186 



GEOLOGY OF THE THmD DISTRICT. 



28. CATSKILL GROUP. 

 Montrose and Oneonta Sandstone of the Reports ; Old Red Sandstone of England. 



(No. 9. Pknnbtlvania Survey.) 



No. 1. CaUkill cyprieardite (C. catskillensis). 



No. 2. Narrow cyprieardite (C. angustata), two views. 



This group is confined entirely to the counties of Otsego, Chenango, Broome and Tioga. 

 In the latter county, it is found only on the south side of the Susquehannah river. Being the 

 terminal group of the New- York series, it therefore holds the highest position relatively to the 

 other rocks, and caps some of the elevations of the four above named counties. 



The group in the district consists of light-colored greenish grey sandstone, usually hard ; 

 of fine grained red sandstone, red shale or slate ; of dark colored slate and shale ; of grindstone 

 grit ; and a peculiar accretionary and fragmentary mass, appearing like fragments of hard 

 slate, cemented by limestone. This mass, though usually but a few feet in thickness, where 

 it is thickest in the district, is a constant associate of the group. It has not yet received a 

 name with us, but is well known in England by the name of cornstone ; and there also, from 

 what we read, it is confined to this group. 



