NO. 1545. NEW FOSSIL MOLL USKS FROM CALIFORNLi—AENOLD. 543 



Plate XLV. 



Fig. 1. Peden {Hinnites) giganteus Gray. Cat. No. 164965, U.S.N.M. Exterior of 

 right valve; altitude 90 inm. Lower Miocene, supposed equivalent of 

 Vaqueros formation, gulch east of Wiley Canyon, southwest of Piru, 

 Ventura County. A very variable species, ranging from the low^er Miocene 

 to the Recent fauna. 



2. Ostrea titan Conrad. Cat. No. 164987, U.S.N.M. View of exterior of larger 



valve; altitude 131 mm. Lower Miocene, 3 miles south of Calabasas, Los 

 Angeles County. A common form in the upper and lower Miocene; often 

 grows to a length of 20 inches (500 mm. ) or more. (See Plate XL, fig. 2. ) 



3. TrochUa costeUata Conrad. Cat. No. 164994, U.S.N.M. View from above; 



maximum diameter 38 mm. Same locality as fig. 2. Common in the 

 Miocene. 



4. Phacoides richthofeni Gabb. Cat. No. 164978, U.S.N.M. Right valve; alti- 



tude 17.5 mm. Sauie locality as fig. 2. 



5. Balnnus concavus Bronn. Cat. No. 164971, U.S.N.M. Type. Lateral view; 



maximum latitude 26 mm. Lower INliocene, Little Sespe Creek, Ventura 

 County. A very connnon species in this horizon. 

 5a. Top view of same species. 



Plate XLVI. 



Fig. 1. PectC7i (CJdamg.'i) .sespeensi.s Arnold. California State Mining Bureau. Cotype. 

 Portion of mold of interior of right valve; altitude 50 mm. Lower Miocene, 

 Vaipieros formation, Sespe Canyon, Ventura County. A connnon species 

 at the type locality; also found elsewhere in central and southern California 

 in the lower Miocene, 

 la. Mold of interior of left valve of same specimen. 



2. Pecten ( Chlamys) sespeemis Arnold. California State Mining Bureau. Plasto- 



type. Cast of exterior of slightly imperfect left valve (young) ; altitude 

 18 mm. Same locality as fig. 1. 



3. Pecten {Lgropecfev) vaughani Arnold. Collection of Delos Arnold. Type. 



Right valve; altitude 37 mm. Lower Miocene, supposed ecjuivalent of 

 Vaqueros formation, Cjai Valley, Ventura County. 

 3«. View of left valve of same specimen. 



4. Do.'iinia ponderosa Gray . Cat. No. 164988, U.S.N.M. Imijerfect I'ight valve; 



altitude 80 mm. l>ower Miocene, 3 miles south of ('ala])asas, Los Angeles 

 County. A common species from the lower Miocene to the Recent south- 

 ern fauna of the west coast. 



5. Pleurotoma (Bathiftoma) keepi, new species. Cat. No. 164993, I'.S.N.M. 



Holotype. Back view of imperfect specimen. Same locality as fig. 4. 

 Found also in this horizon at several localities in southern San Joaquin 

 Valley. 



Plate XLVII. 



Fig. 1. .irca camidoevsis Osmont. California State INIining Bureau. Holotype. 

 Right valve; altitude 89 mm. Fernando formation, lower Pliocene or 

 upper Miocene, 1 mile north of Camulos, ^'entura County. So far as 

 known this species is characteristic of the lower horizon of the Fernando 

 formation. Also reported from the Puente Hills, 

 la. End view of same specimen as fig. 1. 



lb. Portion of surface of same specimen as fig. 1, enlarged, showing nodose ril)s. 

 Proc. N. M. vol. xxxii— 07 35 



