﻿ACADEMY 
  OP 
  SCIENCES. 
  403 
  

  

  tively 
  recent 
  date, 
  it 
  is 
  not 
  generally 
  difficult 
  to 
  recognize 
  and 
  follow 
  out 
  these 
  

   beds 
  throughout 
  their 
  extent, 
  though 
  much 
  more 
  disturbed 
  and 
  altered 
  by 
  vol- 
  

   canic 
  action 
  than 
  the 
  pliocene. 
  In 
  some 
  places, 
  however, 
  the 
  contact 
  of 
  erup- 
  

   tive 
  rocks 
  or 
  infiltration 
  of 
  foreign 
  mineral 
  matter 
  by 
  hot 
  springs, 
  has 
  altered 
  

   them 
  past 
  recognition, 
  though 
  for 
  only 
  limited 
  tracts 
  south 
  of 
  San 
  Francisco 
  

   Bay. 
  

  

  From 
  these 
  marine 
  beds 
  we 
  find 
  that 
  nearly 
  the 
  whole 
  of 
  the 
  coast 
  ranges 
  

   south 
  of 
  here 
  were 
  under 
  the 
  sea 
  in 
  the 
  miocene, 
  and 
  the 
  evidences 
  of 
  extensive 
  

   washing 
  away 
  of 
  the 
  strata 
  are 
  so 
  plain 
  that 
  it 
  is 
  not 
  improbable 
  that 
  the 
  

   whole 
  were 
  submerged. 
  

  

  Beds 
  of 
  excellent 
  miocene, 
  and, 
  possibly, 
  pliocene 
  fossils, 
  are 
  found 
  at 
  the 
  

   mouth 
  of 
  Kern 
  River 
  canon, 
  showing 
  that 
  the 
  sea 
  then 
  washed 
  freely 
  against 
  

   the 
  foot 
  of 
  the 
  Sierra 
  ; 
  there 
  is 
  even 
  reason 
  for 
  believing 
  that 
  it 
  extended 
  far 
  

   up 
  the 
  Colorado 
  River 
  basin 
  ; 
  and 
  certainly 
  it 
  deposited 
  a 
  thick 
  bed 
  of 
  the 
  

   enormous 
  miocene 
  oyster, 
  (O. 
  Titan) 
  with 
  other 
  remains, 
  along 
  the 
  west 
  shore 
  

   of 
  the 
  present 
  Colorado 
  desert, 
  now 
  at 
  an 
  elevation 
  of 
  probably 
  1,000 
  feet. 
  

   Of 
  its 
  extent 
  in 
  the 
  northwest 
  quarter 
  of 
  California 
  very 
  little 
  is 
  known, 
  and 
  

   probably 
  most 
  of 
  that 
  region 
  was 
  above 
  water. 
  

  

  As 
  these 
  changes 
  of 
  level 
  were 
  caused 
  by 
  depression 
  of 
  the 
  land 
  below 
  its 
  

   present 
  level, 
  our 
  mountains 
  were 
  then 
  probably 
  quite 
  insignificant, 
  and 
  no 
  

   doubt 
  a 
  much 
  more 
  level 
  and 
  uniform 
  surface 
  prevailed 
  on 
  shore. 
  As 
  the 
  

   miocene 
  was 
  elsewhere 
  the 
  culminating 
  period 
  of 
  existence 
  for 
  the 
  large 
  and 
  

   strange 
  tertiary 
  mammals, 
  it 
  is 
  altogether 
  probable 
  that 
  some 
  of 
  them 
  inhabited 
  

   portions 
  of 
  the 
  dry 
  land 
  of 
  California, 
  connected 
  with 
  the 
  regions 
  in 
  which 
  they 
  

   were 
  so 
  abundant 
  in 
  the 
  north 
  ; 
  but, 
  so 
  far, 
  the 
  geological 
  surveys 
  have 
  not 
  

   been 
  suEBcient 
  to 
  define 
  their 
  limits, 
  either 
  in 
  time 
  or 
  space, 
  within 
  this 
  State. 
  

  

  That 
  marine 
  monsters 
  frequented 
  our 
  shores 
  is 
  proved 
  by 
  the 
  remains 
  of 
  

   seals, 
  whales, 
  and 
  still 
  undescribed 
  creatures 
  of 
  enormous 
  size, 
  that 
  have 
  been 
  

   found 
  in 
  this 
  formation 
  even 
  more 
  abundantly 
  than 
  in 
  the 
  pliocene 
  of 
  the 
  

   Coast 
  Range. 
  From 
  the 
  great 
  difficulty 
  of 
  obtaining 
  their 
  stone-imbedded 
  relics, 
  

   there 
  will 
  be 
  work 
  for 
  future 
  generations 
  of 
  students 
  in 
  describing 
  them. 
  From 
  

   these 
  animal 
  remains 
  (many 
  of 
  which 
  were 
  only 
  of 
  microscopic 
  size) 
  was 
  pro- 
  

   duced 
  the 
  petroleum 
  of 
  this 
  Coast, 
  a 
  substance 
  so 
  far 
  found 
  only 
  in 
  the 
  miocene 
  

   strata 
  of 
  California. 
  

  

  Of 
  the 
  miocene 
  flora, 
  as 
  distinguished 
  from 
  the 
  pliocene 
  in 
  California, 
  we 
  

   know 
  very 
  little. 
  It 
  was 
  apparently 
  of 
  a 
  less 
  tropical 
  character, 
  more 
  like 
  that 
  

   of 
  the 
  present 
  time, 
  and 
  probably 
  resembled 
  ours 
  now 
  living 
  as 
  nearly 
  as 
  any 
  

   other. 
  Beds 
  of 
  lignite, 
  four 
  feet 
  thick, 
  but 
  poor 
  in 
  quality, 
  are 
  common 
  near 
  

   the 
  coast, 
  containing 
  wood 
  and 
  alga?. 
  

  

  The 
  northern 
  hemisphere 
  seems 
  to 
  have 
  had 
  in 
  the 
  miocene 
  epoch 
  a 
  very 
  

   uniform 
  climate, 
  in 
  which 
  the 
  vegetation 
  of 
  Europe 
  resembled 
  that 
  now 
  in 
  our 
  

   Eastern 
  States. 
  The 
  most 
  wonderful 
  fact 
  connected 
  with 
  it 
  is, 
  that 
  recent 
  dis- 
  

   coveries 
  have 
  proved 
  that 
  Greenland, 
  in 
  lat. 
  70'^, 
  and 
  Spitzbergen, 
  in 
  lat. 
  78^, 
  .58', 
  

   had 
  a 
  rich 
  luxuriant 
  forest 
  of 
  trees, 
  mostly 
  American 
  in 
  character, 
  among 
  them 
  

   a 
  redwood, 
  undistinguishable 
  from 
  that 
  so 
  common 
  here 
  ! 
  In 
  all, 
  137 
  species 
  

   Pkoc. 
  Cal. 
  Acad. 
  Sci., 
  Vol. 
  V.— 
  26. 
  Decembeb, 
  1874. 
  

  

  