﻿PLATE 
  XVIII. 
  

  

  Vaqceros 
  (Lower 
  Miocene) 
  Pelecypoda. 
  

  

  (Unless 
  otherwise 
  indicated 
  all 
  figures 
  are 
  one-half 
  natural 
  size.) 
  

  

  Fig. 
  1. 
  Pecten 
  (Lyropecten) 
  crassicardo 
  Conrad. 
  U.S.N.M. 
  J 
  04967. 
  Exterior 
  of 
  valve, 
  

   showing 
  characteristic 
  sculpture; 
  altitude 
  90 
  mm. 
  Ojai 
  Valley, 
  Ven- 
  

   tura 
  County, 
  Cal. 
  This 
  species 
  ranges 
  throughout 
  the 
  Miocene, 
  being 
  

   commoner 
  in 
  the 
  lower 
  part 
  in 
  southern 
  California, 
  in 
  the 
  upper 
  part 
  in 
  

   central 
  California. 
  

  

  Fig. 
  2. 
  Pecten 
  (Amusium) 
  lompocensis 
  Arnold. 
  Collection 
  of 
  California 
  Academy 
  of 
  

   Sciences. 
  Holotype. 
  Mold 
  of 
  interior 
  of 
  left 
  valve; 
  altitude 
  105 
  mm. 
  

   Four 
  miles 
  south 
  of 
  Lompoc. 
  

  

  Fig. 
  3. 
  Pecten 
  (Amusium) 
  lompocensis 
  Arnold. 
  U.S.N.M. 
  164852. 
  Paratype. 
  Inte- 
  

   rior 
  of 
  a 
  portion 
  of 
  left 
  valve; 
  altitude 
  90 
  mm. 
  Ojai 
  Valley, 
  Ventura 
  

   County, 
  Cal. 
  

  

  Fig. 
  4. 
  Pecten 
  (Amusium) 
  lompocensis 
  Arnold. 
  Collection 
  of 
  California 
  Academy 
  of 
  

   Sciences. 
  Paratype. 
  Imperfect 
  mold 
  of 
  interior 
  of 
  right 
  valve: 
  hinge 
  

   line 
  42 
  mm. 
  Same 
  locality 
  as 
  fig. 
  2. 
  

  

  Fig. 
  5. 
  Pecten 
  (Lyropecten) 
  boiversi 
  Arnold. 
  Collection 
  of 
  University 
  of 
  California. 
  

   Type. 
  Exterior 
  of 
  slightly 
  imperfect 
  right 
  valve; 
  altitude 
  150 
  mm. 
  

   Santa 
  Ynez 
  Canyon. 
  

  

  Fig. 
  6a. 
  Ostrea 
  cldridgei 
  Arnold. 
  U.S.N.M. 
  165320. 
  Left 
  valve; 
  altitude 
  114 
  mm. 
  

   View 
  of 
  exterior. 
  El 
  Jaro 
  Creek 
  (4519). 
  Characteristic 
  of 
  this 
  horizon. 
  

  

  Fig. 
  66. 
  View 
  of 
  exterior 
  of 
  right 
  valve 
  of 
  same 
  specimen. 
  

  

  138 
  

  

  