LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

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