LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

188 LOWER cretaceotffi deposits IN california AND oregon
Puzjjto diadema Anderson, n. sp.
(PI*tail, SHITM t, 10, 11, IS>
The four examples of this species, are small, discoidal compressed, with moderate!
or small umbilicus and fine sinuous costae; umbilical walla sloping, rounded above
and merging into the convex sides; surface of sides marked by three or four shallow,
flexuous grooves, inclining forward, and crossing the ventral zone with a forward
sinus; interspaces between grooves Occupied by 20 or more line costal lines;
section of whorl narrowly elliptical. The holotype (Calif. Acad, Sci. type Coll.),
almost wholly septate, baa the following dimensions; greatest diameter, 20 mm.,
width of umbilicus, 5 mm.; height of whorl, 9 mm.; thickness of whorl, 0 mm.; umbilical
ratio, 0.240:1.
The diameter of the syntype is 16 mm.; thickness of whorl, 5 mm. All the examples
ware found at Locality 1316-A (Calif. Acad. Sci.), a mile above the mouth of
Hulen Creek, on the west branch, associated with Pusflstn bwnaventura and Douvilleictrat
mammillalitm var., in the Buenaventura zone, in the lower part of the
Hulen beds. Tbe form may be the precursor of Puioaia onom nov.
Pujo^ia jimboi Anderson, n, sp.
(pl»te fieun* 5. S- 7)
DESMCCERNA Uhikawai SMITH (not JIMBQ), Calif. State MLN. Bur., Bull. 00, 1914,
Folio, opp. front cover, fig. S; Jackass Flat, near Horsetown, Shasta County.
Shell small, discoidal, compressed, numerously costate; umbilicus of moderate
width, walls abrupt, rounded above; surface marked by eight slightly ainuoua grooves
arising on the umbilical wall and crossing the ventral area with a forward sinus;
younger whorls not showing grooves or costae crossing the periphery; interspaces
hetween grooves occupied by aix or more small rounded costae, often dividing at the
umbilical border, or near the middle of the aide, and stronger on the upper part of
the whorl; sutures not known. The holotype (Calif. Acad. Sci; type Coll.), half
septate, has the following dimensions: greatest diameter, 23 mm.; width of umbilicus,
7 mm.; height of whorl, 10 mm.; thickness of whorl, 9 mm.; umbilical ratio,
0.304:1. The largest example of this species yet seen measures 40 mm. in diameter.
The parntype (Calif, Acad, ScL type Coll.) has tbe following dimensiona: greatest
diameter, 19 mm.; thickneBB of whorl, 7 mm. The horizon is that of the uppermoat
Horsetown group. Many examples were found in 1898 at Jackass Flat, a mile east
gf Horsetown j meet of these were loat in the San Francisco fire of 1900. The holotype
was among those recovered. The specie a differs from "Detmocsra*" ithikavmi
Jimbo (1894) in section, being relatively thinner, the umbilicus being much smaller;
it also has a greater number of transverse grooves; it aleo has only about 50 costae
to the whorl. The horizon of the preeettt species is not younger than upper Albian,
whereas Jimbo'a species is much later, perhaps Senonian.
Puzoaia ertima Anderson, n, sp,
(Pitta II, fluirei)
This species occurs with the preceding in the uppermost beds of the Horsetown
group in the Cottonwood district. The shell is small, discoidal, compressed, flattened
on the sides, numerously costate; Umbilicus small, walls abrupt, rounded on
the border; surface marked by five or more faint sinuous gToovea which cross the
ventral area with a distinct forward sinua; interspaces occupied by eight or more
fairly well marked, rounded costae; Suture line not shown. The holotype (Calif.
Acad. Sci. type Coll,), mostly septate, has the following dimensiona: greatest diam-