WILLIAM B. DWIGHT. 75 
@ 
: 
Prof. William B. Dwight gave a report of some recent 
discoveries by himself, as follows: 
DISCOVERY OF A LOCALITY OF TRENTON LIMESTONE, RICH 
IN OSTRACOID ENTOMOSTRACA AND OTHER FOSSILS, 
AT PLEASANT VALLEY, N. Y. 
While making field explorations at Pleasant Valley, 
six miles northeast of Poughkeepsie, during the autumn 
of 1887, I found a locality of Trenton limestone, contain- 
ing a group of fossils, which appears to be unique in the 
stratigraphy of this county. 
The locality is the deep cut in the limestone on the 
New York and Massachusetts Railroad (lately the 
Poughkeepsie, Hartford and Boston Railroad), situated 
close to the Pleasant Valley station, to the north of it. 
The ledge consists of alternations of thick-bedded 
limestones (in some places of a smooth texture, in others 
very granular, tough, and gritty), with shaly layers of 
the same material. These calcareous shales are in places 
smooth and even slates, while in others they are exceed- 
ingly friable, and to a large extent broken up into small 
lenticular fragments. The smooth and fine-grained slates 
have not so far yielded any fossils ; but the latter abound 
in some of the irregularly fractured ‘shales, and in both 
the smooth and the gritty granular limestones. 
At this locality, the strata have a strike about north 
40° east, with a steep dip to the easterly. 
That the limestone belongs to the Trenton epoch is 
made evident by the presence of the characteristic Tren- 
ton tossils of the vicinity, notably, Solenopora compacta 
and Orthis pectinella, in abundance. This identification 
-is important, since a number of the other fossils present 
are heretofore credited to other epochs than the Trenton. 
One of the most conspicuous paleontological features 
of the locality is the exhibition, at one or two points, of 
large surface covered with well-preserved specimens of 
25 
