﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  89 
  

  

  tion. 
  One 
  of 
  the 
  best 
  examples 
  of 
  such 
  a 
  gorge 
  is 
  that 
  of 
  the 
  

   Perch 
  river 
  at 
  Limerick. 
  Many 
  brooks 
  disappear 
  entirely 
  under 
  

   the 
  Watertown 
  formation, 
  forming 
  long 
  underground 
  courses 
  and 
  

   caves. 
  Several 
  such 
  courses 
  are 
  know 
  in 
  Watertov^n, 
  where, 
  how- 
  

   ever, 
  they 
  have 
  been 
  filled 
  by 
  the 
  damming 
  up 
  of 
  the 
  river. 
  Others 
  

   are 
  known 
  below 
  Watertown 
  and 
  at 
  Black 
  River 
  village. 
  

  

  Phenomena 
  entirely 
  peculiar 
  to 
  this 
  formation 
  in 
  the 
  region 
  are 
  

   the 
  inliers 
  at 
  the 
  Natural 
  bridge 
  and 
  Limerick. 
  A 
  glance 
  at 
  the 
  

   Watertown-Leray 
  belt 
  on 
  the 
  Clayton 
  sheet 
  north 
  and 
  east 
  of 
  Chau- 
  

   mont 
  bay 
  reveals 
  the 
  fact 
  that 
  in 
  several 
  places 
  the 
  typical 
  Lowville 
  

   beds 
  appear 
  from 
  beneath 
  the 
  Watertown-Leray 
  limestones. 
  These 
  

   inliers 
  consist 
  of 
  elongate 
  strips 
  of 
  Lowville 
  limestone 
  exposed 
  

   along 
  brooks 
  and 
  surrounded 
  on 
  all 
  sides 
  by 
  the 
  Watertown-Leray 
  

   limestones. 
  The 
  conditions 
  which 
  have 
  produced 
  this 
  peculiar 
  and 
  

   rare 
  form 
  of 
  inlier 
  are 
  the 
  following: 
  The 
  coincidence 
  of 
  the 
  dip 
  

   of 
  the 
  beds 
  and 
  of 
  the 
  course 
  of 
  the 
  brook 
  and 
  the 
  greater 
  resist- 
  

   ance 
  of 
  the 
  underlying 
  Lowville 
  limestone 
  to 
  solution. 
  The 
  brook 
  

   as 
  a 
  rule 
  reaches 
  the 
  inlier 
  by 
  a 
  fall, 
  and 
  finally 
  leaves 
  it 
  again 
  by 
  

   very 
  gradually 
  passing 
  again 
  upon 
  the 
  overlying 
  rock. 
  

  

  A 
  very 
  characteristic 
  exarnple 
  of 
  such 
  an 
  inlier 
  is 
  seen 
  along 
  

   Threemile 
  creek 
  and 
  a 
  very 
  large 
  one 
  at 
  the 
  head 
  of 
  Gufiin 
  bay. 
  

   The 
  most 
  interesting 
  of 
  all 
  is 
  that 
  below 
  the 
  village 
  of 
  Limerick 
  on 
  

   Perch 
  river. 
  It 
  begins 
  with 
  the 
  fall 
  shown 
  on 
  plate 
  2^ 
  and 
  ends 
  

   above 
  the 
  Natural 
  bridge. 
  At 
  the 
  latter 
  place 
  the 
  river 
  passes 
  under- 
  

   ground 
  through 
  a 
  ridge 
  of 
  Watertown-Leray 
  rocks 
  crossing 
  the 
  

   valley. 
  Below 
  the 
  bridge 
  the 
  river 
  reappears 
  for 
  a 
  short 
  distance 
  

   [pi. 
  38] 
  and 
  disappears 
  again, 
  its 
  course 
  being 
  thence 
  traceaJble 
  as 
  

   a 
  depression 
  between 
  the 
  cliffs 
  of 
  Watertown-Leray 
  rocks 
  on 
  

   both 
  sides. 
  The 
  depression 
  shows 
  in 
  the 
  different 
  tilting 
  of 
  the 
  

   huge 
  blocks 
  of 
  the 
  Seven 
  foot 
  tier 
  that 
  it 
  is 
  the 
  result 
  of 
  a 
  gradual 
  

   sinking 
  down 
  of 
  the 
  vdiole 
  mass 
  ; 
  and 
  this 
  indicates 
  that 
  the 
  river, 
  

   which 
  has 
  its 
  underground 
  course 
  on 
  the 
  top 
  of 
  the 
  typical 
  Lowville 
  

   ■beds, 
  is 
  dissolving 
  the 
  Watertown-Leray 
  beds 
  along 
  its 
  course 
  from 
  

   the 
  base 
  upward. 
  There 
  is 
  little 
  doubt 
  that 
  also 
  the 
  inlier 
  above 
  the 
  

   Natural 
  bridge, 
  which 
  can 
  not 
  have 
  been 
  produced 
  by 
  normal 
  cor- 
  

   rasion, 
  is 
  the 
  result 
  of 
  solution 
  of 
  the 
  Watertown-Leray 
  beds, 
  and 
  

   that 
  finally 
  also 
  between 
  the 
  Natural 
  bridge 
  and 
  the 
  lake 
  the 
  typical 
  

   Lowville 
  beds 
  will 
  be 
  exposed 
  and 
  the 
  river 
  flow 
  again 
  overground, 
  

   as 
  it 
  already 
  does 
  just 
  below 
  the 
  bridge. 
  

  

  One 
  of 
  the 
  best 
  exposures 
  of 
  the 
  Watertown-Leray 
  beds 
  is 
  that 
  

   at 
  Klock's 
  quarry, 
  at 
  the 
  end 
  of 
  Huntington 
  street 
  at 
  Watertown. 
  

   This 
  section 
  which 
  is 
  here 
  inserted, 
  begins 
  close 
  to 
  the 
  base 
  of 
  the 
  

  

  