LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

170 LOWER ChETACEOUS DEPOSITS Ijf CALIFORNIA AND OrEGON
greater involution, a smaller umbilical ratio, and fewer and less sinuous ribs. In
the several examples found the number of umbilical ribs varies from 24 to 28, and tbe
peripheral riba from Jj2 to 60 to tbe whorl.
The holotype (Calif. Acad. Sci. type Coll.) ia entirely costate and has the following
dimensions: greatest diameter, 136 mm.; diameter of umbilicus, 44 mm.; height of
whorl, 62 mm.; width of whorl, 58 mm.; umbilical ratio, 0.430:1,
In cross-section the whorl is broadly semi-elliptical, the thickest part of the whorl
being a little above the umbilical border; whorl heavily coatate, the ribs being of two
ranks; sometimes divided primary riba are less sinuous than in the preceding species;
almost twice as many peripheral ribs as those on the umbilical border; some of the
primary ribs divide into two or three, some do not divide; all ribs cross the broad and
slightly flattened ventral zone; umbilicus narrow and deep, with steep walls, smooth
below, ribbed above,
This specimen was found not far from the horizon of Tropaeum pcreostaium,
PhtjUveeraa onoense, and Parafioplitoidee, about SO feet above the Argonaut zone.
The specimen was found by G. D. Banna, for whom it is named, at Locality 1347
{Calif. Acad. Sci.), half a mile east of Mitchell Creek, 5 miles south of Ono, Shasta
County. An example of closely related species was found by O. W, Friedriah, about
7 miles northeast of Wilbur Springs, western Colusa County. The horizon of both
is near the middle of the Horsetown group and marks a lower Gargwian level.
Parahoplites echarfi Anderson, n. sp.
(Fl&te 73, Biuret 4, S)
The shell of this apecies LB moderately robust, or inflated, and in form is intermediate
between Parahapliles dallati nov, and P. etantom nov. It more nearly
resembles Parahoplilei »ut>campecAt Sinzow (1907), from MaCLgyeehlak, and may be
regarded as its California analogue. The holotype possesses about 40 rather strong,
slightly sinuous ribs, which arise on the umbilical wall, having a backward inclination,
and show a slight swelling on the umbilical border, cross the aides with a slight
forward slant, bending sharply forward in th& ventral zone. Most riba divide into
two below the middle of the aide, although there is an occasional single rib interpolated
between the pairs resulting from division. The holotype has the following
dimensions: greatest diameter (of complete whorl), 85 mm.; width of umbilicus, 35
mm.; height of whorl, 41 mm.; thickness of whorl, 35 mm.; umbilical ratio, 0.204:1.
The suture line is not well shown. This example waa found at the "north end of
the Bald Hills" by D. W. Scharf and W. P. Popenoe, Locality 60S (Calif. Inst. Tech.),
for the first of whom it has been named. The species differs from its analogue at
Mangyschlak in being somewhat more robust, in having stronger and fewer ribs,
which show a slightly more pronounced curvature. The holotype is the property
of the California Institute of Technology, Pasadena. Its horizon is but little above
that of Tropaeum pereoeialum (Gabb) and beneath that of Hcmibaculitcs mirabilit
nov.; it therefore represents the middle part of the Aptian portion of tho Heraetown
group.
Parahopiites maefarlandi Anderson, n. ap.
(Plata 35, Spire I)
Shell large, robust, involute, with moderately broad umbilicus; section of whorl
semi-elliptical in young stages, becoming sub-quadrate in older age; sides costate,
with closely set, rounded, depressed riba, which arise on the umbilical wail with a
backward slant, curving gently forward above; umbilical walls abrupt, rounded