278 
AUG. F. FOERSTE 
show a contraction along the upper part of the cast of the inter- 
ior, a short distance below the aperture. The siphuncle is about 
1.25 mm. in diameter at the base of the specimen and its loca- 
tion is somewhat excentric. No trace of the surface markings, 
beyond the presence of vertical ribs, is present in this type. 
Locality and Horizon. — The type is numbered 685 in the 
State Museum of Indiana, at Indianapolis, Indiana. It occurs 
in a very fine-grained, brownish-gray limestone having a con- 
choidal fracture, resembling some phases of the Plattin limestone 
of eastern Missouri. The same limestone, at Kentland, Indiana, 
contains Columnaria halli, Rafinesquina minnesotensis , Stro- 
phomena trentonensis , Zygospira recurvirostris, Ctenodonta nasutay 
Actinoceras heloitense, Isotelus cf, platycephalus, and Thaleops 
ovatus. This is a typical representative of that fauna in the 
upper Mississippi Valley which is correlated with the Black 
River limestone of New York. 
14. Leurorthoceras hanseni Gen. et Sp. nov. 
Plate XXX y figs, M, IB; pi XXXI y fig: 1; pi XXXII y fig, 8; 
pi XXXIV y fig, 2 
Specimen consisting ‘ of part of a phragmacone having an 
apical angle of 14 degrees in a lateral direction and of 4 or 5 
degrees in a dorso-ventral direction. The cross-section of the 
conch is sub triangular. This subtriangular outline is produced 
chiefly by the strong and broad flattening of the ventral side of 
the conch and the strong transverse curvature of the shell along 
its ventro-lateral angles. Along the dorsal half of the conch 
the transverse curvature is fairly regularly convex, that of the 
smaller end of the specimen corresponding fairly well to the 
curvature of a circle 45 mm. in diameter. The dorso-ventral 
diameter at this smaller end equals 30 mm. 
In a length equal to the lateral diameter of the conch there 
are 6.5 camerae. Along the dorsal half of the conch the sutures 
are directly transverse, but along the ventral half they curve 
distinctly downward. At the upper end of the specimen the 
amount of this downward curvature equals 5 mm. Along the 
