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