LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

DESCRIPTION OF SPECIES 207
Acriocerai itarrkingi Anderson, n. ap.
(PUTO FIGURES T, (A; P!»TE U, FLJUR® 1A}
Shell of medium size, early wborlg not known; shell forming a shaft and bent
body-chamber, with an enlarged recurved limb; abaft closely costate, with small
simple costae arising in the dorsal zone at ita median tine, curving at first strongly
forward to the dorsal border, thence rising with a gentle forward elope toward the
ventral tone; costae prominently tubcrcuiate on the ventral border only, where two,
three, or four lateral costae are gathered into knot-tike, rounded tubercules; ventral
sons depressed, with costae crossing it somewhat irregularly, either singly, in pairs,
or in trios, On the body-chamber the ribs become greatly altered, forming coarse
ridges, which are tube re ul ate chiefly on the dorsal border; ribs a little prominent,
often dividing at the dorse-lateral node, separated by interspaces wider than the
ribs; from soma of thedorao-latcral nodes the ribs branch into pairs, from others they
arise singly, all crossing the ventral zona without interruption; above the dorsal
border are two rows of inconspicuous tubercules on most of the ribs, one above and
another below the median lino of the side, and a single row on the ventral border,
tending to produce an angle on the rib; section of both limbs subeireular, flattened
on the dorsal zone, narrowed slightly toward the ventral none. This specics appears
to belong to the group of AcrioG&raa sileaiaeum (TJhlig) from the Wernsdorfer beds;
A. rilesiaiiuTii seems to be its nearest analogue. The holotype (Calif. Aoad. Sci.
type Coll.) was obtained at Locality lflfil (Calif. Acad. Sci.), & mile west of the
Murphy house in the Roaring River district, It w found with Shasticriocerae
pomenle, Pteudocrtoceras tienlor, Aeroteuihit shmtensu, and Inaceramue otaloidee
nov. Its horizon is probably lower Barremian, somewhat below that of tho
Mi tchell zone.
Aspindetrtu a. gen.
Genotype, AapinaciTos hantlini, n. sp.
Among the ammonoid forme found in the Hamlin-Broatl zone (upper Valanginian)
in the Cottonwood district there is an unusual crioceratid type for which no suitable
generic name has been found, although the type itself is not unknown. Its perisphinctoid
(? aulacosphinctoid) character ae-enuj to appear in ita general form,
subquadrate section of whorl, and manner of costation—that is, in the alternation
of simple and divided ribs. As far as can be seen in the holatype-genotype there
is no evidence of costal spines or tubercules at any stage of its development, and in
this simplicity of ornamentation, aa well as in its manner of coiling, it recalls "Crioceras
{Ancyloccras)" dilatatum d'Orbigny, from the Neocomioo of France, To
this group probably belongs "Crioceras" muhante Astier, aa figured by Saraaiu and
Schoendelmayer (1902, p. 133, pi. 18, figs. 1, 2), who have compared it also with
"Crioceras" dilalatum d'Orbigny. Neither d'Orbigny, Astier, nor later authors
have described any costal ornamentation for these species, and, as far as can be seen
in their figures, none exists at any stage of growth. No description or figure has been
found illustrating the suture line of either of them, and this feature ia poorly shown
in the proposed genotype. The only sutural elements exposed are a stout first
lateral lobe which has asymmetrical, tripartite divisions and an asymmetrical,
deeply cleft second saddle. These add little to the characterization of the genus,
although they conform to a periaphinctoid type of ancestry.
A&pinoceras hamlini Anderson, a. sp.
CP]MIL CO, &PBTJ! 1, I)
Shell of medium size, moderately inflated, coiling at Brat crioceratid, later forming
a short, gently curved shaft and a retroversal bucal limb; section of early whorls
nearly circular, becoming semi-elliptical on the shaft, higher than broad; dorsal