﻿[25] 
  ON 
  DEEP-SEA 
  DEPOSITS. 
  783 
  

  

  spread 
  out 
  over 
  tbe 
  bed 
  of 
  the 
  Central 
  Pacific, 
  Atlantic, 
  and 
  Indian 
  

   Oceans, 
  have 
  they 
  their 
  analogues 
  in 
  the 
  geological 
  series 
  of 
  rocks? 
  

   If 
  it 
  be 
  proved 
  that 
  in 
  the 
  sedimentary 
  strata 
  the 
  pelagic 
  sediments 
  are 
  

   not 
  represented, 
  it 
  follows 
  that 
  deep 
  and 
  extended 
  oceans 
  like 
  those 
  of 
  

   the 
  present 
  day 
  cannot 
  formerly 
  have 
  occupied 
  the 
  areas 
  of 
  the 
  pres- 
  

   ent 
  continents, 
  and, 
  as 
  a 
  corollary, 
  the 
  great 
  lines 
  of 
  tbe 
  ocean 
  basins 
  

   and 
  continents 
  must 
  have 
  been 
  marked 
  out 
  from 
  the 
  earliest 
  geolog- 
  

   ical 
  ages. 
  We 
  thus 
  get 
  a 
  new 
  confirmation 
  of 
  the 
  opinion 
  of 
  the 
  per- 
  

   manence 
  of 
  the 
  continental 
  areas. 
  

  

  But, 
  without 
  asserting 
  in 
  a 
  positive 
  manner 
  that 
  the 
  terrestrial 
  areas 
  

   and 
  the 
  areas 
  covered 
  by 
  the 
  waters 
  of 
  the 
  great 
  ocean 
  basins 
  have 
  

   had 
  their 
  main 
  lines 
  marked 
  out 
  since 
  the 
  commencement 
  of 
  geological 
  

   history, 
  it 
  is, 
  nevertheless, 
  a 
  fact, 
  proved 
  by 
  the 
  evidence 
  derived 
  from 
  

   a 
  study 
  of 
  the 
  pelagic 
  sediments, 
  that 
  these 
  areas 
  have 
  a 
  great 
  antiq- 
  

   uity. 
  The 
  accumulation 
  of 
  sharks' 
  teeth, 
  of 
  the 
  ear-bones 
  of 
  cetaceans, 
  

   of 
  manganese 
  concretions, 
  of 
  zeolites, 
  of 
  volcanic 
  material 
  in 
  an 
  ad- 
  

   vanced 
  state 
  of 
  decomposition, 
  and 
  of 
  cosmic 
  dust, 
  at 
  points 
  far 
  re- 
  

   moved 
  from 
  the 
  continents, 
  tend 
  to 
  prove 
  this. 
  There 
  is 
  no 
  reason 
  for 
  

   supposing 
  that 
  the 
  parts 
  of 
  the 
  ocean 
  where 
  these 
  vertebrate 
  remains 
  

   are 
  found 
  are 
  more 
  frequented 
  by 
  sharks 
  or 
  cetaceans 
  than 
  other 
  re- 
  

   gions 
  where 
  they 
  are 
  never 
  or 
  only 
  rarely 
  dredged 
  from 
  the 
  deposits 
  

   at 
  the 
  bottom. 
  When 
  we 
  remember, 
  also, 
  that 
  these 
  ear-bones, 
  teeth 
  of 
  

   sharks, 
  and 
  volcanic 
  fragments 
  are 
  sometimes 
  in 
  crusted 
  with 
  two 
  cen- 
  

   timeters 
  of 
  manganese 
  oxide, 
  while 
  others 
  have 
  a 
  mere 
  coating, 
  and 
  

   that 
  some 
  of 
  the 
  bones 
  and 
  teeth 
  belong 
  to 
  extinct 
  species, 
  we 
  may 
  

   conclude 
  with 
  great 
  certainty 
  that 
  the 
  clays 
  of 
  these 
  oceanic 
  basins 
  

   have 
  accumulated 
  with 
  extreme 
  slowness. 
  It 
  is 
  indeed 
  almost 
  beyond 
  

   question 
  that 
  the 
  red-clay 
  regions 
  of 
  the 
  Central 
  Pacific 
  contain 
  accu- 
  

   mulations 
  belonging 
  to 
  geological 
  ages 
  different 
  from 
  our 
  own. 
  The 
  

   great 
  antiquity 
  of 
  these 
  formations 
  is 
  likewise 
  confirmed 
  in 
  a 
  striking 
  

   manner 
  by 
  the 
  presence 
  of 
  cosmic 
  fragments, 
  the 
  nature 
  of 
  which 
  we 
  

   have 
  described 
  (" 
  On 
  Cosmic 
  and 
  Volcanic 
  Dust," 
  Proc. 
  Eoy. 
  Soc. 
  Edin.). 
  

   In 
  order 
  to 
  account 
  for 
  the 
  accumulation 
  of 
  all 
  the 
  substances 
  in 
  such 
  

   relatively 
  great 
  abundance 
  in 
  the 
  areas 
  where 
  they 
  were 
  dredged, 
  it 
  

   is 
  necessary 
  to 
  suppose 
  the 
  oceanic 
  basins 
  to 
  have 
  remained 
  the 
  same 
  

   for 
  a 
  vast 
  period 
  of 
  time. 
  

  

  The 
  sharks' 
  teeth, 
  ear-bones, 
  manganese 
  nodules, 
  altered 
  volcanic 
  

   fragments, 
  zeolites, 
  and 
  cosmic 
  dust 
  are 
  met 
  with 
  in 
  greatest 
  abundance 
  

   in 
  the 
  red 
  clays 
  of 
  the 
  Central 
  Pacific, 
  at 
  that 
  point 
  on 
  the 
  earth's 
  sur- 
  

   face 
  farthest 
  removed 
  from 
  continental 
  land. 
  They 
  are 
  less 
  abundant 
  

   in 
  the 
  Radiolarian 
  ooze, 
  are 
  rare 
  in 
  the 
  Globigerina, 
  Diatom, 
  and 
  Ptero- 
  

   pod 
  oozes, 
  and 
  they 
  have 
  been 
  dredged 
  only 
  in 
  a 
  few 
  instances 
  in 
  the 
  

   terrigenous 
  deposits 
  close 
  to 
  the 
  shore. 
  These 
  substances 
  are 
  present 
  

   in 
  all 
  the 
  deposits, 
  but, 
  owing 
  to 
  the 
  abundance 
  of 
  other 
  matters 
  in 
  the 
  

   more 
  rapidly 
  forming 
  deposits, 
  their 
  presence 
  is 
  masked, 
  and 
  the 
  chance 
  

   of 
  dredging 
  them 
  is 
  reduced. 
  We 
  may 
  then 
  regard 
  the 
  greater 
  or 
  less 
  

  

  