LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION Of sPECIES 199
It would have, if complete, a greater diameter of 325 mm.; width of umbilicus, 166
mm.; height of whorl, 85 mm.; thickness of whorl, CO mm.
The "juvenile" ribs are not known, but those of the older stages become heavy and
widely spaced, and each bears a prominent ventrolateral tubercule, an elongated
Bwelllng on the middle of the side, and a similar swelling on the umbilical border;
in some coses the ribs divide from bullae, but this seems to be tare, and most of them
rise singly. The suture line is not yet well known, but the second lateral lobe is
broad, terminating in Btout tripartite branches; tbe second saddle is deeply and narrowly
cleft, with rounded terminations. This species appears to belong to the general
type of PeroinqHieria trinodoaa (Boesc), from the lower Cenomanian of Cerro
de Muleros, Mexico.
In the Hulen beds it Occurs a little above the horizon of the Neptune zone, and
therefore near that of Oxylropidacerae paekardi nov.
At least two other species of Pervinquieria are known from the overlying Chico
scries, but they differ in section and in other features from the present form. Compared
to the number of species of thia genus known in Texas "middle Cretaceous,"
the number appearing in California aeems small at best.
CniocERATrDAE Hyatt 1S09
The "family" group Criocaratidae was originally proposed to include certain
smaller groups of degenerate, evolutc, but often highly ornamented cephalopod
forma that seem to have been derived from different older stocks. Besides the genera
Crioceras Leveille and A crioceras Hyatt, Spath (1924, p. 77, 85) has more recently
segregated other groups from the general assemblage under several names, as A egecriocerae,
Peeudocrioccras, and Paracriocerm, and under the family name Hemihoplitidae
he has included ffoplocriaceraa as a new genua. As judged by thoir forms and
other characteristics, moat of these genera seem to have had lytoccratid ancestry,
although there are others that seem to have descended from hoplitid stocks or from
others farther in tbe background. By hie use of the terms Hemihoplitidae and
Haploerioceras, Spath may have intended to suggest their derivation from Hoplitidae,
although no clear statement of this view has been found,
Neaverson (1928, p. 3®0) says only:
"The genua Hoplocriocerae, including uncoiled Ammonoids with a characteristic
bundling of the ribs at the umbilical tubercuk, furnishes a name for the Hoploerioeeratan
fauna."
Such arrangements aid only partially in the disposition of the crioceratid forms
from the Shasta series of California. If umbilical tubercules and a "bundling of the
ribs" at such points are essentials for entrance into this new ammonoid family, there
are few California species that could be included in it, even by a generous interpretation
of the rule. As far as known at present, only three Species show such
tubercules, or a bundling on the ribs at these points, but there is good evidence that
"Criocerat" remandi (Gabb) had such tubercules up to a diameter of 64 mm., with a
bundling of the costae at these points. These features are lost in later stages of
growth, the tubercules being altered to mere swellings on the umbilical border from
which costal lines radiate. However, Spath himself (1921, p. 77-SO) has included in
Hoptocrioceras some apecies that do not show these charoctcre, as far as can be seen
in the figures, as for example ffoptoerioeerae latviutadum (von Kocnen, 1602, pi. 23,
figs, -la, 5).
Another group of crioceratida appears in the middle Horsetown (Barremian)
beds. Aa judged by form, ornamentation, and sutures, this group seemB to have
come from aa hoplitid stock, cither from .Vrocomt'Jes or from some near ally, but