LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

CSETACEOUS BEDIMENTAHY DIVIBIDNH €5
tbe zone containing Locality 1681 (Calif. Acad. Sci.), which crosses Roaring
River about 840 feet west of the Millsap road. About 250 feet west
of this road Popenoe and Scharf collected A croteuthis shastengia nov. and
PulcheUia popenoei nov. A mile farther south on a tributary of Roaring
River the following species were collected by R. D. Russell and the writer
from Locality 1661, which ilea a few hundred feet lower;
Shaalierioctriu ponicnte nov. Pteudocrioteras nterUor nov,
•* Ancylocerae dvrrelii nov, Acriocera) starrkinpi nov.
Hoplncrtoceroi wyntoaniutn nov. LytOQerai c£. argonautarum Anderson
impresta (Gabb) Inoceram.ui cclonievs nov.
The Mitchell zone, which may include a stratigraphical thickness of
200 feet, begins about 150 feet above the horizon of Locality 1661. It
has been traced for a distance of 2 miles on either side of Roaring River
and has been identified as far north as the North fork, and as far south as
Dry Creek. A composite list of species obtained from it near Roaring
River includes the following:
-SfttMU'cncceraj hwpmim nov, Ancvloeera* elephaa nov,
8. psmient« nov, A. ^JOI nov.
Hoplocrioccros wkiineyi nov. jt. otfrai nov,
Phylloceros occidentale nov. /jfanitacuJiUa MKIM nov.
Ptjfchncerai italriee nov. £T. nauplius nov.
- ehaeientit nov. Inaee.ramu* ovataide* nov.
About 050 feet above tbe Mitchell zone is the Barr zone, locally characterized
by a thin pebbly, tuff-like conglomerate 8 to 10 feet thick, the
whole having a maximum thickness of 30 feet. It has been traced from
Roaring River north for 2 miles, beyond which point it is covered by
alluvium. On Hulen Creek this zone is thought to be represented by the
conglomerate at the gorge on the west branch of this stream. From this
zone the writer has obtained ;
Gabbiocera* anjufatum Anderson Parahoplitet stanicni nov.
Shagtoceraa thasteme nov. P, daluiri nov,
Nautilus awrilli turn Peeten caii/ornicus Gabb
Acrut&ithii aboriainaU* nov, Ntitkea grandicosla Gabb
Tercbratvla averuli nor. Aueella Tadioiiriala nov.
The Argonaut zone, named for the pioneer settlers of this region, is the
next important zone above the Barr conglomerate. The interval between
is about ISO feet, as found in the Mitchell Creek district. It consists
lithologically of dark or slate-colored shales, similar to those of the Mitchell
zone, but its fauna is distinctly different, as may be seen from the following
list of invertebrates obtained from it at Locality 1347 (Calif. Acad. Sci.),
a little east of Mitchell Creek:
Lyicctrais arcanaut&rum Anderson Gabbioceras wynium'urn nov.
L. traaki nov. ParaKoplitoid** ehoupi nov.
L. baled (Tr&ak) P. cerrweniia nov.
, PhyUoeeroti diuiense Stanton P, aenilmdei nov.
Tropaeum ptrcotlaiurrt (Gabb) HemibacidiUs m-irabilie nov.
A uitralieerat arjuj nov.