LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

CRETACEOUS SEDIMENTARY DIVISIONS
MORE NORTHERN AREAS
In the State of Washington various localities have yielded invertebrate
fossils referable to the Paskenta group. White (Becker, 1883) has figured
an example of Aucella from western Washington which Pavlow has regarded
as A. salvia, a form that is abundant in the Paskenta group of
California. Diller has noted Atice/ia-bearing rocks in different parts of
tho State (Cascade Range and Vashon Island). Lower Cretaceous deposits
have been described from the Nooksak River north of Mount Baker,
farther to the east upon the Pasayten River, and in the Hozomeen Range
in northern Washington. Little is known concerning the faunas of these
beds, although Aucella crasskoUia is said to occur in each of these localities.
In the Hozomeen Range tbe steep dips indicate a stratigraphic thickness
of at least 6000 feet of black shale and overlying conglomerates.
SAN JUAN ISLANDS
R. D. McLellan (1927) describes isolated outcrops of conglomerate,
sandstone, and shale occurring on the San Juan Islands, which he includes
in the Spieden formation. Its principal area IB on Spieden Island, adjacent
to San Juan Island on the north. According to McLellan, conglomerates
make up 85 per cent of the rocks within the area mapped us
the Spieden formation. He adds:
"Along the northern margin of Spieden Island there is a group of thin-bedded
and somewhat carhonaceoua shales. These "grade upward into sandy shales and
sandstones with an occasional bed of argillaceous limestone. . .."
"Throughout a thickness of about 35 feet these beds are richly foaaUiferous."
These layers are overlaid by a succession of strata 2000 feet in thickness
in which conglomerates greatly preponderate. The fossil-bearing beds
of Spieden Island have yielded many invertebrate species including the
following, as described by McLellan (1927, p. 114).
Auctlla eroMicalli* Keys er ling Pleuromya lypa McLellan
Holeixtueut ? ttanldni McLellan P. ihor McLellan
Phyllocerai $pieden«nsc MoLelJan Lima spiedenensii McLellan
According to McLellan, AuceUa constitutes 95 per cent of the fauna,
and be adds:
"The fauna was examined by Dr. T. W. Stanton, who determined its ago to be
Lower Cretaceous, and equivalent to the upper part of the Knoxville formation of
California,"
As the upper part of the "Knoxville formation" in California, bearing
an equivalent fauna, is included in the Paskenta group of the Shasta series,
the Spieden formation should be interpreted accordingly.
From the figures given by McLellan, "Holcodiscus ?" stanlcni appears
to belong to the genus Dkholomiles of Spath, near Dichotomilea fragilia as
illustrated by Pavlow.
A small collection of fossils from the north side of Spieden Island, ob-
66