202 
AUG. F. FOERSTE 
The cardinal process in the brachial valve consists of a very 
narrow median vertical plate, on each side of which are the bases 
supporting the crura. The crura project forward from near the 
inner margins of these bases, and the surface of the latter tends 
to be distinctly concave toward the cardinal process. The pos- 
terior part of the bases articulates with the sockets posterior 
to the teeth of the pedicel valve, and sockets for the reception 
of these teeth occur exterior to the bases supporting the crura 
in the brachial valve. The cardinal process and the adjacent 
parts of the bases unite anteriorly and connect with the median 
ridge which extends slightly more than half the length of the 
valve forward. About 4 or 5 mm. in front of the cardinal proc- 
ess there are more or less distinct lateral branches of the ridge, 
evidently limiting the anterior from the posterior adductor scars. 
From the Buffalo or Maquoketa shales 3 miles east of Frank- 
ford, in Pike County, at a small knob on the north side of the 
pike to Louisiana. Named in honor of Prof. R. R. Rowley of 
Louisiana, who for many years has investigated the strata of 
eastern Missouri. Characterized by its large size and by the 
conspicuous and distant concentric striae. 
12. Schizocrania filosa Hall 
In the eastern part of the United States the earliest occurrence 
of this species is in the Trenton. In Minnesota it occurs as low 
as the Decorah shales. In Ralls County, Missouri, it is fairly 
common at several localities near the top of the Plattin limestone; 
among others, at Conn’s Ford, Buford Cave, and along the lower 
part of Big Creek. 
13. Strophomena cf. incurvata Shepard 
Plate XXI, fig. 1 , plate XXII, fig. 1 
A single specimen of Strophomena, 56 mm. wide along the hinge- 
line, and 34 mm. long from the beak of the pedicel valve to its 
margin, was found at locality 3 on Sanders branch, in Ralls 
County, in the Kimmswick limestone. The concavity of the 
