GEOLOGY OF THE ATTICA AND DEPEW QUADRANGLES 29 



the characteristics of the sandstones at the type locahty to 125 to 

 150 feet on these quadrangles and of these some are less compact. 

 Fossils (except lignites) are rarely found in the sandstones and 

 there are very few in the shaly partings. The following forms, 

 collected at Portageville, constitute the fauna of the Nunda sand- 

 stones in this region : 



Manticoceras oxy Clarke 

 M. rhynchostoma Clarke 

 Orbiculoidea sp. 

 Cladochonus sp. 

 Crinoid stems 

 Fucoids 



Exposures. The Nunda beds are well exposed in but two local- 

 ities on these quadrangles. The entire section may be seen in the 

 bed and sides of the upper part of a ravine in the hillside west of 

 Varysburg, and at the highway bridge over the Stony Brook gorge 

 2 miles east of Varysburg. There are small outcrops near South 

 Attica, also on Poland hill and west of Persons Corners. 



WISCOY SHALES 



This formation, named from its exposure at the falls of West 

 Coy creek at Wiscoy in the Genesee River valley, is composed at 

 the type locality of a band of black shale 20 feet thick at the base, 

 succeeded by 150 to 170 feet of light soft shale resembling the 

 Cashaqua beds, with thin bands of black shale and a few thin layers 

 of hard and soft sandstones. Calcareous concretions are common 

 at some horizons. 



The formation is capped by a band of hard, calcareous sand- 

 stones, containing brachiopods, that produces in the bed of the 

 Genesee river a small cascade known as Long Beards riffs. These 

 beds were formerly considered as belonging to the Chemung group, 

 but their close resemblance lithologically and in the character of 

 their fossils, to the Cashaqua beds, and the entire absence of the 

 brachiopods that distinguish the Chemung rocks, have been deemed 

 sufficient grounds for their description as a separate formation. 



Fossils. The following species occur at Wiscoy: 



Manticoceras oxy Clarke 

 Orthoceras sp. 

 Pleurotomaria sp. 

 Hyolithes neapolis Clarke 

 Buchiola rctrostriata (roi Buck) 



