﻿LIMESTONES 
  OF 
  NEW 
  YORI^ 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  457 
  

  

  tends 
  across 
  the 
  eastern 
  portion 
  of 
  the 
  county 
  from 
  north 
  to 
  

  

  south. 
  

  

  It 
  is 
  well 
  exposed 
  between 
  Saugerties 
  and 
  Rondout 
  and 
  about 
  

  

  Wilbur 
  and 
  Whiteport, 
  but 
  exposures 
  of 
  it 
  are 
  rare 
  southwest 
  of 
  

  

  this 
  latter 
  locality 
  excep 
  at 
  Mill 
  Hook 
  and 
  Highfalls. 
  

  

  Samples 
  for 
  analysis 
  were 
  collected 
  from 
  the 
  quarry 
  of 
  the 
  

  

  Newark 
  cement 
  co. 
  at 
  Rondout, 
  and 
  the 
  average 
  of 
  these 
  gave: 
  

  

  Silica 
  3.87 
  

  

  Ferric 
  oxid 
  '. 
  1 
  . 
  34 
  

  

  Alumina 
  1 
  . 
  07 
  

  

  Lime 
  54 
  . 
  11 
  

  

  Magnesia 
  tr 
  

  

  Carbonic 
  dioxid 
  40 
  . 
  60 
  

  

  101.29 
  

  

  Another 
  set 
  of 
  samples 
  from 
  the 
  quarry 
  of 
  B. 
  Turner 
  near 
  

   Wilbur 
  gave: 
  

  

  Silica 
  ,. 
  7.10 
  

  

  Alumina 
  2 
  . 
  50 
  

  

  Ferric 
  oxid 
  1.65 
  

  

  Lime 
  45.22 
  

  

  Magnesia 
  tr 
  

  

  Carbon 
  dioxid 
  39.10 
  

  

  99.57 
  

  

  Pentamerus 
  limestone. 
  This 
  member 
  of 
  the 
  Lower 
  Helderberg 
  

   in 
  Orange 
  co. 
  is 
  a 
  hard, 
  dark 
  blue 
  or 
  lead 
  colored, 
  massive 
  

   limestone. 
  Not 
  infrequently 
  it 
  is 
  somewhat 
  cherty. 
  Its 
  hard 
  and 
  

   tough 
  character 
  frequently 
  causes 
  it 
  to 
  give 
  rise 
  to 
  cliffs. 
  Good 
  

   exposures 
  of 
  this 
  rock 
  occur 
  in 
  the 
  cliffs 
  at 
  Rosendale, 
  about 
  Port 
  

   Jackson, 
  near 
  Eddyville 
  and 
  along 
  the 
  eastern 
  face 
  of 
  the 
  lime- 
  

   stone 
  ridge 
  extending 
  from 
  Rondout 
  to 
  Saugerties 
  and 
  West 
  

   Camp. 
  

  

  They 
  are 
  generally 
  a 
  mile 
  or 
  more 
  from 
  the 
  shore 
  of 
  the 
  Hud- 
  

   son 
  but 
  two 
  miles 
  north 
  of 
  Rondout 
  approach 
  close 
  to 
  it. 
  The 
  

   Pentamerus 
  limestone 
  has 
  a 
  thickness 
  of 
  30 
  to 
  40 
  feet. 
  

  

  Tentaculite 
  limestone. 
  This 
  is 
  generally 
  a 
  thin 
  bedded 
  dark 
  blue 
  

   limestone 
  and 
  forms 
  the 
  base 
  of 
  the 
  Helderberg 
  series. 
  Its 
  thick- 
  

  

  