﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  lOQ 
  

  

  show 
  occasional 
  small 
  surface 
  folds^ 
  or 
  buckles, 
  produced 
  since 
  the 
  

   ice 
  sheet 
  vanished 
  from 
  the 
  region. 
  

  

  Precambric 
  folding. 
  It 
  has 
  been 
  shown 
  that 
  the 
  Grenyille 
  beds 
  

   are 
  now 
  found 
  for 
  the 
  most 
  part 
  in 
  highly 
  inclined 
  condition, 
  

   dips 
  of 
  less 
  than 
  45° 
  being 
  relatively 
  rare, 
  while 
  those 
  approach- 
  

   ing 
  verticality 
  are 
  common. 
  Averaging 
  the 
  dips 
  of 
  the 
  entire 
  

   formation 
  would 
  give 
  a 
  result 
  of 
  at 
  least 
  a 
  55° 
  to 
  60° 
  dip. 
  It 
  has 
  

   also 
  been 
  shown 
  that 
  the 
  dip 
  is 
  not 
  everywhere 
  in 
  the 
  same 
  direc- 
  

   tion 
  but 
  that, 
  with 
  the 
  general 
  direction 
  of 
  strike 
  to 
  the 
  northeast- 
  

   southwest, 
  the 
  dip, 
  while 
  prevalently 
  to 
  the 
  northwest, 
  becomes 
  at 
  

   times 
  southeast. 
  The 
  southeast 
  dips 
  prevail 
  over 
  a 
  belt 
  of 
  country 
  

   some 
  4 
  miles 
  in 
  breadth 
  in 
  the 
  Butterfield 
  lake 
  district 
  of 
  the 
  

   Alexandria 
  sheet. 
  In 
  the 
  country 
  lying 
  south 
  of 
  this 
  belt 
  the 
  dips 
  

   are 
  all 
  to 
  the 
  northwest. 
  In 
  the 
  other 
  direction 
  the 
  Grenville 
  is 
  

   badly 
  cut 
  out 
  by 
  the 
  syenite 
  and 
  granite 
  of 
  the 
  Alexandria 
  and 
  

   Picton 
  bathyliths, 
  but 
  such 
  as 
  remains 
  shows 
  very 
  steep 
  to 
  verti- 
  

   cal 
  dips, 
  chiefly 
  to 
  the 
  northwest. 
  The 
  highly 
  tilted 
  condition 
  oi 
  

   the 
  rock 
  series, 
  and 
  these 
  changing 
  dips 
  seem 
  certainly 
  indicative 
  

   of 
  folding. 
  Moreover 
  many 
  exposures 
  exhibit 
  small 
  folds 
  of 
  ex- 
  

   ceedingly 
  compressed 
  type, 
  often 
  accompanied 
  by 
  extreme 
  plica- 
  

   tion. 
  It 
  is 
  reasonable 
  to 
  suppose 
  that 
  these 
  are 
  merely 
  secondary, 
  

   or 
  minor, 
  folds 
  superimposed 
  upon 
  folds 
  of 
  much 
  larger 
  scale. 
  

  

  In 
  order 
  to 
  demonstrate 
  the 
  presence 
  of 
  these 
  larger 
  folds 
  it 
  

   is 
  necessary 
  that 
  the 
  order 
  of 
  superposition 
  of 
  the 
  various 
  Gren- 
  

   ville 
  beds 
  should 
  be 
  worked 
  out, 
  and 
  in 
  the 
  early 
  stages 
  of 
  the 
  

   field 
  work 
  it 
  was 
  hoped 
  that 
  this 
  might 
  be 
  done. 
  It 
  is 
  possible 
  

   that 
  it 
  might 
  have 
  been 
  successfully 
  accomplished 
  had 
  large 
  scale 
  

   maps, 
  say 
  4 
  inches 
  to 
  the 
  mile, 
  been 
  available. 
  But 
  the 
  structure 
  is 
  

   so 
  complicated, 
  the 
  dips 
  so 
  steep, 
  the 
  folds 
  so 
  compressed, 
  the 
  

   series 
  so 
  greatly 
  cut 
  out 
  by 
  the 
  igneous 
  rocks, 
  or 
  so 
  modified 
  in 
  

   character 
  by 
  them, 
  and 
  so 
  much 
  of 
  the 
  territory 
  is 
  yet 
  covered 
  by 
  

   the 
  Paleozoic 
  rocks, 
  that 
  no 
  certainty 
  as 
  to 
  the 
  Grenville 
  succession 
  

   could 
  be 
  arrived 
  at 
  with 
  the 
  maps 
  in 
  hand. 
  Certain 
  suggestions 
  

   may 
  however 
  be 
  made. 
  

  

  Inspection 
  of 
  the 
  maps 
  will 
  show 
  that 
  the 
  Indian 
  river, 
  from 
  

   Theresa 
  northward 
  to 
  the 
  point 
  where 
  it 
  passes 
  oflf 
  the 
  Alexandria 
  

   sheet, 
  follows 
  a 
  broad 
  belt 
  of 
  Grenville 
  limestone, 
  averaging 
  some- 
  

   what 
  more 
  than 
  a 
  mile 
  in 
  breadth. 
  Except 
  for 
  being 
  much 
  cut 
  up 
  

   by 
  granite 
  dikes 
  and 
  stocks, 
  it 
  is 
  quite 
  pure 
  limestone. 
  The 
  dips 
  

   are 
  steadily 
  to 
  the 
  northwest, 
  and 
  flatter 
  than 
  the 
  usual 
  Grenville 
  

   dips, 
  averaging 
  about 
  45°, 
  and 
  hence 
  indicating 
  a 
  thickness 
  of 
  

   about 
  4000 
  feet 
  for 
  the 
  limestone. 
  A 
  few 
  miles 
  to 
  the 
  northward. 
  

  

  