﻿552 
  Mr. 
  I. 
  L. 
  Bell 
  on 
  Changes 
  in 
  Basaltic 
  Veins. 
  [June 
  17, 
  

  

  fore 
  a 
  true 
  siliceous 
  rock), 
  and 
  that 
  its 
  remaining 
  11-75 
  parts 
  consist 
  of 
  

   substances 
  all 
  of 
  -which 
  occur 
  in 
  the 
  basalt. 
  It 
  is 
  true 
  the 
  same 
  

   may 
  be 
  said 
  of 
  the 
  rocks 
  miderljing 
  the 
  stratum 
  of 
  whin, 
  and 
  that 
  in 
  both 
  

   cases 
  these 
  ingredients, 
  found 
  in 
  small 
  quantities, 
  may 
  have 
  been 
  depo- 
  

   sited 
  with 
  the 
  material 
  constituting 
  the 
  main 
  body 
  of 
  the 
  bed. 
  

  

  Believing, 
  however, 
  in 
  the 
  possibility 
  of 
  the 
  basalt 
  having 
  been 
  the 
  

   source 
  of 
  all 
  or 
  a 
  part 
  of 
  what 
  may 
  be 
  designated 
  as 
  foreign 
  ingredients 
  

   in 
  this 
  white 
  post, 
  three 
  specimens 
  were 
  submitted 
  to 
  examination. 
  One 
  

   was 
  taken 
  from 
  the 
  bed 
  where 
  it 
  adjoins 
  the 
  whin, 
  a 
  second 
  from 
  its 
  

   middle, 
  and 
  the 
  third 
  from 
  its 
  upper 
  portion 
  ; 
  and 
  certainly, 
  so 
  far 
  as 
  

   some 
  of 
  these 
  ingredients 
  are 
  concerned, 
  they 
  tend 
  to 
  confirm 
  the 
  view 
  

   just 
  expressed. 
  This 
  view 
  is 
  based 
  on 
  the 
  fact 
  that 
  the 
  substances 
  in 
  

   question 
  are 
  found 
  in 
  greatest 
  quantity 
  next 
  the 
  basalt, 
  and 
  that 
  they 
  

   gradually 
  diminish 
  in 
  this 
  respect 
  as 
  the 
  distance 
  from 
  the 
  basalt 
  in- 
  

   creases. 
  

  

  Adjoining 
  bed 
  of 
  whin. 
  

  

  Middle 
  portion. 
  

  

  Upper 
  portion. 
  

  

  

  . 
  83-17 
  

  

  . 
  . 
  84-31 
  . 
  . 
  . 
  

  

  , 
  86-22 
  

  

  

  . 
  8-34 
  

  

  . 
  . 
  . 
  8-80 
  . 
  . 
  . 
  

  

  8-47 
  

  

  Peroxide 
  of 
  iron 
  . 
  . 
  . 
  

  

  

  •57 
  . 
  . 
  

  

  1-00 
  

  

  Protoxide 
  of 
  iron 
  . 
  

  

  . 
  1-32 
  

  

  .. 
  1-03 
  

  

  •64 
  

  

  

  , 
  . 
  1-74 
  

  

  •93 
  

  

  •91 
  

  

  

  . 
  -94 
  .... 
  

  

  •83 
  ... 
  

  

  •22 
  

  

  

  . 
  1-02 
  

  

  •89 
  ... 
  

  

  . 
  . 
  -81 
  

  

  

  . 
  -58 
  

  

  •52 
  ... 
  

  

  •38 
  

  

  

  . 
  1-20 
  

  

  

  •60 
  

  

  Water 
  

  

  . 
  1-50 
  .... 
  

  

  . 
  . 
  1-70 
  . 
  . 
  . 
  

  

  1-20 
  

  

  

  

  

  

  

  99-81 
  

  

  " 
  100-35 
  

  

  10045 
  

  

  Before 
  any 
  well-established 
  conclusions 
  can 
  be 
  arrived 
  at 
  on 
  the 
  

   changes 
  of 
  composition 
  experienced 
  by 
  basalt, 
  as 
  well 
  as 
  by 
  those 
  strata 
  

   through 
  which 
  it 
  has 
  been 
  ejected, 
  a 
  veiy 
  extended 
  series 
  of 
  observations 
  

   is 
  indispensable. 
  At 
  some 
  future 
  opportunity 
  I 
  may 
  pursue 
  this 
  inquiry 
  

   into 
  other 
  geological 
  districts 
  traversed 
  by 
  the 
  170 
  miles 
  of 
  whin-dyke 
  

   described 
  in 
  my 
  opening 
  remarks 
  ; 
  in 
  which 
  case, 
  should 
  it 
  be 
  the 
  wish 
  of 
  

   the 
  Society, 
  I 
  would 
  lay 
  before 
  its 
  members 
  the 
  results 
  of 
  my 
  exami- 
  

   nation. 
  

  

  The 
  analyses 
  referred 
  to 
  in 
  this 
  communication 
  were 
  made 
  at 
  the 
  

   Clarence 
  Iron 
  Works 
  by 
  Mr. 
  Eocholl, 
  the 
  superintendent 
  of 
  the 
  laboratory 
  

   attached 
  to 
  the 
  establishment. 
  

  

  P.S. 
  Since 
  writing 
  the 
  above, 
  I 
  have 
  ascertained 
  that 
  the 
  late 
  Professor 
  

   Jukes 
  met 
  with 
  in 
  the 
  Staffordshire 
  coal-field, 
  and 
  described 
  under 
  the 
  

   name 
  of 
  " 
  white 
  rock," 
  an 
  altered 
  basalt. 
  Its 
  composition 
  as 
  given 
  

   is 
  ; 
  — 
  

  

  