64 NEW YORK STATE MUSEUM 



Much more distinct is the difference between the Snake Hill beds 

 and Canajoharie beds in the nongraptolitic portion of the fauna; 

 for the former formation contains a great number of species that 

 have not been observed in the Canajoharie beds, the most important 

 of which are Edrioaster saratogensis, Cara- 

 bocrinus, Orthis (Plaesiomys) retrorsa, 

 Parastrophia hemiplicata, Zygospira recurv- 

 i r o s t r i s , the many species of lamellibranchs, the trilo- 

 bites Eoharpes ottawensis, Proetus undulo- 

 s t r i a t u s, also Pollicipes siluricus, Techno- 

 phorus cancellatus, and the ostracods. On the other hand, 

 the Canajoharie beds also contain a number of species not found in 

 the Snake Hill beds, as Hyolithes pinniformis, 

 Pterinea (Prolobella?) trentonensis and 

 Pterinea insueta and a number of ostracods ( U 1 r i c h i a ? 

 bivertex, Primitia unicornis). 



When we now turn to the question of the relative position of the 

 Snake Hill beds to the Canajoharie beds, we find several lines of 

 evidence. 



1 The common occurrence of a great number of fossils in both, 

 which are absent above and below these two formations, as D i p 1 o - 

 graptus amplexicaulis and Corynoides cali- 

 c u 1 a r i s , would indicate that both are either subdivisions of one 

 formation or were deposited nearly contemporaneously in adjoining 

 areas. If they are subdivisions of one formation, the faunal evi- 

 dence would indicate that the Snake Hill beds are the older forma- 

 tion, for they contain in Cryptograptus tricornis, Cli- 

 macograptus caudatus, C. s ch a r e n b er gi , Plae- 

 siomys retrorsa, Parastrophia hemiplicata, 

 Edrioaster, Eoharpes ottawensis, etc., elements that 

 indicate early Trenton or Black River age. 



2 Geographically the belt of Snake Hill shales lies between the 

 Canajoharie shales on the west and the Normanskill shales on the 

 east. Although the complex folding and faulting of this region is 

 little favorable to the drawing of inferences from the relative posi- 

 tions of the belt, the general observations noted in. Bulletin 42, that 

 the older rocks are found in the east and the beds as a rule become 

 successively younger toward the west in the overturned and over- 

 thrusted closed folds have thus far proved correct. On the east side 

 of Saratoga lake the Snake Hill and Normanskill shales become 



