ITHACA FAUNA OF CENTRAL NEW YORK 



BY JOHN M. CLARKE 



In connection with the studies recently made and published of the 

 western New York fauna of Portage time and with the publication 

 of the Tully, Watkins and Elmira maps whereupon the Ithaca forma- 

 tion is extensively represented, a more complete statement than has 

 heretofore been made of the complexion of the true Ithaca fauna be- 

 comes of special interest. The relations of this fauna to contempo- 

 raneous faunas east and west have been frequently stated by the 

 writer. Briefly recapitulated they are thus: 



Portage time and sedimentation in New York involved very 

 marked geographic distinctions ; at the east was, during its earliest 

 stage, a marine fauna quickly followed by a lagoon deposition known 

 as the Oneonta sandstone. Continuous with these beds through 

 Chenango, Cortland and Tompkins counties are the true Ithaca beds 

 carrying the littoral marine fauna here set forth ; these beds being 

 interleaved with the Oneonta deposits eastward and the true Portage 

 or Naples beds westward. The latter contain an invading and deeper 

 water fauna having nothing in common with that of the Ithaca beds 

 and its composition has been set forth in detail in the i6th Annual 

 Report of the Nezv York State Geologist and Museum Memoir 6. 



Till lo or 12 years ago a singular and deplorable misapprehension 

 of the significance of the Ithaca fauna prevailed and was inadver- 

 tently countenanced in some of the volumes of the Palaeontology of 

 New York. Its fossils, lying well above the horizon of the Hamilton 

 shales of central New York were in many instances described as of 

 the Hamilton fauna, and it is to the work of Prof. C. S. Prosser that 

 we owe the first rectification of these errors and the return to 

 Vanuxem's original conception of the place of the Ithaca fauna. 

 Subsequently Prof. Prosser and the writer at first together and 

 afterward independently further exploited these rocks, the former 

 more specially east of the Chenango river and the latter westward 

 therefrom. Both have incorporated, in the several descriptive ac- 

 counts published by them in the reports of the state geologist, lists 



