﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  

  

  119 
  

  

  accompanied 
  by 
  figures 
  stating 
  elevation 
  above 
  sea 
  level. 
  The 
  

   heights 
  of 
  many 
  definite 
  points, 
  such 
  as 
  road 
  corners, 
  railroad 
  sta- 
  

   tions, 
  railroad 
  crossings, 
  summits, 
  water 
  surfaces, 
  triangulation 
  

   stations, 
  and 
  bench 
  marks, 
  are 
  also 
  given. 
  The 
  figures 
  in 
  each 
  

   case 
  are 
  placed 
  close 
  to 
  the 
  point 
  to 
  which 
  they 
  apply, 
  and 
  express 
  

   the 
  elevation 
  to 
  the 
  nearest 
  foot 
  only. 
  . 
  . 
  . 
  All 
  water 
  features 
  are 
  

   shown 
  in 
  blue, 
  the 
  smaller 
  streams 
  and 
  canals 
  in 
  full 
  blue 
  lines, 
  

   and 
  the 
  larger 
  streams, 
  lakes, 
  and 
  the 
  sea 
  by 
  blue 
  water 
  lining. 
  . 
  . 
  . 
  

   The 
  works 
  of 
  man 
  are 
  shown 
  in 
  black, 
  in 
  which 
  coloring 
  all 
  letter- 
  

  

  

  

  Fig. 
  40 
  Ideal 
  sketch 
  and 
  corresponding 
  contour 
  map 
  (U. 
  S. 
  

   G. 
  S.). 
  

  

  ing 
  also 
  is 
  printed. 
  . 
  . 
  . 
  Houses 
  are 
  shown 
  by 
  small 
  black 
  squares 
  

   which 
  in 
  the 
  densely 
  built 
  portions 
  of 
  cities 
  and 
  towns 
  merge 
  into 
  

   blocks. 
  Roads 
  are 
  shown 
  by 
  fine 
  double 
  lines, 
  trails 
  by 
  single 
  

   dotted 
  lines, 
  and 
  railroads 
  by 
  full 
  black 
  lines 
  with 
  cross 
  lines. 
  

   Other 
  cultural 
  features 
  are 
  represented 
  by 
  conventions 
  which 
  are 
  

   easily 
  understood. 
  The 
  sheets 
  composing 
  the 
  topographic 
  atlas 
  are 
  

   designated 
  by 
  the 
  name 
  of 
  a 
  principal 
  town 
  or 
  of 
  some 
  prominent 
  

   natural 
  feature 
  within 
  the 
  quadrangle 
  and 
  the 
  names 
  of 
  the 
  adjoin- 
  

   ing 
  published 
  sheets 
  are 
  printed 
  on 
  the 
  margins. 
  They 
  are 
  sold 
  

  

  