450 A. W. GRABAU THE SHERBURNE SANDSTONE 



tribiited between the Chenango Eiver and the Schoharie Yallev on the 

 north and the Port Jervis region on the sonth. In Table III, pages 452- 

 459, these species are listed first for Chenango and Cortland counties 

 according to Clarke, and then under six headings which represent the 

 localities from west to east studied by Prosser, as follows : 



1. Chenango Valley. 



2. Unadilla Valley. 



3. Susquehanna Valley. 



4. Charlotte Valley. 



5. Schoharie Valley. 



6. Green County and Port Jervis region. 



In each of these six groujDS, the first column shows the number of 

 localities from which the species has been reported, and the second the 

 summarized abundance for that group of localities. In the next five 

 columns the occurrence in other formations is given, while the last group 

 of columns represents an analysis as to the origin of the various elements 

 of the fauna. 



It should be noted that the Ithaca fauna ranges through several hun- 

 dred feet of strata in the western sections, but becomes more and more 

 restricted as we approach the Schoharie region, where the continental 

 Oneonta beds appear at successive lower horizons. 



On the east side of the Schoharie Valley, in Moheganter Hill, the 

 Ithaca is scarcely represented by fossiliferous beds, there being a few 

 strata with fragments of fossils of this horizon, above the coarse sand- 

 stones referred to the Sherburne and below the red beds of the Oneonta, 

 which latter type of sedimentation here begins lower than it does farther 

 west, as demonstrated by Prosser. Even on the west side of the Schoharie 

 Valley the Ithaca is better developed, covering the high part of the 

 plateau to the south of Panther Creek and west of the Schoharie Eiver, in 

 the southern part of Fulton township. Except for the abundant repre- 

 sentation of Spirifer mesistrialis Hall, the fauna is essentially a Hamil- 

 ton fauna. A remnant of the Ithaca fauna of a pure Hamilton aspect is 

 found in the Catskill Creek section in Green County, where the following- 

 species occur 470 feet above the first appearance of the red beds of the 

 Oneonta type (Prosser, p. 270) : 



1. Spirifer wucronatus (small)'* (c) 



2. Schuchertella clieinringcnMs arcfnstriata (a) 

 .3. TropidoJeptus carinaiiis (r) 

 4. Homalonotus delcapi (rr) 



2s Probably Mucro))otus posterns. 



