LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

204 LOWER CRETACEOtffi DEPOSITS IN CALIFORNIA AND OREGON
flattened. The suture line ia well developed and clearly is hopiitid in character,
strongly resembling that of Neocomila. The small siphonal saddle is high and
narrow, and all the saddles are deeply cleft; the first lateral lobe with a broad stem
has three main branches, showing asymmetry, and terminating in long, narrow,
digitoid points.
SAoaften'ocerM pmienU Anderson, n. sp.
(Pint* ST, flfura 1-3; Plata CT, fig una 4, 5}
Shell large, discoidal, coiling crioceratid; coils closely approximate in young
stages, becoming mora separated with growth, the final body chamber departing
widely from the coil, forming a long straightened arm; section of whorls aubquodrate,
flattened on the sides in young stages, becoming more inflated in older shells; aides
numerously costate in youth with fine, mostly simple, sometimes divided costae,
which at first are slightly sigmoid, but become heavier and straighter in old age;
costae closely spaced in youth, becoming progressively more widely spaced in later
whorls; costae (or ribs) tuberculate only on the angulated ventral border, with
tubercules elightly elongated laterally, sometimes prominent; all ribs crossing tho
ventral zone without interruption, but weakened on the periphery; ventral zone
flattened with respect to ribe, rounded with respect to interspaces.
A single detached large fragment found with the holotype measures nearly IS
inches in length, has widely separated ribs which are rounded and swollen on the
dorsal border, roundly tuberculate on the ventral border, and slightly inflated between.
The holotype (Calif. Acad. Sei. type Coll.) was found at Locality 1657
(Calif. Acad. Sci.), a mile east of the Jordan house near Mitchell Creek, in the
Mitchell zone, associated with Paeudocrioceraa sp., Ptyehocertu natriee nov., and
AeroleutAts sAflstenst's nov. Other species of this genus have been found in or near
the same zone not far distant. Whiteaves has figured a similar form from the Cumshewa
Inlet, Queen Charlotte Islands, under the name "Ajusyloccraa" remondi Gabb,
but its relationship seems to be nearer to iSAostierioceras poniente than to Hoplocriecera*
remondi (Gabb). This is tbe most widely distributed crioceratid species
found in the Cottonwood district in California.
•SfiiMiierioserae heepervm Anderson, n. sp.
(Plate M, tioa 1, J: FUt« M, flm» 3)
Shell large, form similar to the preceding apecies but more finely sculptured;
young whorla in contact, more separated in older stages, and finally forming a
straightened arm, or body-chamber; whorls quadrate in section with distinctly flattened
sides, the ratio of height to width of whorl being about 24 to 17; sides closely
costate in young stages of growth, but with age the costae (or ribs) become thicker,
Straighter, and more distant; ribs tuberculate only on the ventro-lateral angle,
each rib bearing a small, slightly oblique, spineless node; although weakened in
the ventral zone all riba cross it without interruption; ventral zone flattened. The
holotype (Calif. Acad. Sei. type Coll.) waa found near Locality 1681 (Calif. Acad,
Sci.) but in strata about 200 feet higher in the section than the strata exposed here.
It occurs with the preceding species, and also above it, and a little below the horizon
of Ancyloccras ajax nov., and within the Mitchell zone. The holotype has about
103 peripheral costae to the whorl in adult stages of growth, most of which arise
singly oa the dorsal wall, crow the side, on which they occasionally branch, and
occasionally produce short intermediary ribs, alt of which bear tuberculcs on the
ventral border. The holotype, with the outer whorl somewhat displaced, measures
175 mm. in diameter. In form, costation, and autural characters it suggests hopiitid,
perhaps a neocQmitid, ancestry, and for this reason is considered with the preceding