﻿HYDROLOGY 
  OF 
  XEAY 
  YORK 
  

  

  667 
  

  

  the 
  river 
  is 
  Potsdam 
  sandstone, 
  the 
  strata 
  dipping 
  at 
  an 
  angle 
  

   of 
  about 
  30 
  degrees 
  downstream. 
  The 
  banks 
  are 
  of 
  sandstone, 
  

   nearly 
  perpendicular, 
  and 
  about 
  375 
  feet 
  apart 
  up 
  to 
  a 
  level 
  of 
  

   10 
  feet 
  below 
  the 
  crest 
  of 
  the 
  dam. 
  

  

  The 
  material 
  for 
  the 
  construction 
  of 
  the 
  masonry 
  work 
  was 
  

   obtained 
  from 
  quarries 
  near-by. 
  It 
  is 
  Potsdam 
  sandstone 
  which 
  

   -comes 
  out 
  from 
  the 
  quarry 
  with 
  nearly 
  level 
  beds, 
  and 
  no 
  cutting- 
  

  

  Fig. 
  44 
  Cross-section 
  of 
  dam 
  at 
  Hamiawa 
  Falls. 
  

  

  was 
  done 
  except 
  to 
  level 
  the 
  crest 
  of 
  the 
  dam 
  after 
  the 
  stone 
  was 
  

   in 
  place. 
  For 
  the 
  downstream 
  face 
  of 
  the 
  dam 
  stones 
  from 
  12 
  to 
  

   18 
  inches 
  in 
  thickness, 
  2 
  to 
  4 
  feet 
  wide 
  and 
  3 
  to 
  4 
  feet 
  long, 
  were 
  

   used, 
  the 
  beds 
  being 
  laid 
  normal 
  to 
  the 
  surface. 
  For 
  the 
  upstream 
  

   face 
  a 
  rubble 
  wall 
  about 
  3 
  feet 
  thick 
  was 
  laid 
  of 
  smaller 
  stone. 
  

   The 
  space 
  between 
  was 
  filled 
  with 
  large 
  bowlders 
  and 
  irregular 
  

   shaped 
  quarry 
  stones, 
  with 
  concrete 
  rammed 
  in 
  around 
  and 
  be- 
  

   tween. 
  This 
  dam 
  was 
  completed 
  in 
  the 
  fall 
  of 
  1899 
  and 
  has 
  had 
  

   4y 
  2 
  feet 
  of 
  water 
  over 
  its 
  crest 
  in 
  two 
  different 
  seasons. 
  The 
  dam 
  

   is 
  perfectly 
  water-tight. 
  

  

  