﻿Brigham 
  — 
  Drift 
  Bowlders 
  in 
  Central 
  New 
  York. 
  223 
  

  

  the 
  bowlders 
  were 
  swept 
  diagonally 
  across 
  the 
  valley, 
  a 
  mod- 
  

   erate 
  number 
  were 
  carried 
  to, 
  or 
  over 
  the 
  summit 
  of 
  the 
  range, 
  

   but 
  by 
  far 
  the 
  greater 
  number 
  and 
  almost 
  all 
  the 
  larger 
  frag- 
  

   ments 
  were 
  swerved 
  from 
  0° 
  to 
  28° 
  westward 
  by 
  the 
  valley 
  

   wall 
  and 
  caught 
  on 
  the 
  lower 
  slopes. 
  It 
  is 
  a 
  good 
  illustration 
  

   of 
  the 
  law 
  stated 
  for 
  such 
  cases 
  by 
  Professor 
  Chamberlin.* 
  In 
  

   further 
  harmony 
  with 
  the 
  passage 
  cited, 
  it 
  is 
  to 
  be 
  noted 
  that 
  

   the 
  Oriskany 
  valley 
  is 
  neither 
  so 
  broad 
  and 
  shallow 
  as 
  to 
  fail 
  

   of 
  diversion 
  of 
  the 
  basal 
  currents, 
  nor 
  so 
  narrow 
  and 
  deep 
  as 
  

   to 
  cause 
  a 
  decided 
  cross 
  current. 
  There 
  can 
  be 
  little 
  doubt 
  

   that 
  the 
  bowlders 
  in 
  question 
  were 
  moved 
  while 
  the 
  ice 
  was 
  

   deep 
  and 
  its 
  action 
  vigorous, 
  rather 
  than 
  by 
  an 
  ice 
  tongue 
  at 
  a 
  

   later 
  and 
  decadent 
  stage. 
  

  

  Near 
  Hamilton 
  the 
  valley 
  bends 
  toward 
  the 
  east 
  and 
  hence 
  

   the 
  Oriskany 
  bowlders 
  begin 
  to 
  appear 
  on 
  the 
  western 
  slopes. 
  

   East 
  of 
  Hamilton 
  near 
  the 
  base 
  of 
  the 
  hill, 
  an 
  Oriskany 
  block 
  

   measures 
  21x12x10 
  feet. 
  On 
  the 
  campus 
  of 
  Colgate 
  Univer- 
  

   sity, 
  eleven 
  miles 
  from 
  the 
  ledge, 
  the 
  bowlders 
  are 
  abundant, 
  

   the 
  largest 
  measuring 
  15fx 
  12x10 
  feet. 
  From 
  Hamilton 
  to 
  

   Earlville, 
  masses 
  with 
  dimensions 
  of 
  6 
  to 
  8 
  feet 
  are 
  not 
  uncom- 
  

   mon. 
  From 
  Earlville 
  to 
  Smyrna 
  the 
  number 
  is 
  much 
  smaller 
  

   and 
  but 
  three 
  or 
  four 
  w 
  T 
  ere 
  seen 
  having 
  a 
  diameter 
  of 
  four 
  feet. 
  

   Near 
  Norwich 
  the 
  track 
  of 
  the 
  ice 
  was 
  crossed 
  for 
  10 
  miles. 
  

   But 
  two 
  Oriskany 
  pieces 
  were 
  seen, 
  each 
  about 
  one 
  foot 
  in 
  

   diameter, 
  on 
  the 
  lower 
  hill-slope, 
  one 
  mile 
  southwest 
  of 
  Nor- 
  

   wich. 
  The 
  last 
  Oriskany 
  fragment 
  recognized, 
  was 
  an 
  8 
  inch 
  

   piece 
  in 
  the 
  valley 
  1% 
  miles 
  north 
  of 
  Oxford, 
  or 
  40 
  miles 
  from 
  

   the 
  nearest 
  outcrop. 
  

  

  Vertical 
  distribution. 
  — 
  Oriskany 
  material 
  is 
  infrequent 
  in 
  

   the 
  kames 
  and 
  gravel 
  trains 
  of 
  the 
  valleys, 
  which, 
  being 
  of 
  

   somewhat 
  later 
  date, 
  may 
  have 
  buried 
  such 
  of 
  the 
  Oriskany 
  

   blocks 
  as 
  rested 
  in 
  the 
  valleys. 
  The 
  greatest 
  abundance 
  is 
  on 
  

   the 
  lower 
  slopes 
  facing 
  the 
  approach 
  of 
  the 
  ice, 
  w 
  r 
  ith 
  moderate 
  

   carriage 
  to 
  the 
  summits, 
  dropping 
  off 
  to 
  the 
  lower 
  levels, 
  how- 
  

   ever, 
  as 
  we 
  go 
  southward. 
  When 
  we 
  turn 
  to 
  the 
  question 
  of 
  

   amount 
  of 
  glacial 
  elevation, 
  it 
  must 
  be 
  noted 
  that 
  Oriskany 
  

   bowlders 
  occur 
  on 
  the 
  hill 
  range 
  north 
  of 
  the 
  ledge 
  for 
  five 
  

   miles 
  (to 
  O). 
  Portions 
  of 
  the 
  Oriskany 
  terrane 
  were 
  swept 
  

   from 
  the 
  summit, 
  whose 
  floor 
  is 
  now 
  of 
  lower 
  Helderberg 
  lime- 
  

   stone. 
  Taking 
  into 
  account 
  the 
  dip 
  and 
  comparing 
  the 
  highest 
  

   northern 
  extension 
  of 
  the 
  preglaciai 
  ledge 
  with 
  the 
  greatest 
  

   height 
  attained 
  by 
  the 
  bowlders 
  v 
  in 
  Madison, 
  we 
  find 
  that 
  

   248 
  feet 
  in 
  8 
  miles 
  gives 
  the 
  largest 
  rate 
  of 
  ascent 
  which 
  the 
  

   facts 
  compel 
  us 
  to 
  accept. 
  Several 
  considerations 
  make 
  it 
  

   probable 
  that 
  the 
  most 
  important 
  assemblage 
  of 
  blocks 
  (at 
  

   C 
  E 
  F 
  G) 
  was 
  derived 
  from 
  the 
  ledge 
  now 
  seen 
  at 
  Oriskany 
  

  

  * 
  Rock 
  Scorings 
  of 
  the 
  Great 
  Ice 
  Invasions, 
  7th 
  Ann. 
  Rep. 
  U. 
  S. 
  G. 
  S., 
  pp. 
  197-200. 
  

  

  