﻿COHOES 
  MASTODON. 
  113 
  

  

  in 
  this 
  and 
  other 
  parts 
  of 
  the 
  map 
  indicate 
  the 
  depth 
  of 
  soundings 
  

   in 
  feet, 
  the 
  inclined 
  figures 
  being 
  used 
  to 
  designate 
  a 
  list 
  of 
  pot- 
  

   holes. 
  By 
  a 
  study 
  of 
  the 
  sections 
  and 
  map 
  a 
  very 
  clear 
  idea 
  of 
  

   the 
  river 
  bed 
  may 
  be 
  obtained. 
  

  

  Throughout 
  all 
  parts 
  of 
  the 
  riverbed 
  and 
  channel, 
  we 
  search 
  in 
  

   vain 
  for 
  evidences 
  of 
  pot-holes 
  of 
  the 
  character 
  of 
  those 
  described 
  as 
  

   containing 
  pebbles 
  of 
  quartzite 
  and 
  in 
  which 
  the 
  remains 
  of 
  Masto- 
  

   don 
  were 
  found. 
  Ascending 
  the 
  banks 
  at 
  any 
  point, 
  however, 
  these 
  

   ancient 
  pot-holes 
  meet 
  us 
  wherever 
  the 
  gravel 
  or 
  boulder 
  clay 
  has 
  

   been 
  removed 
  from 
  the 
  surface 
  of 
  the 
  rock. 
  They 
  are 
  of 
  all 
  

   dimensions 
  from 
  one 
  foot 
  to 
  fifty 
  feet 
  in 
  depth 
  and 
  diame- 
  

   ter. 
  Sometimes 
  they 
  are 
  entirely 
  without 
  pebbles, 
  having 
  become 
  

   filled 
  with 
  clay 
  or 
  peaty 
  earth 
  according 
  to 
  surrounding 
  circum- 
  

   stances, 
  but 
  usually 
  the 
  lower 
  part 
  is 
  occupied 
  by 
  pebbles. 
  In 
  

   some 
  instances 
  it 
  would 
  appear 
  as 
  if 
  the 
  pot-hole 
  was 
  mainly 
  clue 
  

   to 
  a 
  large 
  boulder 
  having 
  dropped 
  upon 
  the 
  surface 
  of 
  the 
  rock, 
  

   and 
  the 
  water 
  wearing 
  around 
  it 
  had 
  caused 
  the 
  first 
  depression 
  in 
  

   the 
  surface, 
  and 
  this 
  was 
  increased 
  by 
  the 
  lodgement 
  of 
  smaller 
  

   pieces, 
  which 
  being 
  set 
  in 
  motion 
  by 
  the 
  water, 
  produced 
  the 
  wear- 
  

   ing 
  to 
  the 
  depths 
  we 
  find 
  them. 
  

  

  Upon 
  the 
  ground 
  covered 
  by 
  the 
  diagram 
  of 
  pot-holes 
  (Plate 
  IV) 
  

   in 
  the 
  vicinity 
  of 
  Harmony 
  Mills, 
  these 
  cavities 
  were 
  found 
  in 
  all 
  

   varieties 
  of 
  form 
  and 
  in 
  all 
  stages 
  of 
  progress. 
  Although 
  twenty- 
  

   six 
  pot-holes 
  were 
  examined 
  and 
  noted 
  upon 
  this 
  area, 
  it 
  is 
  not 
  

   probable 
  that 
  one-half 
  were 
  seen, 
  on 
  account 
  of 
  the 
  covering 
  of 
  

   clay, 
  etc., 
  which 
  prevented 
  an 
  examination 
  over 
  a 
  large 
  part 
  of 
  the 
  

   ground. 
  The 
  large 
  peaty 
  bog, 
  indicated 
  on 
  the 
  right 
  hand, 
  was 
  

   penetrated 
  far 
  enough 
  to 
  prove 
  it 
  to 
  be 
  an 
  enormous 
  pot-hole, 
  but 
  

   its 
  depth 
  was 
  not 
  ascertained. 
  There 
  was 
  likewise 
  a 
  depression 
  

   in 
  the 
  rock 
  from 
  the 
  large 
  pot-hole 
  No. 
  1, 
  leading 
  towards 
  this 
  bog, 
  

   but 
  no 
  outlet 
  from 
  the 
  latter 
  could 
  be 
  traced. 
  Similar 
  pot-holes 
  were 
  

   traced 
  along 
  the 
  bank 
  further 
  to 
  the 
  southward, 
  and 
  others 
  have 
  

   since 
  been 
  discovered 
  at 
  a 
  greater 
  distance 
  in 
  the 
  same 
  direction. 
  

  

  Although 
  it 
  may 
  be 
  said 
  that 
  there 
  are 
  general 
  characteristics 
  by 
  

   which 
  these 
  pot-holes 
  can 
  be 
  distinguished 
  from 
  those 
  of 
  modern 
  

   origin, 
  like 
  those 
  of 
  the 
  present 
  river 
  bed, 
  they 
  were 
  nevertheless 
  of 
  

   very 
  various 
  forms, 
  sometimes 
  wide 
  at 
  the 
  top 
  and 
  in 
  other 
  cases 
  

   quite 
  narrow, 
  and 
  enlarging 
  downwards. 
  A 
  section 
  of 
  one 
  of 
  these, 
  

   more 
  extreme 
  than 
  the 
  others, 
  is 
  given 
  on 
  the 
  diagram. 
  The 
  smaller 
  

   ones 
  were 
  simple 
  and 
  entire 
  on 
  their 
  margins; 
  those 
  of 
  larger 
  

  

  