Silurian Fossils 
73 
bed northeast of stables on Gant place, two miles northeast of 
Martins mills; Pegram bridge; Bath Springs; east of George Wil- 
son, seven and one-half miles east of Savannah; all in Tennessee. 
Rhipidomella newsomensis, sp. nov. 
{Plate IV, Figs. 72 A, B.) 
Among the specimens of Rhipidomella found in the Waldron 
bed, both in Tennessee and in Indiana, there is a small, strongly 
convex form, apparently mature, which may be distinct from 
Rhipidomella hybrida, as usually identified in the same beds. One 
of the largest of these specimens is 10.5 mm. long, of almost exactly 
the same width, being slightly wider, and its depth is 7 mm. 
Except in their smaller size, and mature appearance at this size, 
these shells do not differ from the associated specimens referred 
to Rhipidomella hyhrida. 
Waldron bed: Newsom, Tennessee. Hartsville, Waldron, and 
at the George Wright locality in Shelby county, Indiana. 
Orthostrophia newsomensis, sp. nov. 
{Plate IV, Fig. 64.) 
Ventral valve moderately convex, with a wide depression along 
the median part toward the anterior margin of the shell. The 
radiate striation of the shell resembles that of Orthostrophia halli., 
judging from fig. 22, plate VA, volume viii, part i, of the New 
York Paleontology, but the individual at hand is distorted inequi- 
laterally. At earlier stages of growth it was much more extended 
along the hinge line than Orthostrophia halli and even at maturity it 
is a relatively wider shell. Most of the radiating striae branch once or 
twice before reaching the margin of the shell. Muscular cavity of 
pedicel valve small; the anterior margin only 6 mm. from the beak, 
considerably elevated above the inner surface of the valve, bor- 
dered laterally by the dental lamellae and their anterior extension 
at the base. The greater part of the base of the muscular area is 
formed by a moderately concave platform separated on each side 
from the base of the dental plates by a narrow groove; the diductor 
muscular impressions are apparently much narrower than in 
Orthostrophia strophomenoides. Ovarian impressions remarkably 
distinct, extending about 7 mm. anterior to the hinge line and 6 
