﻿

  COHOES 
  MASTODON. 
  133 
  

  

  glance 
  at 
  the 
  map 
  shows 
  that 
  its 
  margins 
  conform 
  largely 
  to 
  the 
  

   strike 
  of 
  the 
  strata. 
  The 
  soundings 
  disclose 
  rocky 
  bottom 
  shelving 
  

   easily 
  toward 
  all 
  shores 
  but 
  the 
  eastern, 
  where 
  two 
  or 
  three 
  large 
  

   pot-holes, 
  probably 
  of 
  the 
  ancient 
  system, 
  increase 
  the 
  soundings 
  

   to 
  over 
  20, 
  and 
  in 
  one 
  spot 
  to 
  31 
  feet. 
  If 
  it 
  were 
  the 
  ancient 
  basin 
  

   of 
  a 
  low 
  fall 
  that 
  has 
  now 
  completed 
  its 
  work, 
  one 
  would 
  expect 
  

   to 
  find 
  in 
  its 
  bottom 
  such 
  irregularities 
  as 
  characterize 
  the 
  basin 
  

   and 
  channel 
  below 
  the 
  present 
  fall. 
  

  

  Bed 
  Rock. 
  — 
  The 
  rock 
  over 
  which 
  the 
  Mohawk 
  flows, 
  from 
  the 
  

   Cohoes 
  company's 
  dam 
  to 
  the 
  Hudson, 
  is 
  of 
  very 
  uniform 
  charac- 
  

   ter. 
  The 
  shaly 
  strata 
  dip 
  from 
  45° 
  to 
  70° 
  toward 
  the 
  S. 
  E., 
  and 
  

   their 
  strike 
  is 
  generally 
  N. 
  30° 
  E. 
  The 
  same 
  uniformity 
  holds 
  

   for 
  some 
  distance 
  above 
  the 
  dam, 
  but 
  near 
  Crescent 
  compact 
  lay- 
  

   ers 
  of 
  conglomerate 
  are 
  intercalated. 
  

  

  Ancient 
  Pot-Holes. 
  — 
  Excavation 
  has 
  revealed 
  in 
  Cohoes 
  and 
  

   its 
  vicinity 
  a 
  number 
  of 
  pot-holes 
  formed 
  anterior 
  to 
  the 
  present 
  

   gorge 
  of 
  the 
  Mohawk.* 
  I 
  have 
  noticed 
  six 
  besides 
  the 
  large 
  

   one 
  in 
  that 
  immediate 
  neighbornood. 
  Near 
  the 
  chimney 
  of 
  the 
  

   new 
  mill 
  a 
  pot-hole 
  15 
  feet 
  broad 
  and 
  at 
  least 
  20 
  deep, 
  was 
  

   opened 
  in 
  cutting 
  a 
  race 
  for 
  the 
  water 
  discharged 
  from 
  the 
  new 
  

   mill. 
  I 
  saw 
  in 
  the 
  same 
  cut 
  eight 
  other 
  pot-holes, 
  — 
  none 
  over 
  

   five 
  feet 
  in 
  diameter, 
  and 
  two 
  of 
  them 
  less 
  than 
  one 
  foot. 
  The 
  

   cutting 
  for 
  the 
  south 
  end 
  of 
  the 
  railroad 
  bridge 
  shows 
  a 
  deep 
  pot- 
  

   hole, 
  and 
  a 
  half 
  dozen 
  appear 
  between 
  this 
  and 
  the 
  tow 
  bridge 
  of 
  

   the 
  Champlain 
  canal. 
  I 
  was 
  informed 
  by 
  Mr. 
  Van 
  Auken 
  that 
  

   pot-holes 
  were 
  found 
  in 
  grading 
  for 
  the 
  block 
  of 
  houses 
  north 
  

   of 
  the 
  new 
  mill, 
  and 
  in 
  excavating 
  the 
  mill-race 
  near 
  the 
  falls. 
  

   There 
  are 
  cross-sections 
  of 
  two 
  in 
  the 
  overflow 
  of 
  the 
  race 
  above 
  

   the 
  Cataract 
  House, 
  and 
  between 
  the 
  Cataract 
  House 
  and 
  School 
  

   street, 
  are 
  two 
  marshy 
  spots 
  that 
  probably 
  mark 
  large 
  ones. 
  

   Above 
  the 
  falls, 
  at 
  a 
  distance 
  of 
  from 
  200 
  to 
  300 
  feet, 
  and 
  as 
  far 
  

   west 
  from 
  the 
  river-bank, 
  are 
  four 
  or 
  five 
  depressions 
  indicating 
  

   pot-holes 
  of 
  from 
  five 
  to 
  ten 
  feet 
  diameter. 
  The 
  margin 
  of 
  one, 
  

   eight 
  feet 
  across, 
  is 
  well 
  marked. 
  East 
  of 
  the 
  river 
  are 
  a 
  number 
  

   of 
  small 
  marshes 
  and 
  pools 
  that 
  are 
  determined 
  as 
  pot-holes 
  by 
  

   the 
  following 
  characteristics. 
  They 
  are 
  circular 
  or 
  sub-circular. 
  

   Though 
  surrounded 
  by 
  rock 
  in 
  place, 
  covered 
  by 
  only 
  a 
  few 
  

  

  * 
  Of 
  the 
  group 
  in 
  which 
  the 
  Mastodon 
  was 
  found, 
  Mr. 
  Whitfield 
  has 
  made 
  measurements 
  

   and 
  memoranda, 
  which 
  are 
  communicated 
  in 
  an 
  accompanying 
  diagram. 
  

  

  [Senate, 
  No. 
  92.] 
  11 
  

  

  