﻿766 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [8] 
  

  

  eii'tly 
  when 
  describing 
  the 
  distribution 
  of 
  the 
  various 
  kinds 
  of 
  deposits 
  

   and 
  their 
  reciprocal 
  relations, 
  especially 
  in 
  those 
  regions 
  of 
  the 
  deep 
  

   sea 
  far 
  removed 
  from 
  the 
  mechanical 
  action 
  of 
  rivers, 
  waves, 
  and 
  super- 
  

   ficial 
  currents. 
  The 
  action 
  of 
  life 
  as 
  a 
  geological 
  agent 
  has 
  been 
  indi- 
  

   cated 
  under 
  the 
  heading 
  Materials. 
  

  

  Methods. 
  — 
  We 
  give 
  here 
  an 
  example 
  showing 
  the 
  order 
  followed 
  in 
  

   describing 
  the 
  deposits 
  examined: 
  

  

  Station 
  338 
  ; 
  latitude 
  21° 
  15' 
  S., 
  longitude 
  U° 
  2' 
  W. 
  j 
  March 
  21, 
  1876; 
  

   surface 
  temperature, 
  76°.5; 
  bottom 
  temperature, 
  36°.5; 
  depth, 
  1,990 
  

   fathoms. 
  

  

  Globigerina 
  ooze, 
  white, 
  with 
  slightly 
  rosy 
  tinge 
  when 
  wet 
  j 
  granular, 
  

   homogeneous, 
  and 
  very 
  slightly 
  coherent 
  when 
  dry 
  ; 
  resembles 
  chalk. 
  

  

  I. 
  Carbonate 
  of 
  calcium, 
  90.38 
  per 
  cent., 
  consists 
  of 
  pelagic 
  Foranii- 
  

   nifera 
  (80 
  percent.) 
  ; 
  coccoliths 
  and 
  rhabcloliths 
  (9 
  per 
  cent.) 
  ; 
  Miliolas, 
  

   Discorbiuas, 
  and 
  other 
  Foraminifera, 
  Ostracode 
  valves, 
  fragments 
  of 
  

   Echini 
  spines, 
  and 
  one 
  or 
  two 
  small 
  fragments 
  of 
  Pteropods 
  (1.38 
  per 
  

   cent.). 
  

  

  II. 
  Residue, 
  9.62 
  per 
  cent., 
  reddish 
  brown, 
  consists 
  of 
  — 
  

  

  1. 
  Minerals 
  [1.62] 
  m. 
  di. 
  0.45 
  mm 
  , 
  fragments 
  of 
  feldspar, 
  hornblende, 
  

   magnetite, 
  magnetic 
  spherules, 
  a 
  few 
  small 
  grains 
  of 
  manganese, 
  and 
  

   pumice. 
  

  

  2. 
  Siliceous 
  organisms 
  [1.00], 
  Radiolarians, 
  spicules 
  of 
  Sponges, 
  and 
  

   imperfect 
  casts 
  of 
  Foraminifera. 
  

  

  3. 
  Fine 
  washings 
  [7.00], 
  argillaceous 
  matter 
  with 
  small 
  mineral 
  par- 
  

   ticles 
  and 
  fragments 
  of 
  pumice 
  and 
  siliceous 
  organisms. 
  

  

  The 
  description 
  of 
  the 
  deposits 
  has 
  been 
  made 
  upon 
  this 
  plan, 
  which 
  

   was 
  adopted 
  after 
  many 
  trials 
  and 
  much 
  consideration. 
  This 
  is 
  not 
  

   the 
  place 
  to 
  give 
  the 
  reasons 
  which 
  have 
  guided 
  us 
  in 
  adopting 
  this 
  

   mode 
  of 
  description, 
  or 
  to 
  give 
  in 
  detail 
  the 
  methods 
  that 
  we 
  have 
  sys- 
  

   tematically 
  employed 
  for 
  all 
  the 
  sediments 
  which 
  we 
  are 
  engaged 
  in 
  

   describiug. 
  These 
  will 
  be 
  fully 
  given 
  in 
  the 
  introduction 
  to 
  our 
  Chal- 
  

   lenger 
  report. 
  We 
  limit 
  ourselves 
  here 
  to 
  explaining 
  the 
  meanings 
  

   and 
  arrangement 
  of 
  terms 
  and 
  abbreviations, 
  so 
  that 
  the 
  method 
  may 
  

   be 
  understood 
  and 
  made 
  available 
  for 
  others. 
  

  

  The 
  description 
  commences 
  by 
  indicating 
  the 
  kind 
  of 
  deposit 
  (red 
  clay, 
  

   blue 
  mud, 
  Globigerina 
  ooze, 
  &c), 
  with 
  the 
  microscopic 
  characters 
  of 
  the 
  

   deposit, 
  when 
  wet 
  or 
  dry. 
  

  

  We 
  have 
  always 
  endeavored 
  to 
  give 
  a 
  complete 
  chemical 
  analysis 
  of 
  

   the 
  deposit, 
  but 
  when 
  it 
  was 
  impossible 
  to 
  do 
  this 
  we 
  have 
  always 
  de- 
  

   termined 
  the 
  amount 
  of 
  carbonate 
  of 
  calcium. 
  This 
  determination 
  was 
  

   generally 
  made 
  by 
  estimating 
  the 
  carbonic 
  acid. 
  We 
  usually 
  took 
  a 
  

   gram 
  of 
  a 
  mean 
  sample 
  of 
  the 
  substance 
  for 
  this 
  purpose, 
  using 
  weak 
  

   and 
  cold 
  hydrochloric 
  acid. 
  However, 
  as 
  the 
  deposits 
  often 
  contain 
  

   carbonates 
  of 
  magnesia 
  and 
  iron 
  as 
  well, 
  the 
  results 
  calculated 
  by 
  asso- 
  

   ciating 
  the 
  carbonic 
  acid 
  with 
  the 
  lime 
  are 
  not 
  perfectly 
  exact, 
  but 
  these 
  

   carbonates 
  of 
  magnesia 
  and 
  iron 
  are 
  almost 
  always 
  in 
  a 
  very 
  small 
  pro- 
  

  

  