﻿PRESENT 
  SURFACE 
  OF 
  KEW 
  TORK 
  1 
  TO 
  

  

  The 
  petrified 
  wood, 
  leaves, 
  moss, 
  etc., 
  which 
  are 
  common 
  in 
  our 
  

   limestone 
  districts, 
  are 
  of 
  modern 
  date, 
  and 
  are 
  forming 
  at 
  

   the 
  present 
  time. 
  The 
  rain-water 
  which 
  percolates 
  through 
  the 
  

   crevices 
  of 
  the 
  limestone 
  rocks, 
  by 
  means 
  of 
  the 
  carbonic 
  acid 
  

   which 
  it 
  gathers 
  from 
  the 
  air, 
  dissolves 
  the 
  carbonate 
  of 
  lime; 
  and 
  

   on 
  coming 
  again 
  to 
  the 
  air 
  in 
  springs, 
  re-deposits 
  it 
  in 
  the 
  form 
  

   of 
  tufa, 
  a 
  drab-colored 
  mass 
  which 
  is 
  nearly 
  pure 
  carbonate 
  of 
  

   lime. 
  This, 
  as 
  it 
  gradually 
  forms, 
  incrusts 
  the 
  leaves, 
  sticks, 
  etc., 
  

   with 
  which 
  it 
  comes 
  in 
  contact; 
  and 
  often, 
  as 
  they 
  decay, 
  replaces 
  

   them 
  in 
  such 
  a 
  manner 
  as 
  to 
  present 
  the 
  same 
  form 
  and 
  structure; 
  

   pieces 
  of 
  wood 
  being 
  thus 
  replaced 
  by 
  a 
  stony 
  mass 
  closely 
  re- 
  

   sembling 
  the 
  original 
  substance. 
  

  

  Age 
  of 
  man 
  

  

  Man 
  is 
  the 
  most 
  highly 
  specialized 
  member 
  of 
  the 
  animal 
  king- 
  

   dom. 
  His 
  remains 
  are 
  not 
  found 
  in 
  deposits 
  earlier 
  than 
  the 
  post 
  

   glacial, 
  which 
  appear 
  to 
  have 
  an 
  age 
  of 
  not 
  many 
  thousand 
  

   years. 
  There 
  is, 
  so 
  far, 
  no 
  clue 
  to 
  his 
  origin. 
  The 
  first 
  relics 
  

   of 
  man 
  are 
  rude 
  implements 
  of 
  stone 
  or 
  bone 
  such 
  as 
  knives, 
  

   arrow-heads, 
  etc., 
  and 
  are 
  found 
  in 
  the 
  gravels 
  of 
  streams 
  and 
  in 
  

   caves. 
  

  

  The 
  first 
  period 
  of 
  man 
  is 
  known 
  as 
  the 
  stone 
  age, 
  but 
  though 
  

   it 
  ceased 
  long 
  ago 
  in 
  Europe, 
  in 
  North 
  America 
  it 
  has 
  existed 
  

   to 
  within 
  the 
  present 
  century. 
  The 
  bronze 
  age 
  succeeded 
  the 
  

   stone 
  age. 
  Last 
  of 
  all 
  came 
  the 
  age 
  of 
  iron 
  which 
  is 
  the 
  present. 
  

  

  PRESENT 
  SURFACE 
  OF 
  NEW 
  YORK 
  

  

  Under 
  this 
  head 
  it 
  is 
  important 
  to 
  consider 
  briefly 
  the 
  causes 
  

   which 
  have 
  reduced 
  so 
  large 
  a 
  portion 
  of 
  the 
  rock 
  strata 
  of 
  New 
  

   York, 
  from 
  the 
  original 
  condition 
  of 
  the 
  wide 
  and 
  uninterrupted 
  

   extent 
  in 
  which 
  they 
  were 
  formed 
  to 
  that 
  of 
  an 
  undulating 
  and 
  

   broken 
  aggregate 
  of 
  hills 
  and 
  valleys 
  which 
  we 
  now 
  see. 
  It 
  is 
  

   probable 
  that 
  during 
  the 
  slow 
  process 
  of 
  emergence 
  from 
  their 
  

   native 
  sea, 
  the 
  action 
  of 
  waves 
  and 
  currents 
  wore 
  them 
  deeply 
  

  

  