LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

112 3WJWEH CRETACEOUS DEPOSITS IN CALIFORNIA AND OREGON
The shell cf thia species le email, compressed irregularly subelliptical, equivalve;
anterior side and base forming a regular curve, the posterior margin of the base
curving upward rather abruptly to tbe posterior end, which is straight; ears very
email, the anterior ear triangular, the posterior, narrow, almost linear; posterior
umbonnl slope very narrow; surface ornamented by 20 or 21 prominent, straight,
radiating ribs, with interspaces of equal BUD. Stewart gives the following measure*
menta for the holotype, which is in the collections of the Academy of Natural Sciences
of Philadelphia: length, 15.5 mm,; height, 14.2 mm,; thickness of left valve, about
2 mm.
ANOUIIDAE Gray
Anomia Xinnasus
Anomia aniitem Stanton
Anomia nrtmenv STANTOH, U 3. Geol. Surv., Bull. 133, 1805, p. 35, pi, 2, fig. 2;
2 miles south of Lowry's, Tehama County,
In bis description of this shell Stanton eaye, in part:
"Shell rather Urge, aubcircular in outline, slightly oblique, depressed, convex;
hinge line straight, nearly aa long as the shell; beak inconspicuous, not projecting
beyond the hinge lbs and situated near the middle of it: surface marked by faint
concentric undulations. Length, 25 mm.; height, 33 ram.
This species is included in a fiat of sic specifically named forms given by Stanton
(1835, p. 17) from a locality 2 miles south of Lowry's. The associated forma include
AuceUa eraasicoliit, "Olcottcphanvz" trichotonvmt, and others, all of which are
characteristic of the upper part of the Paskenta group. Stanton statea that the
specimen was inside a fragment of Lylocerat batesi, a species not known below the
Horsetown group, and therefore indicating the age of the present species,
Whiteaves has described a similar form from LLn» Inland (Queen Charlotte
Islands), which is included by Stanton (MacKenzie, 1018, p. 06) in the Haida formation,
under the name Anomia linenxia (Whiteaves), Although MacKenzie indicates
no older Cretaceous strata on Una Island, there are stratigraphic reasons for expecting
them there. The form described by Stanton has not been found in the Kno«ville
aeries.
MODIOLOPSI&A-B Fischer (emend.)
Myoconcha Sowerby
Myoconcba amcricanti Stanton
Mtjoconcha americana STANTON, U, S. Geol. Surv., Bull. 133, 18A5, p. 48, pi. 2, fig, II;
near Stephenson's, Cold fork of Cottonwood Creek, Tehama County.
"Shell small, slender, subovate, gently convex; beak small, almost terminal;
dorsal margin nearly straight, passing by a gentle curve into the rounded posterior
end; ventral margin also nearly straight, slightly contracted toward the front,
gently convex behind; shell gradually broadening from the narrow anterior end for
about two-thirds of its length, and thence rounded to the posterior end, surface
marked by lines of growth. Length, 41 mm.; greatest width, 22 mm."
Thia ap^cies ia among those contained in Stanton's list (ISM, p. 14) of molluBcnn
forma collected from the baa&l beds of the Paskenta group near Stephenson's on the
Cold fork of Cottonwood Creek. Of the 21 forms in this list, 18 are specifically
named, (some doubtfully), of which 13 are new, and described from this locality;
2 species are known from the Cretaceous of Queen Charlotte Islands; 3 are wellknown
Shasta species, of which Peeten cofi/"ornicT« and "Br/cmni