﻿Adams, 
  Barlow 
  and 
  Ells 
  — 
  Canadian 
  Laurentian. 
  173 
  

  

  Art. 
  XYII. 
  — 
  On 
  the 
  Origin 
  and 
  Relations 
  of 
  the 
  Grenville 
  

   and 
  Hastings 
  Series 
  in 
  the 
  Canadian 
  Laurentian 
  ; 
  by 
  

   Frank 
  D. 
  Adams 
  and 
  Alfred 
  E. 
  Barlow, 
  with 
  remarks 
  

   by 
  K. 
  W. 
  Ells.* 
  

  

  As 
  the 
  exploration 
  of 
  the 
  more 
  remote 
  portions 
  of 
  the 
  great 
  

   Canadian 
  protaxis 
  of 
  the 
  North 
  American 
  continent 
  progresses, 
  

   accompanied 
  by 
  the 
  detailed 
  mapping 
  of 
  its 
  more 
  accessi- 
  

   ble 
  parts, 
  the 
  true 
  character, 
  structure 
  and 
  origin 
  of 
  the 
  Lau- 
  

   rentian 
  System 
  is 
  being 
  gradually 
  unfolded. 
  The 
  work 
  of 
  

   Logan 
  during 
  the 
  early 
  years 
  of 
  the 
  Canadian 
  Geological 
  Sur- 
  

   vey, 
  though 
  excellent 
  in 
  the 
  main, 
  is 
  being 
  supplemented 
  and, 
  

   in 
  certain 
  directions, 
  corrected 
  ; 
  and 
  as 
  the 
  work 
  is 
  now 
  being 
  

   pushed 
  rapidly 
  forward, 
  it 
  is 
  believed 
  that 
  the 
  time 
  is 
  not 
  far 
  

   distant 
  when, 
  difficult 
  as 
  the 
  study 
  is, 
  we 
  shall 
  possess 
  as 
  com- 
  

   plete 
  a 
  knowledge 
  of 
  these 
  ancient 
  rocks 
  as 
  we 
  now 
  do 
  of 
  

   many 
  more 
  recent 
  formations. 
  In 
  a 
  paper 
  which 
  appeared 
  in 
  

   1893, 
  f 
  it 
  was 
  demonstrated 
  that 
  Logan's 
  u 
  Upper 
  Laurentian 
  " 
  

   does 
  not 
  exist 
  as 
  an 
  independent 
  geological 
  series, 
  the 
  anortho- 
  

   sites, 
  which 
  were 
  considered 
  as 
  constituting 
  its 
  main 
  feature, 
  

   being 
  in 
  reality 
  great 
  intrusive 
  or 
  batholitic 
  masses 
  ; 
  while 
  in 
  

   a 
  subsequent 
  paper,;f 
  it 
  was 
  shown 
  that 
  in 
  the 
  remaining 
  por- 
  

   tion 
  of 
  the 
  Laurentian, 
  two 
  distinct 
  classes 
  of 
  rocks 
  could 
  be 
  

   distinguished, 
  the 
  first 
  being 
  beyond 
  all 
  doubt 
  igneous 
  rocks, 
  

   and 
  the 
  second 
  consisting 
  of 
  highly 
  altered 
  rocks 
  of 
  aqueous 
  

   origin. 
  In 
  addition 
  to 
  these 
  two 
  classes 
  of 
  rocks 
  of 
  which 
  the 
  

   origin 
  could 
  be 
  recognized, 
  there 
  was 
  yet 
  a 
  third 
  class, 
  concern- 
  

   ing 
  the 
  genesis 
  of 
  which 
  there 
  remained 
  some 
  doubt. 
  

  

  Siuce 
  the 
  appearance 
  of 
  these 
  papers, 
  the 
  present 
  writers 
  

   have 
  been 
  working 
  together 
  in 
  mapping 
  a 
  large 
  area 
  (about 
  

   4800 
  square 
  miles) 
  of 
  the 
  Laurentian 
  in 
  central 
  Ontario, 
  com- 
  

   prising 
  map-sheet 
  No. 
  118, 
  and 
  a 
  portion 
  of 
  119, 
  of 
  the 
  

   Ontario 
  series 
  of 
  geological 
  maps, 
  the 
  district 
  lying 
  to 
  the 
  

   north 
  of 
  Lake 
  Ontario, 
  along 
  the 
  margin 
  of 
  the 
  Protaxis, 
  and 
  

   being 
  especially 
  well 
  suited 
  for 
  purposes 
  of 
  study. 
  Portions 
  

   of 
  three 
  summers 
  have 
  already 
  been 
  spent 
  in 
  the 
  district, 
  and 
  

   as 
  two 
  years 
  more 
  must 
  probably 
  elapse 
  before 
  the 
  work 
  can 
  

   be 
  completed, 
  it 
  is 
  desired 
  here 
  to 
  present 
  a 
  general 
  outline 
  of 
  

   the 
  results 
  so 
  far 
  obtained, 
  indicating 
  certain 
  conclusions 
  which 
  

   seem 
  likely 
  to 
  be 
  reached 
  concerning 
  the 
  origin 
  of 
  the 
  rocks 
  in 
  

   question. 
  

  

  The 
  Fundamental 
  Gneiss, 
  as 
  shown 
  by 
  the 
  work 
  of 
  the 
  Cana- 
  

   dian 
  Geological 
  Survey, 
  occupies 
  by 
  far 
  the 
  larger 
  portion 
  of 
  

   the 
  protaxis 
  as 
  a 
  whole 
  ; 
  while 
  the 
  Grenville 
  Series 
  has 
  prob- 
  

  

  * 
  Published 
  by 
  permission 
  of 
  the 
  Director 
  of 
  the 
  Geological 
  Survey 
  of 
  Canada. 
  

  

  f 
  Adams 
  F. 
  D. 
  — 
  Ueber 
  das 
  Norian 
  oder 
  Ober-Laurentian 
  von 
  Canada, 
  Neues 
  

   Jahrbuch 
  fur 
  Mineralogie. 
  Beilage 
  Band 
  viii, 
  1893. 
  

  

  X 
  Adams, 
  F. 
  D. 
  — 
  A 
  Further 
  Contribution 
  to 
  our 
  Knowledge 
  of 
  the 
  Laurentian, 
  

   this 
  Journal, 
  July, 
  1895. 
  

  

  