﻿458 
  NEW 
  YORK 
  Sf 
  ATE 
  MUSEUM 
  

  

  ness 
  varies 
  from 
  20 
  to 
  40 
  feet 
  and 
  is 
  greatest 
  about 
  Rosen- 
  

   dale. 
  

  

  8 
  alma 
  waterlime 
  leds. 
  These 
  underlie 
  the 
  Tentaculite 
  and 
  are 
  

   of 
  considerable 
  importance 
  as 
  they 
  include 
  the 
  well 
  known 
  cement 
  

   beds. 
  Darton 
  says, 
  " 
  The 
  usual 
  characters 
  of 
  the 
  formation 
  are 
  

   thin 
  bedded 
  water 
  limestones, 
  and 
  the 
  cement 
  is 
  of 
  local 
  occur- 
  

   rence." 
  

  

  It 
  is 
  a 
  blue 
  black, 
  very 
  fine 
  grained, 
  massive 
  bedded 
  deposit, 
  

   consisting 
  of 
  calcareous, 
  magnesian 
  and 
  argillaceous 
  materials 
  

   in 
  somewhat 
  variable 
  proportions. 
  The 
  beds 
  are 
  extensively 
  de- 
  

   veloped 
  in 
  the 
  Kondout 
  and 
  Rosendale 
  regions. 
  They 
  come 
  in 
  

   gradually 
  and 
  are 
  attended 
  by 
  a 
  thickening 
  of 
  the 
  formation 
  

   from 
  its 
  usual 
  average 
  of 
  20 
  to 
  30 
  feet 
  to 
  40 
  or 
  50 
  feet. 
  At 
  Rond- 
  

   out 
  the 
  principal 
  cement 
  bed 
  has 
  a 
  thickness 
  averaging 
  about 
  20 
  

   feet. 
  

  

  It 
  lies 
  directly 
  on 
  the 
  coralline 
  (Niagara) 
  limestone 
  and 
  is 
  over- 
  

   laid 
  by 
  alternating 
  successions 
  of 
  waterlime 
  and 
  thin 
  impure 
  

   cement 
  beds. 
  The 
  cement 
  horizon 
  is 
  not 
  exposed 
  far 
  north 
  of 
  

   East 
  Kingston, 
  but 
  how 
  far 
  it 
  extends 
  to 
  the 
  northward 
  is 
  not 
  

   known. 
  

  

  It 
  is 
  seen 
  to 
  thicken 
  southward 
  and 
  it 
  attains 
  its 
  maximum 
  

   thickness 
  in 
  the 
  vicinity 
  of 
  Rondout, 
  thinning 
  out 
  again 
  and 
  giv- 
  

   ing 
  place 
  to 
  waterlime 
  beds 
  south 
  of 
  Wilbur. 
  

  

  It 
  is 
  seen 
  to 
  have 
  come 
  up 
  again 
  in 
  the 
  Whiteport 
  anticlinal, 
  

   which 
  brings 
  up 
  a 
  great 
  development 
  of 
  cement 
  beds 
  along 
  its 
  

   principal 
  axis 
  from 
  Whiteport 
  to 
  Rosendale. 
  They 
  also 
  come 
  

   out 
  along 
  the 
  eastern 
  limit 
  of 
  the 
  synclinal 
  eastward. 
  " 
  South 
  of 
  

   Rosendale 
  the 
  cement 
  beds 
  continue 
  up 
  the 
  Coxingkill 
  valley 
  and 
  

   around 
  the 
  point 
  of 
  the 
  anticlinal 
  by 
  High 
  Falls 
  on 
  the 
  Rondout 
  

   creek." 
  " 
  Above 
  this 
  place 
  it 
  can 
  be 
  traced 
  but 
  a 
  short 
  distance 
  

   owing 
  to 
  its 
  deep 
  erosion 
  and 
  heavy 
  drift 
  cover 
  in 
  the 
  Rondout 
  

   creek 
  valley." 
  It 
  reappears 
  at 
  Port 
  Jackson. 
  

  

  " 
  There 
  are 
  two 
  cement 
  beds 
  in 
  the 
  Whiteport-Rosendale 
  re-* 
  

   gion. 
  The 
  lower 
  one 
  of 
  these 
  averages 
  21 
  feet 
  in 
  thickness, 
  

   and 
  the 
  other 
  averages 
  12 
  feet 
  in 
  thickness, 
  with 
  an 
  intervening 
  

   member 
  of 
  12 
  or 
  15 
  feet 
  of 
  waterlime 
  beds, 
  but 
  these 
  thicknesses 
  

   are 
  very 
  variable." 
  

  

  