Geol.— Vol. II.] ANDERSON— CRETACEOUS DEPOSITS. 91 



Occurrence. — The type of this species is in the collection 

 of the University of California. It was obtained from the 

 Cretaceous beds near Vacaville, Solano County, California, 

 by Mr. F. A. Steiger. 



33. Helicoceras indicum (?) Slol. 



Plate III, Figs. 96-97. 



cf. Helicoceras indicum Stol., Pal. Ind., Vol. I, p. 184, PI. LXXXVI. 



Shell small, coiled in a spiral, first to the right to a diameter of .7 cm. and 

 then reversed; section of whorls at first nearly circular, but afterward ellipti- 

 cal; surface marked by oblique transverse ridges not quite evenly spaced, 

 also by three or four constrictions. Diameter of spiral, 2 cm. ; septation 

 unknown. 



Occurrence. — A single specimen was obtained from the 

 Smith ranch, two and one-half miles southwest of Phcenix, 

 Oregon, and belongs to the horizon of the Lower Chico. 



The type here described is in the collection of the Cali- 

 fornia Academy of Sciences. 



34. Heteroceras ceratopse, sp. nov. 



Plate III, Figs, ioo-ioi. 



Shell elliptical, or subcircular in section, very helicoid, forming widely open 

 coils in mature age; coiled sometimes toward the right and sometimes toward 

 the left, and therefore neither in one plane nor in a regular spiral; surface 

 ornamented with numerous transverse striations intervening between much 

 larger and elevated ridges that rise abruptly from the surface of the shell at 

 intervals of a few millimeters. These ridge-like ribs begin upon the dorsal 

 side in elevations hardly distinguishable from the intervening striations, and 

 as they pass downward on the sides they become more and more elevated, 

 until on the siphonal side they are often i mm. in height. They are rarely 

 well enough preserved to show their exact character, but appear to be pointed 

 or tuberculated along their thin blade-like summits. 



The average diameter of the specimens collected ranges from .5 cm. to 

 I cm. The largest fragment has a length of 7 cm. All the fragments show 

 a tendency to curve irregularly and to depart from a simple spiral. Tiie 

 suture line is complex, consisting of bifid lobes and saddles; the lateral 

 saddles show a tendency to tripartite division in their main branches, while 

 the lobes retain their bipartite character throughout. In general form and 

 ornamentation this species resembles very closely Heteroceras reussianuin 

 d'Orbigny, as figured by Schliiter in " Paleontographia " (Vol. XXI, PI. 

 XXXII), to which it may be related. 



