LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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154 lower chetaceous deposits ijf california and oregon<br />
POLTPTYCEITIDAB Spath, 1924<br />
Polyplyehitea letoniei Anderson, n. sp,<br />
(P1»t« S, l{iin 1; put* 23, Bcun 1)<br />
Shall large, robust, thickly cost&te, broadly umbilicate; section of whorl in adult<br />
stages subcircular, slightly broader than high, tbe ratio of height to breadth increasing<br />
with the growth of the shell, sides slightly flattened; umbilical walls abrupt,<br />
arising almost vertically; ribs numerous, branching from elongated umbilical bullae<br />
below the middle of the sides into three, four, or five smaller ribs; ribs rarely subdividing<br />
above; umbilical bullae elevated, narrow, rounded, not bearing tubercules,<br />
arising within the umbilicus, sloping at first backward, then vertical on the umbilical<br />
border, and thence inclining alightly forward before dividing; smaller costae rounded,<br />
nearly straight, crossing the ventral zone without interruption or flattening; interspaces<br />
broader than the costae; sides of shell crossed at intervals by broadly rounded<br />
grooves, arising at tho umbilical border; suture lines as shown in the figures. The<br />
holotype (Calif. Acad. Sci. type Coll.), wholly septate, affords the following measurements:<br />
greatest diameter, 195 mm.; width of umbilicus, 58 mm.; height of whorl,<br />
50mm.; width of whorl, 62 mm,; umbilical ratio, 0.352:1,<br />
This species resembles "Olcoatephanus" tratki (Gabb) but differs from it in soma<br />
notable respects, as will be seen upon comparison of the figures. In its ribbing<br />
the ratio of tbe number of umbilical bullae to tbe peripheral ribs is about 1:3.7.<br />
Among European species its nearest analogue seems to be Polyptychic pobjptychus<br />
Keyserling, figured by Pavlow; its horizon appears to be nearly tbe same—namely,<br />
middle or upper Valanginian.<br />
The holotype was found id the Hamlin-Broad zone at Locality 113 (Calif. Acad.<br />
Sci.), 4 miles southwest of Ono, Shasta County, by Dr. E. J. Broad of San Francisco,<br />
who presented it to the California Academy of Sciences, with various other species<br />
and genera from tbe same zone and locality. It was found with Polyptychic httperttu,<br />
iSimWrsHtea browfi, Lytoeeras saturnale, Lylocera* aulaeum, Aipinacerae<br />
hamlini, Anahnmulina I'fiperfina, Acroteulhis thastmria, Belemnoteulhis (Coneteuthis)<br />
poeifica, and many other species representing the upper part of the Paskenta<br />
group of the Shasta series in the Cottonwood district.<br />
The horizon of this zone is atratigraphically about 500 feet beneath the lowest<br />
beds assignable to the Horsetown group in the Shasta series.<br />
Polypiychitei heeperius Anderson, n. sp.<br />
(PUto 24, flcurn J, 2)<br />
Shell large, robust or massive, thick, with heavy branching riba; section of whorl<br />
broadly triangular, with strongly converging sides; periphery relatively narrow, but<br />
rounded; umbilicus apparently not broad; umbilical nodes, or ribs, thick, arising<br />
on the umbilical wall, curving at firBt backward, but inclining forward on the sides,<br />
dividing below the middle into three, sometimes four, straight, rounded ribs which<br />
cross the periphery; sutures as shown in the figure.<br />
The holotype of this species (Calif. Acad. Sci, .type Coll.) was found by £. J.<br />
Broad at Locality 113 (Calif. Acad. Sci.), 4 miles southwest of Ono, Shasta County,<br />
at the head of Mitchell Creek. It is a large fragment representing a little less than a<br />
quarter of a whorl, with a portion of an inner whorl. It ia septate throughout and<br />
accordingly is a part of an inner whorl. In its general form and character it recalls<br />
Poly ply c hi tee ephaericus von Koenen, but has fewer and heavier ribs. Its nearest<br />
west European analogue seems to be Polypiychites tempiughi Pavlow, although there<br />
are obvious differences. In the present species the section of the whorl ia more