MICHIGAN ACADEMY OF SCIENCE. 93 



Oil flows from about 15;) feet below mean tide level on Pelee Island, 

 or from some 700 feet below the surface of the Onondafja. In the 

 Tilbury-Romney iield oil is obtained at about 137 feet below tide, or some 

 600 feet below the Onondaga surface; whereas in Romney gas flows 

 copiously from the Onondaga". In the Chatham Held oil comes from 

 about 108 feet above mean tide level, and from something over tO feet 

 in the Onondaga. In the Petrolia field the oil horizon is about 202 feet 

 AT. and about 6-5 feet in the Onondaga. At Sarnia, flanked by the 

 Hamilton uplift at Thedford, and with tlie .Michigan basin in front, the 

 gas horizon drops to about 190 feet AT., but, from the shale depths at 

 this point, this would appear to be up in the rock of the Hamilton for- 

 mation. 



It is of interest to note that, whereas in Romney Township the very 

 limited flow of oil is from small pools, in Tilbury alongside the greatly 

 enhanced supply is held in crevices. And tlie parties chiefly interested 

 commercially state that in Romney, as the Tilbury and Romney and 

 Chatham oil continued to be drawn ott", the pressure of gas became 

 measurably greater. 



The new discovery of gas at 1,800 feet in the Petrolia field, at Oil 

 Springs, does not affect the argument except to lend it support. The 

 oil in this field is obtained at from 300 to 400 feet from the surface, and 

 some 65 feet in the Corniferous (Onondada of New York state). If 

 strong flow of gas be obtained from below this at 1,800 feet, or at any 

 depth whatever below, it follows that the oil at the upper horizon must 

 be an overflow supply from some other source than that of the lower gas. 



At precisely the same time at which the Pelee Island and Amherst- 

 burg quarry Onondaga sustained uplift in Essex County on the northeast 

 shoulder of the Cincinnati insular dome, the same lower Onondaga beds 

 were disturbed on the north shore of the Ontario arm of the Devonian sea. 

 This is shown in the Horse Shoe quarry at St. Marys, Perth County, 

 where there is a crevice across the field. On one side of this break are 

 the same lower Onondaga beds as were laid down in Essex County in 

 the parts uplifted. But on the other side of the crevice, no fault having 

 developed from the break, the later Onondaga strata begin at once to 

 be added on, and with much sharper dip. The adjacent hard, brittle 

 Anderdon Beds limestone on the north side of the town of St. Marys 

 is heavily faulted, just as it is shattered along the east bank of the 

 Anderdon-Malden trough. 



Add to this evidence the corresponding fact that the rock surface 

 along the Lake Erie shore of Elgin, Kent and Essex Counties, has a 

 greater elevation than the extension north and south of it, and but one 



-So stated l)y tlie operating companies. 



