LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION OF SPECIES 102
TRANSIUTTIUDIE Gray
Terebratula Mflller
Terebratula Aannaiw Anderson, n. sp.
Citato 8. fl(uf« u, IS)
Shell of medium size, circular in outline, regularly lenticular, convexity moderate;
borders below the beak forming on angle of near 110 degress; front nearly circular;
length of dorsal valve (incomplete) in holotype, 22 mm,; length of ventral valve of
paratope, 38 nun.; sculpture of dorsal valve In holotype consisting only of concentric
undulations; sculpture of ventral valve almost without ornament, smooth. The
holotype (Calif. Acad. Sci. type Coll.) consists of a fairly well preserved dorsal valve.
The paiatyp® (Calif. Acad. Sci. typo Coll.) is & well preserved ventral valve. Both
were found by G. D, Hanno, on McCarthy Creek, near the crossing of the Paakenta-
Lowiy road, southern Tehama County. They were associated with a epceioi of
Cheloniceraa, near if not in the zone of Neocraiptditea sigjialu nov., and not far
sbave the zone of AcrotsuMxs onaetmt and Inoceramiui eolonicus nov., the two latter
representing a Hauterivian horizon in this locality and in the Cottonwood district.
It appears, therefore, that its horizon may be regarded as representing a middle
Horsetown (B&rrcmian) horizon.
Terebratula dttrrelli Anderson, n. sp.
(PUta 9, Scon II)
Shell of moderate size, subcircular in outline, irregularly lenticular, owing to
broad plications extending from the beak forward; the ventral valve has a broad
rounded ridge extending from the beak toward the front; the dorsal valve has a
broad crescent-shaped, transverse ridge, in front of which is a broad median sinus;
surface of shell silky, showing only faint concentric lines; length of ventral valve
(incomplete), 25 mm.; length of dorsal valve, 23 mm.; total width of shell, 28 mm.
The holotype (Calif. Acad. Sci, type Coll.) waa found by Cordell Duuell on fiddler
Creek , 10 milee south of Ono, Shasta County, associated with Shaelicrioceras ponienlt
nov. not far beneath the zone containing Chelaniceras hindri and Acroleuihii shastensia.
Its horizon is regarded as middle Horsetown (Barremion), although it may
be somewhat lower.
MOLLUSCA
PELECYPODA
Nucula gahbi Stanton
Nucula BrjiNTOtf, U. S. Geol. Surv., Bull. 133, 1805, p. 51, pi. fl, figa. 11, 12;
upper part of "Knoxville beds," about 3 miles south of Lowry'a, Tehama
County.
Stanton's holotype of this species is comparatively small (19 mm. in length),
of which he gives excellent figures and description. Ho compares the species with
N. solitaria Gabb, from the "Chico" of Texas Flat, near Folsom, and also with
Nucula "aolitaria" Whiteaves, from tho probably Jurassic of Moresby Island, but
at present the relationships seem improbable. Stanton mentions several smaller
specimens of this species collected from a lower horizon in the limestone lens 3 miles
northwest of Paskenta, but this appears to be & distinct species.
The field position and the stratigraphic relations of the type locality of this