WILLIAM B. DWIGHT. 189 
explorations among these limestones during seven years, 
all of the abundant fossils found have indicated the 
presence of either the Calciferous or of the Trenton for- 
mations alone, I have not failed toconsider the question 
carefully whether the present fossils, though of a Pots- 
dam type, may not after all exist here in Calciferous 
strata. But I have found no facts to favor the latter 
supposition. The rock is lithologically considerably 
different from any known fossil-bearing Calciferous in 
Dutchess county. The fossils are all of the type so 
well known in the Potsdam rocks of New York state 
and of Wisconsin, while no single Trenton or Calciferous 
fossil of the vicinity or of any locality, has appeared 
among the hundreds here collected. 
These fossils will require a very careful study for a 
full determination as to the number of genera and 
species. The following preliminary statement will indi- 
cate their nature in general : 
1. Lingulepis pinniformis ; several specimens of both valves, some of 
which are quite perfect. 
. Lingulepis minima ; many specimens of both valves. 
. Lingulepis acuminata, probably ; several good specimens, 
4, Obolella (Lingulella) prima ; several specimens. 
5. Obolella ; a minute species resembling ‘‘ Nana”; one or two speci- 
mens. 
6. Platyceras ; undescribed species ; one or two. 
7, Remains of small encrinal columns ; several. 
8. Ptychoparia (Conocephalites) ; n. sp. resembling Jowensis, but pos- 
sessing an occipital spine ; several glabellas and pygidia. 
9. Dicellocephalus ; two or more species; undetermined ; numerous 
specimens. 
10. Ptychaspis ; one or more undetermined species : several specimens. 
11. Stromatocerium ? undetermined ; abundant. 
The more abundant of these fossils are the L. minima, 
whose fragments are thickly scattered through some 
portions of the shaly limestone, and next the movable 
cheeks of trilobites. 
It will be observed, as has been suggested to me by 
Mr. R. P. Whitfield, that the fauna of this locality forms 
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