Notes on Cincinnatian Fossil Types 
325 . 
from Richmond, in Indiana, and is assumed to have been obtained 
in the Whitewater member of the Richmond group. The specimen 
is altogether too poor to merit its use as a type of a new species. 
The small anterior extension of the shell, the prominent umbonal 
ridges, the rhombic-cordate outline of the shell when viewed from 
the front, the steep post-umbonal slopes of the shell extending from 
the umbonal ridge to the dorsal margin, and the extreme thinness 
of the shell, as far as may be determined from the parts preserved, 
all suggest the affinity of this type specimen with some species of 
Whitella. 
Compared with Whitella cuneiformis, the posterior slope of 
the umbonal ridge is distinctly less flattened, and the curvature 
between the umbonal ridge and the dorsal margin is distinctly more 
concave; moreover, the shell does not appear to have been so strongly 
elongated. The absence of strong flattening along the posterior 
slope of the umbonal ridges distinguishes this type also from Whitella 
hindi Billings and Whitella sterlingensis Meek and Worthen. The 
general outline, as far as may be judged from the imperfect specimen 
at hand, was much more oblique than in Whitella quadrangular is 
Whitfield or Whitella suhovata Ulrich. Compared with Whitella 
umhonata Ulrich, the umbones are far less prominent. Compared 
with Whitella obliquata Ulrich, the umbones appear more gibbous 
and the outline of the shell is more broadly cordate when viewed 
from the front. From both Whitella obliquata and Whitella ohioensis 
Ulrich it differs in being narrower anteriorly, the anterior part of 
the basal margin being less convex and more nearly parallel to the 
umbonal ridge. In other words, Whitella richmondensis does not 
appear to be identical with any of the species of Whitella described 
from the Cincinnatian beds of Ohio or Indiana. This, however, 
might easily be explained by the fact that all of the latter have 
been described from the Waynesville member of the Richmond, 
while Whitella richmondensis probably was obtained from the 
Whitewater member, and may be a distinct species. It must be 
acknowledged, however, that the type does not give much definite 
information as to the characteristics of this species. The most 
disconcerting fact about the type is the presence of a distinct eleva- 
tion along that part of the hingeline, posterior to the beaks, where 
the escutcheon ought to be. I have assumed that this elevation 
is, in part at least, a remnant of the matrix, and that well preserved 
specimens, exposing this part of the shell, would show an escutcheon. 
