﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  1 
  27 
  

  

  west. 
  The 
  presence 
  of 
  this 
  divide, 
  with 
  its 
  sharply 
  cut 
  ravines 
  

   heading 
  against 
  it 
  on 
  both 
  sides 
  is 
  to 
  us 
  one 
  of 
  the 
  most 
  interest- 
  

   ing 
  features 
  of 
  our 
  district. 
  It 
  is 
  most 
  unfortunate 
  that 
  the 
  maps 
  

   of 
  the 
  quadrangles 
  next 
  east 
  are 
  not 
  available 
  so 
  that 
  it 
  could 
  

   be 
  further 
  traced 
  in 
  that 
  direction. 
  Inspection 
  of 
  the 
  Alexandria 
  

   and 
  Theresa 
  maps 
  will 
  show 
  plainly 
  its 
  course 
  across 
  them. 
  In 
  

   the 
  low 
  grounds 
  near 
  the 
  St 
  Lawrence 
  the 
  ravine 
  heads 
  are 
  not 
  

   prominent, 
  though 
  the 
  two 
  lateral 
  ravines 
  into 
  Cranberry 
  creek 
  

   valley 
  from 
  the 
  east 
  are 
  good 
  examples. 
  But 
  at 
  Browns 
  Corners, 
  

   4 
  miles 
  southeast 
  of 
  Alexandria 
  Bay, 
  is 
  seen 
  .the 
  head 
  of 
  the 
  first 
  

   of 
  a 
  series 
  of 
  sharply 
  cut 
  valley 
  heads 
  with 
  northeast 
  trend. 
  The 
  

   next 
  is 
  at 
  Plessis, 
  dropping 
  down 
  sharply 
  into 
  the 
  Clear 
  lake-Mud 
  

   lake-Butterfield 
  lake 
  valley, 
  with 
  a 
  secondary 
  sharp 
  drop 
  at 
  the 
  

   head 
  of 
  Butterfield 
  lake. 
  One 
  and 
  one 
  half 
  miles 
  southeast 
  of 
  

   Plessis, 
  on 
  the 
  extreme 
  south 
  margin 
  of 
  the 
  Alexandria 
  sheet, 
  

   is 
  the 
  head 
  of 
  the 
  Hyde 
  lake-Hyde 
  creek- 
  Perch 
  river 
  valley, 
  on 
  

   the 
  other 
  side 
  of 
  the 
  divide, 
  belonging 
  to 
  the 
  southwest 
  drainage. 
  

   Just 
  east 
  are 
  two 
  sharply 
  cut 
  ravines 
  heading 
  on 
  opposite 
  sides 
  

   of 
  a 
  low 
  pass 
  across 
  the 
  divide, 
  the 
  valley 
  of 
  Crystal 
  lake, 
  which 
  

   is 
  tributary 
  to 
  the 
  Mud 
  lake 
  valley, 
  and 
  the 
  valley 
  without 
  pres- 
  

   ent 
  drainage, 
  followed 
  by 
  the 
  railroad 
  and 
  leading 
  south 
  into 
  the 
  

   Indian 
  river 
  valley 
  on 
  the 
  Theresa 
  sheet. 
  This 
  valley 
  is 
  some- 
  

   what 
  more 
  blocked 
  by 
  drift 
  than 
  the 
  others 
  and 
  seems 
  to 
  have 
  

   held 
  a 
  shallow 
  lake. 
  The 
  Millsite 
  lake 
  and 
  Sixberry 
  lake 
  valleys 
  

   also 
  head 
  sharply 
  against 
  the 
  divide 
  on 
  the 
  north. 
  They 
  are 
  

   however 
  of 
  somewhat 
  abnormal 
  type. 
  Most 
  of 
  the 
  other 
  valleys 
  

   mentioned 
  commence 
  as 
  distinct 
  but 
  shallow, 
  rock-cut 
  trenches, 
  

   which, 
  after 
  a 
  short 
  course, 
  suddenly 
  deepen 
  to 
  gorges 
  with 
  walls 
  

   from 
  40 
  to 
  100 
  feet 
  high. 
  The 
  Clear 
  lake 
  and 
  Hyde 
  lake 
  valleys 
  

   nicely 
  illustrate 
  this 
  type. 
  The 
  lakes 
  are 
  at 
  the 
  heads 
  of 
  long 
  

   \'alleys 
  leading 
  away 
  from 
  the 
  divide. 
  The 
  Crystal 
  lake. 
  Six- 
  

   berry 
  lake 
  and 
  Millsite 
  lake 
  valleys, 
  on 
  the 
  other 
  hand 
  are 
  short 
  

   valleys, 
  tributary 
  to 
  others 
  at 
  the 
  side, 
  and 
  they 
  deepen 
  almost 
  

   at 
  once, 
  instead 
  of 
  having 
  the 
  preliminary 
  shallow 
  course. 
  The 
  

   view 
  of 
  the 
  head 
  of 
  Crystal 
  lake 
  valley 
  [pi. 
  34] 
  gives 
  an 
  excellent 
  

   idea 
  of 
  the 
  general 
  character. 
  

  

  Passing 
  to 
  the 
  Theresa 
  sheet, 
  attention 
  is 
  at 
  once 
  directed 
  to 
  

   the 
  considerable 
  and 
  deep 
  valley, 
  leading 
  north 
  past 
  Theresa, 
  the 
  

   valley 
  into 
  which 
  the 
  modern 
  Indian 
  river 
  breaks 
  at 
  that 
  point, 
  

   with 
  production 
  of 
  falls 
  and 
  short 
  gorge 
  [pi. 
  32]. 
  The 
  valley 
  it- 
  

   self 
  heads 
  3 
  miles 
  further 
  south. 
  Two 
  miles 
  to 
  the 
  west 
  is 
  the 
  

   Hyde 
  creek-Perch 
  river 
  valley, 
  running 
  south*west 
  and 
  heading 
  

  

  