Untitled

198 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA
approaching 90°. Base flattened to slightly convex in
adult. Aperture holostomous, subquadrate. Outer lip
straight. Inner lip strongly arcuate.
Dimensions of holotype : Height, 24.0 mm.; diameter,
6.5 mm. Specimen figured by Mansfield: Height, 27.5
mm.; diameter, 7.9 mm.
Holotype: U.S.N.M. 499110. Specimen figured by
Mansfield: U.S.N.M. 370359.
Type locality: Strickland farm, 11;2 miles northwest
of Magnolia, Duplin County, N. C.; given in Gardner
and Aldrich, 1919, as the Nat ural Well, which is nearby
and of the same formation.
Specimen figured by Mansfield: U.S.G.S. Sta. 3421.
Harveys Creek, half a mile above abandoned mill, Leon
County, Fla. Choctawhatchee fonnation. Cancellaria
zone.
Turritella ( T orculoidella) drupZinensis bears a strong
resemblance, particularly in the young and adolescent
stages, to the laterally compressed races ofT. subannulata
Heilprin from the Choctawatchee and Caloosahatchee
of Florida. It is doubtless closely related to it
and may prove to be a precursor of that species.
In the single adult T. duplinensis in the U. S. National
Museum from the Cape Fear River, the systems
of spiral lirations have broken down, and the lirae are
numerous, equisized, irregularly alternating, and tending
to concentrate on the. anterior portion of the whorl.
This suggests a possible identity with T. carolinensis,
vaguely described and badly figured by Conrad in
1875. It is probable, however, that the latter is characterized
by a relatively broader base, and a consistently
more uniform spiral sculpture. Unfortunately,
Conrad's type is not available.
Turritella holmesii Dall (pl. 27, fig. 23) [ = TerebellumL
striatum Tuomey and Holmes, 1856, not Isaac Lea,
1833] may be a badly figured specimen of some member
of the T. suban.nulata group. Although the illustration
does not indicate such an outline, Tuomey and Holmes
refer in their description to "the large whorls flattened,
those near the apex more convex." They refer also to
"transverse wrinkles distinct only on the lower whorls."
Their type is from Darlington, S. C., and presumably
from the Duplin marl.
Distribution: North Carolina: Duplin marl, llh miles northwest
of Magnolia, Duplin County. Waccamaw formation, Neills
Eddy Landing, 3 miles north of Cronly, Columbus County.
Outside distribution : Miocene: Duplin marl at the Muldrow
Place, Sumter County, S. C. and Porters Landing, Savannah
River, Effingham County, Ga. Choctawhatchee formation, Cancellaria
zone, Leon County, Fla.
Subgenu.s TORCULA Gray
1847. Torcula Gray, Zool. Soc. London· Proc., pt. 15, p. 155.
Type by original designation: Turbo emoletus Linnaeus. Recent,
in the Gulf of Mexico and the West "Indies in 45 to 170
fathoms (C. W. Johnson); Dry Tortugas in 3o to 35 fathoms
(C. W. Merriam).
Shell rather small, slender, polygyrate. Apical angle
very small, not far from 15°. Only about two narrow,
polished nuclear whorls, the initial whorl tilted slightly,
the second turn inflated but tending to flatten toward
its close. Line between conch and protoconch obscure,
indicated by duller texture of shell of conch. The four
or five earliest whorls of conch inflated and keeled anteriorly,
the whorls rapidly flattening and the anterior
keel becoming a low anterior spiral; posterior spiral
introduced on about the fourth or fifth whorl of the
genotype. Original spirals increasingly strong, becoming
the prominent anterior and posterior cords in
the adult; cords rarely simple, usually beaded by the
growth lines which override them. Growth lines
strongly arcuate and symmetrically disposed between
the sutures.
Torcula includes a number of Tertiary and a few
later species. The Tertiary forms are prolific in the
warm temperate and tropical waters of the Province
of the Gulf of Mexico and the West Indies. The Recent
species are not so common and live in deeper
water. Torcula probably reached the peak of development
during the middle Miocene. It includes T. aZtilira
and allied forms, prolific in the Canal Zone and Costa
Rica, allied species in Jamaica and the Dominican Republic,
in northern South America, and in Ecuador and
Peru on the Pacific coast, and the "T. inezana stock" of
Merriam in central and southern California and in
Lower California.
Turritella (Torcula) terstriata Rogers and Rogers
Plate 27, figures 18, 19
1837. Tut-ritella. ter-st1·ia_ta W. B. and H. D. Rogers, Am. Philos.
Soc. Trans., vol. 5, n. ser., p. 331.
1839. Turritella ter-striata W. B. and :k D. Jtogers, idem, vol.
6, n. ser. p. 377, pl. 26, fig. 1.
1884. Tu•JTitella ter-striata W. B. and H. D. Rogers, in Reprint,
Ann. Rept. Geol. The Virginias, p. 661.
1937. Tun·Uella terstriata Hogers. Mansfield, Jour. Paleontology,
vol. 11, p. 608, pl. 85, :fig. 9.
Whorls strongly angulated by three principal revolving eleva
ted spiral ridges ; the lowest, being about one-third from the
base, is the most prominent; the second, which closely adjoins
and almost coalesces with the first, is much feebler ; the third,
which is nearly one-third the height of the whorl from the summit,
is more distinct and is separated from the second by a deep
and wide channel ; next the base of each whorl are three fine
spiral striae; others to the number of four or five, occupy the
space between the principal ridge and the summit ; crossing these
are very fine indistinct tranverse arcuated wrinkles.
This shell is obviously distinct from the va,riabilis in the great
inequality of the three principal ridges, the depth of the central
channel, and the greater delicacy of the transverse wrinkles.
Locality, vicinity of Williamsburg; in the Miocene shell marl.
Length about two inches.-W. B. and H. D. Rogers, 1837.
The type material is in the collection of the Boston
Society of Natural History. Mansfield in 1937 figured
a specimen from U. S. Geological Survey sta. 11783
(Watkins Mill, King and Queen County, Va.; zone 1 of