﻿112 
  TWENTY-FIRST 
  REPORT 
  ON 
  THE 
  STATE 
  CABINET. 
  

  

  der 
  beds 
  of 
  argillaceous 
  sandstone 
  are 
  seen 
  near 
  the 
  river 
  bank 
  

   and 
  forming 
  its 
  bed, 
  but 
  the 
  stream 
  appears 
  to 
  be 
  flowing 
  in 
  an 
  

   ancient 
  wide 
  depression, 
  having 
  accomplished 
  but 
  a 
  veiy 
  moderate 
  

   amount 
  of 
  erosion 
  of 
  the 
  rock 
  in 
  modern 
  times. 
  A 
  section 
  one 
  mile 
  

   below 
  Crescent 
  (PL 
  II), 
  gives 
  the 
  contour 
  of 
  the 
  valley 
  at 
  that 
  

   point. 
  From 
  there 
  the 
  river 
  channel 
  gradually 
  deepens 
  in 
  the 
  

   slate 
  till 
  the 
  nearly 
  vertical 
  banks 
  are 
  from 
  twenty 
  to 
  thirty 
  feet 
  

   above 
  the 
  river 
  level, 
  and 
  even 
  fifty 
  feet 
  at 
  some 
  points, 
  though 
  by 
  

   no 
  means 
  uniform 
  or 
  presenting 
  the 
  same 
  elevation 
  on 
  the 
  two 
  sides. 
  

   At 
  the 
  falls, 
  the 
  river 
  makes 
  a 
  sudden 
  descent 
  of 
  seventy 
  feet 
  (Plate 
  

   II), 
  and 
  pursues 
  its 
  course 
  between 
  the 
  almost 
  vertical 
  walls 
  

   of 
  slate 
  rock, 
  which 
  rise 
  from 
  eighty 
  to 
  more 
  than 
  one 
  hundred 
  feet 
  

   above 
  the 
  river 
  bed. 
  The 
  width 
  of 
  this 
  channel 
  just 
  below 
  the 
  

   falls 
  is 
  about 
  eleven 
  hundred 
  feet, 
  and 
  at 
  a 
  point 
  six 
  hundred 
  feet 
  

   lower 
  down 
  the 
  stream 
  it 
  is 
  eight 
  hundred 
  feet, 
  presenting 
  a 
  

   pretty 
  even 
  rock 
  bottom, 
  except 
  along 
  the 
  center 
  where 
  a 
  deep 
  

   narrow 
  channel 
  has 
  been 
  Avorn, 
  as 
  shown 
  in 
  the 
  section 
  (Plate 
  II.) 
  

   In 
  the 
  summer 
  time 
  this 
  rocky 
  bed 
  is 
  dry, 
  all 
  the 
  water 
  being 
  con- 
  

   fined 
  to 
  the 
  narrow 
  deep 
  channel, 
  but 
  in 
  times 
  of 
  high 
  water 
  it 
  

   is 
  covered 
  to 
  the 
  depth 
  of 
  fourteen 
  feet. 
  

  

  At 
  the 
  base 
  of 
  the 
  falls, 
  and 
  for 
  some 
  distance 
  below, 
  the 
  chan- 
  

   nel 
  is 
  irregularly 
  deepened 
  as 
  shown 
  in 
  the 
  transverse 
  section 
  of 
  

   the 
  river 
  at 
  that 
  place 
  (Plate 
  II, 
  Fig. 
  3). 
  The 
  same 
  feature 
  is 
  shown 
  

   in 
  the 
  longitudinal 
  section 
  (Plate 
  II, 
  Fig. 
  4). 
  The 
  deepest 
  point, 
  how- 
  

   ever, 
  is 
  not 
  directly 
  below 
  the 
  falling 
  water 
  in 
  the 
  center 
  of 
  the 
  

   channel, 
  or 
  at 
  the 
  base 
  of 
  the 
  fall, 
  but 
  at 
  some 
  distance 
  in 
  advance. 
  

   The 
  deepest 
  points 
  near 
  the 
  fall 
  are 
  upon 
  the 
  west 
  side; 
  and 
  

   though 
  both 
  here 
  and 
  along 
  the 
  entire 
  width 
  of 
  the 
  stream, 
  there 
  

   are 
  great 
  irregularities 
  in 
  depth, 
  there 
  are 
  no 
  defined 
  pot-holes. 
  

   In 
  the 
  deep 
  channel 
  below, 
  there 
  are 
  a 
  few 
  small 
  islands 
  of 
  rock, 
  

   and 
  some 
  irregular 
  pot-holes 
  along 
  its 
  margin, 
  which 
  for 
  the 
  most 
  

   part 
  are 
  shallow 
  pools, 
  though 
  some 
  of 
  them 
  have 
  a 
  depth 
  of 
  ten 
  

   or 
  twelve 
  feet. 
  On 
  the 
  margin 
  of 
  the 
  fall 
  above, 
  there 
  are 
  a 
  few 
  

   deeper 
  pot-holes, 
  as 
  shown 
  in 
  the 
  longitudinal 
  section 
  of 
  the 
  river- 
  

   bed; 
  their 
  principal 
  region 
  is 
  an 
  area 
  above 
  the 
  falls, 
  within 
  

   the 
  limits 
  of 
  the 
  rapid 
  water 
  as 
  it 
  approaches 
  the 
  precipice. 
  

  

  The 
  Map 
  of 
  Cohoes 
  Falls 
  and 
  Vicinity 
  (Plate 
  III), 
  is 
  a 
  portion 
  

   reduced 
  in 
  scale 
  from 
  a 
  much 
  larger 
  surveyed 
  map 
  of 
  the 
  river 
  

   and 
  valley 
  in 
  the 
  vicinity 
  of 
  Cohoes. 
  The 
  width 
  of 
  the 
  river 
  

   below 
  the 
  falls 
  is 
  indicated 
  by 
  the 
  topographical 
  lines, 
  and 
  the 
  

   narrow 
  deeper 
  channel 
  is 
  given 
  as 
  surveyed. 
  The 
  upright 
  figures 
  

  

  