CRETACEOUS FOSSILS. 205 



GRYPH^EA, Lam. 

 G. vesicularis, Lam. 



A few small specimens of this species were picked up, not in situ, near San Diego, 

 by Dr. Cooper. It has not been found elsewhere on the west coast. 



EXOGYRA, Say. 



E. PARASITICA, 11. S. 

 PI. 26, Fig. 192, and 192 a, b, and PI. 31, Fig. 273, and 273 a. 



Shell always attached by the lower valve, thin when young, 

 thick and irregular in shape when adult. Lower valve shallow, 

 oblique, elevated and overhanging on the right hand side, flat on 

 the left; beak low, excentric, small; hinge small, oblique, curved; 

 inner margin of both valves minutely crenulated ; muscular scar 

 long, narrow. Upper valve distinctly spiral in young specimens, 

 somewhat oblique, flattened, or with an irregular angular ridge 

 running from beak to base. Surface of upper valve very squa- 

 mose ; of the lower valve less so. 



Figures 192, 192 a, and 192 b, are of young specimens from Texas Flat; 273, 

 and 273 a, adult lower and upper valves, from opposite Folsom. 



Localities: Found at the two above-quoted localities, and at Cottonwood Creek, 

 Shasta County. 



TEREBRATELLA, D'Orb. 



T. OBESA, n. s. 

 PI. 26, Fig. 194, and 194 a, b. 



Shell moderately large, broad, and very convex. Lower valve 

 unknown, except the beak, which is acuminate, high, and with 

 the sides nearly straight; area narrow, sloping slightly back- 

 wards from the foramen; foramen longer than wide, sides 

 straight, and bordered on each side by a small impressed line. 



