Chlamys washburnei (Arnold, 1906)
ARNOLD, R. 1906. The Tertiary and Quaternary pectens of California. United States Geological Survey Professional Paper, 47: 1-264, pls. 1-53 [p. 119, pl. 45, fig. 2]
1906 Pecten (Chlamys) washburnei Arnold, 1906
R. Arnold, 1906, plate 45.
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«Description.— Shell averaging over 100 millimeters in altjtude, somewhat shorter than high, subequivalve, equilateral (except for the ears), rather thin; base regularly rounded; sides somewhat conca:ve above. Left valve with about 65 more or less unequal, faintly squamose, low, squarish ribs; interspaces about as wide as the ribs, and sometimes ornamented by an intercalary thread or riblet; whole surface of disk ornamented by imbricating lamellae; anterior ear somewhat convex in front, and with a faint suggestion of a notch, sculptured by about 12 rather low imbricated radials; posterior ear about one-half as long as the anterior, obliquely truncated, and ornamented by faint radials and imbricating lamellre. Right valve unknown, but, judging by the affinity which this species bears to P. islandicus, it should be similar to the left valve, with the exception that the anterior ear should have a deep byssal notch, and the ribs should be slightly broader and the interspaees correspondingly narrower.
Dimensions.— Alt. 110 mm.; long. about 100 mm.; hinge line about 50 mm.; diameter 30 mm. This species is closely allied to P. islandicus, and may be its direct precursor. It is distinguishable· from the latter, however, by its larger size (being the largest species of this group yet known from the Pacific coast), more numerous, lower, and smoother ribs, and less obliquely truncated posterior ears. P. washburnei occurs in beds on the Yachates River, Lincoln County, Oreg., where it is associated with the following fauna: Opalia condoni Dall, Terebratella transversa Sby, Acmmaea sp., Strongylocentrotus (cf.) purpuratus Stimpson, (Cidaris (?) sp., Natica or Neverita sp., Buccinum (?) sp., Calliostoma sp. Doctor Dall is of the opinion that these beds are the equivalent of those at Eugene, Oreg., of whose position in the stratigraphic column there is much uncertainty. Tentatively, however, this species will be placed with those from the lower Pliocene. · This species is named in honor of Mr. Chester Washburne, of Eugene, Oreg., whose work in the Oregon Tertiary has added many new species to the lists. The type is now in the U. S. National Museum (No. 164843), locality 3593. RANGE.
Pliocene (lower?). Yachates River, Lincoln County, Oreg. (Washburne).»
RALPH ARNOLD, 1906
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