LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

description of bpbcte3 149
;at diameter, 171 mm,; width of umbilicus, 57 mm.; height of whorl, 70 mm.; width
jf whorl, 84 mm.; umbilical ratio, 0.333:1. It constats of tbe inner whorls of a shell
whose diameter had been more than 24 inches (60.96 centimeters). The removal of
one whorl from this example would reduce its diameter to one-fifth of its present
measure. If the increment of growth were by heights of whorl in adjacent coils
these ratios for the holotype would be: 1:3; for a second example from Locality 1347
(Calif. Acad. Sci.), 1:3.3; and for the small figured specimen, 1:2.5. These several
ratios seem to reflect the size (and ages) of the examples measured. Other characteristics
of the group will appear in the description of the holo-genotype.
Lyloceroe (Argonattiieerat) argonautarum (Anderson)
(Plata 17. fi*unj 3; pUta 10. S«QXBH 1,2)
Lylaccraa ARPONATDARUM ANDEHSON, Calif. Acad. Sci., Pr , 3d aer„ vol. 2,1902, p. 85,
' " "gB~ 154, 155; middle Horsetown group, Cottonwood district, Shasta
Shell large, coiling lytoceratid, much inflated, increasing rapidly in diameter;
aectiou of whorl subcircular, broader than high, flattened on the sides and on the
ventral zone; involution slight, having on the dorsum only an impressed zone; surface
of shell ornamented by evenly spaced costae with acute "crinkley" edges, hardly
crcnulated; suture line partly shown in the figure; first lateral lobe not quite symmetrically
bipartite; small siphonal saddle lanceolate in general outline.
An example of thia species, found at Locality 1347 (Calif. Acad. Soi.) near Mitchell
Creek, has the following dimensions', greatest diameter, 250 mm.; width of umbilicus,
87 mm.; height of whorl, 113 mm.; width of whorl, 125 mm.; umbilical ratio, 0.348:1.
This species characterizes the Argonaut zone (middle Aptian) of the Horsetown
group, where it is associated with Gabbioccras angulatum, Pkyllocera* onoenee Stanton,
and Parahopliioidce thoupi nov. The species (and zone) has been found on
Hulen Creek, Roaring River, and Middle fork of Cottonwood Creek. Good examples
of the species were collected by R. M. Kleinpell and E. Wayne Galliber north of
Skidcgatc Indian village, near Village Bay, Graham Island, associated with Detmoeerat
voyi Anderson, Aucella indigenalie nov., and terebraluloidcs Lahusen.
Gabb (1856a, p. 132) seems to have included this specieB in his description oi Lylocera*
bate*i (Traak), regarding it as a variety "in which the whorla increase much more
rapidly in Bias." The species has been found in beds much below the Argonaut
zone in this district.
Qabbioeereu Hyatt, 1366
Genotype, ^MNWMFTEI Batesi GABB (In part), Paleont, Calif,, vol, 2,18&0, p. 132, pi.
20, figa. 0, 9a; pi. 21, &RB. 10, lua, 10b; (not Amm. Traak; not Amm.
bafe*T (Trask) GABB, Paleont. Calif., vol. 1,1864, pi. 13, figs. 10a, L&b).
Gabb gave a good description and figures of a lytoceratid specics in the second
volume of his work on California fossils, but erroneously referred it to A mm. batesi
Trask. This spcciea waa later made the genotype of Cabbiocerae by Hyatt, and in
1002 it was described as Lytoceto* (Gabbiacerat) angulatum, nov. by Anderson. The
holotype of the species is in the Museum of the Academy of Natural Sciences of
Philadelphia.
Charles Jacob (1907, p. 17) proposed the generic name "Jauhertolfo," taking as the
genotype .4mm. Jauberlianua d'Orbigny, said to have come from the Aptian marls of
Barremme. Hyatt's name first appeared in Eastman's translation of Zittel's Textbook
of Paleontology (1000, p. 570). If the two species taken as genotypes by Hyatt
and Charles Jacob respectively prove to be closely related forma, as they appear to