Patinopecten oregonensis oregonensis (Howe, 1922)
HOWE, H. V. W. 1922. Faunal and stratigraphic relationships of the Empire formation, Coos Bay, Oregon. University of California Publications, Bulletin of the Department of Geological Sciences, 14 (3): 85-114, pls. 7-12. [p. 98, pl. 11, figs. 1, 2; pl. 12, figs. 1, 2]
1922 Pecten oregonensis Howe, 1922
H. V. W. Howe, 1922, plates 11, 12.
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«Pecten propatulus (Con.) Martin, Univ. Calif. Publ. Bull. Dept. Geol., voI. 9, p. 253, 1916 (not of Conrad).
Shell averaging about 95 mm. in alt., 100 mm. long., equivalve, equilateral, only slightly ventricose, base regularly rounded, dorsal sides slightly concave and forming a 120 degree angle. Right valve with 17 to 21 wide, squarish ribs, which tend to bifurcate near the end in large specimens. The ribs near the posterior and anterior margins tend to split in such a way as to make the number of ribs variable, and at the same time to make the ribs near the center of the shell broadest.
The interspaces are sub-equal, flat-bottomed, narrower than the ribs. The whole surface ornamented with distinct incremental lines; hinge line less than half the disk; anterior ear longer than posterior with prominent byssal notch, above which it is ornamented by three or four radial ribs, crossed by prominent concentric lines; posterior ear rectangularly truncated and ornamented with incremental lines only. Left valve with low rounded ribs about half the width of interspaces, and ornamented by many very fine sharp concentric incremental lines. Posterior ear ornamented by prominent concentric sculpture. Anterior ear unknown. Dimensions.— Alt. 95 mm.; length 100 mm. Type.—Stanford University Collections from Stanford University locality N. P. 44. Also from locality N. P. 28—from Wildcat series of Scotia, Humboldt County, California. Also University of California specimen no. 30027 from locality 3320, base of Empire formation on east side of South Slough. This species is at first glance very similar to Pecten propatulus Con.,¹¹ but may be distinguished first, by its more numerous ribs, second, by lacking a tessalate sculpture, and third, by having in the left valve much broader interspaces which do not contain a median intercalary riblet; also, the sculpture of the ears is different.» ¹¹ Pecten propatulus Con, Geol. U. S. Expl. Exp., p. 726, pI. 18, figs. 13, 13a, 1849.
HENRY VAN WAGENEN HOWE, 1922
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«Patinopecten oregonensis oregonensis (Howe) (1922, p. 98-99, pl. 11, fig. 1, pl. 12, figs. 1, 2) has been collected from the Empire formation (Pliocene?) at Coos Bay, Oreg. It is a heavier shelled form than P. propatulus, has higher ribs, which are undercut, and also has a wider umbonal angle than P. propatulus.
P. oregonensis cancellosus differs from P. oregonensis oregonensis by having fewer ribs separated by wider interspaces and larger ears bearing a wider and deeper byssal sinus. The left valve of P. oregonensis cancellosus is more inflated than P. oregonensis oregonensis and has fewer ribs, and these ribs are higher and usually less rounded. P. oregonensis cancellosus reaches a larger maximum size than any of the specimens of either P. propatulus or P. oregonensis oregonensis in the collections in the U.S. National Museum; the largest specimen is about 170 mm high and 190 mm wide.» MOORE, E. J. 1963. Miocene Marine Mollusks from the Astoria Formation in Oregon. United States Geological Survey Professional Paper, 419: 1-109, pls. 1-32. [p. 65, 66]
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«Observations. This species is characterized by its broad slightly rounded to flat-topped radiating ribs which often become slightly dichotomous on the anterior and posterior surfaces and also near the ventral margin, the flat-bottomed and much narrower interspaces, and the distinct but faintly developed concentric lines of growth.
Holotype. (S.U. 25.) Empire formation. Figured in the present report, pl. 22, fig. 1.
Paratype. (U.C. 30027.) Empire formation. Figured in the present report, pl. 19, fig. 2. Geologic range. Empire formation, upper Miocene and lower Pliocene. Geographic distribution. Western Oregon. Type locality. Coos Bay, Oregon.» WEAVER, C. E. 1943. Paleontology of the marine Tertiary formations of Oregon and Washington. University of Washington Publications in Geology, Volume. 5 [1942], (parts 1-3), p. 1-789, pls. 1-104. [p. 93]
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Pecten (Patinopecten) oregonensis Howe; C. E. Weaver, 1943, Paleontology of the marine Tertiary formations of Oregon and Washington, plate 19, figure 2; plate 22, figure 1.
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