﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  l6l 
  

  

  A 
  considerable 
  area 
  of 
  planished 
  rock 
  is 
  covered 
  by 
  striae 
  which 
  

   have 
  various 
  directions, 
  from 
  s. 
  56° 
  w. 
  to 
  s. 
  16° 
  w. 
  Apparently 
  the 
  

   markings 
  with 
  the 
  more 
  westerly 
  trend 
  are 
  the 
  older 
  and 
  prevailing 
  

   ones 
  over 
  most 
  of 
  the 
  surface, 
  the 
  later 
  and 
  more 
  southerly 
  abrasion 
  

   having 
  softened 
  the 
  older 
  groves 
  and 
  given 
  a 
  cross 
  polish. 
  But 
  the 
  

   later 
  motion 
  is 
  also 
  represented 
  by 
  a 
  few 
  strong 
  chatter 
  bands 
  which 
  

   quite 
  obliterate 
  the 
  older 
  scorings 
  where 
  the 
  latter 
  are 
  crossed. 
  

  

  The 
  curved 
  markings 
  lie 
  in 
  a 
  belt 
  about 
  10 
  feet 
  wide 
  and 
  over 
  50 
  

   feet 
  in 
  length 
  now 
  exposed. 
  The 
  scorings 
  are 
  strong, 
  clean-cut, 
  

   and 
  perfectly 
  parallel. 
  At 
  the 
  north 
  end 
  they 
  lie 
  for 
  several 
  yards 
  

   perfectly 
  straight, 
  with 
  direction 
  56° 
  west 
  of 
  south, 
  then 
  they 
  gently 
  

   .curve, 
  southing 
  with 
  steady 
  uniform 
  curvature 
  until 
  the 
  direction 
  is 
  

   s. 
  42°. 
  w. 
  The 
  curving 
  is 
  still 
  continued 
  where 
  the 
  belt 
  of 
  scorings 
  

   passes 
  under 
  the 
  turf 
  on 
  the 
  south 
  side 
  of 
  the 
  wagon 
  track. 
  The 
  

   strong 
  furrows 
  may 
  not 
  be 
  confidently 
  traced 
  throughout 
  the 
  entire 
  

   length 
  of 
  the 
  curve 
  in 
  distinct 
  individuality, 
  as 
  later 
  abrasion 
  has 
  

   somewhat 
  obscured 
  thehi 
  in 
  places, 
  but 
  they 
  are 
  practically 
  con- 
  

   tinuous 
  and 
  retain 
  their 
  relation 
  and 
  character. 
  The 
  belt 
  of 
  curved 
  

   scorings 
  is 
  exceptional 
  to 
  the 
  general 
  striae 
  of 
  the 
  broad 
  surface 
  and 
  

   surrounding 
  bare 
  patches, 
  the 
  prevailing 
  direction 
  being 
  s. 
  30-35° 
  w. 
  

  

  The 
  curving 
  lines 
  have 
  no 
  angularity 
  and 
  show 
  no 
  hesitation 
  nor 
  

   pauses 
  or 
  spasms 
  in 
  the 
  ice 
  motion. 
  In 
  one 
  place 
  a 
  few 
  of 
  the 
  

   strong 
  scorings 
  in 
  a 
  narrow 
  strip 
  exhibit 
  a 
  perceptible 
  variation 
  

   from 
  the 
  true 
  curvature, 
  or 
  a 
  tendency 
  to 
  straightness, 
  but 
  taking 
  

   the 
  belt 
  as 
  a 
  whole 
  the 
  curvature 
  and 
  the 
  parallelism 
  of 
  the 
  lines 
  

   appear 
  to 
  the 
  eye 
  to 
  be 
  true. 
  The 
  radius 
  of 
  the 
  curve 
  is 
  about 
  60 
  

   or 
  70 
  feet. 
  The 
  chord 
  of 
  the 
  exposed 
  belt, 
  including 
  about 
  15 
  feet 
  

   of 
  the 
  straight 
  beginning 
  of 
  the 
  scorings, 
  is 
  54 
  feet; 
  and 
  the 
  ordinate 
  

   is 
  23 
  inches. 
  

  

  This 
  glaciated 
  surface 
  is 
  the 
  northern 
  side 
  of 
  a 
  broad 
  rock 
  plain, 
  

   with 
  no 
  apparent 
  cause 
  in 
  the 
  surrounding 
  topography 
  for 
  the 
  de- 
  

   flection 
  in 
  the 
  ice 
  flow. 
  A 
  narrow 
  valley 
  lies 
  near 
  on 
  the 
  north, 
  

   across 
  which 
  is 
  a 
  somewhat 
  higher 
  plain. 
  The 
  map, 
  plate 
  44, 
  shows 
  

   the 
  general 
  topography. 
  

  

  A 
  significant 
  fact 
  is 
  that 
  the 
  curving 
  belt 
  of 
  scorings, 
  even 
  at 
  the 
  

   southern 
  deflected 
  end, 
  so 
  far 
  as 
  uncovered, 
  is 
  much 
  more 
  westerly 
  

   in 
  trend 
  than 
  the 
  prevailing 
  ice 
  movement, 
  not 
  only 
  in 
  the 
  immediate 
  

   locality 
  but 
  in 
  the 
  great 
  area. 
  

  

  Chatter 
  marks 
  and 
  gouges. 
  The 
  innumerable 
  exposures 
  of 
  

   the 
  Potsdam 
  sandstone, 
  often 
  of 
  large 
  extent, 
  coupled 
  with 
  the 
  very 
  

   hard 
  and 
  brittle 
  texture 
  of 
  the 
  rock, 
  furnish 
  many 
  excellent 
  ex- 
  

  

  