﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  1 
  67 
  

  

  the 
  Cape 
  Vincent 
  branch 
  of 
  the 
  New 
  York 
  Central 
  Railroad, 
  a 
  

   hard, 
  gray 
  blue 
  till 
  appears 
  that 
  is 
  very 
  unlike 
  the 
  prevailing 
  drift 
  

   of 
  the 
  northward 
  area. 
  The 
  latter 
  exposure 
  is 
  shown 
  in 
  plate 
  52. 
  

   The 
  resemblance 
  of 
  this 
  drumlin 
  till 
  to 
  the 
  " 
  old 
  " 
  tills 
  farther 
  south 
  

   is 
  as 
  close 
  as 
  might 
  be 
  expected 
  when 
  the 
  differences 
  in 
  latitude, 
  

   source 
  of 
  the 
  material, 
  etc. 
  are 
  considered. 
  However, 
  we 
  must 
  

   recognize 
  that 
  the 
  drumlin 
  till 
  was 
  subglacial, 
  deposited 
  beneath 
  the 
  

   ice 
  and 
  under 
  tremendous 
  grinding 
  pressure; 
  while 
  the 
  surficial 
  

   drift 
  of 
  the 
  area 
  was 
  dropped 
  in 
  standing 
  water, 
  and 
  is 
  conse- 
  

   quently 
  incoherent, 
  sandy, 
  inclined 
  to 
  yellow 
  or 
  gray 
  colors, 
  and 
  

   carry 
  few 
  striated 
  or 
  abraded 
  stones. 
  The 
  .production 
  of 
  masses 
  of 
  

   subglacial 
  drift 
  or 
  drumlins 
  is 
  a 
  sort 
  of 
  work 
  which 
  the 
  later 
  ice 
  

   did 
  not 
  do 
  north 
  of 
  Watertown, 
  at 
  least 
  to 
  noticeable 
  extent, 
  and 
  

   it 
  is 
  doubtful 
  if 
  it 
  did 
  such 
  work 
  at 
  AVatertown. 
  However, 
  the 
  

   drumlin 
  till 
  is 
  inconclusive, 
  until 
  we 
  know 
  if 
  the 
  Watertown 
  drum- 
  

   lins 
  are 
  the 
  work 
  of 
  the 
  latest 
  ice 
  or 
  of 
  some 
  earlier 
  invasion. 
  

   This 
  Watertown 
  till 
  is 
  not 
  in 
  valley 
  bottoms 
  or 
  deeply 
  buried, 
  but 
  

   in 
  hills 
  above 
  the 
  levels 
  of 
  the 
  plain. 
  

  

  Limestone 
  ribbing. 
  Over 
  the 
  southern 
  part 
  of 
  the 
  Clayton 
  

   quadrangle 
  the 
  limestones 
  frequently 
  exhibit 
  series 
  of 
  parallel 
  ribs 
  

   or 
  flutings, 
  a 
  sort 
  of 
  washboard 
  structure 
  on 
  a 
  vast 
  scale 
  [pi. 
  60-63]. 
  

   These 
  ribs 
  positively 
  have 
  no 
  genetic 
  relation 
  to 
  the' 
  joint 
  structure 
  

   of 
  the 
  rock. 
  They 
  are 
  pronounced 
  convexities, 
  often 
  quite 
  cylindri- 
  

   cal 
  but 
  commonly 
  rather 
  flat, 
  with 
  a 
  breadth 
  from 
  crest 
  to 
  crest, 
  

   or 
  across 
  the 
  base, 
  from 
  2 
  to 
  10 
  feet; 
  the 
  usual 
  breadth 
  being 
  3 
  to 
  

   5 
  feet. 
  The 
  hollows 
  between 
  the 
  ribs 
  are 
  usually 
  filled 
  with 
  drift 
  

   or 
  soil, 
  but 
  when 
  cleared 
  they 
  show 
  quite 
  cylindrical 
  troughs 
  of 
  

   uniform 
  width 
  and 
  fair 
  curvature, 
  and 
  parallelism 
  with 
  the 
  ribs. 
  By 
  

   solution-weathering 
  the 
  sides 
  of 
  the 
  flutings 
  are 
  rarely 
  steepened 
  

   and 
  the 
  bottoms 
  perforated 
  by 
  solution 
  holes, 
  as 
  in 
  plate 
  63. 
  

  

  Within 
  any 
  single 
  exposure 
  these 
  flutings 
  are 
  strikingly 
  parallel 
  

   [pi. 
  61] 
  and 
  are 
  approximately 
  so 
  over 
  the 
  whole 
  region, 
  having 
  

   a 
  direction 
  about 
  s. 
  45° 
  w. 
  Scores 
  of 
  them 
  have 
  been 
  measured 
  with 
  

   that 
  direction, 
  over 
  all 
  the 
  area 
  between 
  Dexter 
  and 
  St 
  Lawrence 
  

   village. 
  The 
  extreme 
  variation 
  in 
  direction 
  is 
  s. 
  40° 
  w. 
  for 
  the 
  

   heavy 
  ribbing 
  east 
  of 
  Dexter, 
  and 
  s. 
  50° 
  w., 
  south 
  of 
  Dexter, 
  shown 
  

   in 
  plate 
  63. 
  Two 
  other 
  localities 
  toward 
  St 
  Lawrence 
  gave 
  the 
  

   latter 
  compass 
  direction. 
  

  

  Speaking 
  broadly 
  the 
  flutings 
  have 
  lost 
  all 
  their 
  glacial 
  surfaces;- 
  

   retaining 
  only 
  the 
  erosional 
  form, 
  for 
  their 
  origin 
  by 
  ice 
  erosion 
  of 
  

   the 
  limestone 
  seems 
  certain. 
  In 
  a 
  very 
  few 
  cases 
  a 
  suggestion 
  of 
  

   the 
  heavier 
  scorings 
  are 
  preserved, 
  and 
  some 
  minor 
  flutings 
  on 
  the 
  

  

  