BUFFALO SOCIETY QF NATURAL SCIENCES 7 



All the formations lie bedded as they were originally laid 

 down, being neither folded nor, excepting in some few instances, 

 faulted. With one exception all the beds meet conformably, the 

 one inconformity being at the junction of the Onondaga and the 

 Cobleskill, and representing the division between the Devonic 

 and Siluric systems. 



The rock formations of Erie county can be traced far to the 

 eastward through the state. Some disappear west of Seneca 

 lake. Others persist as far as the Hudson river. Nearly all 

 are thicker at their eastward extension than in their Erie county 

 exposures. Westward the formations in the middle of the section 

 are terminated by Lake Erie under whose waters they disappear. 

 The most northern formations cross Niagara river and enter 

 Ontario then bend southward under the lake and reappear in 

 northern Ohio. The most southern formations in the county, 

 the strike of which is parallel to the south shore of Lake Erie, 

 extend across northwestern Pennsylvania and northern Ohio. 



Camillus Shale. 



This thick formation of the upper Salina beds, named from 

 Camillus, in Onondaga county, should be the surface rock of all 

 that portion of Erie county north of a line connecting Buffalo 

 and Akron. It is, however, almost entirely covered with drift 

 and is occupied in this county by the southern side of the wide 

 valley of Tonawanda creek. Few outcrops are visible and these are 

 insignificant representatives of the great formation which is 

 concealed from view. Eastward it extends as far as Albany 

 county. 



The Camillus shale is limited below by the Guelph dolomite 

 of the Niagaran group. Above, it merges into the more calcareous 

 and magnesian layers of the Bertie limestone which it joins 

 without any definite line of demarcation. 



In its eastward extension it is characteristically a grayish-green 

 shale, weathering to a light pink. It contains gypsum in nodules 

 and in thick beds. 



A few of its upper layers may be seen on the Canadian side 

 of the Niagara river below the International bridge and at the 

 southern end of Grand Island. Lower beds are exposed at 

 Edgewater on the eastern side of Grand Island. Irving Bishop 

 has described these exposures as follows: 



