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  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  In 
  addition 
  to 
  the 
  more 
  technical 
  books 
  described 
  above, 
  there 
  

   are 
  many 
  accurate 
  and 
  important 
  works 
  written 
  for 
  popular 
  read- 
  

   ing 
  both 
  at 
  home 
  and 
  abroad. 
  The 
  number 
  of 
  these 
  is 
  constantly 
  

   increasing 
  and 
  they 
  can 
  be 
  found 
  in 
  the 
  large 
  libraries 
  or 
  obtained 
  

   through 
  the 
  book 
  sellers. 
  

  

  Field 
  Work 
  

  

  OUTCROPS 
  

  

  There 
  are 
  in 
  general 
  two 
  classes 
  of 
  geologic 
  strata, 
  the 
  hard 
  

   and 
  the 
  soft. 
  In 
  New 
  York 
  the 
  hard 
  strata 
  include 
  all 
  rocks 
  

   older 
  than 
  the 
  Cretaceous. 
  The 
  soft 
  include 
  the 
  formations 
  of 
  

   the 
  Cretaceous, 
  Tertiary 
  and 
  Quaternary. 
  Almost 
  everywhere 
  

   the 
  hard 
  rocks 
  are 
  overlaid 
  by 
  soft 
  deposits, 
  usually 
  of 
  Quarter- 
  

   nary 
  age, 
  Sio 
  that 
  in 
  any 
  locality 
  there 
  is 
  generally 
  both 
  hard 
  and 
  

   soft 
  geology. 
  

  

  The 
  hard 
  geology 
  is 
  probably 
  best 
  for 
  the 
  beginner 
  to 
  take 
  up 
  

   first, 
  where 
  he 
  has 
  a 
  choice 
  between 
  the 
  two. 
  In 
  Dana's 
  Manual 
  

   of 
  Geology 
  and 
  Sir 
  Archibald 
  Geikie's 
  Outlines 
  of 
  Field 
  Geologyy 
  

   detailed 
  directions 
  are 
  given 
  for 
  methods 
  of 
  study 
  among 
  the 
  hard 
  

   rocks. 
  

  

  The 
  most 
  important 
  habit 
  to 
  be 
  cultivated 
  by 
  the 
  beginner 
  in 
  

   geology, 
  is 
  that 
  of 
  recognizing 
  outcrops 
  when 
  they 
  occur, 
  or 
  in 
  

   their 
  absence, 
  of 
  determining 
  by 
  surface 
  indications 
  the 
  character 
  

   of 
  the 
  rock 
  which 
  underlies 
  the 
  soil. 
  

  

  The 
  beginner 
  must 
  form 
  early, 
  the 
  habit 
  of 
  distinguishing 
  loose 
  

   fragments 
  or 
  boulders 
  from 
  ledges 
  or 
  outcrops, 
  and 
  in 
  regions 
  

   devoid 
  of 
  outcrops 
  must 
  study 
  carefully 
  the 
  stone 
  fences 
  for 
  frag- 
  

   ments 
  of 
  the 
  local 
  rock. 
  The 
  fences 
  as 
  a 
  rule 
  represent 
  the 
  aggre- 
  

   gate 
  of 
  loose 
  rock 
  fragments 
  gathered 
  from 
  the 
  surface 
  of 
  the 
  

   agricultural 
  lands 
  and 
  these 
  fragments 
  have 
  usually 
  come 
  from 
  

   the 
  underlying 
  rock. 
  In 
  parts 
  of 
  western 
  New 
  York, 
  over 
  the 
  

   soft 
  Salina 
  shales 
  no 
  fragments 
  of 
  local 
  rock 
  are 
  found 
  because 
  

   it 
  decomposes 
  into 
  clay. 
  There 
  the 
  fences 
  are 
  formed 
  of 
  small,^ 
  

   hard 
  cobblestones 
  chiefly 
  derived 
  from 
  the 
  granite 
  and 
  gneisa 
  

   rocks 
  of 
  Canada 
  and 
  brought 
  to 
  their 
  present 
  resting 
  place 
  by 
  the 
  

   great 
  ice 
  sheet. 
  

  

  