shale bed of the Hamilton formation, the upper 

 limestone bed of which, found at Petrolea and elsewhere, is wanting. In 

 the township of Dawn, and again east of Oil Springs, 7<> feet of black 

 shales are found. In this instance they rest upon the upper limestone 

 of the Hamilton. In a syncline lying between Petroleaand Oil Springs, 

 and separating the two fields, 40 feet of black shales are found in a well 

 drilled on Fox creek, the elevation of which is considerably less than 

 that of Oil Springs. These shales in no instance afford oil, but are prob- 

 ably the source of the considerable quantities of shale gas found in the 

 overlying gravel ami sand. 



Hamilton. — Thewells in Petroleaand Oil Springs and the greater num- 

 ber of those drilled in Lambton county show that the black shales of the 



1 Report of Progress, Geol. Survey of Canada, 1866, p. _:I7. 



