60 NEW YORK STATE MUSEUM 



c 1 a r k e i Hall. Over this surface f*or a brief period flourished 

 a plantation of these crinoids and their substance has largely con- 

 tributed to the lime content of the rock containing them. 



Standish shales and flags 

 Fauna very spa^rse and chiefly that of the beds below. 



Bactrites aciculum Hall? 

 Gephyroceras sp. 

 Pleurotomaria cognata Clarke 



Pterochaenia fragilis Hall 

 Ontaria suborbioularis Hall 



Middlesex shale 



These densely bituminous deposits, similar in all respects to 



the Genesee shale bear only the miost meager evidences of organic 



life. Indeterminable plant remains occasionally appear and with 



them are: 



Conodonts I Ontaria suborbicularis Hall 



Sandbergeroceras syngonum Clarke \ 



The affinity of the fauna with that of the Cashaqua shales is 



herein evident. 



Cashaqua shale 



In these soft shale beds, with their accompanying flags and 

 sands, the peculiar western Portage fauna attains its culmina- 

 tion. This interesting congeries of fossils has been termed the 

 Naples fauna for it is here that it attains its best development. 

 The term has been employed because of the indefiniteness of the 

 term Portage as applied to the fauna, for the faunas existing 

 in Portage time are known to differ highly according to their 

 geographic location; brackish in eastern New York (Oneonta), a 

 profuse brachiopod fauna in central New York (Ithaca) and in 

 western New York a fauna essentially devoid of brachiopods 

 but characterized by its abundance of cephalopods and lamelli- 

 branchs. In our latest studies of this fauna in its extent 

 throughout western New York it has become evident that, in 

 this western Portage province covering the field occupied by the 

 fauna from Cayuga lake west to Lake Erie, the Genesee prov- 

 ince as it has been designated, there are actually two subprov- 



