436 A. W. GRABAU THE SHERBURNE SANDSTONE 



The pelecypods likewise show the Hamilton character. Of these 

 Palceoneilo constricta is the most frequently found, the next being Nucu- 

 lites ohlongatus. Other species occurring more than once are Leda di- 

 ver sa (2) ; Cypricardella tenuistriata (2) ; Liopteria deJcayi (2) ; Nucu- 

 lites triqueter (2) ; Goniophora hamiltonensis (2) ; Pterinea flahella (2) ; 

 Pterinopecten vertumnus (2) ; Nyassa arguta (2) ; Tellinopsis subemar- 

 ginata (2) ; Ortlionoia undulata (3) ; Actinopteria hoydi (3). 



Of other species only Tentaculites hellulus, Coleolus tenuicinctum, 

 Belleropkon cf. leda, Homalonotus dekayi, and Tceniopora exigua occur, 

 the first twice, the others in only one section each. 



The table shows that out of the 59 species identified from the eastern 

 Sherburne, 54, or about 91 per cent, are characteristic Hamilton fossils. 

 Of the 5 remaining species, three brachiopods — Spirifer mesistrialis, 

 Crania Jeoni, and Camarotoechia stephani — are doubtfully identified, 

 while the other brachiopod, Liorliynclius mesicostalis, occurs in only one 

 locality and is rare. Moreover, this may be a local development of the 

 specific character from L. multicosta by the obsolescence of the lateral 

 plications. The only post-Hamilton pelecypod Modiomorpha subalata 

 var. chemungensis, of which only a single specimen was found, and that 

 not of the typical form. Thus this eastern Sherburne fauna may be re- 

 garded as a persistent Hamilton one. 



The Sherburne Horizon "West of the Chenango Yalley 



Westward from the Chenango Yalley, to the meridian of Cayuga Lake, 

 the "Lower Portage'^ beds which overlie the Genesee are for the most 

 part sandstones and represent the horizon of the Sherburne, by whicli 

 name they have come to be known. On Cayuga Lake these beds exhibit 

 the remarkable jointing which Yanuxem, Hall, and Dana have illustrated 

 and which has generally been regarded as the best example of prismatic 

 jointing in stratified rocks. The thickness of these Lower Portage beds 

 is approximately 250 feet. 



The fauna which has so far been obtained from these beds is listed in 

 the second column of the table on page 437. The list is compiled from 

 the studies of Kindle on this region, which is perhaps the most ex- 

 haustive so far made.^^ The Ithaca species of the type section are also 

 included in the first column of this list. In the third column are given 

 the species which also occur in the Sherburne east of the Unadilla region, 

 while the fourth column shows those which occur in the Hamilton beds 



-3 Bull. Am. Pal., vol. ii, December. 1806. Also, "Note on the range and distribution 

 of ReticKlaria Iwvis." .Tourn. Geol.. vol. 14. 1906, pp. 188-19.3. 



