214 - FIELD CoLuMBIAN MusEUM—GEOLOGY, VOL, I, 
shells several feet in thickness, having a meagre arenaceous matrix, 
are traceable for miles. Farther north in Kansas they still form the 
most abundant types. . 
OST REAGED Pas Ol dam. 
(Pl. XXV, Figs. 7 and 8. Mus. No. P 5944.) 
Shell thin, oblong, moderately capacious, and possessing more 
than ordinary symmetry. Beaks are long and sharply pointed; fit- 
ting closely. Lower valve deep; area broad, triangular, with rounded 
borders, possessing a slight depression in the posterior-central por- 
tion; posterior border, rounded; anterior border, pointed ; dorsal 
border, slightly concave, nearly straight; ventral border, convex. 
Upper valve, flat or slightly convex transversely; in general out- 
line it 1s very similar to the lower valve; area much the same, perhaps 
a little shorter. Muscularimpression in both valves, sub-central and 
indistinct. Surface not rough or but little imbricated. 
Dimensions—Length, 45mm.; width, 25mm.; height, 8mm. 
The species occurs in the Lincoln Marble horizon of the Benton. 
It is not abundant and has been collected from two localities only. 
The specimen here described was collected from an outcrop on the 
Solomon river in the Kansas area. 
FASCIOLARIA sf. 
(Pl. XXV, Figs. 1 and3. Mus, No. P 5941.) 
Shell a little more than moderate size, stout fusiform; spire con- 
sisting of three rather convex volutions. The body whorl large and 
possessing in the central region a flat area; whorl merging into a 
rather short canal which is slightly curved; last whorl (body) and 
canal more than equalling the length of the spire. Surface ornamen- 
tation not distinct in specimen, hence the difficulty of determining 
the species. 
Several fragmentary specimens which probably belong to the 
genus Fasciolaria were collected by the writer from the septaria of 
the Blue Hill shales (Benton), The material is in such a condition 
as not to warrant specific determination. They are figured and men- 
tioned only for the purpose of making our literature as complete as 
possible and with the hope that in the future better material may 
be obtained through the suggestion of the presence of such forms. 
