80 Cincinnati Society of Natural History. 
They are evidently not more than half this on the inner side. They 
decrease constantly but rapidly in size and length, so that the shell 
tapers regularly to the apex of the coils. The whole surface is fluted 
with parallel coarse striz, obliterated in the type, evidently markings 
of the shell ornamentation, as indicated by other fragments of thesame 
species. The shell was exceedingly thin and fragile. Its markings 
are most pronounced on that part of the cast which filled the body- 
chamber. In transverse section this cavity was nearly circular. Di- 
ameter of the specimen, measured across from outside of body-chamber, 
56 mm., of body-chamber at mouth, as preserved, 20 mm. 
I collected this fine species, as represented by the type, and several 
fragments, in the subcarboniferous rocks of the lower Waverly, at 
King’s Mountain Tunnel, on the C. S. R. R. 
It was there associated with another, much larger and coarser species, — 
and with fossils belonging both to the Kinderhook and Keokuk Groups. 
A fuller study of this part of the subcarboniferous rocks of Kentucky, 
and more extensive collections of its fossils, which are abundant and 
well preserved, is very much needed. I hope to make further explora- 
tions in this region during the coming spring and summer, and hence 
assign no closer geological limits to the horizon of this fossil for the 
present. I take great pleasure in dedicating this species to my valued 
correspondent, Dr, L. de Koninck, of Liege, Belgium, who has done 
more to develop a scientific and accurate knowledge of the carbonifer- 
ous fossils of Europe than any other student of its geology. 
CRUSTACEA, 
Isocuitina, Jones, 1858, Can. Org. Rem., Dec. 3. 
IsoCHILINA JONESI, nov. sp. (Plate II, figs. 7, 7a.) 
GENERAL DESCRIPTION. 
“Equivalve, the margins of the valves meeting uniformly, not over- 
lapping as in Leperditia; greatest convexity of the valves, either 
central or toward the anterior portion. Eye-tubercle present, Mus- 
cular spot not distinct externally.” Carapace having much the: size 
and shape of the Leperditia baltica; dorsal margin straight, ventral 
gently curved. Anterior and posterior margins, rounded. Marginal 
border very wide at the posterior extremity of the valves, narrowing 
much anteriorly in the inferior margin, at the center, and widening . 
again, somewhat, at the anterior side. Valves very convex, with the 
greatest elevation as seen in profile, sub-central, near to the anterior, 
