﻿772 
  EEPOET 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [14] 
  

  

  pelagic 
  organisms, 
  and 
  especially 
  in 
  the 
  presence 
  of 
  Pteropod 
  and 
  He- 
  

   teropod 
  shells, 
  such 
  as 
  Diacria, 
  Atlanta, 
  Styliola, 
  Carinaria, 
  &c. 
  The 
  

   shells 
  of 
  the 
  more 
  delicate 
  species 
  of 
  pelagic 
  Foraminifera 
  and 
  young 
  shells 
  

   are 
  also 
  more 
  abundant 
  in 
  these 
  deposits 
  than 
  in 
  a 
  Globigeriua 
  ooze. 
  

   It 
  must 
  be 
  remembered 
  that 
  the 
  name 
  " 
  Pteropod 
  ooze 
  " 
  is 
  not 
  intended 
  

   to 
  indicate 
  that 
  the 
  deposit 
  is 
  chiefly 
  composed 
  of 
  the 
  shells 
  of 
  these 
  

   mollusks, 
  but 
  as 
  their 
  presence 
  in 
  a 
  deposit 
  is 
  characteristic 
  and 
  has 
  an 
  

   important 
  bearing 
  on 
  geographical 
  and 
  bathymetrical 
  distribution, 
  we 
  

   think 
  it 
  desirable 
  to 
  emphasize 
  the 
  presence 
  of 
  these 
  shells 
  in 
  any 
  great 
  

   abundance. 
  It 
  may 
  here 
  be 
  pointed 
  out 
  that 
  there 
  is 
  a 
  very 
  considera- 
  

   ble 
  difference 
  between 
  a 
  Globigeriua 
  ooze 
  or 
  a 
  Pteropod 
  ooze 
  situated 
  

   near 
  continental 
  shores 
  and 
  deposits 
  bearing 
  the 
  same 
  names 
  situated 
  

   towards 
  the 
  centers 
  of 
  oceanic 
  areas, 
  both 
  with 
  respect 
  to 
  mineral 
  par- 
  

   ticles 
  and 
  remains 
  of 
  organisms. 
  

  

  Diatom 
  ooze. 
  — 
  This 
  ooze 
  is 
  of 
  a 
  pale 
  straw 
  color, 
  and 
  is 
  composed 
  

   principally 
  of 
  the 
  frustules 
  of 
  Diatoms. 
  When 
  dry 
  it 
  is 
  a 
  dirty 
  white 
  

   siliceous 
  flour, 
  soft 
  to 
  the 
  touch, 
  taking 
  the 
  impression 
  of 
  the 
  fingers, 
  

   and 
  contains 
  gritty 
  particles 
  which 
  can 
  be 
  recognized 
  by 
  the 
  touch. 
  It 
  

   contains 
  on 
  an 
  average 
  about 
  25 
  per 
  cent, 
  of 
  carbonate 
  of 
  lime, 
  which 
  

   exists 
  in 
  the 
  deposit 
  in 
  the 
  form 
  of 
  small 
  Globigeriua 
  shells, 
  fragments 
  

   of 
  Echinoderms 
  and 
  other 
  organisms. 
  The 
  residue 
  is 
  pale 
  white 
  and 
  

   slightly 
  plastic 
  ; 
  minerals 
  and 
  fragments 
  of 
  rocks 
  are 
  in 
  some 
  cases 
  

   abundant 
  ; 
  these 
  are 
  volcanic, 
  or, 
  more 
  frequently, 
  fragments 
  and 
  min- 
  

   erals 
  coming 
  from 
  continental 
  rocks 
  and 
  transported 
  by 
  glaciers. 
  The 
  

   fine 
  washings 
  consist 
  essentially 
  of 
  praticles 
  of 
  Diatoms 
  along 
  with 
  ar- 
  

   gillaceous 
  and 
  other 
  amorphous 
  matter. 
  We 
  estimate 
  that 
  the 
  frustules 
  

   of 
  Diatoms 
  and 
  skeletons 
  of 
  siliceous 
  organisms 
  make 
  up 
  more 
  than 
  50 
  

   per 
  cent, 
  of 
  this 
  deposit. 
  

  

  Radiolarian 
  ooze. 
  — 
  It 
  was 
  stated 
  when 
  describing 
  a 
  Globi 
  gerina 
  ooze 
  

   that 
  Radiolarians 
  were 
  seldom, 
  if 
  ever, 
  completely 
  absent 
  from 
  marine 
  

   deposits. 
  In 
  some 
  regions 
  they 
  make 
  up 
  a 
  considerable 
  portion 
  of 
  a 
  

   Globigeriua 
  ooze, 
  and 
  are 
  also 
  found 
  in 
  Diatom 
  ooze 
  and 
  in 
  the 
  terrige- 
  

   nous 
  deposits 
  of 
  the 
  deeper 
  water 
  surrounding 
  the 
  laud. 
  In 
  some 
  

   regions 
  of 
  the 
  Pacific, 
  however, 
  the 
  skeletons 
  of 
  these 
  organisms 
  make 
  

   up 
  the 
  principal 
  part 
  of 
  the 
  deposits, 
  and 
  to 
  these 
  we 
  have 
  given 
  the 
  

   name 
  " 
  Radiolarian 
  ooze." 
  The 
  color 
  is 
  reddish 
  or 
  deep 
  brown, 
  due 
  to 
  

   the 
  presence 
  of 
  the 
  oxides 
  of 
  iron 
  and 
  manganese. 
  The 
  mineral 
  parti- 
  

   cles 
  consist 
  of 
  fragments 
  of 
  pumice, 
  lapilli, 
  and 
  volcanic 
  minerals, 
  rarely 
  

   exceeding 
  0.07 
  mi 
  " 
  in 
  diameter. 
  There 
  is 
  not 
  a 
  trace 
  of 
  carbonate 
  of 
  

   lime 
  in 
  the 
  form 
  of 
  shells 
  in 
  some 
  samples 
  of 
  Radiolarian 
  ooze, 
  but 
  

   other 
  specimens 
  contain 
  20 
  per 
  cent, 
  of 
  carbonate 
  of 
  lime, 
  derived 
  from 
  

   the 
  shells 
  of 
  pelagic 
  Foraminifera. 
  The 
  clayey 
  matter 
  and 
  mineral 
  

   particles 
  in 
  this 
  ooze 
  are 
  the 
  same 
  as 
  those 
  found 
  in 
  the 
  red 
  clays, 
  

   which 
  we 
  will 
  now 
  proceed 
  to 
  describe. 
  

  

  Red 
  clay. 
  — 
  Of 
  all 
  the 
  deep-sea 
  deposits 
  this 
  is 
  one 
  which 
  is 
  dis- 
  

   tributed 
  over 
  the 
  largest 
  areas 
  of 
  the 
  modern 
  oceans. 
  It 
  might 
  be 
  said 
  

  

  