454 
[Assembly 
Ludlowville Shale, 
(upper part.) 
(lower part.) 
Compact, calcareous 
blue shale. 
Black Shale, (pyri- 
tous.) 
Marcellus Shale. 
Dark, or olive Shale. 
Seneca Limestone. 
Atrypa concentrica, Leptssna, Delthyris, Cala- 
mopora Gothlandica, Favosites, Cyathophyl- 
lum, several species. 
Several species of Pterinea, Strophomena ca- 
rinata. 
> A few undetermined species are peculiar to 
5 this mass. 
\ Posidonia lirata, Orbicula, (small,) Orthis — , 
> Pterinea , Leptaena Spinulosa ? 
Orthis 
Delphinula 
Onondaga Limestone 
I Strophomena lineata, Cytherina — , Favosites. 
"I Icthyodorulite, Odontocephalus selenurus(A5a- 
I phus selenurus,) Calymene bufo, or C. ma- 
y cropthalma, Atrypa Wilsoni, Strophomena 
I rugosa, Leptasna indenta, Cyathophyllum 
J ceratites, Favosites. 
\ Ichtyodorulites. The characteristic fossils, 
* Oriskany Sandstone. > Atrypha elongata and Delthyris arenosa, are 
) not found in this rock in the fourth District. 
Hydraulic Limestone. ^ 
Gypseous marls and. 
shales, or Ononda- 
ga Saliferous group. 
Red Shale. 
Lockport Limestone. 
Orthis, Cytherina, Tentaculites, — usually in 
the upper portions of the mass. 
A thin shelled bivalve has been found in the 
rock overlying the plaster beds in Genesee 
county. 
Seen only in the eastern part of Wayne county. 
Catenipora escharoides, C— — ,t Calamopo- 
ra fibrosa, Cyathophyllum ceratites. Several 
other coralline fossils are peculiar to this 
rock. In its eastern prolongation, this rock 
is characterized by a species of Delthyris 
and Cytherina. 
* In some places in the 4th District, this rock consists of a few inches of coarse 
sandstone or conglomerate, between the hydraulic limestone and the Onondaga lime- 
stone. 
t This is an nndescribed species, entirely distinct from C. escharoides, found in the 
Limestone in Ogden, Monroe county. 
