74 
A ug. F . Foerste 
mm. laterally from the muscular area; with linear dendritic ovarian 
striae. Vascular markings in the form of deep grooves with few 
branches excepting n€ar the anterior margin of the shell. 
Waldron bed: Newsom, Tennessee. 
Orthostrophia dixoni, sp. nov. ( 
{Plate IV, Fig. 65.) I 
Pedicel valve slightly convex at the beak, flattened or slightly 
reversed in curvature anteriorly, but it is possible that this ante- 
rior flattening of the shell is due partly to crushing. The radiate 
striation of the shell is rather coarse and resembles that of an 
orthoid rather than that of a strophomenoid shell. There are 
about 6 or 7 rather broad striae in a width of 5 mm., and these are 
crossed by concentric striae and lines of growth which resemble 
those of an orthoid shell. Muscular area of the pedicel valve 
very small and remarkably deep, the base of the dental plates 
uniting with the curved anterior edge of the muscular area in such 
a manner as to produce a border sharply and considerably raised 
above the inner surface of the valve. The median part of the area 
is occupied by a low median elevation bordered on each side by a 
lower lateral elevation, representing the position of the adductor 
impressions, and occupying about one-third of the width of the 
area. Length of muscular area, 5 mm. ; width, 6 mm. No evidence 
of ovarian or vascular markings. Delthyrium wide, covered by 
a small deltidium at the apex. 
Brownsport bed: glade southwest of Dixon Spring, Tennessee. 
Orthis flabellites. 
{Plate III, Fig. 43.) 
Orthis flabellites is the name suggested for the specimen repre- ' 
sented by fig. 6, on plate 52, of volume ii. New York Paleontology, 
This is the species which occurs in the Rochester shale in New 
York. The species is figured also in figs. 37 to 41 on plate v of 
volume viii. New York Paleontology. 
In the list of fossils from the Niagara limestones of Wisconsin, 
Illinois and Iowa, published in the Twentieth Annual Report on 
the State Cabinet of Natural History of New York, on p. 397, the 
name Orthis flabellites is used evidently for the northwestern form 
belonging to the group typified by Orthis flabellites. Exactly what 
