LAMELLIBRANCHIA TA. 
427 
with the Cardiola retrostriata (von Buch) of various authors, and with Cardium 
palmatum of Goldfuss. Its citation by numerous authors shows its wide distri¬ 
bution in Europe. 
Formations and localities. In the shales of the Hamilton group near Geneva, 
Ontario county; Sherburne creek, Chenango county, and on the shores of 
Cayuga lake. In the Genesee slate at Bristol, Ontario county, and numerous 
other localities. In the Portage group at Branchport, Yates county; and at 
Ithaca, Tompkins county, N. Y. 
PRiECARDIUM, Barrande. 1881. 
PRjECARDIUM vetustum. 
PLATE LXX, FIGS. 18-20. 
Cardium ? vetustum, Hall. Geol. Surv. N. Y., Rep. Fourth Dist., p. 245, t. 107, fig. 2. 1843. 
Cardiola vetusta (Hall), S. A. Miller. Cat. Am. Pal. Foss., p. 1S6. 1877. 
PrWcardium vetustum, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 70, figs. 18-20. 1883. 
Compare “ despectum, Barrande. Syst. Silur. de BohSme, vol. vi, pi. 285, III, figs. 5-8. 1881. 
Shell small, trigonal, arcuate, oblique ; length greater than the height. Ante¬ 
rior margin concave, becoming rounded below; basal margin gently curved. 
Posterior margin contracted below, and obliquely truncate above. 
Valves moderately convex below, becoming gibbous in the umbonal region. 
Hinge-line declining posteriorly. 
Beaks anterior, prominent and strongly incurved. 
Surface marked by fine concentric strife and by from ten to fourteen strong 
elevated flattened radii, which show a tendency to duplication on the ante¬ 
rior end. Interspaces flat, as wide or wider than the radii. 
Three specimens measure respectively 17, 17 and 16.5 mm. in length, and 
14, 10.5 and 13 mm. in height. 
This is a smaller species, but very similar to Prcecardium despectum , of Bar¬ 
rande, loc. cit. 
Formation and locality. In the shales of the Portage group on the shore of 
lake Erie, near Portland Harbor, N. Y. 
