NEW YORK STATE MUSEUM 



50 



Centerfield limestone 



Profusion of Trilobites representing 

 all species of the Hamilton fauna 

 except Homalonotus d e - 

 kayi. Cirripedes and Schizodis- 

 cus 



Cephalopods rare or absent 

 Bellerophon pelops 



Platyceras c 



Pleurotomaria lucina 

 P. disjuncta 



Actinopteria decussata 



Lingulas c 



Pholidostrophia nacrea cc 



Leptostrophia perplana r 



Spirifer divaricatus 



Corals very abundant forming a well 

 marked plantation 



Canandaigua shale 



Trilobites relatively rare, the only 

 common species Phacops 

 ran a, Dalmanites booth i, 

 Proetus macrocephalus, 

 H. d e k a y i . Other Crustacea, 

 except ostracodes rare or absent 



Orthoceras, Gyroceras, Bactrites, 

 Tornoceras 



B. leda 

 B. lyra 

 B. acutilira 



Platyceras cc 



Diaphorostoma lineatum c 



Murchisonia 

 Alacrochilus 

 Cyclonema 



Modiomorpha complanata 

 M. concentrica 

 M. macilenta 

 Goniophora acuta 

 Grammysia arcuata 

 Palaeoneilo constricta, emarginata, 

 fecunda, plana, tenuistriata 



P. nacrea r 



L. perplana cc 



Trematospira nobilis 

 Athyris spiriferoides 

 Trigeria lepida 

 Tropidoleptus carinatus 

 Corals quite rare 



Future investigations may obliterate some of these differences 

 yet there will doubtless remain a distinction in the upper and 

 lower elements of this fauna though these are bound together 

 by a multitude of identities. 



Tichenor limestone 



Fossils are extremely few in this layer of semicrystallirie <*;vax 

 limestone. They arc frequently replaced wholly or in part by 



