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