154 



Annals of the Carnegie Museum. 



Cayuga Lake section which lies above'the Encrinal limestone, and 52 

 in the corresponding strata of the Livonia section. The three have 

 40 species in common. These facts show that our faunule was a very 

 typical one for the region and made ii]) principally of the common 

 species. 



There aie 34 species which are common to our faunule and the 

 Chenango to Albany counties composite fauna, while there are 60 

 forms common to the Eighteen Mile Creek section and this faunule. 

 With the fauna of the Thedford section there are only 31 species in 

 common, showing that if this is not an eastern fauna, it is not a west- 

 ern one, but is more nearly allied to the faunas from Eighteen Mile 

 Creek, Livonia and Cayuga Lake. 



The present faunule has no dominant species which ally it to any 

 particular faunule of the detailed sections of Cleland or Grabau. The 

 abundance of Crystodicia inscisuraia suggested that this faunule might 

 be compared with the Stictoponi faunules of Grabau and Cleland. 

 That faunule occurs in a one-inch bed of shale just below the Encrinal 

 limestone at P^ighteen mile Creek and in the top zone (Zone Y) of 

 Cleland's section at Cayuga Lake. The s])ecies may be compared by 

 classes as follows : 



Stictopora Faunule. 



Class. 



18 Mile Creek. 



Canandaigua Lake. 



Cayuga Lake. 



From this table it is seen that all three faunules are rich in brach- 

 iopods and poor in cephalopods and gastropods. In the matter of 

 pelecypods there is not a close agreement, the Cayuga Lake Stictopora 

 faunule having a much greater proportion than the others. At 

 Cayuga Lake, 31 per cent, of the number of species are lamellibranchs, 

 while at Canandaigua Lake it is reduced to 14 per cent, and at 

 Eighteen Mile Creek to 13 per cent. The last two agree very closely 

 in this class as in the other mollusca. There are twenty-five species 

 which are common to all these faunules. These are : 



