LAMELLIBRANCHIA TA. 
505 
Formation and locality. In the shales of the Hamilton group, near Jefferson, 
Schoharie county, N. Y. 
Elymella patula, n. sp. 
PLATE XL, PIG. 11. 
In part Modiomorpha? hyalea, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 40, tig’s. 
5-11. 1883. 
Not “ “ “ Prelira. Notice Lamellibranchiata, 2, p. 79. 1870. 
Shell below the medium size, obliquely sub-ovate, broader anteriorly; length 
one-third greater than the height; basal margin gently curved, abruptly 
recurving into the anterior and posterior extremities; posterior margin 
abruptly rounded, more gently recurving to the hinge-line; cardinal margin 
nearly straight for about half the length of the shell, then gently curving 
toward the posterior end. Anterior end regularly rounded, short, abruptly 
curving into the lunule, not limited by any sinus or depression. 
Yalves depressed-convex in the posterior and lower portion, and more con¬ 
vex in the umbonal region. 
Hinge-line straight, about one-half the length of the shell. 
Beaks small, sub-anterior, distinct, incurved. Umbonal region moderately 
convex, not defined nor continued as a ridge on the posterior slope. 
Test thin, marked by line, sharp, elevated concentric strirn, which are 
sometimes aggregated into fascicles, giving the surface an undulated charac¬ 
ter. Interior unknown. 
The specimen has a length of 32 mm. and a height of 20 mm. 
This species resembles E. miculoides, but differs in the slightly longer and 
wider anterior end, less gibbous valves and less prominent umbo ; the posterior 
end is also more narrowed toward the extremity. 
Formation and locality. In the shales of the Waverly group, at Medina, 0. 
