79 



is of very limited thickness and is exposed, over a small 

 area only, in the eastern part of the region. 



The Onondaga (Corniferous) is the chief Lower Devo- 

 nian formation: it consists largely of limestone which is 

 highly fossiliferous in places. This formation forms the 

 greater part of the province west of the Salina boundary : it 

 is divided into two areas by a broad belt of Middle Devo- 

 nian strata (Hamilton) which overlies it. This belt 

 consists largely of shales with some intercalated lime- 

 stones and presents, in places, an extraordinary profusion 

 of excellently preserved fossils. 



The highest member of the Devonian series in Ontario 

 is exposed on the shore of Lake Huron near the south end. 

 The rocks are highly bituminous shales, but fossils are 

 rare or confined to a few obscure plant remains. The 

 rocks are commonly ascribed to the Genessee shale of the 

 Portage and Chemung formations of the New York 

 geologists. 



It will be seen from the above sketch that the inter- 

 esting formations from a palseontological point of view 

 are the Guelph, the Onondaga and the Hamilton. The 

 excursion is planned to afford an opportunity for collecting 

 on these formations as below : 



Oriskany and Onondaga — Hagersville and vicinity. 

 Hamilton — Thedford and valley of Aux Sables river. 

 Guelph — Guelph, Hespeler and Gait. 



TABLE OF FORMATIONS. 



The Silurian and Devonian formations of western 

 Ontario are as follows: 



Upper Devonian — Genesee shales. 

 Middle Devonian — Hamilton. 



j Onondaga. 

 Lower Devonian [Oriskany. 



[Upper Monroe. 

 Upper Silurian jSylvania. 



I Lower Monroe. 



(Salina. 

 Middle Silurian \ Guelph. 



(Niagara. 



