REPORT OF THE STATE PALEONTOLOGIST 1901 653^ 



The blending of these two different faunas can be seen to best 

 advantage in the townships of Oneida and Xorth Cayuga, Out., 

 where there is a sandstone filled with late Oriskany fossils. 

 The sandstone rapidly passes into a sandy limestone and then 

 into the typical Onondaga limestone. If it were not for the 

 structural dissimilarity of the beds, these two faunas could not 

 be separated, since it has been shown that out of 71 species 

 found here, not less than 42 pass up from the lower horizon 

 into the Onondaga;^ yet the lower horizon has such characteristic 

 Oriskany species asSpirifer arenosus, Ohonostro- 

 phia complanata, Rhipidomella musculosa, 

 Stropheodonta magniventra, S. vascularia, 

 Eatonia peculiar is, etc. On account of the marked 

 Onondaga aspect of its fauna, it is unwise to call this Ontario 

 deposit Oriskany any longer, and we here propose to call it the 

 Decewville formation, taking the name from the village nearest 

 to its exposures. We include in the formation the coarse basal 

 sandstone and the thin bedded sandy limestones up to where 

 the typical Onondaga limestone appears. 



A careful analysis of the Schoharie grit fauna of eastern New 

 York, and of the Pendleton sandstone of Indiana- will probably 

 also show a blending of the invading Oriskany and Onondaga 

 faunas, though probably less marked than it is at Decewville 

 Out. 



A further instance, or rather, a survival of the blending of the 

 Oriskan}'- and Onondaga faunas, is shown at Clarence Hollow 

 N. Y., where Spirifer arenosus (described as S. u n i c a 

 Hall) occurs in the Onondaga limestone. 



By the time the Onondaga invasion had become established 

 in the MississipjDian province, the Cumberland basin, including 

 its last remnant, the Oriskanian channel already discussed, had 

 been wholh^ emerged, thus cutting off all communication with 

 the Atlantic in this region. This severance, however, was of 



' Schuchert. N. Y. state geol. 8th an. rep't. 1889. p. 51-54. Also Geol. 

 soc. Am. Bui. 1900. 11:323-26. 

 ^'Siebentlial. lud. dep't geol. and nat. res. 25th an. rep't. 1901. p. 347. 



