LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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description of species 173<br />
diameter, 220 mm,; diameter of umbilicus, 78 ram.; height of whorl, 85.5 mm.; width<br />
of whorl, mm.; umbilical ratio, 0.355:1.<br />
The holotype was obtained from the North fork of Cottonwood Creek, probably<br />
above the Argonaut zone, by J, W. Gardner. It ia now in the collection* of the California<br />
Academy of Sciences.<br />
Acanlhvplitet perrini Anderson, n. sp.<br />
(Plata 38, 6(UJ« I)<br />
Shell large, thickly discotdal, laturnbilicate, rounded on the periphery, heavily<br />
costate; umbilicus broad, with abrupt walla, rounded on the borders; having slightly<br />
curved, rounded primary and secondary ribs; primary ribs mostly simple, occasionally<br />
branching, arising on the umbilical wall as a backward sloping ridge, curving<br />
on the umbilical border and rising nearly at right angles across the side to the ventral<br />
zone; nearly twice aa many secondary ribs as primary, arising at or above the middle<br />
of the aide; all ribs cross the ventral zone without interruption; suture line, as shown<br />
in the figure, has a deeply cleft aiphonal saddle, showing asymmetry with reference<br />
to the siphonel plane, and asymmetry in the successive divisions of tho lobes.<br />
The holotype (Calif. Acad. Sci. type Call.}, almost wholly septate, affords the<br />
following measurements: greatest diameter, 230 mm.; diameter of umbilicuB, 90<br />
mm.; helghtof whorl, SO mm.; width of whorl, 65 mm.; umbilical ratio, 0.39:1.<br />
This specimen was obtained in the Ferrin zone on the west branch of the east fork<br />
of Hulen Creek, cast of Ono, at Locality 145 (Calif. Acad. Sci.). It was associated<br />
with Chtloniccra* sp., CUoniceToi cf. lecontei, Nautitut gabbi, and other species. Its<br />
position is above that of the Buenaventura zone of the Hulen beds referable to a lower<br />
middle Albian horizon.<br />
This species seems to have ita nearest analogue in Aeanihoplites notani (Seunea),<br />
as illustrated by Sinzow (1007, pi. S, fig. 1) from the Caucasus Mountains. The<br />
species is named in honor of the late James Perrin Smith, for many years Professor of<br />
Paleontology at Stanford University,<br />
Acanthtiptocs tpaihi Anderson, n. sp.<br />
(Plate 41, flpirn 3-&)<br />
Like the preceding forma, thia ahell ia of moderate size, discoidal, inflated, with<br />
moderately broad umbilicus; section of whorl subcircular, rounded on aides and<br />
periphery; walls of umbilicua sloping, rounded above, blending with the sides; 32<br />
to33elevated primary and aecondary ribs; primary ribs arising on the umbilical wall,<br />
rectiradiate, often branching in younger stages of growth, and bearing short spinelike<br />
processes at the points of division; secondary ribs, in older stages of growth,<br />
arising near or above tbe middle of the side; shell in younger stages having the aspcct<br />
of Cheloniccras; interspaces between ribs deep, sa broad aa the riba themselves.<br />
The holotype (Calif, Acad. Sci. type Coll.) affords the following measurements:<br />
greatest diameter, 70 mm.; width of umbilicus, 20 mm,; height of whorl, 25 mm.;<br />
thickncss of wborl, 25 mm.; umbilical ratio, 0.371:1. In older stages the branching<br />
of the ribs and the spines become obsolete and are finally lost, the ventral tone<br />
becomes flattened, and the ribs become more prominent on the periphery. The<br />
species appears to belong to a group represented by AcanlAoptftea abithi (Anthula)<br />
as figured by Sinzow (1007, pi. 0, figs. 1-3). Tbe holotype and the other figured examples<br />
were found at Locality 1346-A (Calif. Acad, Sci.), on the west branch of Hulen<br />
Creek, in the Buenaventura zone, or just beneath it, ia the upper part of the Horsetown<br />
group. It has been found also on Alderson Creek and on Bee Creek, presumably<br />
in the same zone. Its horizon is near the top of the Aptian portion of the<br />
Horsetown group.