Clarke — Onkonta, Ithaca and Portage Groups. 



51 



ton fauna " lying not far below the " Ithaca fauna " (as restricted by Williams), 

 is such a reappearance of strong Hamilton types as w e have observed in even 

 greater force at a lower horizon in the rocks both at South Otselic and at 

 Norwich, and is not in any sense out of harmony with the rest of the fauna 

 which is, in the main, a similar recurrence of Hamilton types. Williams's 



Chemung 



G'C N E5tE SLATE 

 Figure 5. 



" Ithaca fauna " is that part of the more easterly fauna which conies in above the 

 horizon of Spirifer tnesastriaUs, a division w hich is of local significance as, in 

 the counties to the east, Cortland and Chenango, Spirifer ines<istri<ilix having 

 once appeared, manifests itself throughout all higher beds of the formation. 

 A comparison of the succession at Ithaca with the results w e have obtained 

 in Chenango and Cortland counties indicates a general equivalence exemplified, 



