﻿180 
  Adams, 
  Barlow 
  and 
  Ells 
  — 
  Canadian 
  Laurentian. 
  

  

  field 
  investigations 
  showed 
  very 
  clearly 
  the 
  intrusive 
  nature 
  

   and 
  later 
  age 
  of 
  many 
  of 
  these 
  masses, 
  while 
  the 
  aid 
  of 
  the 
  

   microscope 
  fully 
  established 
  the 
  non-clastic 
  and 
  igneous 
  char- 
  

   acter 
  of 
  the 
  great 
  bulk 
  of 
  the 
  gneisses. 
  The 
  more 
  recent 
  and 
  

   probably 
  sedimentary 
  origin 
  of 
  the 
  limestones 
  and 
  associated 
  

   gneisses 
  of 
  the 
  Grenville 
  series, 
  as 
  distinct 
  from 
  the 
  great 
  

   mass 
  of 
  the 
  underlying 
  Laurentian 
  Fundamental 
  Gneiss, 
  was 
  

   pointed 
  out 
  some 
  years 
  ago 
  in 
  a 
  paper 
  by 
  the 
  author, 
  read 
  

   before 
  the 
  Geological 
  Society 
  of 
  America. 
  The 
  subsequent 
  

   investigations 
  on 
  these 
  rocks, 
  to 
  the 
  west 
  and 
  southwest, 
  showed 
  

   that 
  the 
  conclusions 
  then 
  presented 
  were 
  correct, 
  but 
  that 
  as 
  the 
  

   work 
  extended 
  westward 
  to 
  the 
  south 
  side 
  of 
  the 
  Ottawa 
  the 
  

   character 
  of 
  the 
  various 
  groups 
  of 
  rocks 
  gradually 
  changed. 
  The 
  

   areas 
  of 
  limestone 
  became 
  much 
  more 
  extensive, 
  and 
  there 
  was 
  

   a 
  large 
  development 
  of 
  hornblende 
  and 
  other 
  dark-colored 
  rocks, 
  

   rarely 
  seen 
  to 
  the 
  north 
  of 
  the 
  Ottawa. 
  The 
  limestones 
  also 
  

   were 
  very 
  often 
  highly 
  dolomitic, 
  and 
  in 
  certain 
  areas 
  were 
  

   blue 
  and 
  slaty, 
  with 
  but 
  little 
  of 
  the 
  aspect 
  of 
  the 
  Grenville 
  

   limestones, 
  except 
  where 
  they 
  were 
  in 
  close 
  contact 
  with 
  

   masses 
  of 
  intrusive 
  granite 
  or 
  diorite. 
  There 
  is 
  also 
  in 
  the 
  

   rocks 
  of 
  this 
  group 
  to 
  the 
  south 
  of 
  the 
  Ottawa, 
  where 
  they 
  

   have 
  been 
  styled 
  the 
  Hastings 
  series, 
  from 
  the 
  fact 
  that 
  they 
  

   were 
  first 
  studied 
  in 
  the 
  county 
  of 
  Hastings, 
  a 
  very 
  consider- 
  

   able 
  proportion 
  of 
  schists, 
  micaceous, 
  chloritic 
  and 
  hornblendic, 
  

   with 
  certain 
  regularly 
  slaty 
  beds, 
  and 
  others 
  of 
  true 
  conglom- 
  

   erate 
  containing 
  quartz 
  pebbles. 
  In 
  certain 
  portions 
  the 
  litho- 
  

   logical 
  resemblances 
  between 
  the 
  Grenville 
  and 
  Hastings 
  

   rocks 
  are 
  very 
  close, 
  and 
  they 
  may, 
  for 
  all 
  practical 
  purposes, 
  

   be 
  regarded 
  as 
  one 
  and 
  the 
  same 
  series. 
  From 
  a 
  number 
  of 
  

   sections 
  made 
  in 
  the 
  counties 
  of 
  Renfrew 
  on 
  the 
  south 
  of 
  the 
  

   Ottawa, 
  and 
  in 
  Pontiac, 
  to 
  the 
  north 
  of 
  that 
  river, 
  it 
  would 
  

   appear 
  that 
  the 
  original 
  Grenville 
  limestones 
  and 
  associated 
  

   grey 
  and 
  rusty 
  gneiss 
  form 
  the 
  lower 
  part 
  of 
  the 
  series, 
  since 
  

   it 
  is 
  only 
  on 
  their 
  development 
  westward 
  towards 
  the 
  typical 
  

   Hastings 
  locality 
  that 
  the 
  characteristic 
  Hastings 
  schists 
  and 
  

   associated 
  strata 
  are 
  met 
  with. 
  

  

  In 
  character 
  and 
  general 
  aspect 
  these 
  rocks 
  of 
  the 
  Hastings 
  

   series 
  are 
  almost 
  identical 
  with 
  many 
  of 
  those 
  which 
  in 
  the 
  

   Eastern 
  Townships 
  and 
  in 
  New 
  Brunswick 
  have 
  been 
  regarded 
  

   as 
  probably 
  Huronian 
  for 
  many 
  years 
  ; 
  and 
  so 
  marked 
  is 
  the 
  

   resemblance 
  that 
  the 
  author, 
  in 
  presenting 
  his 
  summary 
  report 
  

   for 
  1894, 
  referred 
  the 
  rocks 
  seen 
  near 
  the 
  Bristol 
  iron 
  mines 
  

   to 
  that 
  division. 
  It 
  now 
  appears 
  very 
  conclusively 
  established 
  

   that 
  both 
  in 
  the 
  eastern 
  and 
  western 
  areas 
  we 
  have 
  a 
  well 
  

   developed 
  series 
  of 
  rocks, 
  including 
  limestones, 
  gneiss 
  and 
  

   schists, 
  which 
  are 
  of 
  undoubted 
  sedimentary 
  origin, 
  but 
  which 
  

   have 
  been 
  enormously 
  acted 
  upon 
  by 
  great 
  intrusive 
  masses 
  as 
  

   well 
  as 
  by 
  other 
  dynamic 
  agencies, 
  so 
  that 
  in 
  many 
  parts 
  their 
  

   original 
  characters 
  have 
  almost 
  entirely 
  disappeared. 
  

  

  