16 PALEOZOIC PALEONTOLOGY. 
Eecyliomphalus subelliptica n. sp. 
Polygyrata sinistra n. sp. 
Platyceras? columbiana n. sp. 
Cyrtoceras sp. undet. 
Isotelus canalis (Whitf.). 
Tllenurus columbiana n. sp. 
Bathyurus? sp. undet. 
This fauna contrasts sharply with the Cambrian fauna of the Kitta- 
tinny limestone, by reason of the predominance of gastropods, a char- 
acteristic in which the fauna agrees with that of the Beekmantown 
limestone of New York in most of its localities. 
Of the species identified with already-described forms, two, Syntro- 
plia lateralis and Isotelus canalis, occur in the beds of Beekmantown 
age at Fort Cassin, on Lake Champlain. One species, Dalmanella 
electra, was described from the Levis beds of similar age on the St. 
Lawrence river, near Montreal. Dalmanella wemplet was described 
from the same horizon at Fort Hunter, New York, in the Mohawk 
valley; this species, however, is closely allied to, and perhaps should 
he considered as identical with, D. macleodi (Whitf.), from the typical 
Beekmantown limestone at Beekmantown, New York. Jllenurus 
columbiana, also, occurs at Fort Hunter, New York, but has been 
described from there under another name. Cyrtolites sinuatus was 
originally described from the Pogonip limestone of Nevada. Aside 
from these species, which are identical with forms in the Beekman- 
town limestone of New York and Canada, all of the new species de- 
scribed have their nearest allies in the same fauna, and there can be 
no question whatever as to the correctness of the correlation of the 
beds at Columbia with the Beekmantown limestone of New York. 
TRENTON LIMESTONE. 
In the Kittatinny valley and in most of the outlying areas, aside 
from the Green Pond mountain region, two conspicuous rock forma- 
tions are met with. One of these is the great magnesian limestone 
series already described under the name Kittatinny limestone, and 
the other is the Hudson River slate, whose outcrop covers a consider- 
ably greater area than does the limestone. Wherever the normal 
sequence from the great limestone formation to the slate is present 
in New Jersey, a much less conspicuous limestone formation may 
