﻿402 
  PROCEEDINGS 
  OF 
  THE 
  CALIFORNIA 
  

  

  istence, 
  and 
  few 
  of 
  vegetable 
  life. 
  It 
  is, 
  however, 
  most 
  probable 
  that 
  such 
  ex- 
  

   isted, 
  and 
  will 
  in 
  time 
  be 
  determined 
  or 
  distinguished 
  from 
  the 
  pHocene 
  with 
  

   which 
  they 
  are 
  now 
  mixed. 
  That 
  there 
  was 
  an 
  extensive 
  and 
  most 
  interesting 
  

   terrestrial 
  fauna 
  in 
  the 
  adjoining 
  regions 
  of 
  Eastern 
  Oregon, 
  Wj'oming, 
  and 
  Utah 
  

   has 
  been 
  proved 
  by 
  the 
  treasures 
  of 
  animal 
  remains 
  found 
  within 
  ten 
  years 
  past 
  

   in 
  those 
  regions, 
  to 
  enumerate 
  merely 
  the 
  names 
  of 
  which 
  now 
  would 
  take 
  up 
  

   too 
  much 
  time. 
  

  

  As 
  there 
  was 
  much 
  less 
  land 
  above 
  water 
  in 
  this 
  part 
  of 
  the 
  continent 
  during 
  

   the 
  miocene, 
  the 
  field 
  for 
  such 
  animals 
  to 
  exist 
  in 
  was 
  much 
  more 
  limited 
  than 
  

   in 
  the 
  pliocene, 
  and, 
  therefore, 
  their 
  history 
  requires 
  longer 
  time 
  to 
  work 
  out. 
  

   Besides 
  this, 
  the 
  convulsions 
  and 
  removals 
  of 
  animal 
  relics 
  from 
  their 
  original 
  

   beds, 
  during 
  the 
  volcanic 
  and 
  glacial 
  periods, 
  were 
  so 
  general 
  as 
  to 
  mix 
  them 
  

   up 
  in 
  a 
  manner 
  too 
  puzzling 
  to 
  be 
  deciphered 
  for 
  a 
  long 
  time 
  to 
  come. 
  An 
  

   instance 
  of 
  this 
  is 
  shown 
  by 
  the 
  tooth 
  of 
  an 
  Archegosaurus, 
  found 
  by 
  me 
  on 
  

   Mare 
  Island, 
  some 
  years 
  since, 
  and 
  mentioned 
  in 
  our 
  Proceedings, 
  Vol. 
  V., 
  p. 
  

   194. 
  This 
  tooth, 
  identified 
  by 
  the 
  lamented 
  Agassiz, 
  belonged 
  to 
  an 
  animal 
  

   believed 
  to 
  have 
  been 
  one 
  of 
  the 
  earliest 
  reptilian 
  forms 
  known, 
  and 
  character- 
  

   izing 
  the 
  carboniferous 
  age. 
  It 
  was 
  an 
  enormous 
  development 
  of 
  the 
  strange 
  

   " 
  four-legged 
  fish," 
  or 
  larval 
  salamanders 
  still 
  found 
  in 
  the 
  Columbia 
  River 
  and 
  

   other 
  western 
  waters, 
  but 
  must 
  have 
  been 
  several 
  feet 
  long, 
  and 
  no 
  similar 
  re- 
  

   mains 
  are 
  found 
  in 
  any 
  later 
  formations. 
  Though 
  it 
  is 
  not 
  certain 
  that 
  they 
  may 
  

   not 
  be 
  yet 
  found 
  to 
  have 
  existed 
  among 
  the 
  monsters 
  of 
  the 
  pliocene 
  epoch 
  on 
  

   this 
  Coast, 
  as 
  their 
  supposed 
  descendants 
  live 
  in 
  our 
  fresh 
  waters, 
  still 
  the 
  evi- 
  

   dence 
  of 
  this 
  single 
  tooth 
  would 
  have 
  gone 
  far 
  to 
  prove 
  the 
  age 
  of 
  Mare 
  Island 
  

   to 
  be 
  carboniferous 
  if 
  no 
  other 
  fossils 
  had 
  been 
  found 
  there. 
  As 
  it 
  happens, 
  

   however, 
  to 
  be 
  one 
  of 
  the 
  richest 
  fossil-beds 
  of 
  pliocene 
  remains 
  in 
  California, 
  

   the 
  single 
  tooth 
  found 
  on 
  the 
  surface 
  of 
  that 
  formation 
  was 
  probably 
  transported 
  

   by 
  ice 
  from 
  the 
  Sierra 
  Nevada, 
  where 
  the 
  nearest 
  carboniferous 
  strata 
  are 
  known 
  

   to 
  exist. 
  Of 
  course, 
  the 
  same 
  may 
  be 
  the 
  case 
  with 
  some 
  of 
  the 
  pliocene 
  re- 
  

   mains, 
  and 
  possibly 
  others 
  elsewhere. 
  But 
  the 
  peculiar 
  position 
  of 
  Mare 
  Is- 
  

   land 
  makes 
  it 
  the 
  most 
  likely 
  place 
  for 
  such 
  mixtures, 
  as 
  it 
  lies 
  just 
  where 
  the 
  

   outlet 
  of 
  pliocene 
  or 
  post-pliocene 
  lakes 
  or 
  rivers 
  must 
  once 
  have 
  met 
  a 
  great 
  

   obstruction 
  to 
  their 
  flow. 
  On 
  this, 
  animals 
  embedded 
  in 
  floating 
  ice 
  would 
  

   naturally 
  lodge 
  and 
  decay, 
  just 
  as 
  the 
  celebrated 
  extinct 
  elephant 
  of 
  Siberia 
  

   was 
  carried 
  by 
  ice 
  to 
  its 
  resting 
  place 
  at 
  the 
  mouth 
  of 
  an 
  Arctic 
  river. 
  The 
  

   obstruction 
  referred 
  to 
  was, 
  no 
  doubt, 
  an 
  elevation 
  of 
  the 
  Mt. 
  Diablo 
  ridge, 
  cross- 
  

   ing 
  the 
  Straits 
  of 
  Carquinez 
  at 
  this 
  point, 
  during 
  the 
  volcanic 
  period 
  before 
  

   mentioned. 
  By 
  this, 
  pliocene 
  beds 
  were 
  made 
  to 
  accumulate 
  to 
  a 
  depth 
  of 
  over 
  

   fifty 
  feet, 
  which 
  they 
  still 
  show 
  on 
  the 
  adjoining 
  shores, 
  though 
  the 
  rivers 
  have 
  

   washed 
  away 
  the 
  obstruction 
  itself, 
  and 
  the 
  greater 
  part 
  of 
  these 
  beds 
  also. 
  

  

  The 
  fossil 
  evidence 
  which 
  we 
  possess 
  relating 
  to 
  the 
  miocene 
  epoch 
  in 
  Califor- 
  

   nia 
  is, 
  however, 
  abundant 
  and 
  interesting. 
  It 
  so 
  far 
  consists 
  of 
  beds 
  of 
  marine 
  

   shells, 
  found 
  at 
  short 
  intervals 
  throughout 
  the 
  Coast 
  Range 
  and 
  the 
  foot-hills 
  of 
  

   the 
  Sierra 
  Nevada, 
  which 
  contain 
  the 
  proper 
  proportion 
  of 
  living 
  species 
  to 
  

   prove 
  their 
  age 
  as 
  relatively 
  older 
  than 
  the 
  pliocene. 
  From 
  their 
  compara- 
  

  

  