58 



University of California PubUcations in Geology [Vol. 12 



STRONGYLOCENTEOTUS PUEPUEATUS (Stimpson) 



Echinus purpuratus Stimpson. Crust. Eehin. Pae. Coast, 1857, p. 86. 

 Stroiigylocentroius purpuratus. A. Agassiz, Rev. Ech., 111. Cat. Mus. Comp. 



Zool., pt. 1, 1872, p. 165; pt. 3, p. 449, pi. 5a, figs. 5-6, p. 16, fig. 7, pi. 



36, fig. 9. 



StrongyJocentrotus purpuratus. Arnold, Calif. Acad. Sci. Mem., vol. 3, 

 1903, pp. 90, 91. 



Strongylocentrotus purpuratus. Stefanini, Boll. Soe. geol. ital., vol. 30, 

 1911, p. 707. 



Strongylocentrotus purpuratus. Clark and Twiteliell, U. S. Geol. Surv. 

 Mon., vol. 54, 1915, p. 223. 



The occurrence of spines of this form is rather common in the 

 Upper Pliocene and the Pleistocene formations of the west coast. 

 Arnold discusses their occurrence as follows : 



Numerous spines of this small purple sea urchin have been found in the 

 San Pedro series. No part of the test has ever been discovered in these deposits, 

 to the writer's knowledge. Several nearly perfect tests of this species were 

 found in the Pleistocene (lower San Pedro series) deposits at the bath house, 

 Santa Barbara. A nearly perfect test was also found in the upper horizon of 

 the San Diego formation (Pleistocene (?) at Pacific Beach, near San Diego. 



Geologic horizon. — Upper Fernando, San Diego, and San Pedro 

 formations, Upper Pliocene, Pleistocene, and Recent. 



Localities. — Pacific Beach, San Diego County ; Fourth and Hill 

 streets, Los Angeles (Moody) ; San Pedro and Santa Barbara, Cali- 

 fornia ( Arnold ) . 



Order EXOCYCLOIDA Jackson 

 Suborder CLYPEASTRINA Gregory 



Family CLYPEASTRIDAE Agassiz 

 Genus CLYPEASTER Lamarck 



CLYPEASTEE BOWEESI Weaver 

 Plate 5, figures la, Ih; plate 6, figure 1 



Clypeaster boiversi Weaver. Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, 



1908, pp. 271-272, pi. 21, fig. 1, pi. 22, fig. 1. 

 Clypeaster bowersi. Stefanini, Boll. Soo. geol. ital., vol. 30, 1911, p. 701. 

 Clypeaster bowersi. Kew, Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1914, 



pp. 50-51, pi. 3, figs, lo-lb, and pi. 4, fig. 1. 

 Clypeaster bowersi. Clark and Twitehell, U. S. Geol. Survey Mon., vol. 54, 



1915, p. 209, pi. 96, figs. la b. 



