﻿Adams, 
  Barlow 
  and 
  Ells 
  — 
  Canadian 
  Laurentian. 
  177 
  

  

  The 
  question 
  of 
  the 
  relations 
  of 
  the 
  Grenville 
  series 
  to 
  the 
  

   Hastings 
  series 
  then 
  presents 
  itself. 
  Although 
  repeated 
  trav- 
  

   erses 
  have 
  been 
  made 
  from 
  one 
  series 
  into 
  the 
  other, 
  no 
  sharp 
  

   line 
  of 
  division 
  has 
  been 
  found. 
  Towards 
  the 
  southeast 
  the 
  

   limestones 
  of 
  the 
  Grenville 
  series 
  in 
  many 
  places, 
  though 
  still 
  

   highly 
  crystalline, 
  seem 
  to 
  be 
  less 
  highly 
  altered, 
  and 
  finally, 
  

   as 
  the 
  Hastings 
  series 
  is 
  approached, 
  present 
  in 
  places 
  the 
  

   bluish 
  color 
  of 
  the 
  limestones 
  of 
  the 
  latter 
  series 
  ; 
  so 
  that 
  it 
  is 
  

   often 
  impossible 
  to 
  determine 
  to 
  which 
  series 
  they 
  should 
  be 
  

   referred. 
  The 
  limestones 
  of 
  both 
  series 
  also 
  have 
  the 
  numer- 
  

   ous 
  small 
  interstratified 
  gneissic 
  inclusions 
  or 
  bands 
  so 
  fre- 
  

   quently 
  referred 
  to 
  in 
  the 
  descriptions 
  of 
  the 
  limestones 
  of 
  the 
  

   Grenville 
  series, 
  making 
  the 
  resemblance 
  still 
  more 
  complete. 
  

   In 
  fact, 
  although 
  the 
  true 
  relations 
  of 
  the 
  two 
  series 
  are 
  

   obscured 
  by 
  the 
  presence 
  of 
  numerous 
  great 
  intrusions 
  of 
  gran- 
  

   itic 
  and 
  basic 
  pyroxenic 
  rocks, 
  and 
  can 
  only 
  be 
  determined 
  

   with 
  absolute 
  certainty 
  by 
  the 
  completion 
  of 
  the 
  mapping, 
  the 
  

   investigations 
  so 
  far 
  indicate 
  that 
  in 
  the 
  region 
  in 
  question 
  the 
  

   Hastings 
  series 
  would 
  seem 
  to 
  represent 
  the 
  Grenville 
  series 
  in 
  

   a 
  less 
  altered 
  form. 
  In 
  other 
  words, 
  the 
  Hastings 
  series, 
  when 
  

   invaded, 
  disintegrated, 
  fretted 
  away 
  and 
  intensely 
  metamor- 
  

   phosed 
  by 
  and 
  mixed 
  up 
  with 
  the 
  underlying 
  magma 
  of 
  the 
  

   Fundamental 
  Gneiss, 
  constitutes 
  what 
  has 
  elsewhere 
  been 
  

   termed 
  the 
  Grenville 
  series. 
  The 
  Grenville 
  series 
  may, 
  how- 
  

   ever, 
  represent 
  only 
  a 
  portion 
  of 
  the 
  Hastings 
  series, 
  and 
  the 
  

   work 
  so 
  far 
  done 
  in 
  this 
  district 
  has 
  not 
  been 
  sufficient 
  to 
  

   determine 
  the 
  stratigraphical 
  position 
  of 
  this 
  portion. 
  

  

  Concerning 
  the 
  age 
  of 
  the 
  Hastings 
  series 
  but 
  little 
  is 
  known 
  

   as 
  yet. 
  To 
  the 
  southeast 
  of 
  the 
  area 
  under 
  consideration, 
  how- 
  

   ever, 
  its 
  clastic 
  character 
  is 
  well 
  marked, 
  breccias 
  and 
  conglom- 
  

   erates, 
  often 
  greatly 
  deformed 
  by 
  pressure, 
  being 
  present 
  as 
  

   well 
  as 
  certain 
  fine-grained 
  and 
  comparatively 
  unaltered 
  lime- 
  

   stones, 
  in 
  which 
  a 
  very 
  careful 
  search 
  may 
  yet 
  be 
  rewarded 
  by 
  

   the 
  discovery 
  of 
  fossils. 
  Both 
  lithologically 
  and 
  stratigraphi- 
  

   cally 
  the 
  rocks 
  bear 
  a 
  striking 
  resemblance 
  to 
  rocks 
  mapped 
  as 
  

   Huronian 
  in 
  the 
  region 
  to 
  the 
  north 
  and 
  northeast 
  of 
  Lake 
  

   Huron, 
  and 
  it 
  seems 
  very 
  likely 
  that 
  the 
  identity 
  of 
  the 
  two 
  

   series 
  may 
  eventually 
  be 
  established. 
  The 
  two 
  areas, 
  however, 
  

   are 
  rather 
  widely 
  separated 
  geographically, 
  so 
  that 
  the 
  greatest 
  

   care 
  will 
  have 
  to 
  be 
  exercised 
  in 
  attempting 
  such 
  a 
  correlation. 
  

  

  Like 
  the 
  Grenville 
  series, 
  the 
  rocks 
  of 
  the 
  Hastings 
  series 
  

   are 
  unconformably 
  overlain 
  by 
  and 
  disappear 
  beneath 
  the 
  flat- 
  

   lying 
  Cambro-Silurian 
  rocks 
  of 
  the 
  plains, 
  which 
  limit 
  the 
  pro- 
  

   taxis 
  on 
  the 
  south 
  and 
  are 
  separated 
  from 
  it 
  in 
  time 
  by 
  an 
  

   immense 
  erosion 
  interval. 
  Further 
  investigation 
  in 
  this 
  area, 
  

   as 
  well 
  as 
  in 
  that 
  adjoining 
  to 
  the 
  east, 
  now 
  being 
  mapped 
  by 
  

   Dr. 
  R. 
  W. 
  Ells, 
  will, 
  however, 
  it 
  is 
  hoped, 
  before 
  long 
  throw 
  

   additional 
  light 
  on 
  the 
  age 
  of 
  this 
  very 
  interesting 
  and 
  impor- 
  

   tant 
  series 
  of 
  rocks. 
  If 
  further 
  investigation 
  proves 
  that 
  the 
  

   relations 
  of 
  the 
  several 
  series 
  have 
  been 
  correctly 
  diagnosed, 
  

  

  