LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

122 loweb cbetaceodb depOSitS in california. and oregon
t&ceoua (Senonian) beds ol Texas Flat, near Folaom, but is more like that from Sucia
Island, figured by White. Tho present apecies is somewhat more inflated than either
form mentioned above, lacks the atrsight hinge line of tbe first, and has more prominent
beaks than the latter. The holotype (Calif. Acad. Sci. typo Coll.) was found
at Locality 1353 (Calif. Acad. Sci.) in the Ono tone near the bridge on the Cottonwood
Creek, Shasta County. Its Btratigraphical position is near the base of the
Hometown group; it was found associated ytithNeocratpediiet aguila, nov., and many
other species characteristic of this zone. It has the following dimensions: length,
SO nun.; height, 25 mm.; thickness of both valves, 20 mm.; form sub-spherical. This
is the oldest Bpaciea of the genus found in the Cretaceous of the West Coast.
VENBRIDAB Leach
Venus Linnaeus
Venus callinium Anderson, n. sp.
(Ptale 1, icun 3; FUta 4, flcuro 8)
Shell of medium size, aubcircular in outline, as broad aa high, moderately inflated,
test rather thick; cardinal margin gently rounded, the curve merging regularly
to that of the rounded basal margin; lunule well defined, narrow and lanceolate;
basal margin of shell denticulate within; beaks a litttq depressed; surface of shell
marked only by coarse, concentric, somewhat irregular lines, without radial sculpture;
hinge plate apparently bearing three cardinal teeth.
Three incomplete examples of this species were found by E. J. Broad in the Hamlin-Broad
zone at Locality 113 (Calif. Acad, Sci.), 4 miles southwest of Ono, Shasta
County. Of these, the holotype (Calif. Acad. Soi. type Coll.) measures: length,
39 mm.; height, 39 mm.; thickness of one valve, 11 mm. The other examples were
smaller. The horizon from which these examples were obtained ia in the upper part
of the Paskenta group, about 500 feet beneath the lowest bed of the Horsetown
group in tbe Cottonwood district Two other examples of tho same apacies were
found by 0, D. Hanna at Locality 1691 (Calif. Acad. Sci.) near Clements ranch,
eastern Trinity County. At its type locality the species was associated with Polyptychitea
lecontei, Lytocerot auta«um, jSu&a^ien'a chanchelula, and many other forms.
At the Clements ranch it was found associated with Periplomya Teddingensit, Pholadamya
allumbanaia, and various other species regarded as representing the upper
part of the Paskenta group, from which came the holotype of Criocerm latum Gabb,
reported from the Trinity River.
Venus corella Anderson, n. sp.
(Pkt«4, Scant, J)
Shell small, cordiform, inflated; beaks rather high, prominent, incurved, and
approximate; lunule distinct, impressed, semicircular in outline; hinge line nearly
straight; base circular; surface marked by uniform radiating ribs and by faint
eoncentric lines of growth; interior margin of the valves denticulated with interlocking
denticles.
The holotype (Calif. Acad. Set. type Coll.) was found at Locality 1346-A (Calif.
Acad. Sci.) in tbe Buenaventura zone of the Hulcn beds, on the went branch of Mulen
Creek, a mile above its entrance Into the Xorth fork of tbe Cottonwood Creek. It
was associated with Puiosia buenmienlura nov., Cheloniceraa sp., Acanlhoplile* sp.,
and Douwlfeiceras cf. mammillatum. Its dimensions arc: length, 11 mm.; height,
12 mm.; thickness of both valves, 11 mm.
The same species was found also at Locality 162 (Calif. Acad. Sci.) in the Porrin