MIOCENE PECTENS. 73 



Mr. Homer Hamlin and the writer found /*. crassicardo associated with the fol- 

 lowing fauna in beds of somewhat uncertain age, in a small ravine one-half mile south 

 of J. C. Griflin's ranch house, Priest Valle}-, Monterey County: P. discus Conrad, 

 Agasoma {(tff.) harkerianum Cooper. Mytilus {of.) inatheicsonii Gabb, Veinis pertenuis 

 Gabb, and Ostrea titan Conrad. 



In the Valcito Valley, Fresno County, Mr. H. W. Turner found P. crassicardo 

 with Venus j)erteiiuis. Doslnia {cf.)j>onderom. and Telllna sp. 



Mr. Eldridge foiuid P. crassicardo associated with the following species in Ijeds 

 of probable lower Miocene age on the ridge between the Upper and Lower Ojai 

 valleys. \'entura County: Pecten lornpocensis, TurriteUa (cf.) hoffmunni, Phacoides 

 sp. (flat), Oxtredi^^.., Nassa sp., Dentalium sp., Chione s^., Ledasp., Balaniis sp., 

 and Tritonium or Fnmis sp. 



Dr. Stephen Bowers has found /'. crassicardo with the following species in the 

 Miocene of Laguna Cannon, San Joaquin Hills, Orange County: Pecten estrellanus, 

 Glycymeris '( sp., Tarritella hoffmanni, Chione n. sp. (large, coarse sculpture), 

 Agasomaliernianum. and Gyrodes i sp. 



A beautiful specimen of P. crassicardo in the National Museum (No. 1.54154) 

 labeled from " California " is associated in the matrix with Sa.cldoinns (jraciUs. Tresus 

 nuttalli., and Litorina renumdi. As the last mentioned species is found only at 

 Kii'ker Pass it is safe to assume that this magnificent specimen (which is figured) is 

 from that locality. 



The type of P. crassicardo (PI. XYHI, tig. Ij. wliich is now in the collection 

 of the Philadelphia Academy of Natural Sciences, is simply labeled •"California. 

 Pres. by Dr. Wilson." 



KAXGE. 



Miocene (upper). San Pablo Bay, Contra Costa County (Merriam. Arnold, and 

 others); KirkerPass, Contra Costa County (U. S. N. M.): Mount Diablo, Contra 

 Costa County (Pioche collection, Univ. Cal.): Scott Valley. Santa Cruz 

 County (Miss L. J. F. Hecox): Camniatta ranch and San Juan Valley, east of 

 San Luis Obispo, San Luis Obispo County (Fairbanks, Moran, Arnold); Priest 

 Valley. Monterey County (Hamlin, Arnold); San Ardo. Monterey County 

 (Fairbanks. Hamlin. Anderson. W. C. Dudley' for Cal. St. Min. Bureau, 

 Arnold); Quail water Creek, San Luis Obispo County (Anderson); Ventura 

 County (No. 1:2772, C. S. M. B.); Sunset district. Kern County (Eldridge); 

 Valcito Valley, Fresno County (Turner). 



Miocene (middle or lower). Devils Den, Kern County; Ojai Valley, Ventura 

 County (Eldridge); ? El Toro and Laguna Canyon, Orange County (Bowers, 

 Arnold). 



Pecten (Ltropecten) Crassicardo Conrad var. hamiltoxi n. var. 



PI. XI, figs. .5 and fi. 



Description. — Adult shell averaging about 60 millimeters in altitude, sub- 

 equivalve, equilateral, convex; sides concave above; margins smooth. Right valve 

 with 15 to 17 prominent convex-topped ribs, separated by interspaces narrower 



