APPENDIX E —PALAEONTOLOGY. 179 



Gryphjsa Pitcheri, Morton, 



Paleontology, PI. 6, fig. 5. 



Gryphcea Piickeri,Morton, Synops. Cretaceous Group, 55, PL xv, fig. 9« 

 Ostrea vesicularis, D'Orbig. Prod, de Palseont. II, 256, (pars.) 

 Gryphtea Pitcheri, Roemer, Kreid. Texas, 13, taf. ix, fig. 1, a — c. 

 Shell ovate, thick, gibbous, irregular; inferior valve boat-shaped, 

 inflated, divided into two unequal lobes by a longitudinal furrow, 

 which begins at the umbo and runs the whole length of the shell; 

 umbo large, elongate, incurved and slightly compressed laterally. Su- 

 perior valve irregular, sub-oval, nearly plane, marked with concentric 

 imbricating lamellae. Occurs in great numbers in the cretaceous clays 

 at Fort Washita, and more sparingly at Cross Timbers, Texas. Dr. 

 Morton's specimens were obtained from the plains of Kiamesha, Arkan- 

 sas, and Dr. F. Eoemer found it quite common near New Braunfels, 



Exogyra Texana, Roemer. 

 Paleontology, PI. 5, fig. 1, a — b, and fig. 5. 



Exagyra Texana, F. Roemer, Texas, 396. 



Ostrea matheroniana, (pars) D'Orbigny, Prod, de Palaeont. II, 255. 



Exogyra Boussingaultii, Conrad's Geolog. Report of Lynch's Expe- 

 dition to Red Sea, 213, pi. i, fig. 9, pi. ii, fig. 10 and 11. 



Exogyra Texana, Roemer, Kreid. Texas, 69, taf. x, fig. 1, a— e. 



The specimens of this shell in the collection were obtained by Dr. 

 G. G. Shumard, at Camp No. 4, Cross-Timbers, Texas. They vary 

 very much in their characters, scarcely any two examples being alike. 

 In some the shell is quite thin, in others massive ; some exhibit promi- 

 nent rugose ribs, while in others the ribs are but slightly elevated and 

 nodulose. According to Dr. Roemer, this Exogyra characterizes the 

 cretaceous deposites near Fredericksburg and New Braunfels, Texas. 

 Mr. Conrad figures a shell from Syria, which he refers to Exogyra 

 BoussingaultU, D'Orbig., and which appears to be identical with the 

 species under consideration. 



Ostrea subovata, Shumard. 



Paleontology, PI. 5, fig. 2. 



Sub-ovate, trigonal, elongate, massive ; inferior valve irregularly con- 

 vex, inflated, thick, umbo obtusely angulated, somewhat prominent; 



