PART 1 1. 



THE UPPER DEVONIAN OF SOUTHERN NEW YORK. 



Subdivisions. 



The Portage Group. — Many local names have been applied 

 to the rocks of this group on account of their varied appearance 

 at different localities. At base, from Chenango river westward 

 to Lake Erie, is the Genesee shale, a thin-bedded, fragile, shah- 

 mass, varying in thickness from a few feet only in the east to 125 

 feet in central New York. Its fossils are few and generally 

 small, and mainly confined to the basal and upper layers. (See 

 Fig's. 1-9, Pl.V. ) Fish remains are reported from these shales on 

 the shore of Lake Brie and at a few other localities. 



Above, are the Sherburne shales and sandstones in the east, 

 the Lower Portage shaly sandstones of Cayuga lake section, the 

 lower Cashaqna and Gardeau shales (Naples beds) and sandstones 

 of the Genesee section and west to Lake Erie. Thickness, 150- 

 250 feet. Fossils, rare: Chonetes,Cardiola, Eunulicardium , Clad- 

 ochonus, etc. See Pl.V and VIII. 



Still higher up in the Portage are the Ithaca beds of the 

 Cayuga section and to the east, 300-500 feet thick, represented 

 farther west by the upper Naples beds. Very fossilferous from 

 Ithaca eastward. See Plates V-VIII. Somewhat fossiliferous 

 westward, though bearing a very different fauna, especially char- 

 acterized by coiled Cephalopods and fish remains. 



