84 
A ug. F. Foerste 
representation of the curvature of the Tennessee specimens. Our 
fig. 20 A is taken from a specimen which evidently equaled his 
fig. 3b in size. 
Brownsport bed: on hill side south of road leading east from 
New Era; also north of landing at Cerro Gordo^ Tenn.; and in 
massive limestone northeast of stables on Gant place northeast of 
Martins mills^ Tennessee. 
Strophonella williamsi^ - described by E. M. Kindle from the 
Silurian of northern Indiana^ appears to be a much more convex 
species^ when viewed from the side of the brachial valve, 
Strophonella roemeri. 
{Flate II, Fig. 24) 
Shell subtrigonal in fully developed specimens, probably more 
semicircular in young specimens, the subtrigonal form being due 
chiefly to the greater growth of the shell along the anterior edge 
and the rapid deflection of the shell antero-laterally. Width at 
hinge-line 56 mm.; brachial valve distinctly flattened anterior to | 
the beak for a distance of about 18 to 20 mm., slightly concave j 
toward the beak, abruptly deflected anterior to the flattened area, I 
the deflection being greater toward the antero-laterai margin than i 
toward the anterior median parts of the shell. Antero-lateral 
slopes more or less flattened. Erom the anterior part of the flat- ! 
tened area to the anterior part of the shell may be a distance in | 
the largest specimens of 37 mm., but usually 34 to 30 mm., or | 
even less. Pedicel valve slightly convex- near the beak, following | 
the curvature of the brachial valve. Cardinal margin crenulated ' 
for a distance of about 7 mm. on each side of the delthyrium. 1 
Muscular area of pedicel valve 13 mm. long, 16 mm. wide, lateral ' 
margins thickened and raised abruptly above the inner surface 
of the valve, open along the median line anteriorly; adductor 
scars distinctly defined posteriorly by low elevations which ' 
begin at the beak and branch within i mm. of the same, the }; 
two exterior branches defining the postero-lateral margins of j' 
the scar, the two inner and much shorter branches defining the 
inner margins at the posterior extremity. Between the two inner ! 
branches arises the narrow median elevation which divides the j 
adductor area. Inner surface granulose, the granules arranged | 
in lines approximately following the exterior ornamentation of the 
