LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

150 lower chetaceous deposits ijf california and oregon
be, tbe rule of priority would. make the name "JVtutxrtelfa" a synonym of Gahbiaeeras
Hyatt, and it should ba discarded.
Lyloceras (Gabbioeeras) angulation Anderson
IPUte IS, l(un 3, i; pt»Uaj, 6fUi« 3)
Ammonites Balesi, GABH (in part), Paleont. Calif., vol, 2. I860, p. 132, pi. 211, figs.
9, 9a; pi. 21, figs. 10, 10a, 10b; (not Amm. Batesi TRASK, Calif, Acad. Sci,,
Pr. vol. 1, 1856, p. -10)—GABB, Paleont. Calif,, vol. 1, 18W, p. 67, pi. 13, figs.
10, 16a, 16b.
Lyloceraa {Gabbioeeras) angulatum ANDERSOJJ, Calif, Acad. Sci., Pr., 3d ser., vol. 2,
1002, p. 87, pi. 6, fig. 130; plesiotypc at the University of California.
ThiB species was well described by Gabb, who erroneously regarded it as a variety
of Lyloceraa baiesi (Trask.). Concerning this form ho says (in part):
"A third variety has since been obtained, in which, in the young state, up to
an inch, or an inch and a half in diameter, the whorls are broader than high, the
dorsum (venter) broadly rounded, and the umbilicus occupies more than half the
diameter of the shell, is funnel-shaped, very deep, and is bordered by a sharp angle,
the surface between this angle and the sutute being flat. As the shell of this variety
grows older, the angle disappears, the flattening gradually rounds out, and the older
shell assumes tho normal form of the species, except that it bears an occasional wellmarked,
rounded, slightly sinuous rib."
The holotype of this species is in tho Museum of the Academy of Natural Sciences
of Philadelphia. The locality of its discovery is not definitely known, Although
its horizon is probably near that of the Argonaut zone, in which it has been found
at Locality 1347 (Calif. Acad. Sci.), and on Aldersoa Creek, 2 miles south of Ono,
Shasta County. Its range is stratigraphically not very great,
LylQctras {Gabbioccrax) wtnlunium Anderson, n. sp.
(PUV> 14S, figut* 5; plate 1«. flew** t, 1.4, t)
Lytoceras rel. dtiMlianum A_VDEK3ON (in part), Calif. Acad, Sci., Pr., 3d ser., vol. 2,
1602, p. 81, (not pi. 6, figs. 140, 143).
By some oversight some confusion resulted in the earlier discussion of this species,
since there waa figured for it a much later type. The error was discovered too
late for correction, and this opportunity is taken for its re-deacription. In its
younger stages, aa well aa at maturity, the whorls of this species are quadrate in
section, and thus are "gradumbilieate"; in this respect it differs from the preceding
species. In young stages the aides and ventral surface are flattened, but in adult
stages this feature is lost and the whorls become rounded. At a diameter of 30
millimeters the shell has acquired 10 to 12 forward-curving periodic constrictions
which cross the ventral rone without a sinus. Between these constrictions the surface
is marked by numerous fine lines of growth which sometimes become prominent.
Tbe holotype (Calif. Acad. Sci. type Coll.) has the following dimensions: greatest
diameter, 57 mm.; width of umbilicus, 20 mm.; height of whorl, 23 mm.; width of
whorl, 24 mm.; umbilical ratio, 0.337:1.
This species has been found sparingly in the Argonaut zone, middle Horsetown
group, at Locality 1347 (Calif. Acad, Sci,), and in the some horizon on Alderson
Creek. Its nearest European analogue ia probably "Jaubertcila" jaubertiana (d'Orbigny).
The holotype was obtained at Locality 1348 (Calif, Acad, Sci.) on Alderaon
Creek, 2 milea south of Ono, Shasta County.