LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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216 lower cretaceotffi deposits in california and oregon<br />
Hamiticcras pilsbryi Anderaoo, a. sp.<br />
(Flit* 79, Spin t)<br />
Helicanajlus atQuicosiaiut GABB (in part only), Paleont, Calif,, vol, 2, 18SG, p. 141,<br />
pi. 25, 30b, c, d, e, f, (T g), all belonging to a single individual; locality<br />
not certainly known,<br />
This remarkable species ia of medium aise; its limbs are circular in section but<br />
ace diverse in form and ornamentation; the smaller limb, which is also the longer,<br />
possesses oblique ribs of two kinds, alternately smooth and simple, and trituberculate<br />
thicker ribs; body-chamber sharply bent, not ahown in Gabb's figures; ribs on the<br />
smaller limb interrupted on the siphonal line by a nearly smooth depression bordered<br />
by ventro-lateral tubercules; larger limb heavily costate, with simple noii-tubereulate<br />
ribs, much stronger than those on the amaller limb; near the dorsal border the<br />
ribs are reduced in strength and bent forward; all are more prominent on the ventral<br />
side; intercostal apace* broader than the ribs. The trituberculate ribs on the similar<br />
limb show its ancyloceratid character, aa do also the aepta, as drawn by Gabb (1606,<br />
pi. 25, fig. 20g). The several fragments illustrated by Gabb (ISM, pi. 25, figs. 20b,<br />
c. d. e. f) have DO close relation to the others (Gabb, pi. 25, figs. 20,2&V) which belong<br />
to a distinct genus. The holotype of this species is in the museum of the Academy<br />
of Natural Sciences of Philadelphia and waB loaned to the California Academy o(<br />
Sciences for study and illustration. It has tho following dimensions: total length,<br />
62 mm.; maximum diameter of larger limb, 33 mm.; maximum diameter of smaller<br />
limb, 28 mm.; width across both limbs, 59 nam, An example of this spedes has been<br />
found by W. P. Popeaoe and B. W. Scharf in the Argonaut zone on the North fork of<br />
Cottonwood Creek, near Ono, Shasta County, and tho horiion of the holotype is<br />
believed to be the same.<br />
Hamilietrat philadelphium Anderson, n sp.<br />
(PUta 19, fiffurtit 3, S)<br />
In the collections of tbe Academy of Natural Sciences of Philadelphia there ie a<br />
well-preserved example of this genua—the holotype of the present apeciea. It bears<br />
Gabb's label, "Helieancylu* aequicastatus" Gabb, and is No, 4707 (Acad. Nat. Sei.<br />
Phila ); it is said to have been found on the North fork of Cottonwood Creek, Shasta<br />
County. It has the following dimensions: total length, fll mm.; width aero® both<br />
limbs, 45 mm.; maximum diameter of larger limb, 20 mm.; section of both limba,<br />
nearly circular. A line of faint tubereulca appears on the side of the smaller limb,<br />
and a row of depressed bullae ie shown on the ventral border. As far as can be<br />
seen this apecies is not unlike the figures given by Stolley (1912, p. 11, 14, pi, 1) for<br />
"Ancyloceras" pataffonicunt, from the district of Lugo San Martin in western Argentina,<br />
Stolley regards hie species as rapresenting an upper Xeoconiian or Aptian<br />
horizon, perhaps near that of the present species. The nearest European analogue<br />
foe which a description has hcon found is N Aneyioc«ra»" ofiomfwm von Koernsa. Moat<br />
of the species and examples of Hamiticeras so far obtained from the Cottonwood<br />
district belong in, or above, the Argonaut zone of the Horsetown group, here regarded<br />
aa being middle Aptian in age.<br />
Hamiiicerai aequic-osialum (Gabb)<br />
(Flute IT, Siurra I, Si, 3; plila ft. Stun 4)<br />
Pfythoctras aeijuicostatus GABB, Paleont. Calif., vol. 1, lfKH> p. 74, pi. 13, fig. 20;<br />
North fork of Cottonwood Creek (not Hehcanajlus aequicoiiatua GAUD, vol. 2,<br />
1869, p. 141, pis, 25,20, SOa),<br />
Hamites (Piyckoa>raB) aequicosiatua (Gahb) <strong>AND</strong>ERSON, Calif. Acad. Sci., Pr,,<br />
3d ser., vol. 2,19€2, p. 30; Locality as by Gabb.