LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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description of bpbcte3 163<br />
umbilicus abrupt, rounded above, but curving rapidly to the flattened aides; section<br />
of whorl semi-elliptical, higher than broad, narrowing toward tho rounded periphery;<br />
Strong umbilical ribB arising at the whorl suture, inclining strongly backward, thickened<br />
to bullae on the margin; ribs branching from these into two, or rarely into three,<br />
Smaller, rounded, sinuous ribs; between these groups are interpolated a few simple<br />
ribs; other intermediary ribs arise at intervals above the middle of the Bides; all<br />
ribs crossing the ventral zone without interruption and with a forward bend; the 60<br />
or more costae on the periphery arc about three times the number occurring on the<br />
umbilical border; the interspaces between the ribs are broader than the ribs, and<br />
are concavely rounded; in adult stages the ribs bccome heavier and more widely<br />
spaced; the sutures are hoplitid, although not clearly exposed.<br />
This species greatly resembles Thurmannia boiaaieri (Pictet), as figured by tFhlig<br />
(1903, pi. 80), and it may be its nearest California analogue. It differs from this<br />
apecies in having a more rounded ventral border, in its more elongated umbilical<br />
bullae, and its fewer intermediary ribs arising above the middle of the sides.<br />
The holotype (Calif, Acad. Sci. type Coll.) was found in a calcareous concretion<br />
buried in dark shale in the Hamlin-Broad zone 3 miles southwest of Ono, Shasta<br />
County, and about 1600 feet above the local base of the Paskenta group. Its<br />
stratigraphic position appears to be near that of Dichotomies, BcrriaseUa, and<br />
Aucella crassicollis on tho Wilcox ranch and on McCarthy Creek, Tehama County,<br />
and therefore aids in the correlation in the two districts, -<br />
BBUMABELLIDAB Spath 1924<br />
BerriatellQ Ublig 1903<br />
Berriaaella angulata (Stanton)<br />
Soplites ANPUTOLTM STANTON, U. S. Geol. Surv., Bull. 133,1896, p. 80, pi. 18, Bgs. 3, t;<br />
Sheltoa's ranch, fi miles north of Paskenta, Tehama County.<br />
Concerning this species Stanton says (in part):<br />
"This species is evidently related to Hopliles storrti. but its whorls are proportionally<br />
somewhat more convex, its sculpture is relatively coarser, with broader and<br />
more strongly curved ribs, and the border of the umbilicus is more angular."<br />
Stanton also compares it to a specimen from Speeton, England, figured by Pavlow,<br />
which the latter regarded as "Hoplites" amblygontus Neumayr and Uhlig. According<br />
to Burckhardt (1930, tables 0, 10) "Hoplites" alvrrsi Stanton should be regarded<br />
as a Berrioeella, and seems to belong to the group of Berriasella calitto (d'Orbigny).<br />
This observation should also apply to "Hoplites" angulatus Stanton, and to other<br />
forms described from the lower part of the Paskenta group. The association of this<br />
apecies with Auc«tfa cra-sso, A. croeticollis, "Simbirskitee" mutabilis Stanton, and<br />
Bochianilcs, and other forms of Berriasella indicate a horizon not higher than the<br />
upper part of the Paskenta group, and therefore not higher than Valangintan.<br />
ifarrtaseiJa crassiplicata (Stanton)<br />
Hoplites crassiplicalua STAKTCIJJ, U. 9. Geol. Surv., Bull. 133, 1895, p. 81, pi. 18, figure<br />
8; 3 miles north of Paskenta, Tehama County, associated with Aucclla craasieollia.<br />
Stanton compares this species with "Russian Lower Volgian species 'Hoplilc*'<br />
rjaaensU Lahuacn," as figured by Xikitin, However, as noted by Stanton, the form<br />
is perisphinctoid, and is characterized by a<br />
"Surface ornamented by relatively large, distant riba that arise on the edge of the<br />
umbilicus, and nearly all bifurcate after passing over about two-thirds of the distance<br />
to the periphery, on which they are interrupted."