308 
Aug. F. Foerste 
of the Richmond group. The species however makes its appearance 
already in the Arnheim. About a mile south of Milton, Kentucky, 
along the road to Bedford, a specimen referred to this species was 
found 11 feet above the Dinorthis carleyi horizon, and 13 feet below 
the lowest strata containing Strophomena planumbona and Dalman- 
ella jugosa. 
18. Lingula brookvillensis, n. sp. 
{Plate IV, Figs. 6 A, B) 
A medium sized Lingula, found at Boundary Hill, about two 
miles west of Brookville, in Indiana, closely resembles Lingula 
cincinnatiensis Hall and Whitfield in its internal features. Lingula 
cincinnatiensis is characteristic of the Fairmount division of the 
Maysville group, in Ohio, Indiana, and Kentucky, and a form not 
to be distinguished from this species occurs in the Rogers Gap 
member of the Cynthiana group, about one mile north of Rogers 
gap, in Kentucky. Lingula rectilateralis Emmons, from the Utica 
and Trenton of New York, and Lingula iowensis Owen from the 
Trenton of Wisconsin, Iowa, Minnesota, Illinois, and Manitoba, 
are closely related to, and almost identical with Lingula Cincinnati- 
ensis. All of these species belong to the group, typified by Lingula 
quadrata Eichwald, for which the term Pseudolingula was proposed 
by Mickwitz, in 1909. As defined by Schuchert Pseudolingula is 
characterized by a ventral pedicel groove and a pair of umbonal 
muscles, features ordinarily not likely to be exposed. 
From the species mentioned above, the Brookville specimen 
differs conspicuously in its smaller size. The length of the brachial 
valve is 15.5 mm., the width is 9.5 mm., and the thickness from 
valve to valve is about 3.4 millimeters. The beak of the pedicel 
valve extended at least half a millimeter beyond that of the brachial 
valve. The sides of the shell are subparallel for a length of about 
7 mm., and then curve posteriorly into the postero-lateral margin, 
which forms an angle of about 140 or 145 degrees with the lateral 
margin. The beak of the brachial valve is rather narrowly rounded. . 
The anterior margin of the shell is moderately convex, rounding 
rather strongly into the lateral margins, producing a quadrangular 
outline very similar to that of Lingula cincinnatiensis, but distinctly 
more elongated. 
Along the middle parts of the shell, between two imaginary 
lines extending from the beak to the antero-lateral angles, the valves 
