No. 1617. NHW CRETACEOUS AND TERTIARY FOSSILS—ARNOLD. 8361 
of the two systems producing a slightly nodose-cancellate appearance ; 
varices 2 to a volution, prominent, rounded, not reflexed; suture ap- 
pressed, shehtly wavy. 
Dimensions.—Of imperfect specimen, length, 17 mm.; latitude, 
13 mm.; length of body whorl, 10 mm.; apical angle, 76°. 
Notes—Owing to the poor state of preservation of the type of this 
species, which happens to be the only one so far found, it is impos- 
sible to diagnose the characteristics of the aperture, lips, and details 
of sculpture. It belongs to the same general group as 7. californicum 
Gabb* from the Tejon formation, upper Eocene, but is relatively 
much wider and has much stronger but less numerous revolving and 
axial coste than the latter. The varices appear to be continuous on 
adjacent whorls in 7’. newsomé rather than more or less irregularly 
disposed, as in 7’. californicum. 
Named in honor of Dr. John Flesher Newsom, professor of mining 
and metallurgy in Stanford University. 
Zype.—An imperfect specimen, lacking apex and canal, Cat. No. 
165436, U.S.N.M. 
[orizon.—Martinez (%) formation, lower Kocene. 
Locality —sSanta Cruz quadrangle, San Mateo County, locality No. 
25, ridge between headwaters of San Lorenzo River and Pescadero 
Creek. (R. Arnold.) 
Genus HIPPONYX De France. 
HIPPONYX CARPENTERI, new species. 
Plate XXXU, figs. 3, 3a. 
Description.Shell averaging only 11 mm. in longitude, tumid. 
with elongate oval base; apex distinct, small, curved shghtly to right, 
situated almost directly above posterior extremity of base; profile 
from apex to anterior extremity of base is slightly but regularly 
bowed upward; profile from apex to posterior extremity of base is 
straight or bowed slightly inward. Surface sculptured by numerous 
regular, rounded, radiating ridges separated by narrow incised inter- 
spaces and by less prominent, wider, less regular, imbricating con- 
centric lamellz; the radiating ridges are divaricate along a median 
line from anterior to posterior extremities; in some instances the in- 
cremental sculpture simply gives the radiating ridges a granulose ap- 
pearance. Interior unknown. 
Dimensions—Length, 11 mm.; latitude (restored), 9 mm.; altitude, 
4 mm. 
Notes.—This beautiful little shell is quite closely allied to the living 
Hipponyx twmens Carpenter, but may be distinguished from the lat- 
ter by its relatively narrower base, less prominent apex, and by its 
radiating ribs, which are equal instead of alternating large and small. 
Pal Cal., Ll. p: 1545 \pl. xxvi, fig. 33; 
