REPORT OP THE STATE PALEONTOLOGIST 1901 667 



Naturally its fauna includes some Helderbergian species, partly 

 picked up in its travels hither from Gaspe' and partly found on 

 the ground on its arrival in New York. As pointed out in our 

 previous studies of this fauna, its species trangressed for a very 

 brief period the eastern limits of calcareous deposit and spread 

 themselves westward over the irregular, deeply embayed and 

 probably rocky coast line of central New York and Ontario. 



Onondaga fauna 

 Primarily this fauna is of reef-building corals, and entered 

 the state from the west, where its reefs and attendant organ- 

 isms attained their greatest prolixity. The lessening and dis- 

 appearance of the coral facies eastward and the final loss of the 

 limestone deposit evince this derivation. Any submarine bar- 

 rier in the east however was so deeply submerged at this epoch 

 as not to interfere with the deposition of chert-bearing lime- 

 stone in Columbia county east of the Hudson river. The east 

 presents in the arenaceous beds of the Cauda-galli and Scho- 

 harie grit a facies which is not elsewhere seen. In clastic 

 character, there is excellent reason for associating these beds 

 directly with the deposition of Oriskany sediments as 

 a closing stage thereof, and indeed several elements of 

 the striking Schoharie fauna indicate derived relations to the 

 Oriskany. This might be predicated of the trilobites specially, 

 of the brachiopods and lamellibranchs in part, but not of the 

 most conspicuous element of the fauna, the cephalopods. For 

 the origin of the latter we have yet to search; they may have 

 entered New York from the west with the fauna of the lime- 

 stone and have wandered into the shallow waters where Scho- 

 harie sediment was depositing; they may have, on the other 

 hand, come in from some source, northeast or southeast, as yet 

 unknown to us, and hence be related ancestrally to similar forms 

 of the overlying Onondaga limestone. Present evidence seems 

 to favor the former conclusion without disparagement to the 

 genetic relations of these cephalopods to those of the Onondaga. 

 It seems justifiable however to assert that the fauna of the 

 Onondaga period as a whole, with its noteworthy coral, trilo- 



