﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  I45 
  

  

  hagen 
  and 
  Champion 
  are 
  the 
  glacial 
  channels 
  [see 
  footnote 
  

   p. 
  142]. 
  The 
  Rutland 
  Hollow 
  is 
  a 
  capacious 
  valley 
  cut 
  ob- 
  

   liquely 
  across 
  the 
  nose 
  of 
  the 
  promontory, 
  parallel 
  in 
  direction 
  with 
  

   both 
  higher 
  and 
  lower 
  glacial 
  channels 
  of 
  Black 
  valley 
  outflow, 
  and 
  

   was 
  undoubtedly 
  given 
  its 
  form 
  and 
  dimensions 
  by 
  glacial 
  drainage. 
  

   When 
  the 
  Black 
  valley 
  waters 
  were 
  lowered 
  into 
  Lake 
  Iroquois 
  the 
  

   Black 
  river 
  built 
  its 
  delta 
  in 
  the 
  lake 
  northwest 
  of 
  Carthage, 
  partly 
  

   banked 
  against 
  heavy 
  moraine. 
  When 
  Lake 
  Iroquois 
  was 
  lowered 
  

   into 
  Gilbert 
  gulf 
  the 
  Black 
  river 
  found 
  its 
  ancient 
  course 
  obstructed 
  

   by 
  the 
  delta 
  and 
  moraine 
  deposits 
  and 
  was 
  compelled 
  to 
  follow 
  

   around 
  the 
  rock 
  promontory 
  in 
  the 
  path 
  of 
  the 
  stronger 
  shore 
  cur- 
  

   rents 
  in 
  the 
  lake. 
  West 
  of 
  Watertown 
  the 
  river 
  dropped 
  its 
  detritus 
  

   in 
  the 
  sea-level 
  waters 
  (Gilbert 
  gulf), 
  and 
  when 
  these 
  waters 
  were 
  

   lowered 
  by 
  the 
  land 
  uplift 
  the 
  river 
  pursued 
  its 
  chance 
  course 
  over 
  

   the 
  rock 
  toward 
  the 
  retreating 
  water 
  body. 
  

  

  To 
  epitomize 
  : 
  It 
  seems 
  certain 
  that 
  the 
  earliest 
  drainage 
  which 
  

   we 
  can 
  locate 
  must 
  have 
  been 
  along 
  the 
  weak 
  zone 
  of 
  the 
  overlap 
  

   of 
  the 
  sedimentar}- 
  rocks 
  on 
  the 
  Precambric. 
  in 
  north 
  and 
  north- 
  

   east 
  continuation 
  of 
  the 
  Black 
  valley. 
  Preceding 
  the 
  latest 
  ice 
  in- 
  

   vasion 
  the 
  Black 
  river 
  probably 
  flowed 
  north. 
  Just 
  what 
  may 
  have 
  

   occurred 
  during 
  the 
  Tertiary 
  uplift 
  and 
  the 
  earlier 
  Pleistocene 
  we 
  

   do 
  not 
  know. 
  It 
  is 
  possible 
  that 
  there 
  are 
  unsuspected 
  elements 
  

   in 
  that 
  long 
  history, 
  but 
  there 
  is 
  no 
  discovered 
  reason 
  for 
  any 
  

   preglacial 
  southward 
  drainage 
  across 
  the 
  divide 
  as 
  mapped 
  in 
  plate 
  

   43. 
  The 
  really 
  uncertain 
  factor 
  is 
  the 
  glaciation 
  earlier 
  than 
  the 
  

   Wisconsin 
  epoch. 
  The 
  writer 
  is 
  inclined 
  to 
  credit 
  to 
  glaciation 
  

   earlier 
  than 
  the 
  Wisconsin 
  considerable 
  influence 
  in 
  producing 
  the 
  

   parallelism 
  of 
  the 
  rock 
  forms 
  and 
  the 
  drainage 
  lines 
  along 
  the 
  St 
  

   Lawrence 
  depression 
  : 
  and 
  the 
  bluntness 
  and 
  roundness 
  of 
  the 
  Rut- 
  

   land 
  promontory 
  ; 
  and 
  the 
  cutting 
  of 
  the 
  Rutland 
  Hollow. 
  

  

  Topographic 
  features. 
  Parallelism. 
  The 
  topographic 
  ele- 
  

   ments 
  of 
  the 
  area 
  have 
  a 
  conspicuous 
  parallelism, 
  about 
  northeast 
  

   and 
  southwest, 
  in 
  accordance 
  with 
  the 
  St 
  Lawrence 
  valley 
  and 
  river. 
  

   On 
  the 
  Clayton 
  and 
  Theresa 
  sheets 
  this 
  shows 
  clearly 
  in 
  the 
  stream 
  

   and 
  valley 
  courses 
  and 
  in 
  the 
  trend 
  of 
  the 
  plateaus 
  and 
  rock 
  hills. 
  

   On 
  the 
  Alexandria 
  and 
  Grindstone 
  sheets 
  the 
  parallelism 
  appears 
  

   in 
  the 
  elongation 
  of 
  the 
  rock 
  knobs 
  and 
  the 
  form 
  of 
  the 
  lakes 
  and 
  

   the 
  islands 
  in 
  the 
  river. 
  This 
  character 
  prevails 
  down 
  the 
  valley 
  

   far 
  beyond 
  our 
  district, 
  as 
  shown 
  by 
  the 
  river 
  courses 
  which 
  instead 
  

   of 
  flowing 
  directly 
  to 
  the 
  St 
  Lawrence 
  follow 
  along 
  in 
  parallel 
  

   courses 
  [pi. 
  43] 
  . 
  

  

  