TRENTON LIMESTONE. 
95 
131. 5. LINGULA RICINIFORMIS. 
Pl. XXX. Figs. 2 a, b, c. 
Oval, convex, slightly attenuated towards the beak, which is obtuse ; surface nearly 
smooth, or with fine nearly obsolete concentric lines. Fine radiating striae are sometimes 
visible ; and the surface is sometimes slightly ridged, as if from elevated lines beneath the 
outer lamina of the shell. 
The general oval form and equal convexity of the shell are almost its only distinguishing 
characters. It is less attenuated towards the beak than the last, and the surface is not so 
distinctly striated. 
The length of this species does not exceed T \ of an inch, with a width of little more than 
yL. Compared with figs. 1 a, b, it is less attenuated towards the beak, and not depressed 
towards the front, which latter feature appears to be constant in the L. attenuata. That 
species also becomes more spatulate or expanded towards the base as it increases in size, 
which is shown in 1 b. 
The figures 2 a, b, c, are from three specimens, varying in size, but all presenting the 
same form. 
Position and locality. This species occurs with the last in compact dark limestone near 
Middleville, Herkimer county. (State Collection.) 
132. 6. LINGULA iEQUALIS ( a variety of the last species ?). 
Pl. XXX. Figs. 3 a, b. 
Broadly oval, very obtuse, somewhat attenuated near the beaks, regularly convex, 
rounded in front; surface marked by fine radiating strife and less conspicuous concentric 
lines. 
This shell differs from the last, in its greater proportional width, and almost equally 
obtuse extremities. Length and breadth about as 5 to 6. 
In addition to the very fine radiating strife upon the surface of the shell, there are some 
undulating ridges or wrinkles which are not very distinct. The radiating strife are often 
obsolete or inconspicuous, and, to the naked eye, the surface appears entirely smooth. The 
shell is usually less convex than the last species, which it closely resembles. 
Position atid locality. In the compact limestone, near the centre of the mass, at Middle¬ 
ville, Trenton Falls, &c. 
