Oyrtolites carinatus.] SCE nee : Bue 
carinated like the dorsum, the dorsal slopes strongly concave on the first and 
second whorls, nearly flat on the last, without undulations except near the aperture 
of the largest examples; transverse lines sweeping backward from the edge of the 
umbilicus, stronger than the connecting lines, the difference between the two sets 
increasing with age. 
The original description of the species is not entirely correct, Dr. Miller 
claiming that the surface “never presents a cancellated appearance,” but he seems 
to have doubted the correctness of his observations since he adds, “at least not on 
any specimen observed.” Out of more than twenty specimens belonging to the 
cabinet of one of the authors several preserve the surface markings in a fairly 
satisfactory manner. These show that on the inner volutions the surface is 
minutely though distinctly cancellated. The short connecting lines are delicate, 
and as growth proceeds they become relatively more so, a short exposure to the 
weather sufficing in many cases to efface them entirely, when the specimen will 
appear to have transverse striz only. Generally, however, when the stronger 
set of lines is preserved, more or less convincing traces of the other set also are 
retained. 
Compared with C. ornatus the present species is distinguished by its sharper 
lateral carine, flatter and more concave dorsal slopes, almost total absence of 
surface undulations, and by the backward sweep of the lines of growth. From C. 
retrorsus it differs in being practically without dorsal undulations, in having a less 
prominent dorsal carina, and in the flattening of the dorsal slopes of the last 
volution. So far as the two species mentioned are concerned, C. carinatus is clearly 
distinct, but we cannot say as much when we compare it with C. conradi, a species 
named and figured by Hall (oc. cit.), without a description, as one of the fossils of 
the Hudson River or Maquoketa shales of Wisconsin and Iowa. Hall’s illustration 
represents a small Cyrtolites very similar to C. carinatus, and, as the geological 
horizon is about the same for both, it is not unlikely that the two names apply to 
the same species. To establish this as a fact would in our opinion necessitate a 
comparison with Hall’s original type of C. conradi, and if that is no longer possible, 
it would be well to drop the name entirely. 
Formation and locality.—Not uncommon in the Utica group at Cincinnati, Ohio, and a numberof 
localities in the vicinity of that city. The species occurs probably also in the lower shales of the Cincin- 
nati period in Wisconsin and Iowa, in which case it may be looked for in southern Minnesota as well. 
