NO. 1545. NEW FOSSIL MOLLUSKS FROM CALIFORNIA— ARNOLD. 531 



Locality. — Head of Topanga Canyon, 3 miles south of Calabasas, 

 Los Ano-eles County, California. (G. W. Edmond and Ralph Arnold.) 

 Horizon. — Lower Miocene. 



CERITHIUM TOPANGENSIS, new species. 

 Plate XL, figs. 7 and 8. 



Description. — Shell turreted; apex acute; whorls nine or ten, 

 slightly convex, with a faint suggestion of a shoulder at the posterior 

 margin. Whorls ornamented by a varying number of spiral and 

 longitudinal ridges of which there are eight of the former and twenty- 

 one of the latter on the penultimate whorl of the type; the relative 

 prominence of the two sets of ridges varies somewhat, ))ut they are 

 normally of about equal importance. Suture impressed; distinct. 

 Aperture subquadrate; outer lip effuse, broadly rounded below and 

 slightly produced in a columellar l)eak; inner lip straight above this 

 beak. 



Dimensions. — Longitude, 23.5 mm.; latitude, 7.5 nun.; l)ody whorl, 

 10.5 mm.; aperture, 7 nmi. 



Notes. — Quite unlike any other West Coast Cerithium, l)eing closest, 

 possibly, to C. (jcnimatu Hinds, from which it differs b}' having more 

 numerous and more delicate longitudinal ridges and ver}^ much less 

 pronounced nodose sculpture below the suture. Named after the type 

 locality, Topanga Can3'^on. 



Type.— Q?ii. No. 101070, U.S.N.M. 



Locality. — Head of Topanga Can^^on, 3 miles south of Calabasas, 

 Los Angeles County, California. (G. W. Edmond and Ralph Arnold.) 



Llorizon. — Lower Miocene. 



TURBO TOPANGENSIS, new species. 

 Plate XLI, figs. 6, tV/, and (i/*. 



Description. — Shell tur1)inated, solid; whorls somewhat convex and 

 prominently tuberculated, one row of about nine sharp tu])ercles 

 surmounting the whorl just below the suture, another band of less 

 prominent ones in the middle of the whorl, and the base of the whorl 

 ornamented by another spiral row, the tubercles of which are almost 

 as prominent as the top row; in addition to this there is a secondary 

 sculpture consisting of numerous faint ridges crossing the whorls 

 diagonal!}" from the base posteriori}^ toward the suture. Base 

 ornamented by three prominent spiral ridges, the outer one tuber- 

 culated. Suture impressed, distinct. Aperture round, slightly pro- 

 duced and somewhat flaring in front. 



Dimensions. — Altitude, 10.5 mm.; latitude, 18 mm. 



Notes. — A unique species, somewhat resembling Turlw t<quamigera 

 Reeve, but differing from the latter in having less tal)ulated and 

 angulated whorls, a simpler sculpture of tubercles, and in having a 



