LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION OF 8PEC1EB 187
Dt-tmocerat haffmanni STANTON, Geol. 9OC. Am., Bull., vol. 5, 1894—AHTEHSON,
Calif. Acad. Sci., Pr., 3d aer., vol. 2, 1002, p. 94 (inpart), pi. 10, fig, 203; Cottonwood
district, Shasta County (not pi. 5, figs. 120-123); upper beds of the
Horsetown group, Horsetown, Shasta County.
The holotype of this species seems to have been lost, andit is therefore permissible
to choose a lectotype. Gabb's original figures of the species seem to be composite,
and to be based upon more than one species, and therefore are defective. The
lectotype (Calif. Acad. Sci. type Coll.) has the following dimensions: greatest
diameter, 80 mm.; width of umbilicus, 31.5 mm.; height of whorl, 35 mm.; thickness
of whorl, 30 nun.; umbilical ratio, 0.339:1. This specimen was obtained at the
old mining camp of Horsetown and is the only form of Ptuosia found theTc that can
properly represent Gabb's spcciea. In thia lectotype the section of the whorl is
more inflated than in Gabb's figures; the constrictions are brood and are bordered
behind by a rounded ridge; there are usually six or seven constrictions on a single
whorl; they are Sexiradiate, curving at first forward near the umbilical border, then
gently backward to above the middle of the side, then forward again, crossing ths
ventral zone with a forward sinus; between the constrictions the surface is marked
by 18 to 22 rounded costae, all of which eroBS the ventral zone. The walls of the
umbilicus are abrupt below, rounded above, the curvature merging into that of tbe
slightly inflated sides. The examples of this specics obtained by the writer from the
type locality may be regarded as topotypes; moat of them have only six constrictions,
and all have fewer than are shown in Gabb'a drawings, but the measurements given
above do not differ materially from those obtained from his figures.
This apecies appears to belong to the group of Putosict mayoriajut (d'Orbigny), as
seen in its external form, ornamentation, and autural characters. Other examples of
the apecies have been obtained from Locality 1650 (Calif. Acad. Sci.) in the Neptune
zone on Hulen Creek, and on Bee Creek, and on the North, fork of tbe Cottonwood
Creek.
Puzasta rtetidei Anderson, n. sp.