Strophomena and Other Fossils 
101 
and a locality 4 miles east of Bardstown, in Nelson county, in the 
Liberty member. If the fossiliferous strata overlying the Saluda 
are to be regarded as Whitewater, then Strophomena vetusta 
occurs in the Whitewater as far south as the northwestern corner 
of Ripley county, and the southern part of Decatur county. 
Farther northward, in Indiana and Ohio, it is abundant at the 
Whitewater horizon. 
Strophomena vetusta is found occasionally in the lower part of 
the Saluda member, above the Columnaina horizon, in Jefferson 
and Ripley counties, in Indiana. 
Strophomena vetusta-approximata, James 
{Plate VI, Figs. 1 A, B, C, D) 
Strophomena approximata was described by U. P. James from 
the upper part of the Cincinnati group, in Dearborn county, 
Indiana. Two specimens, numbered 2394, and labelled Stropho- 
mena approximata, occur in the James collection, preserved in 
the Walker Museum, at Chicago University. These are illus- 
trated in this Bulletin. The larger specimen was used for the 
original description by James. An examination of the types 
indicates that they are very closely related to Strophomena vetusta, 
and differ only in outline. The specimens are subtriangular, 
rather than subquadratic in outline. Specimens of this type are 
very rare, and occur only as isolated individuals at distant locali- 
ties, and only where Strophomena vetusta is abundant. Apparently 
these triangular specimens are to be regarded merely as patho- 
logical variations from Strophomena vetusta, and not as varieties 
tending toward the formation of a new species. The types have 
the appearance of specimens from the Whitewater bed, but there 
is also a possibility of their having been obtained in the Liberty 
bed, and the latter is exposed at Moores Hill, at Weisburg, and 
at other localities in the northwestern part of Dearborn county, 
in Indiana. The brachial valve of the type of Strophomena 
vetusta-approximata is flattened for some distance anterior to the 
beak. The length of the shell is 3.2 mm., and the greatest con- 
vexity equals 10.3 mm. at 18.5 mm. from the beak. The thick- 
ness of the shell at this point is 4.1 mm. The width of the shell 
Paleontologist, No. 5, p. 43, June 10, 1881. 
