﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  I5I 
  

  

  stream 
  erosion 
  of 
  the 
  clays 
  which 
  constitute 
  the 
  bulk 
  of 
  the 
  drift. 
  

   The 
  existence 
  of 
  the 
  Redwood 
  lakes 
  in 
  the 
  northern 
  district 
  is 
  an 
  

   evidence 
  of 
  lack 
  of 
  drift 
  filling. 
  

  

  The 
  normal 
  and 
  common 
  form 
  of 
  drift 
  in 
  regions 
  of 
  glaciation, 
  

   the 
  stony 
  clay 
  or 
  clayey 
  mixture 
  of 
  rock 
  rubbish 
  known 
  as 
  " 
  till," 
  

   is 
  widely 
  found 
  but 
  in 
  relatively 
  small 
  amount. 
  The 
  larger 
  drift 
  

   masses 
  are 
  of 
  three 
  kinds: 
  sandy 
  or 
  '' 
  kame 
  " 
  areas; 
  boulder 
  mo- 
  

   raines 
  : 
  and 
  pitted 
  clay 
  plains. 
  The 
  extensive 
  plains 
  of 
  water-laid 
  

   clay 
  are 
  regarded 
  as 
  glacio-aqueous 
  deposits, 
  and 
  are 
  described 
  in 
  

   a 
  later 
  chapter. 
  

  

  Till. 
  In 
  the 
  northern 
  portion 
  of 
  the 
  area, 
  Avhere 
  the 
  rocks 
  are 
  

   Potsdam 
  and 
  crystallines 
  and 
  arenaceous 
  materials 
  prevail, 
  the 
  

   scanty 
  till 
  is 
  sandy 
  and 
  stony. 
  In 
  the 
  southern 
  district 
  where 
  the 
  

   strata 
  are 
  wholly 
  limestone 
  these 
  give 
  a 
  clayey 
  texture 
  to 
  the 
  drift 
  

   sheet. 
  

  

  The 
  superficial 
  till 
  is 
  usually 
  incoherent 
  and 
  yellow 
  or 
  yellowish 
  

   gray 
  in 
  color. 
  In 
  a 
  few 
  places 
  a 
  compact, 
  hard, 
  blue 
  or 
  blue 
  gray 
  

   till 
  may 
  be 
  found 
  which 
  is 
  regarded 
  as 
  the- 
  product 
  of 
  ice 
  action 
  

   earlier 
  than 
  the 
  Wisconsin. 
  The 
  most 
  massive 
  exposures 
  of 
  the 
  blue 
  

   till 
  are 
  found 
  south 
  of 
  our 
  area, 
  at 
  Watertown 
  [p. 
  i66]. 
  

  

  No 
  drift 
  masses 
  that 
  could 
  be 
  definitely 
  recognized 
  as 
  drumlin 
  

   have 
  been 
  noted 
  in 
  our 
  territory, 
  though 
  they 
  do 
  occur 
  over 
  the 
  

   line 
  on 
  the 
  south, 
  north 
  and 
  south 
  of 
  Watertown. 
  Some 
  molding 
  

   of 
  the 
  till 
  surfaces 
  suggest 
  drumlinizing 
  of 
  the 
  drift, 
  but 
  appar- 
  

   ently 
  the 
  till 
  was 
  too 
  scant}- 
  to 
  be 
  rubbed 
  into 
  definite 
  drumlin 
  

   masses. 
  

  

  Moraines. 
  One 
  heavy 
  moraine 
  lies 
  in 
  the 
  southeast 
  corner 
  of 
  

   our 
  area, 
  between 
  Black 
  River 
  and 
  Evans 
  Mills, 
  mapped 
  in 
  plate 
  

   41. 
  This 
  is 
  the 
  only 
  mass 
  of 
  drift 
  of 
  notable 
  size 
  in 
  the 
  Hmestone 
  

   district. 
  In 
  the 
  northern 
  part 
  of 
  the 
  area, 
  where 
  the 
  Potsdam 
  sand- 
  

   stone 
  and 
  the 
  knobby 
  crystallines 
  give 
  irregular 
  surface 
  and 
  rather 
  

   sharp 
  relief, 
  patches 
  of 
  rough 
  and 
  stony 
  drift 
  that 
  may 
  be 
  re- 
  

   garded 
  as 
  morainal 
  are 
  quite 
  frequent; 
  but 
  the 
  only 
  grouping 
  

   which 
  merits 
  the 
  name 
  of 
  moraine 
  belt 
  lies 
  about 
  Clayton 
  and 
  east- 
  

   ward 
  north 
  of 
  Lafargeville, 
  shown 
  in 
  plate 
  46. 
  In 
  general 
  it 
  may 
  

   be 
  said 
  that 
  the 
  peripheral 
  or 
  morainal 
  drift 
  is 
  not 
  collected 
  in 
  well 
  

   marked 
  lines 
  but 
  is 
  scattering, 
  patchy 
  and 
  indefinite. 
  In 
  districts 
  

   where 
  the 
  Potsdam 
  prevails 
  at 
  the 
  surface, 
  with 
  scarps 
  and 
  ledges 
  

   that 
  supplied 
  very 
  coarse 
  material 
  the 
  ice-piled 
  blocks 
  are 
  liable 
  to 
  be 
  

   confused 
  with 
  tbe 
  postglacial 
  debris 
  from 
  frost 
  fracturing 
  of 
  the 
  

   jointed 
  sandstone. 
  As 
  the 
  Gilbert 
  waters 
  have 
  rinsed 
  away 
  the 
  

   lighter 
  drift 
  from 
  the 
  higher 
  masses 
  it 
  is 
  not 
  easy 
  to 
  readily 
  dis- 
  

  

  