LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

52 LOWEB CRETACEOt?fi DEPOSITS EJ CALIFORNIA AND OREGON
From tbe sandy abides overlying the Franciscan rocks were obtained
AuceUa crass a, A. infiata, and from the limestones, other species. Stanton
(1895, p. 19, 20) reports from this district AuceUa crassicollis, Pecten
coniplexicosla, Modiolus major, Astarte irapezoidalis, Turbo morganensis,
Airesius liratus, and various other species, all of which are of Paskenta
age. White (1885) had reported other forms from this district, some of
them of Horsetown age, but their occurrence in Morgan Valley needs
confirmation. la this district the relations of the Paskenta beds to the
older rocks are the same as at Wilbur Springs, tbat is, one of unconformity.
The limestones here are similar to the "white limestones" of the latter
district.
Berryessa Valley, Napa County,—Strata of the Paakenta group are well
represented along tbe western border of the Berryessa Valley, west of
Monticello. At the base they include pebbly conglomerates and sandstones,
and higher in the section are scattered lenses of limestone. The
latter occur at many points on the small hills a few miles west of Monticello.
From the lower beds of this group west of Monticello, Eldridge
Drew obtained Aucella piriformis, A. keyserltngi, Bdemnites sp., Inoceramus
maius Stanton, and from the limestone lenses higher in the section,
Modiolus major, M. stantoni nov., M. (Yohella) onmnsis nov., Turbo?
humerosm Stanton, and -Airesius sp.
Pope, Valley.—West of the Berryessa Valley the sandy beds of the
Paskenta group form the floor of the smaller Pope Valley. The sandy
shales and sandstones with lenses of limestone rest unconformably upon
Franciscan strata, or upon intrusive rocks by which the latter have been
cut. From tbe sandy shales of the Paskenta group on the south border
of the valley the writer collected Aucella -piriformis, A. unciU>idess A. crassa,
and fragments of belemnitea. The overlap of the Paskenta beds upon
pre-Knoxville formations is well illustrated in this valley, and upon both
north and south borders of it
Napa Junction. —From the old "cement-rock" quarry, 4 miles north of
Vallejo, where the basal beds of the Paskenta group are exposed, the writer
obtained a email collection of fossils, including Modiolus onoensia, Lima
muliilineata Stanton, Inoceramus uaUejoensis nov., and numerous borings
of pholads. The beds here include calcareous shales, pebbly sandstones,
and limestones. They rest unconformably upon Franciscan rocks.
Mount Diablo District.—The lower beds of tbe Paskenta group are well
exposed about Mount Diablo, cropping out on both its east and west
flanks. On the east flank near Olafsen's house and west of Curry Canyon,
the writer obtained an example of Lytoceras of, saturmlc nov., and near
the quicksilver mine, northeast of North Peak, weU preserved examples
of Aucella injlata have been collected and are in the possession of the
"University of California. On the northwest flank of the mountain, west