86 
Aug, F. Foerste 
cave anterior to the hinge line, the flattening extending for a dis- ! 
tance of almost 6 mm. anterior to the beak; at this point the shell 
is strongly curved, the anterior part of the shell being deflected 
almost vertically downward. Pedicel valve following the curva- I 
ture of the brachial valve. Radiating striae strong and coarse con- 
sidering the size of the shell, about ii in a. width of 5 mm. along 
the anterior margin. I 
Brownsport bed : glade southwest of Dixon Spring, also at ' i 
Clifton, Tennessee. | 
!| 
Strophonella ganti, sp. nov. 
{Plate II, Fig, 22.) j| 
Shell small, about i 6 mm. in width along the hinge line, and | 
varying from 8 to lo mm. in length. Resembling Strophonella \ 
gemculata^ Hall, from the Lower Helderberg, in having a broad 
median depression along the brachial valve, becoming stronger 
toward the geniculate border. The striations appear to be rather 
coarse, as in Strophonella prolongata. There is not sufiicient 
material to establish the validity of this foim as a species. 
Brownsport bed: in the coarse sandy limestone at the base of jj 
the Gant layer, forming the upper part of the Brownsport forma- S 
tion, at the A. B. Gant place, and at Martins Mills, Tennessee, j 
i| 
Strophonella laxiplicata. ! 
{Plate II, Fig. 25.) : 
The most perfect specimen appears to be only a young form of | 
this species. The brachial valve is slightly concave, and the pedi- I 
cel valve is moderately convex anterior to the beak. The reversal 11 
in curvature takes place about ii mm. anterior to the beak. The 
most characteristic part of the shell is the nature of the radiating 
striae. The striae are rather sharply elevated above the general i 
surface of the shell; and are separated by comparatively wide j 
spaces in which finer intermediate stri^ are absent or practically I 
obsolete. Only a small number of striae, usually less than lO, I 
begin at the beak, and new plications are added usually by inter- | 
calation, appearing near the middle of the comparatively wide i 
intermediate spaces. Cardinal area striated vertically. Radiating 
striae crossed by fine concentric striae which are seen only under 
a lens, chiefly in the spaces between the stri^. Width of type 
