52 W. B. Dwight— Wappinger Valley Limestone. 
Moreover its weathered surface is almost invariably white 
(frequently as much so as white lead), and highly arenaceous ; 
and its fossils are, when weathered, of the same character. 
fracture is apt to be much more splintery and conchoidal than 
that of the Trenton beds. 
The fossils which in several places abound in this lighter- 
colored rock, do not leave us in doubt as to its nature. 
found specimens of the following identified specimens: 
Ophileta complanata. This species is found at Wallace’s 
quarry, Salt Point, and is one of the coiled univalves of that 
place mentioned, but not identified, in my previous article. It 
occurs also at the railroad cut two miles northeast of Pleasant 
Valley, and abundantly at Rochdale. In general appearance 
it resembles the figure given by Vanuxem in his New York 
Geological Report (p. 30), though it is often larger and more 
delicate in its structure than the somewhat rough figure repre- 
sents. It is possible that this may be the 0. compacta, the two 
species differing so slightly that some authors (as Billings *) 
suppose them to be only varieties of the same. 
Ophileta levata, This is less numerous than the preceding, but 
is quite as well marked. It is found at Salt Point, and at 
Rochdale. 
Ophileta (Maclurea) sordida. A number of specimens occur 
at both localities last mentioned. The ellipsoid form which 
induced Vanuxem to call the species Ellipsolites leaves little 
room for doubt. 
Orthoceras primigenium. I have found perhaps a dozen speci- 
mens of this Orthoceras, all quite well marked ; and from the 
indications of fragments, should say that it is rather abundant 
at both localities, but especially at Rochdale. The numerous, 
delicate, considerably curved septa are very distinct. Some o 
my specimens are from two to three inches long. In every 
instance they are shown in nearly central longitudinal sections. 
There are other univalves like Ophileta, or Helicotoma, 
which I have not yet made out; and some smaller Orthocerata. 
The univalves from Salt Point, previously described as appar- 
ently containing septa, and which I supposed therefore might 
be Trocholites, are probably Ophileta (levata?) as the septa 
prove to be false. 
These fossils often occur within the meshes of a network of 
fucoidal fronds, which, at Rochdale at least, assume a more or 
less tubular form for the stems. These may be Buthotrephis 
antiqguata, but are too indistinct to be identified satisfactorily. 
This rock does not contain the abundant Cheetetes, the encrin 
columns of the contiguous Trenton, nor any other of the fossils 
found in that stratum. 
* Geol. Can., vol. i, p. 246. 
