﻿1875.] 
  Sea-bottom 
  procured 
  by 
  H.M.S. 
  ' 
  Challenger/ 
  

  

  239 
  

  

  that 
  the 
  " 
  white 
  mud 
  " 
  of 
  the 
  Levant 
  is 
  mainly 
  a 
  Foraminiferal 
  deposit 
  ; 
  

   I 
  f 
  oimd 
  a 
  similar 
  mud 
  covering 
  the 
  bottom 
  along 
  the 
  Tripoli 
  coast 
  ; 
  Mr. 
  

   J. 
  Grwyn 
  Jeffreys 
  has 
  dredged 
  Poraminifera 
  in 
  abundance 
  in 
  the 
  Bay 
  of 
  

   Spezzia, 
  Captain 
  Spratt 
  in 
  the 
  iEgean, 
  Oscar 
  Schmidt 
  in 
  the 
  Adriatic, 
  and 
  

   I 
  myself 
  at 
  various 
  points 
  in 
  the 
  "Western 
  basin 
  along 
  the 
  northern 
  coast 
  

   of 
  Africa. 
  That 
  Poraminifera, 
  especially 
  Globigerince, 
  abound 
  in 
  its 
  

   surface-water 
  at 
  Messina, 
  is 
  testified 
  by 
  Haeckel 
  in 
  the 
  passage 
  cited 
  by 
  

   Prof. 
  "Wyville 
  Thomson 
  ; 
  and 
  when 
  it 
  is 
  considered 
  how 
  large 
  an 
  influx 
  

   of 
  Atlantic 
  water 
  is 
  constantly 
  entering 
  through 
  the 
  Strait 
  of 
  Gibraltar, 
  

   and 
  is 
  being 
  diffused 
  throughout 
  the 
  Mediterranean 
  basin, 
  and 
  how 
  

   favourable 
  is 
  its 
  temperature-condition, 
  it 
  can 
  scarcely 
  be 
  doubted 
  that 
  if 
  

   the 
  doctrine 
  now 
  upheld 
  by 
  Prof. 
  Wyville 
  Thomson 
  were 
  correct, 
  the 
  

   deposit 
  of 
  Globigerina-she\ls 
  over 
  the 
  whole 
  bottom-area 
  ought 
  to 
  be 
  

   as 
  abundant 
  as 
  it 
  is 
  in 
  the 
  Atlantic 
  under 
  corresponding 
  latitudes. 
  Yet 
  

   I 
  found 
  the 
  deeper 
  bottoms, 
  from 
  300 
  fathoms 
  downwards, 
  entirely 
  

   destitute 
  of 
  Grlobigerine 
  as 
  of 
  higher 
  forms 
  of 
  Animal 
  life 
  ; 
  and 
  this 
  was 
  

   not 
  my 
  own 
  experience 
  only, 
  but 
  was 
  also 
  that 
  of 
  Oscar 
  Schmidt, 
  who 
  

   made 
  a 
  s 
  imil 
  ar 
  exploration 
  of 
  the 
  Adriatic. 
  In 
  my 
  first 
  visit 
  to 
  the 
  Medi- 
  

   terranean, 
  in 
  the 
  ' 
  Porcupine 
  ' 
  (1870), 
  many 
  hundredweight 
  of 
  the 
  fine 
  

   mud 
  brought 
  up 
  by 
  the 
  dredge 
  from 
  great 
  depths 
  in 
  the 
  "Western 
  basin 
  

   were 
  laboriously 
  sifted, 
  and 
  the 
  siftings 
  carefully 
  examined, 
  without 
  

   bringing 
  to 
  light 
  more 
  than 
  a 
  stray 
  drift-shell 
  here 
  and 
  there. 
  And 
  in 
  

   my 
  second 
  visit, 
  in 
  the 
  ' 
  Shearwater 
  ' 
  (1871), 
  I 
  examined 
  all 
  the 
  samples 
  

   of 
  bottom 
  brought 
  up 
  by 
  the 
  sounding-apparatus 
  from 
  great 
  depths 
  in 
  

   the 
  Eastern 
  basin, 
  with 
  the 
  same 
  result 
  — 
  giving 
  all 
  the 
  more 
  care 
  to 
  this 
  

   examination, 
  because 
  Capt. 
  Nares 
  (probably 
  through 
  not 
  having 
  kept 
  

   separate 
  in 
  his 
  mind 
  the 
  results 
  of 
  the 
  deeper 
  and 
  of 
  the 
  shallower 
  

   soundings 
  which 
  he 
  had 
  previously 
  made 
  in 
  the 
  Mediterranean) 
  assured 
  

   me 
  that 
  I 
  should 
  find 
  minute 
  shells 
  imbedded 
  in 
  the 
  mud. 
  

  

  I 
  can 
  see 
  no 
  other 
  way 
  of 
  accounting 
  for 
  the 
  absence 
  of 
  Globigerina- 
  

   ooze 
  from 
  the 
  bottom 
  of 
  the 
  Mediterranean, 
  save 
  on 
  its 
  shallow 
  borders, 
  

   than 
  by 
  attributing 
  it 
  to 
  the 
  unfavourable 
  nature 
  of 
  the 
  influences 
  affect- 
  

   ing 
  the 
  bottom-life 
  of 
  this 
  basin 
  : 
  that 
  is 
  to 
  say, 
  the 
  gradual 
  settling-down 
  

   of 
  the 
  fine 
  sedimentary 
  deposit 
  which 
  forms 
  the 
  layer 
  of 
  inorganic 
  mud 
  

   everywhere 
  spread 
  over 
  its 
  deeper 
  bottom, 
  and 
  the 
  deficiency 
  of 
  oxygen 
  

   and 
  excess 
  of 
  carbonic 
  acid 
  which 
  I 
  have 
  shown 
  to 
  prevail 
  in 
  its 
  abyssal 
  

   waters 
  giving 
  them 
  the 
  character 
  of 
  a 
  stagnant 
  pool 
  — 
  these 
  influences 
  

   acting 
  either 
  singly 
  or 
  in 
  combination. 
  

  

  Another 
  fact 
  of 
  which 
  Prof. 
  "Wyville 
  Thomson 
  is 
  fully 
  cognizant, 
  and 
  

   to 
  which 
  he 
  formerly 
  attached 
  considerable 
  importance 
  as 
  indicative 
  of 
  

   the 
  bottom-life 
  of 
  the 
  Globigerince, 
  is 
  unnoticed 
  in 
  his 
  recent 
  communica- 
  

   tion 
  : 
  I 
  refer 
  to 
  the 
  singular 
  limitation 
  of 
  the 
  Globigerinco-ooze 
  to 
  the 
  

   " 
  warm 
  area 
  " 
  of 
  the 
  sea-bed 
  between 
  the 
  North 
  of 
  Scotland 
  and 
  the 
  

   Paroe 
  Islands. 
  It 
  will 
  be 
  recollected 
  by 
  those 
  who 
  have 
  read 
  my 
  

   ' 
  Lightning 
  ' 
  and 
  ' 
  Porcupine 
  ' 
  Reports 
  on 
  the 
  exploration 
  of 
  this 
  region, 
  

  

  