12 
University of Texas Bulletin 
PERN ID AE 
Genus INOCERAMOUS Sowerby. 
Inoceramous sp. 
PI. I, fig. 5. 
Dimensions. — Length, 50mm.; breadth, 35mm. 
Description. — Shell subovate, ventricose, inequilateral; hinge 
oblique to long axis; umbo narrow, prominent, incurved. Shell 
ornamented externally and internally with rounded, concentric 
plications, separated by grooves of similar width. The plica- 
tions are very fine at the beak, but gradually increase in size 
toward the base. 
There is only one specimen of this species in this collection, 
and it is too- fragmentary for determination. The outlines shown 
in the figure may not be accurate, but are the result of following 
down the parts of shell and cast while removing the rock cover- 
ing them. 
Locality. — Barton Creek, Austin, Texas. 
OSTREIDAE 
Genus ALECTRYONIA Fischer. 
Alectronia carinata Lamarck. 
PL I, figs. 1, 2. 
Ostrea carinata Roemer, 1849, Texas, p. 304. 
Ostrea carinata Roemer, 1852, Die Kreide. von Texas, p. 75, 
Taf. 9, fig. 5. 
Ostrea carinata Conrad, 1857, Rept. U. S. and Alex, Bound. 
Surv., Vol. I, Pt. 2, p. 156, PI. 10, fig. 6. 
Ostrea carinata White, 1884, Fourth Ann. Rept. U. S. Geol. 
Surv., p. 293, PI. 43, figs. 1-4. 
Ost rea carinata Hill, 1889, Texas Geol. Surv., Bull. No. 4, p. 6. 
Alectryonia carinata Hill, 1898, U. S. Geol. Surv., Bull. No. 151, 
p. 26. 
Dimensions. — Length, 42mm.; breadth, 10mm. 
Description. — Shell narrow, curved, moderately auriculate; 
beaks depressed, slightly twisted; surface ornamented with 
twelve or more strong, narrow, sharp ribs, which, in some sped- 
