LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION OF SPECIES 101
this species was found at Napa Junction, Napa County, in 1012, in the excavation
made for "cement rock." In length this shell was 10 inches or more; in width about
7 inches; in thickness 2 inches. It was found with Lima tmdtilineala Stanton,
Modiolm onoensis nov., and the borings of Pholade, A single example of the same
type and form, hut somewhat smaller, was found in 1908 by Joaiah, Owea near Alma,
Santa Clara County. Tho strata in both cases belong to the Paskenta group of the
Shasta series, as determined by other molluscan species. These examples recall
the statement found in the San Francisco folio (Lawson, U. 3. Geo). Surv., 1014,
p. 8} that fragments of a large Inoeeramus and a small Peeten had been found in
Strawberry Canyon ia the Berkeley Hills, in strata that aeem to belong to the same
group. Mention of a species of "Hoptite*" found near tbe same place is also made,
and aarves to support the age determination of the locality.
PTBKIIDAE Meek
Avieuta Bruguifere
Ain'cuio (Oxyloma) whiteavexi Stanton
Avicula {Gsuloma) ahiteaveti STANTON, U. S. Gaol. Surv., Bull, 133, 1095, p. 33.
pi. 4, fig. 1; Shclton'B ranch, 5 miles north of Paskenta, Tehama County.
Stanton compares thia spceita with a shell found on Maude Island, one of the
Queen Charlotte Islands group. Stanton's holotype was found in beds cropping out
on theShelton ranch, associated with Autxila. crassicollit, "Oleotlcphanut" mu(ato(i«,
and other Paskenta species. A similar species has also been found in the basal beds
of the Horsetown group near Ono. Lower Cretaceous strata have not been reported
on Maude Island before, and for this reason Stanton's comparison ia the more important.
A considerable list of Lower Cretaceous species found about Skidegate
Inlet is given in another part of thiB memoir.
MaeKenzie (1916, p. 46—17} has given a list of species, including this, from Maude
Island, which Stanton regarded as of Jurassic age, including it in the Maude formation.
MTAiiNiDAH Freeh
Aucetla Keyserltng 1848
In an excellent review of the genus Amelia Stanton (1695, p. 41) stales its ciroumpolar
distribution thus:
"It is found over a large part of Russia, in Siberia, Nova Zembla, Spitzbcrgon,
on the Island of Andoe on the coast of Norway, Kuhn Island on the coast of Greenland,
in Alaska, British Columbia, including Queen Charlotte and Vancouver
Islands, and the west coast of the United States as far south as San Luis Obispo
County, California {about latitude 35')."
Within its geographical range the genus occurs in both Jurassic and Lower Cretaceous
deposits, and locally forma tho dominant faunal element in parts of each
sequence.
As these Aucellan elements are related to those of atber regions, their occurrence
in tho Knoxville and Shasta series in California becomes important, not only as an
aid in correlation, but as showing the routes of migration and the spread of tbe
genus.
In the Shasta aeries, with few exceptions, they are confined to the Paskenta
group. Most of the forms found in these beds are robust, thick-shelled species of tbe
general character of A. etMticollit Keyacrling, although this epeciee is somewhat