﻿298 
  PROCEEDINGS 
  OF 
  THE 
  CALIFORNIA 
  

  

  5Y. 
  Sigaretus 
  debiUs, 
  Gld. 
  

  

  58. 
  Ranella 
  Matliewsonii, 
  Gabb. 
  

  

  59. 
  OUvclla 
  bcetica, 
  Cpr. 
  

  

  60. 
  Nassa 
  fossata, 
  Gld. 
  

  

  61. 
  Nassa 
  mendica, 
  Gld. 
  

  

  62. 
  Astyris 
  tuberosa, 
  Cpr. 
  

  

  63. 
  Astyris, 
  sp. 
  indet. 
  jun. 
  

  

  64. 
  Ocinebra 
  lurida, 
  Cpr, 
  

  

  65. 
  Pteronotus 
  festiwus, 
  Hinds. 
  

  

  66. 
  Trophon 
  orplieus, 
  Gld. 
  

  

  67. 
  Fums 
  {Colus) 
  Dupetit-Thouarsi 
  ? 
  Kien. 
  

  

  68. 
  Chrysodomus, 
  n. 
  s. 
  Too 
  imperfect 
  for 
  description, 
  but 
  very 
  distinct 
  ; 
  perhaps 
  

  

  a 
  Volutopsis, 
  as 
  the 
  nucleus 
  would 
  indicate. 
  

  

  69. 
  Chrysodomus 
  Diegoensis, 
  n. 
  s. 
  

  

  Shell 
  large, 
  solid, 
  fusiforra 
  ; 
  apparently, 
  when 
  fresh, 
  of 
  a 
  brownish 
  yellow 
  

   color 
  ; 
  sculpture 
  consisting 
  of 
  regular, 
  even, 
  rounded, 
  spiral 
  ridges, 
  slightly 
  

   larger 
  toward 
  the 
  anterior 
  end 
  of 
  the 
  last 
  whorl, 
  with 
  from 
  two 
  to 
  four 
  sharp 
  

   grooves 
  intercalated 
  between 
  each 
  two 
  of 
  the 
  primary 
  ridges, 
  forming 
  fine 
  and 
  

   small 
  secondary 
  threads 
  of 
  spiral 
  sculpture. 
  On 
  the 
  posterior 
  whorls 
  these 
  are 
  

   crossed 
  by 
  slightly 
  oblique 
  waves 
  or 
  plications, 
  evanescent 
  toward 
  the 
  sutures 
  

   and 
  strongest 
  on 
  the 
  apical 
  whorls. 
  On 
  the 
  last 
  whorl 
  and 
  a 
  half 
  these 
  are 
  ab- 
  

   sent. 
  The 
  posterior 
  fourth 
  of 
  the 
  whorls 
  slightly 
  impressed 
  and 
  the 
  sutures 
  

   appressed. 
  Whorls 
  eight 
  and 
  a 
  half, 
  periphery 
  rounded. 
  Canal 
  short, 
  re- 
  

   curved, 
  siphonal 
  fascicle 
  short 
  and 
  strong. 
  Outer 
  lip 
  slightly 
  thickened 
  behind 
  

   the 
  edge, 
  inner 
  lip 
  covered 
  with 
  an 
  even 
  callus. 
  Columella 
  smooth, 
  slightly 
  

   arched 
  ; 
  throat 
  with 
  internal 
  sharp 
  threads, 
  as 
  in 
  C.dirm, 
  ending 
  some 
  distance 
  

   behind 
  the 
  edge 
  of 
  the 
  outer 
  lip. 
  

  

  Length, 
  4.0 
  inches 
  ; 
  width, 
  1.75 
  inches. 
  Length 
  of 
  aperture, 
  1.8 
  inches. 
  

   Deflection, 
  42°. 
  

  

  The 
  upper 
  whorls 
  of 
  this 
  shell 
  bear 
  a 
  slight 
  resemblance 
  to 
  Siphonalia 
  Kel- 
  

   lettii 
  ; 
  though 
  the 
  transverse 
  waves 
  are 
  very 
  dififerent 
  from 
  the 
  knobs 
  of 
  that 
  

   Species. 
  There 
  appears 
  to 
  be 
  no 
  special 
  reason 
  for 
  referring 
  the 
  present 
  form 
  to 
  

   Siphonalia, 
  while 
  it 
  presents 
  so 
  great 
  a 
  resemblance 
  to 
  many 
  Chryiodomi. 
  

  

  Habitat, 
  with 
  other 
  tertiary 
  fossils, 
  in 
  a 
  sand-bed 
  cut 
  through 
  by 
  a 
  well- 
  

   shaft, 
  at 
  San 
  Diego, 
  California, 
  at 
  a 
  depth 
  below 
  the 
  surface 
  of 
  about 
  one 
  hun- 
  

   dred 
  and 
  fifty 
  feet. 
  

  

  Besides 
  these 
  are 
  several 
  small 
  bivalves, 
  which 
  belong 
  to 
  different 
  species 
  ; 
  

   but 
  the 
  specimens 
  are 
  too 
  imperfect 
  for 
  description, 
  or 
  even 
  recognition. 
  

  

  On 
  an 
  examination 
  of 
  the 
  list 
  it 
  will 
  be 
  seen, 
  that 
  of 
  sixty-nine 
  specimens 
  

   only 
  three 
  are 
  strictly 
  Miocene, 
  while 
  many 
  are 
  reported 
  by 
  Gabb 
  as 
  extending 
  

   from 
  the 
  Miocene 
  to 
  the 
  present 
  epoch. 
  Of 
  fifteen 
  indeterminate 
  species, 
  some 
  

   will 
  probably 
  prove 
  to 
  be 
  new, 
  though 
  I 
  have 
  only 
  felt 
  justified 
  in 
  describing 
  

   one 
  species, 
  from 
  the 
  lack 
  of 
  specimens 
  for 
  comparison. 
  

  

  The 
  age 
  of 
  the 
  deposit, 
  in 
  general 
  terms, 
  may 
  be 
  taken 
  as 
  Pliocene 
  ; 
  though 
  

   it 
  is 
  evident 
  that 
  the 
  different 
  epochs 
  of 
  the 
  Tertiary 
  are 
  not 
  as 
  sharply 
  sepa- 
  

   rated 
  on 
  this 
  coast 
  as 
  in 
  some 
  other 
  parts 
  of 
  the 
  world. 
  

  

  