﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  I3I 
  

  

  region. 
  Only 
  a 
  little 
  of 
  this 
  is 
  within 
  the 
  map 
  limits, 
  in 
  the 
  ex- 
  

   treme 
  southeast 
  portion 
  of 
  the 
  Theresa 
  quadrangle. 
  Such 
  Trenton 
  

   as 
  there 
  is 
  north 
  of 
  the 
  river 
  shows 
  itself 
  in 
  rounded 
  hills 
  without 
  

   prominent 
  in 
  face 
  and 
  this 
  is 
  its 
  normal 
  and 
  usual 
  character. 
  The 
  

   high 
  clift 
  referred 
  to 
  is 
  unusual 
  and 
  due 
  to 
  proximity 
  to 
  the 
  Black 
  

   river. 
  

  

  Elinor 
  modifications 
  of 
  these 
  general 
  features 
  are 
  produced 
  be- 
  

   cause 
  of 
  the 
  low 
  folds 
  of 
  the 
  Paleozoic 
  rocks. 
  The 
  discussion 
  of 
  

   these 
  has 
  shown 
  how 
  low 
  domes 
  and 
  shallow 
  basins 
  are 
  thus 
  pro- 
  

   duced 
  in 
  the 
  rocks, 
  resulting 
  in 
  the 
  formation 
  of 
  outliers 
  and 
  inliers 
  

   of 
  the 
  various 
  foniiations, 
  with 
  their 
  local 
  infacing 
  or 
  outfacing 
  

   cliffs 
  ; 
  resulting 
  also 
  in 
  a 
  lobation 
  of 
  the 
  general 
  formational 
  in- 
  

   facing 
  fronts. 
  As 
  Ruedemann 
  has 
  stated 
  these 
  lobes 
  are 
  most 
  con- 
  

   spicuous 
  in 
  the 
  Leray 
  fronts, 
  an 
  additional 
  cause 
  being 
  there 
  

   at 
  work 
  to 
  accentuate 
  them. 
  Nevertheless 
  they 
  are 
  primarily 
  due 
  

   to 
  the 
  folding, 
  the 
  other 
  infaces 
  showing 
  similar, 
  even 
  though 
  less 
  

   conspicuous 
  lobes. 
  The 
  topographic 
  maps 
  show 
  these 
  general 
  feat- 
  

   ures 
  excellently. 
  

  

  The 
  lowdands 
  of 
  our 
  region 
  today 
  are 
  chiefly 
  the 
  result 
  of 
  the 
  

   stream 
  wear 
  during 
  the 
  Tertiary. 
  The 
  prominent 
  rock 
  infaces 
  and 
  

   platforms 
  of 
  the 
  various 
  formations 
  are 
  owing 
  to 
  the 
  considerable 
  

   differences 
  in 
  level 
  between 
  the 
  low 
  grounds 
  and 
  the 
  adjacent 
  up- 
  

   lands, 
  and 
  terrace 
  broadly 
  the 
  ascents 
  from 
  the 
  one 
  to 
  the 
  other. 
  

   These 
  features, 
  together 
  with 
  those 
  of 
  the 
  drainage 
  outlined 
  above, 
  

   were 
  substantially 
  what 
  they 
  are 
  now 
  at 
  the 
  end 
  of 
  Tertiar}- 
  time. 
  

   There 
  are 
  few 
  northern 
  regions 
  in 
  which 
  the 
  general 
  topography 
  is 
  

   so 
  little 
  changed, 
  and 
  has 
  its 
  Tertiary 
  features 
  so 
  little 
  masked 
  by 
  

   subsequent 
  Pleistocene 
  changes 
  as 
  is 
  the 
  case 
  here. 
  

  

  Lakes 
  

  

  The 
  group 
  of 
  lakes 
  in 
  the 
  southeastern 
  portion 
  of 
  the 
  Alexandria 
  

   quadrangle, 
  together 
  with 
  a 
  few 
  more 
  of 
  the 
  same 
  type 
  in 
  the 
  dis- 
  

   trict 
  to 
  the 
  eastward, 
  constitute 
  one 
  of 
  the 
  very 
  interesting 
  features 
  

   of 
  the 
  district. 
  Their 
  interest 
  arises 
  in 
  part 
  from 
  their 
  localization 
  ; 
  

   they 
  are 
  abundant 
  in 
  this 
  restricted 
  area 
  and 
  are 
  scarce 
  or 
  lacking 
  

   elsewhere. 
  In 
  some 
  features 
  they 
  resemble 
  the 
  much 
  more 
  abundant, 
  

   and 
  more 
  widely 
  dispersed, 
  lakes 
  of 
  central 
  Ontario, 
  as 
  described 
  

   by 
  Wilson 
  ; 
  in 
  one 
  respect 
  they 
  are 
  sharply 
  contrasted 
  with 
  them. 
  

  

  Wilson 
  describes 
  the 
  Ontario 
  district 
  as 
  characterized 
  by 
  a 
  prom- 
  

   inent 
  cuesta 
  front 
  at 
  the 
  north 
  edge 
  of 
  the 
  Paleozoic 
  limestones, 
  

  

  