Pecten (Pecten) merriami 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. 99, pl. 30, figs. 1, 1a, 2]
«PECTEN (PECTEN) MERRIAMI n. sp.
Pl. XXX, figs, 1, 1a, and 2. 1900. Pecten meekii Merriam (not of Conrad, 1857 = P. caurinus Gould), Bull. Cal. St. Min. Bureau, No. 19, 1900, p. 222.
Description. — Shell averaging about 115 millimeters in altitude, longer than high, inequivalve, equilateral. of medium thickness, and with smooth margins; base evenly rounded; sides straight or only slightly concave above, sloping at a rather low angle. Right valve decidedly ventricose. with 18 or 19 subequal, strong, square ribs, some of which show faint medial sulcations near their extremities; interspaces flat-bottomed and somewhat narrower than ribs: whole surface of disk sculptured by more or less prominent lines of growth; hinge line more than one-half length of shell; ears about equal in length; anterior ear with faint byssal notch, obsolete radiating ridges and tine incremental sculpture; posterior ear rectangularly truncated, and with faint radial and fine concentric sculpture. Left valve flat to concave, with a more or less prominent bulge just below the umbo, as in P. bellus; ribs prominent and rounoed, relatively flatter and broader as the periphery of the disk is approached; interspaces about as wide as the ribs, round-bottomed, and some of them showing a faint intercalary riblet; surface sculptured by fine, sharp, looped, concentric lines; ears ornamented by 5 or 6 rather prominent radiating ridges and numerous flne concentric lines. Dimensions.— Alt. 11.5 mm; long. 130 mm.; hinge line 70 mm.; diameter 80 mm. P. merriami is distinguishable from P. bellus, to which it is allied, by its much larger size when adult, more numerous ribs (18 to 19 in the former, 14 to 15 in the latter), relatively longer hinge line (the hinge line of the former being about 60 per cent of the length of the disk, while that of the latter is only about 45 per cent), and the radial ridging of the ears. The types of this species, which are the only specimens of it so far known, were collected by Mr. Watts from light-colored shale underlying the conglomerate on San Felician Creek, near Piru, Ventura County. The following fauna, as given by Doctor Merriam, was associated with P. merriami at the type locality: Echinarachnius near excentricus, Macoma near secta, Nassa sp. indet., Pachypoma n. sp., Solen sicarius, and, as determined by the writer, Pecten cerrosensis. This fauna indicates beds of probable lower Pliocene age. The type of P. merriami is now in the collection of the California State Mining Bureau, San Francisco. Named in honor of Dr. John C. Merriam. professor of paleontology, University of California, to whom paleontologists are indebted for so much of their knowledge regarding the faunas of the California Tertiary. RANGE.
Pliocene (lower). San Felician Creek, near Piru, Ventura County (Watts).»
RALPH ARNOLD, 1906
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R. Arnold, 1906, plate 30.
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