﻿640 
  * 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  point 
  named 
  is 
  composed 
  of 
  stratified 
  gravels 
  and 
  sands 
  with 
  yel- 
  

   lowish 
  layers, 
  dipping 
  nearly 
  flat 
  on 
  the 
  north 
  side 
  of 
  the 
  summit 
  

   bnt 
  inclining 
  to 
  30° 
  south, 
  and 
  evidently 
  truncated 
  on 
  the 
  west. 
  

   This 
  section 
  was 
  exposed 
  in 
  June 
  1900 
  in 
  the 
  excavation 
  for 
  a 
  

   large 
  house 
  then 
  in 
  process 
  of 
  erection. 
  Other 
  small 
  sections 
  in 
  

   driveways 
  along 
  the 
  western 
  slope 
  exhibited 
  stratified 
  beds 
  dip- 
  

   ping 
  in 
  places 
  5° 
  northward 
  and 
  usually 
  eroded. 
  On 
  the 
  western 
  

   slope 
  bouldery 
  till, 
  reddish 
  from 
  oxidation, 
  appears 
  about 
  5 
  feet 
  

   thick; 
  but 
  till 
  is 
  wanting 
  over 
  the 
  summit, 
  which 
  evidently 
  has 
  not 
  

   been 
  run 
  over 
  by 
  the 
  ice. 
  

  

  A 
  complete 
  section 
  through 
  this 
  hill 
  would 
  be 
  required 
  to 
  satisfy 
  

   the 
  needs 
  of 
  an 
  exact 
  analysis 
  of 
  its 
  mode 
  of 
  formation 
  ; 
  but 
  the 
  

   gravel 
  beds 
  dipping 
  30° 
  south 
  at 
  the 
  summit 
  on 
  the 
  southern 
  face 
  

   of 
  the 
  knob 
  appear 
  clearly 
  to 
  place 
  it 
  in 
  the 
  group 
  of 
  glacial 
  cones, 
  

   formed 
  along 
  the 
  ice 
  front, 
  homologous 
  to 
  the 
  alluvial 
  cones 
  which 
  

   form 
  in 
  the 
  lower 
  course 
  of 
  a 
  drainage 
  furrow 
  on 
  the 
  side 
  of 
  a 
  

   mountain 
  valley, 
  with 
  this 
  difference, 
  that 
  the 
  mass 
  at 
  whose 
  base 
  

   it 
  was 
  formed, 
  being 
  ice, 
  has 
  melted 
  away. 
  

  

  The 
  glacial 
  gravel 
  in 
  these 
  cones 
  and 
  mounds 
  arranged 
  along 
  the 
  

   ice 
  front, 
  would 
  appear 
  to 
  have 
  been 
  washed 
  off 
  from 
  the 
  top 
  of 
  

   the 
  thinning 
  ice 
  border 
  or 
  to 
  have 
  issued 
  from 
  tunnels 
  in 
  the 
  upper 
  

   part 
  of 
  the 
  ice. 
  .The 
  character 
  of 
  the 
  material 
  in 
  Harbor 
  hill 
  gives 
  

   a 
  decisive 
  clue 
  to 
  its 
  origin. 
  The 
  gravels 
  are 
  mostly 
  yellow 
  quartz 
  

   from 
  the 
  older 
  Pleistocene 
  deposits 
  which 
  flank 
  the 
  moraine 
  on 
  the 
  

   north. 
  They 
  probably 
  have 
  not 
  been 
  transported 
  for 
  distances 
  

   greater 
  than 
  10 
  miles 
  ; 
  they 
  may 
  have 
  been 
  caught 
  up 
  from 
  the 
  

   base 
  of 
  the 
  ice 
  within 
  3 
  or 
  4 
  miles. 
  At 
  all 
  events, 
  they 
  are 
  locally 
  

   derived 
  material 
  already 
  existing 
  in 
  the 
  district 
  when 
  this 
  advance 
  

   of 
  the 
  ice 
  was 
  accomplished. 
  

  

  The 
  elevation 
  of 
  Harbor 
  hill, 
  nearly 
  400 
  feet 
  above 
  present 
  sea- 
  

   level, 
  affords 
  conclusive 
  evidence 
  as 
  to 
  the 
  least 
  estimate 
  which 
  may 
  

   be 
  made 
  on 
  the 
  hight 
  of 
  the 
  ice 
  front 
  at 
  this 
  point. 
  This 
  hight 
  was 
  

   at 
  least 
  400 
  feet 
  and 
  probably 
  more. 
  This 
  least 
  elevation 
  agrees 
  

   well 
  with 
  the 
  data 
  found 
  by 
  Smock^ 
  in 
  the 
  longitudinal 
  valleys 
  of 
  

   northern 
  New 
  Jersey, 
  where 
  ice 
  tongues 
  rose 
  northward 
  tor 
  a 
  few 
  

  

  ^ 
  Smock, 
  J. 
  C. 
  On 
  the 
  surface 
  limit 
  or 
  thickness 
  of 
  the 
  continental 
  glacier 
  in 
  

   New 
  Jersey 
  and 
  adjacent 
  states. 
  Am. 
  jour. 
  sci. 
  3d 
  ser. 
  1882. 
  35 
  : 
  339-50. 
  

  

  