134 



University of California Ptiblications in Geology [Vol. 12 



Related forms. — This form is most closely related to Calaster inter- 

 lineaius (Stimpson), but may be distinguished by its more eccentric 

 apical system ; the smaller size of the test ; the subpentagonal to sub- 

 elliptical outline ; and petals which are less symmetrical in shape. 

 From the true California dendrasters it is easily separated by its 

 supramarginal periproct, and from the scutellid forms by the posterior 

 eccentricity of the apical system. 



Geologic horizon. — Lower Merced series, Upper Pliocene; occur- 

 ring stratigraphically below Calaster interlineatus; also in the Empire, 

 Elk River, and Purisima formations. Upper Pliocene. Associated in 

 the Purisima formation with D. perrini (Weaver) and D. gibhsii var. 

 humilis Kew. 



Locality. — Holotype from "Upper Miocene sandstones at Fossil 

 Point, Coos Bay, Oregon" (Dall) ; figured specimens also from this 

 locality. 



DENDEASTER (CALASTER) OREGONENSIS GIBBOSUS Kew, n. var. 

 Plate 33, figures 3a, 3b, 3c 



Ooiypes.— Nos. 11385 and 11386 Univ. Calif. Coll. Invert. Pal. 



This form differs from Calaster oregonensis (Clark) in that its 

 upper surface is markedly elevated; the degree of slope is less in 

 the submarginal area, which gives the abactinal surface a distinctly 

 humped appearance. 



Geologic horizon. — Upper Wildcat formation. Upper Pliocene. 



Locality. — Cotypes from near Shively, Humboldt County, Cali- 

 fornia, Univ. Calif, loc. 3 881. 



DENDRASTER (CALASTER) OREGONENSIS MA,JOR Kew, n. var. 

 Plate 34, figures la, \h, Ic 



Scutella interlmeata. Merriani, Proc. Calif. Acail. Sci., ser. 3, Geol., vol. 1, 



no. 5, 1899, pp. 168-169, pi. 22, fig. 6. 

 Bendraster (?) interlineatus. Stefaniui, Boll. Soc. geol. ital., vol. 30, 1911, 



p. 706. 



Bendraster interlineatus. Clark and Twiteliell, U. S. Geol. Surv. Mon., 

 vol. 54, 1915, pp. 216-217, pi. 100, figs. 2a-2h. 



Cotypes.— Nos. 11044 and 11352 Univ. Calif. Coll. Invert. Pal. 



This form differs from the typical Bendraster (Calaster) orego- 

 nensis only in its much greater size. Measurements of specimen no. 

 11352 : anteroposterior diameter 73.3 mm., transverse diameter 76.3 

 mm., greatest thickness 9 mm. 



