Strophomena and Other Fossils 45 
Strophomena millionensis, sp. nov. 
{Plate I, Figs. 9 A, B, C; Plate X, Fig. I 4 ) 
About 1 mile west of Million, in Madison county, Kentucky, 
the railroad passes through a tunnel. An eighth of a mile west of 
the tunnel, at the Marion Newby locality, the base of the Eden is 
exposed 10 feet above the railroad. A short distance west of this 
locality, the base of the Eden contains, in addition to numerous 
specimens of Plectambonites sericea, a few of Dalmanella multisecta, 
and an occasional specimen of the trilobite familiarly known as 
Trinucleus concentricus, also a small species of Strophomena. The 
largest specimen of this species, found so far, has a width of 19 mm. 
and a length of 13.5 mm. The relation of length to width, how- 
ever, varies, being in most specimens about 14 to 17. The outline 
of the shell is subquadratic, the postero-lateral angles being rec- 
tangular, or between 80 and 90 degrees, with a tendency toward 
rounding at the tip of the angle in some specimens. 
The brachial valve is flattened posteriorly, this flattening extend- 
ing forward for about half the length of the shell, beyond which 
the sides of the shell slope toward the antero-lat era! margins, 
producing a low, broad, median elevation anteriorly, whose crest 
makes a moderate angle with the flattened posterior part of the 
valve. 
The hinge-area of the pedicel valve has a height of about 1 mm. 
at the beak; it forms an angle of about 125 to 130 degrees with 
the general plane of the shell. The sides of the delthyrium form 
an angle of 80 degrees, and the deltidium is evenly convex. The 
posterior half of the valve is gently convex, with a variable amount 
of flattening toward the postero-lateral margin. The anterior 
half is characterized by a broad and shallow median depression 
or sinus, corresponding to the median fold on the opposite valve. 
At the anterior margin of this fold and sinus the shell frequently 
is slightly produced, resulting in a slightly triangular, rather than 
evenly convex outline. 
The radiating striae are rather coarse. Usually about 5 striae 
occupy a width of 2 mm., but on some parts of some shells the 
number may be as low as 4, or as high as 6 in the same width. 
The general appearance of the shell closely resembles that of 
Strophomena sulcata. The chief difference appears to be that in 
Strophomena millionejisis the spaces between the radiating striae 
