LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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206 <strong>LOWER</strong> CRETACEOtffi <strong>DEPOSITS</strong> IN <strong>CALIFORNIA</strong> <strong>AND</strong> <strong>OREGON</strong><br />
with two kinds of ribs, of which each third, fourth, or fifth rib is tuberculate, with<br />
rounded mammillary tubercules in three rows os either side of the aiphonal plane;<br />
the intervening riba are si triple and without tubercules; the coiling is crioceratid in<br />
its early stages but later departs from this manner and forma a partly straightened<br />
shaft (cyrtocone) on which the ribs become coarser. The ribs have an ancyloceratid<br />
aspect which, according to Anthula, rocalls Ajtcyioccrae wrbam Neumayr and Uhlig.<br />
At least two species of this genus seem to have been found in the lower Cretaceous<br />
(Barremian) of California, but, for lack of sufficient charac tarnation perhaps, this<br />
cannot be stated with entire confidence.<br />
PstTidocri&ceras stemtor Anderson, n. sp.<br />
(Plato 91, E*ww I, I A)<br />
Shell large, robust, coiling openly crioceratid, coils not contiguous; section of<br />
whorl circular, slightly flattened on the dorsum, closely ooatate; ribs of two classes,<br />
major and minor; major ribs arising as broad, transverse, trituhereulate ridges,<br />
between which are six to eight slightly sinuous costae extending around the whorl<br />
almost at right angles to its axis, but with a slight deviation, or sinus, in the dorsal<br />
zone; sutures not well shown. The holotype (Calif. Acad. Sci. type Coll.) waa found<br />
at Locality IfMU (Calif. Acad. Sci.), a mile west of the Murphy house in the Hearing<br />
River district, 7 miles south of Ono, Shasta County. It has the following dimensions:<br />
length of cone along the siphonal zone, 260 mm.; traneverac diameter at<br />
larger end, 65 mm.; tapering to a-diameter of 27 mm. This species was found Associated<br />
with Ho-plocriocertu tumiu-m'um, Shaaticrioceras ponunle, AcrotdtitAfj fcernenstj,<br />
and Inoceramus oaatoides. nov. The species bears some resemblance to AvztraliceTae<br />
irregulars (TeniBon-Woods) as illustrated by Whitebouse, although the similarity is<br />
probably in form only. The horizon is believed to be upper Barremian, and it can<br />
hardly be younger,<br />
Acriocerea Hyatt 1806<br />
Acmcflros ppyanum Anderson, n. sp.<br />
I Hit® 29, Sjrure 1)<br />
Shell of medium size, coiling at first crioceratid, but later forming a shaft and<br />
body-chamber having a recurved limb; section of early whorls nearly circular,<br />
becoming gradually compressed on the sides, particularly on the shaft and bodychamber;<br />
surface marked by major and minor costae; major costae trituhereulate,<br />
the tubercules on the ventral border being epinoae in early stages, but depressed in<br />
later stages of growth; minor costae simple, normally three or four intervening<br />
between pairs of major cestui; co&tation on the shaft oblique, without spines; on the<br />
later part of the shaft all costae tending to become equal and smooth, only a few<br />
showing tubercules; three or four constrictions appear on the holotype near the<br />
top of the crosier. The holotype of this species is in the Museum of Paleontology,<br />
University of California (No. 110) and was a part of the Voy collection. It is said<br />
to have been found on Cottonwood Creek, Shasta County, but more definite indication<br />
of its position was not given. It is partly encased in a hard calcareous concretion,<br />
such as abounds in the lower part of the Horsetown group, and seema to have<br />
come from a zone somewhat above the base of the group. The apeciei belongs to<br />
the group represented by tho genotype, "Ancyloeeras" tabarclli (Astier), as illustrated<br />
by Sarasin and Schoendelmayer, differing from it chiefly in the thickness<br />
of the shaft and in the number of minor costae. The concretion containing the holotype<br />
contains also remnants of carbonized wood, in which there arc various fragments<br />
of a wood-boring shell, possibly that of Turnm plenm Gabb,