No. 50.] 
371 
Trenton limestone. This Hmestone is usually in thin layers, of a 
black, dark and a light grey colour. The layers are generally separated 
by black shale or slate, and to which the colour of the rock is owing. 
This hmestone is abundant, and is found in the counties of Montgomery, 
Fulton, Herkimer, Oneida and Lewis. On the Mohawk its thickness 
rarely exceeds 30 feet, but increases through Oneida and Lewis, being 
300 feet in the north part of the latter county. 
Being the only rock at Trenton falls, it from thence derives its name. 
There are two divisions of this rock, the dark which is the lowest 
mass, and the grey which is the upper mass. This latter is less abun- 
dant and is principally found in the towns of Trenton, Floyd and Steu- 
ben of Oneida, and Newport of Herkimer. The Trenton limestone is 
loaded with the remains of animal life. In the preceding rocks there 
was but the dawn, but in this the full existence for the kind. 
Of the Crustacea we have Isotelus gigas, L Cyclops, Cryptolithus 
Tessellatus, Asaphus tuberculatus, Calymene blumenbachii, Ceraurus 
pleurexanthemus and Illanus perovalis ? 
The Testacea are Strophomena deltoidea, S. alternata, S. semiovalis, 
Delthyris microptera, D. pecten, Orthis' glabella, O. testudinaria, 
Lingula ovata, Orbicula , Bellerophon apertus, Pleurotoma- 
ria cirriformis, Trocholites ammonius, Phragmolites compressus, Con- 
ularia quadrisulcata, Orthoceras duplex, O. striatum. 
The Polyparia are Trianisites cliiOfordii, Columnaria sulcata, Cya- 
thophyllum ceratites, Gorgonia. 
Of Plants. Fucoides dentatus. 
These are but a part of the many fossils which have been obtained 
from the Trenton limestone, but these are all that have as yet been 
identified and named. In this rock is the Lead mine of Martinsburg and 
the supposed silver mine of Lowville. 
Black slate or shale. There is no mineralogical difference between 
the shale which separates the dark coloured layers of the Trenton lime- 
stone and this rock, but though in many localities it contains thin beds 
or flags of limestone in the lowest part of its mass, yet we often find 
above these thin beds, a thickness of two or more hundred feet, without 
any limestone whatever. A separation therefore was necessary. 
