62 TERTIAKY AND QUATERNARY PECTENS OF CALIFORNIA. 



raised, concentric lines; ears subequal, and having- incremental and sometimes 

 obsolete radial sculpture. 



Dinieniilons. — Alt. 110 mm.; long. 115 mm.; hinffe line 54 mm.; diameter 

 'it! ram. 



This fine species is distinguishable l)y the gi-eat number and shape of its ribs. 

 Specimens found at Howe's place, northeast of Corvallis, Benton County. Oi'eg., 

 have only from 26 to 27 ribs on the right valve. Otherwise the specimens are 

 similar to the typical form. 



Found abundantly in the Empire beds at Coos Bay, Oregon, whence the type 

 came. 



Miocene. Coos Bay, Oregon (.Sjuunard; Dall: A. W. Crawford and others); 

 Howe's place, northeast of Corvallis, Benton County, Oreg. (Diller). 



Pectex (Patinopecten) oilleri Dall. 



PI. V. tiii. L'. 

 1901. T'rctrii (Lyropeden) ilillrri Dall, Nautilus, vol. Iti, uo. U), Feb., IHOl, p. 117. 



The original desci'iption is as follows: 



Dcwrlption. — "Shell large, a\eraging about 190 millimeters in altitude, I'ather 

 compressed, nearly orliicular with a relatively short, straight, hinge line, dorsally 

 rectangular, nearly smooth, subcHpial ears, the post(>rioi' with ',i small ribl(>t.s; a well- 

 marked though shallow ])yssal fold; and modei'ately thick valves. Th(> right valve is 

 somewhat more convex and strongly sculptured, bearing 29 to Sn high, nai-row. Trail 

 shaped ribs, flattened above, overhanging narrower, deej). nearly smooth channels; 

 and with marked concinitric imbrication, feebl(> on top of the ribs l)ut articularly 

 scaly at their sides. The sculptun> of the left valve is le.ss jjionounced, liiddeii in the 

 matrix. l)ut apparently similar." 



[>iinriisi(nit>. — "Alt. I'.tSnnn.; long. 175 mm.: diameter about 35 nun." 



In the type the lateral edges are slightly defectixe. th<' submargins very narrow. 



This species is close to P. jiurislinaeniilx, and is no doubt genetically related 

 to that form. Although the left valve of P. diUeri has not been seen, it is safe to 

 assume from the close relationship of this species and /'. jmrisiinaetistn that the 

 left valve of the former is ornamented with narrow, ridge-like ribs which are 

 separated by concave- bottomed interspaces relatively widei- than those of the right 

 valve. 



/'. d/'lleri is so fai' known only from beds of probable upper Miocene (although 

 possibly lower Pliocene) age at Rio Dell, on the Eel River, Humboldt County, 

 where the type was collected ))y Mr. J. S. Diller. of the United States Cxeological 

 Survey. 



RANGE. 



Upper Miocene or lower Pliocene. Rio Dell, Eel River, Humboldt County (Dall; 

 Diller). 



