LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON
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203 <strong>LOWER</strong> <strong>CRETACEOUS</strong> <strong>DEPOSITS</strong> IN <strong>CALIFORNIA</strong>. <strong>AND</strong> <strong>OREGON</strong><br />
102 mm.; diameter of umbilicus, 32 mm.; height of whorl, 43 urn; width of whorl,<br />
36mm.; umbilical ratio, 0.313:1.<br />
The inner whorla are more compressed than tho outer whorlB, and the rihs tend to<br />
develop tubercules on the umbilical borders, which later disappear, leaving the border<br />
of the older whorls smooth. Only three examples of this shell have been found.<br />
Its horizon is near that of its congeners, which is about 900 feet below the top of the<br />
Horsetown group in tbe Hulen Creek district. Tho holotype was found in the Perrin<br />
zone at Locality 152 (Calif. Acad. Sei.) on the east branch of Hulen Creek, where it<br />
was Associated with Deamaceras merriami, DouvilleiceTas ma>nmi(ioiuw var., and<br />
Phylloceraa thereeae nov. Spath has referred S. aacrameniica (Anderson) to "Pleuro-<br />
•pachydiecua'' Hyatt, whose genotype is Dexmaceras merriami (Anderson), to which<br />
it has little resemblance except in tbe character of the suture lines. The name<br />
"PieuropotJijifTJcui" Hyatt is clearly a nomen nudum.<br />
Sonnerada stanloni Anderson<br />
(Plata SO, figuro {, 4,7)<br />
£onnera(ICI«tofttoni AKSBRSOM, Calif. Acad. Sei., Pr., 3d ser., vol. 2,1902, p. 105, pi. 3,<br />
figs, 91-03; pi. 10, fig. 108; Horsetown, Shasta County, California.<br />
The original description of thia specieB, somewhat emended, reads in part as<br />
follows:<br />
"Shell small, not often above a diameter of 35 mm.^discoidal, laterally compressed<br />
and flattened; sides converging gently toward the periphery; ventral surface rounded<br />
or subquadrate; umbilicus not Large, less than one-third the total diameter, generally<br />
funnel-form, due to its sloping sides and the increasing thickness of the whorls;<br />
surface ornamented by about 30 transverse flexuoua ribs which usually cross the<br />
ventral surface, arising at the umbilical border In distinctly tuberculide nodes, from<br />
which they branch in pairs. The surface of the shell, both on tbe ribs and in the<br />
interspaces, shows fine striae, always parallel to the ribs. The Buture tine ia simple,<br />
consisting of a few broadly rounded saddles, and wide lobes with very short branches.<br />
The saddles are but little indented, are aividod by rounded incisions; lobes unequally<br />
tripartita."<br />
This apecies was once abundant at Horsetown, and many were collected at this<br />
place by the writer but most of them were lost in the San Franoisco fire of 1D0G.<br />
Many of its congeners have since been found on the east branch of Hulen Creek,<br />
about 000 feet below the top of the Horsetown group.<br />
This species was proposed as the genotype of "Colobdceraa" by Crickmay (1927,<br />
p, 603-616) hut upon what characteristics and for what practical use ia not made<br />
clear, and It is therefore disregarded aa not sufficiently defined for adoption.<br />
Sonneralia erotai Anderson, n. sp,<br />
(Pint* 49. I. S, », 7)<br />
Shell small, discoidal, compressed, having a email umbilicus and rounded, nearly<br />
smooth sides and ventral border; sides flattened, ornamented chiefly by lines of<br />
growth, costate only on and near the umbilical border, upon which appear 20 or more<br />
rounded linear nodes, not rising to the middle of the side; only faint costal lines<br />
appear on the ventral border, inclining forward; section of whorl narrowly clliptical;<br />
Suture lines similar to those of .Sonncrajia atantoni, with which it occurs.<br />
The holotype (Cftlif. Acad. Sci. type Coll.) was found by the writer at tbe old<br />
mining camp of Horsetown, where it waa associated with PUJTOJI'O JtojJmanni, Bfudanticeras<br />
breweri, and Beudanliccraa haydeni Gabb, This is Locality 1344 (Calif.<br />
Acad. Sci.) on Clear Creek, Shaata County. Four examples of the specics wera<br />
found here, but it has not been found at any other locality.