﻿156 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Considering- 
  their 
  relation 
  to 
  the 
  ice 
  sheet, 
  the 
  kames 
  are 
  essen- 
  

   tially 
  morainal 
  in 
  so 
  far 
  as 
  they 
  are 
  peripheral 
  or 
  marginal 
  to 
  the 
  

   ice 
  sheet. 
  Eskers, 
  specially 
  if 
  of 
  great 
  length, 
  are 
  longitudinal, 
  or 
  

   parallel 
  to 
  the 
  ice 
  movement, 
  and 
  correspond 
  to 
  drumlins 
  of 
  the 
  

   ice-laid 
  drift. 
  The 
  esker-kames 
  noted 
  above 
  are 
  not 
  quite 
  typical 
  

   of 
  either 
  class, 
  and 
  are 
  therefore 
  all 
  the 
  more 
  instructive. 
  In 
  the 
  

   field 
  these 
  four 
  or 
  five 
  chains 
  are 
  distinct 
  and 
  clean-cut 
  features. 
  

  

  It 
  should 
  be 
  borne 
  in 
  mind 
  that 
  all 
  these 
  detrital 
  deposits 
  were 
  

   formed 
  when 
  the 
  ice 
  front 
  was 
  bathed 
  by 
  several 
  hundred 
  feet 
  of 
  

   water 
  of 
  Lake 
  Iroquois, 
  The 
  streams 
  which 
  drained 
  the 
  ice 
  sheet 
  

   may 
  have 
  flowed 
  in 
  tunnels 
  beneath 
  the 
  ice 
  (subglacial), 
  or 
  in 
  

   trenches 
  on 
  the 
  ice 
  (superglacial), 
  or 
  rarely 
  within 
  the 
  ice 
  (engla- 
  

   cial). 
  To 
  enter 
  the 
  standing 
  water 
  with 
  sufficient 
  force 
  to 
  carry 
  

   detritus 
  the 
  subglacial 
  streams 
  must 
  have 
  been 
  under 
  considerable 
  

   head 
  or 
  hydraulic 
  pressure. 
  

  

  The 
  various 
  differences 
  in 
  these 
  water 
  deposits 
  must 
  be 
  sought 
  

   in 
  the 
  variation 
  of 
  the 
  glacial 
  drainage 
  in 
  its 
  complex 
  relation 
  to 
  

   the 
  inclosing 
  ice 
  and 
  to 
  the 
  receiving 
  waters, 
  and 
  to 
  the 
  amount 
  

   and 
  kind 
  of 
  rock 
  debris 
  at 
  different 
  depths 
  in 
  the 
  ice 
  and 
  within 
  

   reach 
  of 
  the 
  streams.^ 
  

  

  Glacio-aqueous 
  deposits 
  

   Clay 
  plains. 
  The 
  largest 
  in 
  volume 
  and 
  the 
  most 
  extensive 
  of 
  

   the 
  deposits 
  due 
  to 
  glacial 
  agency, 
  direct 
  or 
  indirect, 
  are 
  the 
  clay 
  

   plains 
  which 
  were 
  spread 
  by 
  the 
  Iroquois 
  and 
  Gilbert 
  waters. 
  Ex- 
  

   cept 
  where 
  in 
  the 
  Black 
  river 
  district 
  the 
  moraine 
  and 
  delta 
  oc- 
  

   cupy 
  the 
  ground 
  the 
  prevailing 
  drift 
  of 
  practically 
  all 
  the 
  terri- 
  

   tory 
  south 
  of 
  the 
  parallel 
  of 
  Lafargeville 
  is 
  this 
  clay; 
  and 
  also 
  

   large 
  areas 
  of 
  the 
  lower 
  ground 
  north 
  of 
  this 
  line. 
  With 
  exception 
  

   of 
  some 
  till 
  and 
  thinly 
  till-masked 
  rock 
  ridges 
  all 
  the 
  lower 
  ground 
  

   of 
  the 
  Cape 
  Vincent 
  sheet 
  and 
  the 
  southwest 
  half 
  of 
  the 
  Clayton 
  

   sheet 
  is 
  clay. 
  East 
  of 
  Clayton 
  and 
  east 
  and 
  west 
  of 
  Lafargeville 
  

   the 
  plains 
  are 
  clay, 
  blending 
  into 
  till, 
  or 
  eastward 
  at 
  Strough 
  into 
  

   sand. 
  Excellent 
  views 
  are 
  afforded 
  of 
  these 
  prairielike 
  plains 
  from 
  

   the 
  railroads 
  to 
  Clayton 
  and 
  Cape 
  Vincent. 
  In 
  the 
  northern 
  dis- 
  

   trict 
  the 
  clay 
  occupies 
  only 
  the 
  valleys 
  and 
  hollows, 
  where 
  the 
  

  

  1 
  The 
  reader 
  who 
  wishes 
  to 
  pursue 
  the 
  study 
  of 
  water-laid 
  drift 
  will 
  find 
  

   a 
  philosophic 
  discussion 
  by 
  R. 
  D. 
  Salisbury 
  in 
  Glacial 
  Geology 
  of 
  New 
  

   Jersey. 
  Final 
  Rep't, 
  5:113-45. 
  

  

  Kames 
  of 
  Central 
  New 
  York 
  are 
  briefly 
  described 
  by 
  the 
  present 
  writer. 
  

   Jour. 
  Geol. 
  4:19^-59. 
  See 
  also 
  Am. 
  Geo!. 
  22:177-80; 
  Am. 
  Ass'n 
  Adv. 
  

   Sci. 
  Proc. 
  47:278-81. 
  ,,r 
  r^ 
  

  

  On 
  eskers, 
  favoring 
  their 
  superglacial 
  position, 
  see 
  an 
  article 
  by 
  W. 
  U 
  

   Crosby, 
  Am. 
  Geol. 
  30:1-39. 
  

  

  