78 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



the portion covered by the body-whorl in one of the speci- 

 mens, and the outermost layer is marked by minute granu- 

 lations that have a systematic arrangement in rows parallel 

 to the median plane. 



13. Nautilus charlottensis Whitcaves. 



Nautiltts sttciaensisyNH\TK\\'Ti.s, Mes. Foss., Vol. I, 1876-84, p. 197, PI. XXI. 

 Nautilus charlottensis Whitcaves, Mes. Foss., Vol. I, p. 269. 



A fine example of this species was found at Horsetown, 

 Shasta County, California; it is in the museum of Stanford 

 University. Whiteaves reports it from the Upper Creta- 

 ceous of the Queen Charlotte Islands. In the Horsetown 

 examples the siphonal tube is perhaps a little lower in its 

 position than in the northern specimens. It appears to be 

 very similar to JV. pseudo-clegans d'Orbigny,' although the 

 position of the siphonal tube is a little higher than in 

 d'Orbigny's figure. There is a relationship between N. 

 gabhi and ^V. charlottensis, similar Indian species mentioned 

 in the preceding description. 



14. Nautilus sp. 



Among the collections obtained by Dr. Bowers from the 

 Santa Ana Mountains are two imperfect specimens of 

 NaiitiliLS that appear to be related to N. gabhi and N. char- 

 lottensis, though not identical with either. It forms, perhaps, 

 a third member of this group belonging to the Pacific border 

 province. 



AMMONOIDEA. 

 15. Placenticeras californicum, sp. nov. 



Plate VIII, Figs. 173-177. 



The shell is discoidal, compressed, narrowing regularly from the umbilical 

 region outward; inclined to be rough or with coarse ribs; costee flexuous, 

 extending to the umbilicus, and terminating outward in tubercles upon the 



1 Pal. Franc. Terr. Cret., Vol. I, Pis. IX and XIX. 



