LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

description of species
triangular, the umbilical riba are thicker and stouter, and they divide at a higher
level than in the English form.
The holotype was found associated with other forms of the genus, as given under
Palyptych.itea ieeonfei, no?.
Palyptychile* iratki (Gabb)
Ammonite* iratki GABB, Paleont. Calif., vol. 1,1864, p. S3, pi. 11, fig. 10; pi. 12, fig. 11
(septum); "Arbuckle Diggings," Shasta County.
OtawlspAanus irasfci STANTON, S. Geol. Surv., Bull, 133,1895, p. 18, 22; near Wilcox
ranch, Tehama County, and (?) Riddle, Oregon,
From the description and figure of this species given by Gabb, although they
are defective, it is evident that this form represents some species of Palyplychiies,
a genus not uncommon in the Paskenta group of the Shasta aeries. Various congeners
of tbe species have been found in the upper part of this group, not only in the
Cottonwood district, but in tho Elder Creek-McCarthy Creek district, The holotype
figured by Gabb was the property of the California Academy of Sciences and was
in tho care of the writer prior to 190B, but waa Inst in the San Francisco fire of that
year. In section the younger whorls were nearly circular, becoming higher than
broad in older stages. According to Gabb's description the surface was marked by
numerous dichotomouB ribs, but this is scarcely borne out by his figure, which shows
the stout umbilical ribs branching into four or more costae below the middle of the
sides. In this respect it is unlike any other of tho group found in the Cottonwood
district.
Tbe locality of discovery given by Gabb is subject to much doubt, as elsewhere
shown. It ia believed to have been found in the Hamlin-Broad zone, which passes
about 2 miles to the east of the old Arbuckle mine in western Shasta County. Its
horizon would be, accordingly, in the upper part of the Paskenta group (upper Valanginian),
as will be shown later. The occurrence of this species near the Wilcox
ranch in Tehama County (Stanton, 1895, p, 18) appears to mark the same horizon
as that of the Hamlin-Broad zone in the Cottonwood district.
The species is also recorded from Riddle, Oregon, by Stanton (1805, p. 22), and
in both these areas it aids in tho correlation of the beds with those of tho Cottonwood
district and the Paskenta group of the Shasta series.
In the Oregon area near Riddle, as will bs shown, more than a single faunal
zone appears to be represented. Stanton has given a list of 15 genera and with them
has named at least eight species. Half of the forms given in the list may weil be of
Chico age, others undoubtedly represent the Horsetown group, and some are from
the Paskenta group, including the present species and A ucella cratmcollit.
Simbirtkitet breadi Anderson, n. sp.
(FlaW S3, firms 2, J; pis l« 28, Spire* 1,1*)
Shell not large, inflated, broadly umbilicate, section of whorl reniform, broader
than high, in younger stages depressed; umbilical walls abrupt, sloping above; umbilical
ribs stout, arising on the wall of the umbilicus with a slight backward slant,
then rising to near tbe middle of the side where it forms a tuberculate node from
which it divides normally jtto three (rarely two) peripheral ribs which cross the
ventral area without interruption; ribs rounded, inclined forward on tho upper part
of tho shell, separated by rounded interspaces, which are broader between the rib
clusters than between the ribs themselves. This species appears to have its nearest
analogue in Simbirtkites dechcni Pavlow (not Roemer), from the Neocomiaa of England,
which Spath appears to regard as synonymous with "OUotlephtiriui"kleini
162