LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

description of species 151
Gandryeera* Groaaouvre
Genotype, 4«im. duvalianum d'Orbigny
The basis of Groaaouvre'a characterization of this subgenus ia primarily in tho
form and ornamentation of the shell. At first sight the shell resembles that of Lyloceras
(*.«.), both in. form and ornamentation, but these features are soon lost.
According to Groaaouvre:
"In most of tbe forms of this group, the whorls clasp very lightly in youth and
ordinarily are little involute" and ' the shell presents the appearance of a true
Lytourat, then the dimensions of the whorla increase rapidly in size and especially
in height, the involution becomes accentuated, and the aspect of the shell changes
notably.' 1
In the upper part of the Horsetown group, species within the range of this definition
are not uncommon, most of them coming in the middle or upper Albian, associated
with Beudaniicerai breweri (Gabb) and DouMleieeras mammillalum, var.
At least three distinct species are found in the Hulen beds, north of Cottonwood
Creek. None have been found outside of the Cottonwood district in California.
Lytoeeras {Gavdrycerai) vacya (Forbes)
Ammonitet sacya FORBES, Ceol. Soc. London, TR., 2d ser., vol. 7, 1845-1856, p. 113,
pi. 14, figs. 10, a, b; southern India—STOUCZKA, Paleont. Ind., vol. 1, 1865,
p. 154, pi. 75, figs. 6, a, b; figs. 7, a, b; Ootatoor group—WBITSAVES, Mes.
Fosa., vol. 1, pt. 2, 1884, p. 203, pi. 25; Bearskin Bay, Skidcgate Inlet, Queen
Charlotte Islands—STAXTOW, TN DULSR AND STANTON, Geol. Soc. Am., Bull.,
vol. 5, 1894, p. 445—WHITEAVEB, Mea, FOBS., vol. 1, pt, 4, 1900, p. 270—AN-
DEKSON, Calif. Acad. Sci., Pr., 3d ser.. vol. 2, 1902, p. 82; upper part of Horsetown
beds, Hulen Creek, Cottonwood district, Shasta County.
This species has been found in the upper beds of the Horsetown group on Hulen
and Cottonwood creeks, but it is less abundant than has been supposed. In the form
found in California the section of the whorl la not quite circular, being higher than
broad. An average example has the following relative dimensions: greatest diameter,
85 mm, ; width of umbilicus, 33 mm,; height of whorl, 38 mm.; width of whorl,
3ft mm.; umbilical ratio, 0,388:1.
Four good examples of this apccies were collected by R. M, Kleinpell and E.
Wayne Galliher in 1929, near the Indian village of Skidegate, Graham Island. They
were given to the California Academy of Sciences, with other species with which
they were associated, and haw b sen compared with the California types. In young
stages, up to a diameter of 55 mm., the shell is almost smooth; at this diameter the
surface begins to show undulations on the sidea, and a little later on the periphery
of tho shell; these soon develop into characteristic ribs inclined obliquely forward,
in tbe manner shown by WMteaves.
Lytoeeras (Kotsmalcllo ?) auranum Anderson, n. sp.
{Plato SO, Scum 1. 2)
The shell of this species is of medium size, discoidal, somewhat compressed, moderately
involute, nearly smooth in young stages, becoming coat ate in older stages,
as shown chiefly in the irregularly spaced growth lines; sides crossed by five or six
straight, transverse periodic constrictions; umbilicus broad, walls nearly vertical
below, rounded above to the slightly compressed sides; section of whorl broadly
elliptical, higher than broad; ventral region narrower than the dorsal half of the
shell; section changing with growth from a nearly circular form in youth to the
elliptical form in older stages; surface of shell nearly smooth, except for the periodic