226 



Repokt of the State Geologist. 



West of the Genesee river, however, several salt wells are located south 

 of the upper line of the Portage sandstones, which since 1842 have been 

 regarded as the top of the Portage group. 



In Wyoming county there occurs immediately overlying the sandstones a 

 bed of soft, light, bluish-grey shales nearly 100 feet thick, with concretionary 

 calcareous layers at frequent intervals, and a few thin layers of bituminous 

 black shale, the whole mass resembling strongly the grey band at the base of 

 the Portage. Fossils are exceedingly rare, and such as do occur are nearly 

 all of the same species as are found in the Portage soft shales. This bed is 

 well exposed at Wiscoy and in some small ravines on the eastside of the 

 Genesee valley in the vicinity of Rossburg. 



Above these beds a succession of sandstones and shales come in that con- 

 tain typical Chemung fossils abundantly. 



The geologic horizon of the mouths of the salt wells at Silver Springs, 

 Bliss, Eagle and Castile is in the lower part of the Chemung group. 



