Notes on Cincinnatian Fossil Types 
327 
University. Both of these types are impressions of the exterior 
of right valves, preserved in limestone. The original of figure 9 
on plate 11 occurs in limestone containing numerous fragments of 
Rafinesquina alter nata but only one fragment of Dalmanella jugosa; 
a single squarish columnal, possibly belonging to Compsocrinus, 
also is present. Twenty-four radiating plications are indicated 
plainly but the margin of the byssal opening is not preserved, so 
that there may have been one or two additional plications in this 
region. The original of figure 10 on plate 12 appears to have come 
from the same rock layer as the original of the specimen just de- 
scribed. Twenty-eight radiating plications can be recognized readily 
and in addition to these there were probably one or two more in 
the region of the byssal opening. Both of these types probably 
were derived from the Waynesville member of the Richmond group, 
at Clarksville, in Clinton county, Ohio. 
A third specimen, also numbered 2341, but evidently not at 
hand at the time the figures of the types were prepared, since it is 
a much better specimen than the other two and presents a well 
preserved and nearly entire left valve, is included in rock containing 
Dalmanella jugosa, several square columnals suggesting Comp- 
socrinus, and various minute ostracods. The specimen is especially 
interesting in presenting an excellent example of the margins of 
the different stages of growth (in this case, four stages) remaining 
free from the main body of the shell, producing more or less squa- 
mose concentric bands. 
The specimen figured in this bulletin was obtained by the writer 
on Clifty Fork, west of Madison, Indiana, a considerable distance 
below the lowest horizon in the Waynesville member of the Rich- 
mond group at which Dalmanella jugosa is found. The thickness 
of this shell from valve to valve is 27 millimeters. Twenty-four 
radiating plications are exposed and the original number may have 
equalled twenty-eight. 
The distinguishing features of Anomalodonta alata are the 
rather concave anterior outline, the moderately sinuous posterior 
outline with the moderate prolongation of the shell along the hinge- 
line, and the relatively moderate width of the interspaces between 
the radiating plications, which may equal the latter but frequently 
are somewhat narrower. Toward the antero-ventral margin of 
the shell, the plications curve moderately forward. Most of the 
plications originate at the beak, but along the hinge-line and on the 
