384 New York State Museum 



the Schoharie grit has a thickness of five or six feet; 

 in the northern Helderberg and Capital District area it 

 varies from nothing to a thickness of about eight feet. 

 Farther east, or southeast, it thickens. A thickness of 

 about 100 feet has been found in the Catskill area and 

 there it is more of a fine-grained impure limestone (Chad- 

 wick). At Becraft mountain 150 to 200 feet of shale 

 are referred to the Schoharie, because some of the char- 

 acteristic fossils have been found in it, though in rock 

 aspect the shale is more similar to the Esopus. The 

 variable occurrence of the Schoharie grit and its charac- 

 ter in the northern Helderberg and Capital District area 

 suggest that it is a sandy facies of the Onondaga. Not 

 only is it found merging into the overlying Onondaga, 

 with the lower Onondaga somewhat sandy, but inter- 

 fingering of the grit and the limestone has been ob- 

 served and fossils (corals and cephalopods) have been 

 found passing freely across the welded contacts. On 

 the other hand disconformities at the top and bottom of 

 the Schoharie grit, indicated by the presence of glau- 

 conite have been reported from the Catskill region (Chad- 

 wick). Thin as the formation is, the wealth of fossils 

 in the Schoharie grit is astonishing. In this fauna occur 

 species of the corals Zaphrentis and Streptelasma, the 

 brachiopods Atrypa impressa, Pentamerella arata, Meris- 

 tella nasuta, Strophonella ampla, Stropheodonta demissa, 

 Leptostrophia perplana, Rhipidomclla alsa, Delthyris 

 raricostata, Chonetes hemisphericus; the pelecypods Pan- 

 enka dichotoma, Conocardium cuneus, Goniophora peran- 

 gulata; the gastropods Bellerophon pelops and Pleuroto- 

 mar'xa arata; the cephalopods, Orthoceras thoas, O. 

 pelops, O. sens, etc., Cyrtoceras eugenium, Trochoceras 

 eugenium and T. clio; the trilobites Dalmanites anchiops 



