66 Cincinnati Society of Natural History. 
BRACHIOPODA. 
Crania scabiosa Hall. (c) Trematis millepunctata Hall. 
Rafinesquina alternata Conrad- Zygospira modesta Say-Hall. (c) 
Emmons. (c) 
PELECYPODA. 
Byssonychia radiata (Hall). (c) Ctenodonta obliqua Hall. 
GASTROPODA. 
Cyclora depressa Ulrich. Lophospira tropidophora (Meek). 
“hoffmanni Miller. Microceras inornatum Hall. (c) 
S minuta Hall. (c) Protowarthia cancellata (Hall). (c) 
“ parvula Hall. 
CEPHALOPODA. 
Cameroceras sp. (proteiforme Hall?). 
VERMES. 
Nereidavus varians Grinnell. 
CRUSTACEA. 
Aparchites minutissimus (Hall). Bythocypris cylindrica (Hall). 
Asaphus gigas DeKay. Calymmene callicephala Green. (c) 
ee maximus Locke. Ulrichia nodosa Ulrich. (c) 
Bollia persulcata Ulrich (c) 
POSITION UNCERTAIN. 
Arthraria biclavata Miller. Pasceolus globosus Billings. 
Bythotrephis gracilis Hall. Rusophycus bilobatum Vanuxem. 
ss gracilis-crassa Hall. 
The Utica Group. 
The Utica group in its typical exposures in the State of 
New York is described as consisting of black bituminous 
slates with a thickness at Utica, New York, of over 600 feet.* 
The Utica in northern Ohio, as revealed by drillings from the 
wells at Findlay and other places, is a black shale. Prof. 
Orton,f comparing the records of drillings, finds that the 
Utica or black shale thins out towards the south as the Ohio 
River is approached, but the overlying Hudson River shales, 
as he calls them, are increased in thickness. The thickness 
* Walcott, C.D. The Utica Slate and Related Formations. Trans. Albany Insti- 
tute, X, 1879, p. 1. — 
+ Geol., Ohio, VI, p. 8. 
