LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

110 3WJWEH CRETACEOUS DEPOSITS IN CALIFORNIA AND OREGON
Stewart gives tbe timbonal angle of the holotype aa 100 degrees, and if the same
species has a stratigraphic range throughout the Shasta series this angle is variable;
if the angle is regarded as diagnostic of speciee, there may be several species in tbe
series.
jVeifAea Drouet
Neithta grandicoita Gabb
Neither grandicoaa GABB, Paleont. Calif., vol. 2, 186ft, p. 200, pi, 33, figs. 90, 09a;
rare in the "Shasta Group," Cottonwood Creek, Shasta County—A>T>EBSON,
Calif. Acad. Sci., Pr.t vol. 2, 1902, p. 41; Horsetown graup, Shasta County.
Neithea (Neitheaps) grandicoeta, STEWART, Phila. Acad. Slat. Set., Spec. Publ. no. 3,
1930, p, 116; new subgenus proposed.
Gabb's description of this species reads in port;
"Shell minute, very in.equiva.lve, equilateral, elongate; lower valve, sides tapering
a little aoncavely; general contour of tbe base semicircular, with six prominent
angles and concave interspaces. Surface marked with six very large, round, equidistant
ribs, the interspaces carrying a small rib, Banked on each side by one still
smaller;..
This species seems to be very rare in the Shasta series, and only the holotype has
beeu known. Its horizon was not given by Gabb, and its exact locality has been
conjectural. Recently a single valve clearly identifiable with the species has been
found in the Barr zona of the Horsetown group, near tbe small school on Mitchell
Creek, f> miles south of Ono, Bhaata County. Ita length is 13 mm.; height, nearly
the same. It was found associated with Acroteuthis aboriginaliij nov., TerebraUlla
averifK, nov,, and Parahopliloidet sp. Its occurrence in the thin conglomerate of
this aone fixes its horizon here 83 in the lower Aptian beds of the Horsetown group.
SFONUYUDAE Fleming
Spondylug Linnaeus
Spprulyluj Jragilit Stanton
Spondylus fraffilii STANTON, U. S. Geol. Surv., Bull. 133, 1895, p. 36, pL 2, fig. 3;
near Stephenson's, on Cold fork of Cottonwood Creek, Tetania County.
This species was described from a small left valve, showing well-defined, subcqusl
ears, low beak, and irregularly undulating radial lines upon the surface. These
iines are said to show a tendency to become subepinoBa on well-preserved examples.
The species is one of the IS moll us can forms specifically named by Stanton (1895,
p. 14) in the list obtained near Stephenson's on the Cold fork of Cottonwood Creek.
It was believed to belong in "the tipper part of the Knoxville beds," but as the list
also contains various other diagnostic spcciea belonging in the Shasta series (Lower
Cretaceous), it can hardly be regarded as representing Knoxville beda in the tense
of this paper. The list includes Cyprina occidentalis Whiteaves, Aucella crasaieeHis
Keyserling, and Acrottulhis intpressa (Gabb); the last two of these indicate that the
horizon is not older than the Paakenta graup, and in fact ie found near its base at
tSiia locality.
•Piicaltiia Lamarck
Plica tula variata Gabb
Plicaiula u&riata GABD, Paleont. Calif., vol. 1, 1884, p. 200, pi. 28, fig. 190, Battle
Creek, Shasta County; vol. 2, IMS, p. 252; "Shasta Group," Battle Creek,