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