LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

CRETACEOUS SEDIMENTARY DIVISIONS 53
of Peach tree SpringB, a basal conglomerate of the Paakenta group forms
a conspicuous outcrop. From boulders embedded in this conglomerate,
Taff, Hanna, and Cross collected AuceUa piochi and other related species,
and from the matrix they obtained examples of Acrotcuthis d. onoenrns
nov., a form characteristic of tbe Paskenta, From overlying shales nearby
they collected numerous fragments of Acrotcuthis impressa (Gabb), and
well-preserved specimens of Aucella inflata, A. piriformis, and various
small gastropods. This exposure is probably that from which Turner
(IS91) obtained specimens of Belcmnites.
Berkeley Hills.—A. complete account of the Lower Cretaceous sequence
in the Berkeley Hills cannot be given here, since these beds have not yet
been segregated from the underlying Knoxville, both of which occur here,
and in unconformable relation. Only the lower beds of the Paskenta
group have been identified by fossils, but they are much disturbed and
broken by faulting. From the western flank of the bills in the northern
part of Berkeley, Lawson (1914) has reported a number of Paskenta species
occurring in limestone, including Modiolus major, Lucina cohtsaensis,
Pecten complexicasia, Myoconeha ap., Turbo sp,, Atresia* liratus, and
"Hoplites" sp. All these forms are characteristic of the lower beds of the
Paskenta group, as found farther north. In the vicinity, and also from
the basal beds of the group, Leonard Henry obtained Mytilus arlingtoni,
Aucella erassicollis, A. inflata, Belemniies sp., Balanus berkeleyensis nov.,
and Balanus sp. These fossils were obtained from a pebbly sandstone
overlying Knoxville shales. From a calcareous boulder embedded in tbe
pebbly matrix, Henry obtained examples of Aucella piochi. All these
fossils are in the Museum of Paleontology, University of California.
That the pebbly sandstone represents a near-beach deposit is evidenced
by the presence in it of species of Mytilm, Balanus and many broken shells
of other species. The beds here described resemble those found at Napa
Junction, 4 miles north of Yallejo.
Knoxville beds consisting for the most part of dark clay shales, often
fossiliferous, have been identified at other points along the west flank of
these bills farther south. They are usually involved with masses of serpentine,
or overlie Franciscan cherts, and are greatly faulted. On the
south border of the Concord quadrangle, 1 j miles northwest of Lake Chabot,
C. Durrell discovered an invertebrate fauna containing A ucella hyatti
Pavlow, Terehralella cf. califomica, Ophioglypha ? (brittle star), and
Penlacrinus sp. From similar dark shales about 1500 feet higher in the
section, R. L, Rist and the writer obtained species of Pcrisphinctes.
Santa Clara Valley,—As in most other areas in the Coast Ranges in
which beds of the Paskenta group occur in association with Knoxville
strata, no attempt has been made to distinguish these formations in the
Santa Clara Valley, in which both occur. R. Crandall (1007) has sup-