DEVONIAN FORMATIONS OF ONTARIO. 229 



tion, with the exception of a belt of higher Devonian rocks which crosses the 

 country from Lake Huron to Lake Erie and divides the region into two areas. 

 These newer strata occupy a saddle-shaped depression in the great Cincinnati anti- 

 clinal, which runs nearly east and west through the peninsula, while the course of 

 this depression or synclinal is nearly north and south from Plympton, on Lake 

 Huron, to Orford, on Lake Erie. The belt of higher rocks has a breadth of only 

 about twenty-five miles on the anticlinal between the Thames and Sydenham 

 rivers, but on either side it spreads to the northeast and to the southwest along the 

 shores of the two lakes." 



In two wells, those of London and the " Test well," at Petrolea, the 

 Corniferous is shown to have an approximate thickness of about 200 feet, 

 consisting throughout of hard gray limestone. In all wells where this 

 formation has been struck the rocks appear to have been of uniform 

 character and to consist of white or grayish limestones holding nodules 

 and layers of chert. 



Oriskany.— The Oriskany formation is but slightly developed in Ontario, 

 being entirely wanting in most of the wells sunk to or beneath its horizon ; 

 again, owing to the carelessness of drillers, its presence may not have 

 been noted. In the townships of Oneida and north Caynga, in Haldi- 

 mand county, it is exposed and forms beds of sandstone aggregating at 

 the most twenty-five feet in thickness. In many of the records obtained 

 from drillers mention is made of a sandstone at about the summit of the 

 Onondaga, but in most cases close inquiry has proven these statements 

 to be fallible, the so-called sandstone being generally a granular dolomite. 

 However, in two wells at least there is strong, evidence of a sandstone 

 occurring at a point near the position occupied by the Oriskany. One 

 of these was a well drilled at Dresden, Camden township, Kent county, 

 wherein the following record was met with, according to the driller: 



Surface deposits 43 feet. 



Shale, black 180 " 



Limestone 12 " 



Shale ("soapstone") 172 " 



Limestone 75 " 



Sandstone 44 " 



Again, in a well sunk near Dresden, on lot 3, concession 2, Camden 

 township, the following section was, according to the driller, obtained : 



Sn [face deposits 00 feet, 



Shale, black 20 " 



Limestone 30 



Shale (" soapstone ") 204 " 



Limestone 117 



Sandstone -10 



