LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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210 <strong>LOWER</strong> CRETACEOtffi <strong>DEPOSITS</strong> IN <strong>CALIFORNIA</strong> <strong>AND</strong> <strong>OREGON</strong><br />
not known; tuhereules on body-chamber at first low and rounded, becoming stronger<br />
and more prominent above; heaviest ribs and tubercules near the top of the crosier;<br />
ventral lone relatively narrow, bordered on each side by rounded tubercules on tho<br />
shaft and lower part of the body-chamber; section of shaft sub-elliptical, higher<br />
than broad, but becoming in the body-chamber transversely expanded, broader than<br />
high; bend of crosier abrupt; sutures not shown. The holotype (Calif. Acad. Sci,<br />
type Coll.) was found in the Mitchell zone, a mile north of Barr's corral on Mitchell<br />
Creek, accompanied by ParaAoph'bndes cerroiemii nov. in strata that may be referred<br />
to a lower Aptian horizon. As far aa known thiB is the latest species of Aneyiecna*<br />
found in the Cottonwood district. A large fragment of thia apecies including<br />
the body-chamber showing the last septum was found near the holotype; the<br />
body-chamber near tlila septum was compactly filled with fragments of smaller sheila,<br />
including smaller cephalopoda.<br />
Ancyloceras ajax Anderson, n. sp.<br />
(Plata is, fiiu i, 2. a)<br />
Shell large, robust, coiling ancyloceratid, closely costate, costae changing with<br />
growth of the shell; earliest coils unknown, shaft increasing regularly in diameter<br />
up to the position of the last septum; coatae at first nearly straight, simple, and<br />
normal to the dorsal border, becoming gradually oblique, and at the same time<br />
more distinct, and on the body-chamber developing tubercules on each fifth or sixth<br />
rib, ss in A, eiephas, to which it is nearly related; tubercuka at first email, elongated<br />
in tha direction of the rib; later tubercules becoming stronger, those at the top<br />
of the crosier being heavier, but most developed on the reverse limb; aperture unknown;<br />
body-chamber inflated transversely, but less so than in either A. aitrox<br />
or A, eiipAoa; shaft expanding less uniformly than in A. oliroi, the transition from<br />
shaft to body-chamber being more abrupt; greatest diameter of the body-chamber<br />
ia near the top of the crosier and transverse to median plane; section of the shaft<br />
always higher than broad; on the body-chamber the reverse ia true.<br />
Tha holotype (Calif. Acad. Sci. type Coll.) was found at the top of the Mitchell<br />
sane, south of Rearing River, atratigraphically about 200 feet above the horizon of<br />
Locality 1601 (Calif. Acad. Sci.); its horizon is thought to be near the boundary of<br />
Barremian and Aptian strata. In this specimen the shaft is crushed Immediately<br />
below the body-chamber as if from an injury while living, the sides being broken<br />
longitudinally by over-thrust of the shell, aa by compression. All parts of the shell<br />
were found in place in the position shown in the figure.<br />
Ancylaecraa durrdli Anderson, n. ap.<br />
(Plato ft?, &eutm 1, S; plate 00. Sgura 1)<br />
Shell large, robust, coiling ancyloceratid, closely costate in early coil and on the<br />
shaft; costae non-tuberculate on the shaft, trituberculate on the earlier coil and on<br />
tbe body-chamber; section of shaft nearly circular; section of body-chamber becoming<br />
sub-elliptical; ribs on body-chamber becoming suddenly thick and broad, bearing<br />
low, tumid tubercules; ribs on bue&l limb narrow and elevated, but strong. In its<br />
manner of eoatation and ornamentation,, this spccies is intermediate between A«eyhcetae,<br />
of the type of A. aj.ax, and SAasfcceroj (gen. nov.), tha latter possessing no<br />
tuberculsa except on the earliest coils, which are weakly tuberculate on the ventral<br />
border. The holotype (Calif. Acad, Sci. type Coll.) consists of the larger p&rt of the<br />
shaft, gently curved, bearing slightly oblique, and nearly straight, rounded costae,<br />
which occasionally divide above the dorsal border. The suture line consists of long,<br />
tripartite, and branching lobes and broad, deeply cleft saddles, showing hopiitid (or<br />
possibly perisphinctoid) charaetera. The pamtype (Calif. Acad- Sei. type Coll.)