﻿COHOES 
  MASTODON. 
  103 
  

  

  bution 
  of 
  parts, 
  Hon. 
  A. 
  S. 
  Johnson 
  first 
  suggested 
  that 
  the 
  skele- 
  

   ton 
  must 
  have 
  been 
  imbedded 
  in 
  ice, 
  and 
  that 
  during 
  the 
  thawing 
  

   of 
  the 
  mass 
  the 
  bones 
  had 
  become 
  separated 
  and 
  dispersed 
  as 
  they 
  

   were 
  found. 
  The 
  pot-holes 
  were 
  supposed 
  to 
  lie 
  in 
  the 
  bed 
  of 
  a 
  

   former 
  river 
  channel, 
  at 
  a 
  time 
  when 
  the 
  waters 
  flowed 
  at 
  a 
  much 
  

   higher 
  level 
  than 
  at 
  present; 
  th!s 
  view 
  was 
  the 
  only 
  one 
  entertained 
  

   at 
  that 
  time, 
  and 
  our 
  investigations 
  were 
  directed 
  to 
  the 
  discovery 
  

   of 
  evidence 
  in 
  support 
  of 
  this 
  hypothesis. 
  

  

  An 
  examination 
  of 
  the 
  present 
  river 
  channel 
  for 
  some 
  distance 
  

   above 
  the 
  falls 
  and 
  of 
  the 
  gravel 
  accumulation 
  in 
  what 
  we 
  inferred 
  

   to 
  have 
  been 
  the 
  former 
  valley 
  of 
  the 
  river, 
  gave 
  no 
  satisfactory 
  

   solution 
  of 
  the 
  difficulty. 
  To 
  produce 
  pot-holes 
  of 
  the 
  depth 
  and 
  

   magnitude 
  of 
  those 
  examined 
  at 
  Harmony 
  Mills, 
  would 
  have 
  

   required 
  not 
  only 
  a 
  large 
  body 
  of 
  water, 
  but 
  a 
  considerable 
  fall 
  

   in 
  the 
  stream. 
  A 
  survey 
  of 
  the 
  valley 
  above, 
  furnished 
  no 
  evidence 
  

   that 
  at 
  any 
  time 
  subsequent 
  to 
  the 
  drift 
  period 
  had 
  there 
  been 
  a 
  

   barrier 
  or 
  elevation 
  to 
  give 
  a 
  descent 
  to 
  the 
  water 
  sufficient 
  to 
  

   produce 
  such 
  a 
  result 
  as 
  described. 
  We 
  were, 
  in 
  fact, 
  able 
  to 
  

   trace 
  similar 
  pot-holes 
  to 
  the 
  west 
  and 
  northwest, 
  directly 
  beneath 
  

   the 
  drift 
  gravel 
  of 
  the 
  old 
  valley, 
  thus 
  connecting 
  their 
  occurrence 
  

   with 
  a 
  condition 
  of 
  things 
  no 
  longer 
  existing. 
  

  

  III 
  the 
  following 
  spring 
  and 
  summer, 
  a 
  careful 
  survey 
  of 
  the 
  

   Cohoes 
  falls 
  and 
  the 
  surrounding 
  country 
  was 
  made, 
  mainly 
  with 
  

   a 
  view 
  of 
  determining 
  the 
  relations 
  of 
  the 
  pot-holes 
  in 
  which 
  the 
  

   Mastodon 
  remains 
  were 
  found, 
  to 
  those 
  of 
  the 
  River 
  bed 
  and 
  

   adjacent 
  valley. 
  From 
  this 
  survey 
  it 
  was 
  clearly 
  ascertained 
  

   that 
  the 
  large 
  and 
  deep 
  pot-holes 
  were 
  entirely 
  outside 
  of 
  the 
  

   present 
  river 
  channel 
  ; 
  that 
  all 
  the 
  pot-holes 
  existing 
  within 
  

   limits 
  overflowed 
  by 
  the 
  present 
  Mohawk 
  river 
  in 
  any 
  of 
  its 
  

   stages, 
  are 
  shallow 
  basins, 
  the 
  larger 
  part 
  of 
  them 
  having 
  a 
  diam- 
  

   eter 
  at 
  the 
  top 
  equaling 
  or 
  greater 
  than 
  the 
  depth. 
  The 
  form 
  or 
  

   contour 
  of 
  these 
  latter, 
  was 
  such 
  that 
  they 
  were 
  readily 
  distinguished 
  

   from 
  those 
  on 
  the 
  banks 
  of 
  the 
  river 
  at 
  a 
  higher 
  level. 
  We 
  there- 
  

   fore 
  began 
  to 
  distinguish 
  the 
  pot-holes 
  as 
  ancient 
  and 
  modem, 
  and 
  

   with 
  a 
  few 
  exceptions 
  about 
  the 
  falls 
  — 
  apparently 
  the 
  bottom 
  of 
  

   ancient 
  pot-holes 
  not 
  yet 
  quite 
  worn 
  out 
  — 
  all 
  those 
  of 
  the 
  river 
  

   bed 
  seem 
  to 
  be 
  of 
  modern 
  origin. 
  

  

  It 
  wfis 
  found, 
  moreover, 
  that 
  the 
  ancient 
  pot-holes 
  did 
  not 
  follow 
  

   the 
  line 
  of 
  the 
  present 
  river 
  valley. 
  An 
  examination 
  upon 
  the 
  

   north 
  side 
  of 
  the 
  river 
  detected 
  numerous 
  small, 
  somewhat 
  circu- 
  

  

  