36 PALAEONTOLOGY OF CALIFORNIA. 



Figures, natural size. 



Localities and position : From the Miocene, one mile cast of the Excelsior Mine, 

 Napa County, Prof. "Whitney ; and twenty miles east of Clear Lake, on the road 

 from Colusa to the Hot Sulphur Springs ; Dr. George. 



MORRISIA, Davidson. 

 M. Hornii. 



PL 12, Fig. 63. 

 (M. Hornii, Gabb; Proc. Phila. Academy, 1861, p. 371.) 



Shell minute, subcircular, flattened; beak acute; area narrow, 

 long; a faint sinus usually occupies the middle of the lower por- 

 tion of the upper valve; foramen large, acute above, and rounded 

 or subaugular in the upper valve. Surface, under a lens, presents 

 a minutely granular appearance. 



Figure, highly magnified. Length about .11 inch. 



Locality and position : From the Post-Pliocene marl at Santa Barbara; collected 

 by Dr. A. L. Heermann. This shell seemed to be abundant in the marl collected 

 by Dr. Heermann ; but I have never seen it among the shells collected by the Sur- 

 vey in that vicinity or elsewhere, and failed to find it myself, on subsequently 

 visiting the locality. 



ECHINODERMATA. 



CLYPEASTER, Lam. 

 C. Gabbii. 



PI. 12, Fig. 64, 64 a. 

 (C. Gabbii, Remond; Proc. Cal. Acad., 1863, p. 63.) 



i ECHINARACHNIUS, Van Phels. 



E. Brewerianus. 



PI. 12, Fig. 65, 65 a. 

 (E. Brewerianus, Remond; Proc. Cal. Acad., 1863, p. 53.) 



