﻿66 
  THE 
  STJDBTJKY 
  NICKEL 
  DISTE1CT 
  (CANADA). 
  [Feb. 
  1 
  89 
  7, 
  

  

  Mickle, 
  G. 
  E. 
  ' 
  The 
  Eelation 
  between 
  Pyrrhotite, 
  Gangue, 
  and 
  the 
  accom- 
  

   panying 
  Eocks 
  of 
  the 
  Sudbury 
  District.' 
  Sudbury 
  Journal, 
  1894. 
  

  

  Peters, 
  E. 
  D., 
  Jun. 
  ' 
  Sudbury 
  Ore 
  Deposits.' 
  Trans. 
  Am. 
  Inst. 
  Min. 
  Eng., 
  

   vol. 
  xviii. 
  (1890) 
  p. 
  278. 
  

  

  Selwyn, 
  A. 
  E. 
  C. 
  ' 
  Descriptive 
  Sketch 
  of 
  the 
  Physical 
  Geography 
  and 
  Geology 
  

   of 
  the 
  Dominion 
  of 
  Canada.' 
  Geol. 
  Survey 
  of 
  Canada, 
  1884. 
  

  

  Stelzner, 
  A. 
  W. 
  (Notes 
  on 
  Sudbury 
  Eocks, 
  communicated 
  by 
  G. 
  E. 
  Mickle. 
  

   Sudbury 
  Journal, 
  1894.) 
  

  

  Vogt, 
  J. 
  H. 
  L. 
  ' 
  Bildung 
  von 
  Erzlagerstatten.' 
  Zeitschr. 
  f. 
  prakt. 
  Geologie, 
  

   1893-1894. 
  

  

  ■ 
  . 
  ' 
  Nikkelvorkomester 
  og 
  Nikkelproduktion.' 
  Kristiania, 
  1892. 
  

  

  Walker, 
  T. 
  L. 
  ' 
  Diabase 
  Dykes 
  in 
  the 
  Sudbury 
  District.' 
  Trans. 
  Ontario 
  

   Mining 
  Institute, 
  1895. 
  

  

  Williams, 
  G. 
  H. 
  ' 
  Notes 
  on 
  the 
  Microscopic 
  Character 
  of 
  Eocks 
  from 
  the 
  

   Sudbury 
  Mining 
  District, 
  Canada.' 
  Geol. 
  Survey 
  of 
  Canada, 
  1891, 
  Ann. 
  

   Eep. 
  pt. 
  i. 
  F. 
  App. 
  i. 
  

  

  Discussion. 
  

  

  The 
  Peesident 
  said 
  that 
  all 
  additional 
  information 
  in 
  regard 
  to 
  

   the 
  Huronian 
  rocks, 
  which 
  resemble 
  so 
  closely 
  the 
  volcanic 
  rocks 
  of 
  

   pre-Cambrian 
  age 
  in 
  Wales, 
  was 
  most 
  useful 
  at 
  the 
  present 
  time. 
  

   The 
  Author's 
  paper, 
  therefore, 
  was 
  one 
  in 
  which 
  British 
  geologists 
  

   would 
  necessarily 
  be 
  much 
  interested. 
  

  

  Prof. 
  Bonnet 
  said 
  that, 
  so 
  far 
  as 
  he 
  had 
  seen 
  the 
  district, 
  he 
  doubted 
  

   whether 
  the 
  ore 
  was 
  the 
  result 
  of 
  differentiation. 
  He 
  believed 
  

   that 
  it 
  was 
  more 
  likely 
  to 
  have 
  been 
  introduced 
  afterwards, 
  as 
  is 
  

   commonly 
  the 
  case 
  with 
  mineral 
  ores. 
  He 
  thought 
  also 
  that 
  the 
  

   Author 
  was 
  pushing 
  this 
  idea 
  of 
  differentiation 
  too 
  far 
  in 
  regard 
  to 
  

   the 
  rocks 
  of 
  the 
  country. 
  So 
  far 
  as 
  he 
  knew, 
  there 
  was 
  a 
  number 
  

   of 
  separate 
  bosses 
  of 
  various 
  kinds 
  of 
  rocks. 
  

  

  Mr. 
  Teall 
  said 
  that 
  hyperites 
  were 
  associated 
  with 
  the 
  Loch 
  Dee 
  

   granite 
  in 
  the 
  South 
  of 
  Scotland, 
  and 
  that 
  pyrrhotite 
  occurred 
  in 
  

   some 
  of 
  the 
  altered 
  forms 
  of 
  these 
  rocks. 
  This 
  pyrrhotite, 
  however, 
  

   in 
  the 
  specimen 
  he 
  had 
  examined 
  was 
  certainly 
  not 
  nickeliferous 
  to 
  

   anything 
  like 
  the 
  same 
  extent 
  as 
  the 
  Swedish 
  and 
  Canadian 
  varieties. 
  

   The 
  association 
  of 
  nickeliferous 
  pyrrhotite 
  with 
  hyperites 
  and 
  

   norites 
  was 
  now 
  known 
  from 
  a 
  very 
  large 
  number 
  of 
  localities 
  in 
  

   various 
  parts 
  of 
  the 
  world, 
  and 
  the 
  differentiation-hypothesis 
  had 
  

   been 
  advanced 
  by 
  Vogt 
  to 
  explain 
  the 
  association. 
  

  

  The 
  paper 
  was 
  based 
  on 
  a 
  large 
  amount 
  of 
  field 
  as 
  well 
  as 
  labora- 
  

   tory 
  work. 
  Its 
  main 
  object 
  was 
  not 
  to 
  establish 
  a 
  theory, 
  but 
  to 
  

   describe 
  facts. 
  

  

  Gen. 
  M 
  c 
  Mahon 
  referred 
  to 
  the 
  theoretical 
  . 
  portion 
  of 
  the 
  paper, 
  

   and 
  commented 
  on 
  the 
  difficulty 
  of 
  understanding 
  how 
  the 
  law 
  of 
  

   gravitation 
  could 
  be 
  appealed 
  to 
  as 
  the 
  explanation 
  of 
  the 
  basic 
  

   portions 
  of 
  slowly- 
  cooling 
  magmas 
  concentrating 
  in 
  the 
  centres 
  of 
  

   eruptive 
  masses, 
  combined 
  with 
  the 
  formation 
  of 
  acid 
  rocks 
  on 
  both 
  

   margins. 
  

  

  The 
  Rev. 
  J". 
  E. 
  Blake 
  also 
  spoke. 
  

  

  