LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION OF SPECIES 103
Not all aperies of Aucalla found in the Paskenta group, and in overlying beds,
can be described at this time, but a few of the more common forms are included in
the following account; in this much reliance bos been placed upon the work ol Pavlow
and other Russian paleontologists. However, no spcciea contained in these accounts
seems to have been derived from forms of Aucella found in the underlying Knoxville
scries, although this view of the subject should not be considered final. The Aucellae
found in the Paskenta group aecm to be more eloeely related to Russian types from
beds that are probably contemporary with this group. From this viewpoint it
seems more probable that their appearance in California and Oregon was due to
migrations, or immigrations from north-European sources,
Aucella erasricollU Keyserling
a, Vim i, 2)
Aueclla crazsicollia KETBEHLINO, Seiie in doe Petschora^Land, 1840. p. 300, pi. 10,
figs. 0-12.
Aucella Piochii GASH (in part), Paleont. Calif., vol. 2, 1869, p. 194, pi. 32, fig. 92a
only; probably from western Colusa County (not A. piochii GABB, vol. 1,
1854, p. 187, pi, 25, fi$. 173; north side of Mount Diablo).
Aucella crasticolti* Keyserling, var. $raeilie Lahusen, STAN TO X, U, S. Geol. Surv.,
Bull. 133, 1895, p. 45, pi. £, figs. 10, 11; Paskenta group, Tehama County—
PAVLOW, Soc. Imper. Natur. Moscou, Nftuv. Mem. T. 17, 1007, p. 62.
"Buchia" cra*aicelli», STEWART (in part), Phila, Acad. Nat. Sci., Spec. Publ. no. 3,
1030, pp. 112-114.
This species is rather rare in tbe Paskenta. group in California and Oregon. As
many of the allied forms found in these deposits were included under this name by
earlier writers, most of their references indicate other specics, rather than this.
The species (a.«.) is found occasionally at different levels in the Paskenta group,
but it occurs more frequently 1500 to 2000 feet above the base, in the zone of JXthotomilea
mutabilia (Stanton). Moat examples of the spcciea so far obtained are of
tho variety figured by Stanton (1805, PI. 5, figs. 10, 11), This f TO is plentiful on
tbe Wilcox ranch, 5 miles north of Paskenta, where it is associated with forma of
Berriasella, Bochianitet •paskentaensit nov., and two or mors forms of Dichotomiten.
Examples of the species are in the collections of tbe Academy of Sciences whic 1were
collected by H. W. Fairbanks and the writer in 1894, about 7 miles east of Coyucosr
San Luis Obispo County, where they have since been found associated with A.
crataa and A. lahtueni. They are not known to occur in any part of the Knoxville
series (upper Jurassic) or in any beds later than Paskenta.
Aucella erosea Pavlow
(FLAW S, FTPIM J)
Aucella Piochii GABB (in part), Paleont. Calif., vol. % 1869, p. 1M, pi. 32, flga. 02,
92b only; probably from western Colusa County, near Wilbur Springs.
Aucella concentnca var. WHITE, U. S. Geol. Surv,, Bull. 4, 1884, p. 14, pi. 6, figs. 9,
10: "Fossil point," Port Moller, Alaska.
AuceUa (ventrico&e left valve) WHITE, U. S. Geol. Surv,, Men. 13, 188S, p. 2312, pi. 4,
figB, 19, 17; near Knoxville, California.
Auecfio crasiicollit, STANTOK (in part), D. S. Geol. Surv.. Bull. 133, 1895, p. 45-47,
pi.