﻿Report 
  of 
  the 
  State 
  Geologist. 
  503 
  

  

  rise 
  to 
  the 
  Shawangunk 
  mountain. 
  The 
  first 
  appearance 
  of 
  the 
  

   formation 
  northward 
  is 
  between 
  Binnewater 
  and 
  Whiteport 
  sta- 
  

   tions, 
  on 
  the 
  Walkill 
  Valley 
  railroad, 
  and 
  in 
  the 
  cement 
  quarries 
  

   on 
  the 
  eastern 
  side 
  of 
  the 
  ridge 
  eastward, 
  as 
  before 
  noted. 
  In 
  

   the 
  anticlinal 
  north 
  of 
  Binnewater 
  station, 
  the 
  thickness 
  rapidly 
  

   increases 
  to 
  sixty 
  feet, 
  but 
  to 
  the 
  eastward 
  it 
  thickens 
  less 
  rapidly 
  

   and 
  it 
  is 
  discontinuous 
  at 
  several 
  points. 
  Just 
  south 
  of 
  Rosen- 
  

   dale 
  it 
  thickens 
  rapidly 
  from 
  east 
  to 
  west 
  to 
  about 
  forty-five 
  feet, 
  

   and 
  to 
  100 
  feet 
  in 
  the 
  ridges 
  which 
  rise 
  to 
  the 
  southwest. 
  

   About 
  Lake 
  Mohonk 
  fully 
  160 
  feet 
  are 
  exposed 
  and 
  at 
  the 
  falls 
  

   of 
  the 
  Peterkill 
  there 
  are 
  210 
  feet 
  in 
  all, 
  but 
  these 
  are 
  localities 
  

   at 
  which 
  the 
  upper 
  part 
  of 
  the 
  formation 
  has 
  been 
  removed 
  by 
  

   erosion. 
  The 
  thickness 
  of 
  the 
  formation 
  in 
  the 
  wider 
  part 
  of 
  the 
  

   mountain 
  is 
  about 
  200 
  feet, 
  for 
  on 
  Sam's 
  Point 
  and 
  Millbrook 
  moun- 
  

   tain 
  the 
  precipices 
  expose 
  fully 
  this 
  amount. 
  Along 
  the 
  western 
  

   slope 
  near 
  Ellenville 
  200 
  feet 
  seems 
  to 
  be 
  a 
  fair 
  estimate; 
  and 
  the 
  

   entire 
  thickness 
  is 
  here 
  exposed, 
  but 
  I 
  made 
  no 
  precise 
  measure- 
  

   ments. 
  

  

  In 
  greater 
  part 
  the 
  rock 
  consists 
  of 
  white 
  quartz 
  pebbles 
  of 
  

   small 
  or 
  moderate 
  size 
  in 
  a 
  matrix 
  of 
  sand 
  and 
  silicious 
  cement. 
  

   Locally 
  there 
  are 
  beds 
  of 
  coarse 
  quartzite 
  or 
  quartzitic 
  sandstones, 
  

   but 
  the 
  conglomerate 
  is 
  the 
  predominant 
  rock. 
  The 
  color 
  is 
  

   white, 
  with 
  local 
  exceptions 
  of 
  gray, 
  blue 
  or 
  buff, 
  the 
  latter 
  due 
  

   mainly 
  to 
  staining 
  from 
  pyrites 
  which 
  is 
  frequently 
  dissemi- 
  

   nated 
  in 
  the 
  rocks. 
  The 
  bedding 
  is 
  predominantly 
  massive, 
  aver- 
  

   aging 
  three 
  to 
  four 
  feet, 
  but 
  thinner 
  bedding 
  is 
  sometimes 
  seen 
  

   particularly 
  in 
  the 
  finer-grained 
  materials. 
  The 
  most 
  conspicu- 
  

   ous 
  exposure 
  of 
  thinner 
  bedding 
  is 
  at 
  Awosting 
  or 
  Peterkill 
  falls 
  

   as 
  shown 
  in 
  an 
  accompanying 
  plate. 
  

  

  The 
  unconformity. 
  — 
  Throughout 
  Ulster 
  county 
  there 
  is 
  uncon- 
  

   formity 
  between 
  the 
  upper 
  and 
  lower 
  Silurian 
  sediments, 
  but 
  

   its 
  amount 
  varies 
  considerably. 
  In 
  the 
  northeastern 
  townships 
  

   the 
  attenuated 
  eastern 
  representative 
  of 
  the 
  Magara 
  limestone 
  

   lies 
  unconformably 
  on 
  the 
  Hudson 
  river 
  shales 
  and 
  the 
  Clinton, 
  

   Medina 
  and 
  Oneida 
  deposits 
  are 
  absent. 
  South 
  from 
  Rondout 
  

   the 
  supposed 
  representatives 
  of 
  the 
  Clinton, 
  Medina 
  and 
  Oneida 
  

   formations 
  come 
  in, 
  in 
  succession, 
  and 
  the 
  Niagara 
  limestone 
  is 
  

   lacking. 
  In 
  the 
  southern 
  part 
  of 
  the 
  county, 
  where 
  the 
  Shawan- 
  

  

  