LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

description 1 of species 143
Phylloecrat aldcraoni Anderson, n, sp.
(Pill® 11, &CWI9 3. t. S. S)
Shell email, discoidal, slightly inflated, rounded on the sides which slope rapidly
to the periphery; umbilicus small, with steep walls curving roundly to tho sides;
surface mostly smooth, or polished, but marked by six or more slightly sinuous
periodic constrictions, between which are numerous fine costal lines (10 or more
to a centimeter) arising on the umbilical walls, curving at first forward, then gently
backward, and again forward on approaching the ventral border; intercostal spaces
relatively wide and smooth; cross-section of whorl somewhat elliptical, being broadest
near the middle of the side, and rounding ofT above and below.
The suture line ia not unlike that of P. onoenne Stanton, although the septa are
more numerous and more crowded, and also more complicated; the small siphonal
saddle is narrower and more pointed. The essential differences between this species
and the latter are in its smaller size, more inflated Bides, its periodic constrictions,
and the form and character of its costal markings. The largest specimen of this
species so far found has a diameter of mm., including the body-chamber. About
14 examples of the species were obtained, most of them from Locality 1348 (Calif.
Acad. Sci.) on Alderson Creek, 2 miles south of One, Shasta County, The holotype
(Calif. Acad. Sci. type Coll.), septate throughout, has the following dimensions:
greatest diameter, 40 mm.; width of umbilicus, 5 mm.; height of whorl, 21 mm.;
thickness of whorl, 17 mm.; umbilical ratio, 0.125:1. All the examples came from the
Alderson aone and were associated with Jfclefcimfti thaslmtit nov., Lyioteta* baltti
(Trask), Kamilicera* aequicoitatum nov., and a species of Aucella resembling A.
keyserlingi Lahusen.
Phylloc&raa californieum Anderson, n. sp.
(Tints 19, figurc 7)
Thia epecies is intermediate between Phylloceraa onotmw Stanton and the California
form of P. velledae Michelin in both form of ahcll and in its stratigraphic
position. It differs from both also in the character of its suture lines. The species
occurs in tho upper part of the Hulen hede (middle Albian) on Huleo Creek, and has
also been found at the upper limit of the Horsetown group at the old mining camp of
Horsetown on Clear Creek, Shaata County, where it is associated with Putoria
hoffmanni (Gabb) and Bcudanliceras breweri (Gabb),
The epecice differs from P. onoeme in its thicker and more robust form, in its
stronger and straighter coatae, which have little forward curvature upon their
approach to the ventral zone, and in Butural details.' In its outward form it resembles
the figures of P. velledae given by Stoliczka (1858, PI. 19, figs. 1-4), although it is
larger, whereas in the general and detailed character of its sutures it more nearly
approaches P. onoente Stanton. Phylloceraa velledae, or a closely related form, has
been found in the lower beds of th e Chico series half a mile cast of the mouth of Hulen
Creek, and about 1100 feet above the position of P. ealifornicum of the Horsetown
group.
The holotype (Calif. Acad. Sci. type Coll.) is a large fragment, representing an
individual 8 inches (203 mm.) in diameter, obtained from the upper part of the Hulen
beds, 50 feet beneath the Neptune zone at Locality 1580 (Calif. Acad. Sci.).
Phylioceras umpquanum Anderson, n. sp.
(I>Uu 30, figures », 10)
Shell small, robust, with small but deep umbilicus and inflated cross-section;
surface thickly coatate, with almost uniform, rounded costae, separated by some-