Conus
cowlitzensis (Weaver, 1912)
Conus
cowlitzensis maynardensis (McWilliams,
1971)
Description (1).
Shell biconical; spire a little over one-fourth
of total length; whorls seven and a half to eight, and very sharply angulated; upper
two forming the apex arc smooth and rounded; angle set with nodes. Body whorl
conical below the angle; nearly flat above but sloping close to the suture
maki11g the upper surface of each whorl decidedly convex; eighteen very
distinct nodes on the angle; these do not continue above or below as ribs;
although blunt and rounded they are pointed slightly to the left. Surface
marked by forty revolving lines below the angle which are more distinct toward
base of whorl; portion of whorl above angle obscurely sculptured by revolving
lines. Numerous faint lines of growth are present. Aperture linear and narrow,
and extending to end of spire. The spire varies somewhat in length, but the
upper surface of whorls are extremely convex.
Dimensions.
Altitude 38 mm.; diameter 15 mm.; altitude of
spire 13 mm.; angle of spire ,50° ; angle of lower part of body whorl 88°.
Occurrence.
Common at Loc. N. 1 (University of Washington
Palaeontological Collection) one and one-half miles east of Sopenah (Little
Falls) in bank of Cowlitz River, Lewis County.
Horizon.
Cowlitz formation, Upper Eocene.
The species
described by Weaver under this name is abundant in the Cowlitz Group near
Vader, Washington, where the senior author and Mr. Martin obtained a number of
good specimens at loc. 182 (C.A.S. Coll.). Dickerson figured a specimen from
then as C. cowlitzensis, but his “cotype No. 352” differs from Weaver’s
species in a number of important details; the apical angle of Weaver’s figured
specimen in 60°, the number of nodes is 16 to 18, on then body whorl which
contains 40 revolving lines below then angle; while the specimen figured by
Dickerson has an apical angle of only 45°, only 12 nodes on the angle of the
body whorl and latter is quite smooth, or faintly marked by few spiral lines
near then base. In other words it is evidently a distind species, and does not
represent Weaver’s species, as Dickerson supposed. Moreover, his so-called
“cotype” was merely a plesiotype. No specimen of Weaver’s species has yet been
recognized in any of the collections from the type locality of the Tejon Group
studied by us, and no confirmation has been found of its occurring there (3).
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Conus cowlitzensis (1)
Plate
II fig. 20 |
mm. 36 |
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Conus cowlitzensis
? (2)
Plate 11 fig. 8 |
Conus
cowlitzensis maynardensis (McWilliams,
1971)
The shell is small and biconical.
The spire is one-third to one-half the length of the shell. There are nine
whorls set with 16 to 18 nodes which are nor continuous above or below the
angle and which are weakly directed anteriorly. The body whorl is nearly
straight sided. It is rounded slightly just below the angle and slightly concave just below
the suture. The surface below the angle on the body whorl is sculptured by
approximately 15 to 20 coarse, flat-topped revolving ribs which are separated
by fine, flat-bottomed interspaces of one-fourth to one-sixth of the width of
the rib. The surface is crossed by many fine growth lines which are worn off
the holotype. The aperture is long and narrow.
Dimension of the holotype: height
22 mm, diameter 8 mm, angle of spire 25 °.
Remarks: This new subspecies is
characterized by the coarse ornamentation on the body whorl.
C. cowlitzensis
Weaver has about 40 revolving ribs while C. cow!itzensis subsp. Maynardensis has 15 to 20 ribs on the body whorl.
This new subspecies was originally
described by Richard C. Allison in an unpublished University of Washington masters thesis (
1959).
Occurrence:
Lyre Formation: UWA 217, UWA 887, UWA 892.
Tukwilla Formation: UWA 1050, UWA 3490.
Holotype: 8050, UWA 217, figured paratypes: 20314, UWA 1050, 18207, UWA
3490.
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Conus
cowlitzensis subsp. maynardensis McWilliams
n. subsp. Plate 1: 9. Holotype:
8050, UWA 217, 3X. mm. 22 x 8 10. Paratype: 20314, UWA 1050, 3X. 11. Paratype: 18207, UWA 3490 Upper Eocene Turkwilla Fm. – South Seasttle
(Washsington) |
Bibliografia Consultata
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(1) - Weaver, C. E., 1912. A
Preliminary Report on the Tertiary Paleontology of Western
Washington. Washington Geological Survey Bulletin, 15
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(2) - Dickerson (1915) “Fauna of the type Tejon: its
relation to the Cowlitz phase of the Tejon Group of Washington”
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(3) - Anderson & Hanna (1925) “Fauna and stratigraphic
Relation of the Tejon Eocene at the Type Locality in Kern County, California”
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(4) - McWilliams (1971). Northwest
science : Official Publication of the Northwest Scientific Association, 45
(4 )
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