LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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142 lower chetaceous deposits ijf california and oregon<br />
Tho nearest European analogue, although much earlier, ia P. Tfi/undibujuni d'Orbigny.<br />
This species does not appear to be closely related to either P. vciledae Michelin,<br />
P. onoense Stanton, or P. aldcrgoni nov., but it belongs in tbe lineage of P. occidentals<br />
nov. The holotype of this species is in the Museum of Paleontology, University<br />
of California, and waa found by the writer at tbo old mining camp of Horsetown,<br />
Shasta County, in the uppermost beds of the Horsetown group. A topotype of<br />
tho apociea is in the collections of the California Academy of Sciences.<br />
Phylloceraa onoerue Stanton<br />
(Pluto 11, Bgura 1,2)<br />
Ammonites RANTOATHA, GABS (not MEEK), Paleont. Calif., vol. 1, 1BW, p. 63, pi. 11,<br />
figs. 12, 12a; pi. 12, fig. 12b; Lower Crctacooua, Cottonwood Creek, Shasta<br />
County.<br />
Phyllot-eroti onotnae STANTON, U. S. Geol. Surv,, Bull. 133, 1895, p. 74; Horsetown<br />
beds, Shasta County.<br />
Phylloeertu ramoswn (Meek) is a species belonging strictly to the Upper Cretaceous<br />
(Senonian) of tbe West Coast, and has not been found in the Shasta scries.<br />
Gabb erroneously identified a species found in the Cottonwood district with that<br />
of Meek, as was pointed out by Stanton. Gabb's figuras of the Horsetown species<br />
are defective, although there can be no doubt aa to the form he endeavored to represent.<br />
To this species Stanton has given the name Phyiloceras oiutcnac.<br />
The shell of this species is discoidal, compressed, or somewhat lenticular, with<br />
a small but open umbilicus; sides flattened, but sloping to a narrowly rounded<br />
periphery; surface at first almost smooth, but with growth it acquires numerous<br />
rounded, radiating threads (18 to a ccntimeter in adult specimens), separated by<br />
concavc interspaces, broader than tho threads; costal threads arising near the umbilicus,<br />
curving at first forward, then rising vertically, and finally curving gently<br />
forward on approaching the periphery. Gabb's (1S64, pi. 11, fig. 12) figure shows the<br />
curvature of these lines to be backward, contrary to fact, and the suture lines do not<br />
show correctly the pbylliform terminations that are characteristic of this species.<br />
The smaller terminations on the saddles are obovate, showing the spccies to be a truo<br />
PAjriioceras. Its horizon IB commonly in the middle Horsetown group (Bedoulian),<br />
in which beds it is usually associated with ilytoceraa argonaularum, Parahoplilaidea<br />
ccrrctensis nov,, and Acroteulhin aboriginalis nov. Six or more good specimens were<br />
collected from the Argonaut zone at Locality 1347 (Calif. Acad. Sci.), half a mile<br />
east of Mitchell Creek and 5 miles south of Ono, Shasta County.<br />
The example figured by Gabb has been listed ae being in the Museum of Paleontology,<br />
Univcreity of California, by Men-ism (1595, p. 1), but it has not been found.<br />
Under the circumstances attached to this specimen, it seems better to propose a<br />
lectotype for the specica, and a more complete example (Calif. Acad. Sci. type Coll.)<br />
is selected to represent it. This example was obtained on the west branch of Bee<br />
Creek, half a mile east of the Shoup ranch house, in the Argonaut zone. It has the<br />
following dimensions: greatest diameter, 120 mm.; width of umbilicus, 7 mm.;<br />
height of ivhorl, 65mm.; thickness of whorl, 35 mm.; umbilical ratio, .058:1. Some<br />
fragmentary examples of the species have been found which indicate an original<br />
diameter of 12 inches, although the usual size is about 4 to 6 inchca. It differs from<br />
P. knoivilleMe Stanton in its finer ribbing, and distinctly different suture lines,<br />
particularly in its broad, short sipbonal saddle. It also differs from P, cali/ornicum<br />
no v., in its finer and more sinuous costal lines, in its thinner section, and in its lower<br />
horizon.