LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

de8crlpti0n of species 169
broader than the rounded interspaces, divided, or in two ranks; primary ribs arising
on the umbilical walla, eloping backward below tbe rounded umbilical border, sometimes
dividing below the middle of tbe side, more often single, alternating with
secondary ribs; all ribs cross the ventral zone without weakening. In its younger
stages the aboil of this apecies resembles Parahopliltt dtshayt-ti, as figured by Neumayr
and Uhlig (1881, pi. 46), which according to Kilian represents P. contobrintis
d'Orbigny. The suture line IB very similar to that of Parahopliioidet thou pi nov.,
the siphonal saddle being unaymmetrically divided by a deep cleft, tbe left side being
the larger and more developed.
The holotype (Calif. Acad. Sci. type Colt.) affords the following measurements:
greatest diameter, 136 mm.; width of umbilicus, 47 mm.; height of whorl, 38 mm.;
thickness of whorl, S3 mm,; umbilical ratio, 0.31B:1.
This specimen was found near Roaring River, 5J miles south of Ono, Shasta
County, in the Argonaut zone near the middle of the Horsetown group. It is not
uncommon in this horizon in the Cottonwood district, from its type locality north to
Hulen Creek and south to the middle fork of the Cottonwood Creek, The species
seems to have an analogue in "Acanthaplites" laticoalaius Siniow (1007, p. 482,
pi. 5, figs. 0-13), from the Caucasus Mountains, from which it differs chiefly in its
more rounded periphery, Battened sides, and slightly more sinuous ribs,
Parahoplilw Anthula
ParahopliUs alantom Anderson, n. sp.
(Fist* S3, flfara i; piste 1ft. Eguro 3)
Among the interesting hoplitid species found in the Horsetown group of the
Cottonwood district are three species akin to Parahoplitet uhligi Anthula. All are
robust forms with a relatively large umbilical ratio. The present species ia represented
by only the holotype (Calif. Acad, Sci. type Coll.), found at Locality 1348
(Calif. Acad. Sol.), near the forks of Alderson Creek, 1 miles south of Ono, Shasta
County.
This example ia almost wholly septate and affords the following measurements:
greatest diameter, 149 mm.; diameter of umbilicus, 51 mm.; height of whorl, 58 mm.;
width of whorl, 46 mm.; umbilical ratio, 0.340:1.
In section tbe whorl is ellipsoidal, somewhat quadrate, the greatest thickness
being below the middle of the side; surface strongly coatatc, with riba of two ranks;
2B stronger primary riba sinuous, arising on the umbilical wall, inclining at first
backward to tbe umbilical border, then rising vertically to the middle of the aide,
there curving gently backward, then forward to the periphery; secondary riba
smaller, arising singly or in pairs near the middle of the side; on the periphery, about
75 ribs to the whorl; all riba cross the ventral zone without interruption; ventral zone
slightly flattened, rounded on the borders; umbilical walls abrupt, rounded above;
sides flattened, or only slightly convex; septal sutures not fully shown, although the
siphonal saddle and lobes show the lack of symmetry common to most of the California
species of Parahoplitidae, The holotype has the general form and surface
characters of Parahoplitta uhligi Anthula, but a somewhat larger umbilical ratio,
more sinuous ribs, and a thicker section. It was found with Tropaeum percotlalum,
Parahoplitoidet, and other Bpecies in the middle part of the Horaetown group.
FaraJtopiifes daHasi Anderson, n. sp.
mU»34, Sturm S. 3)
A more extreme member of the same group was found in the lower part of the
Shoup zone east of Mitchell Creek. It is considerably thicker and stouter, with