﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  85 
  

  

  The 
  white 
  weathering 
  cherty 
  beds. 
  Associated 
  with 
  the 
  black 
  

   shales 
  of 
  the 
  Normanskill 
  formation 
  occurs 
  a 
  series 
  of 
  very 
  hard, 
  

   splintery, 
  dark 
  to 
  light 
  greenish 
  or 
  black, 
  cherty-looking 
  beds 
  

   which 
  weather 
  with 
  very 
  light 
  gray 
  or 
  white 
  crust. 
  These 
  siliceous 
  

   beds 
  frequently 
  through 
  their 
  greater 
  hardness, 
  stand 
  out 
  as 
  white 
  

   ridges 
  and 
  form 
  characteristic 
  landmarks. 
  According 
  to 
  Dale 
  

   (o/*. 
  cit.j 
  page 
  186) 
  the 
  white 
  surface 
  gives 
  the 
  reaction 
  for 
  

   kaolinite 
  1 
  and 
  the 
  rock 
  was 
  probably 
  originally 
  a 
  feldspathic 
  mud, 
  

   with 
  quartz 
  fragments 
  and 
  muscovite 
  scales 
  ; 
  the 
  latter 
  two 
  appear- 
  

   ing 
  under 
  the 
  microscope 
  as 
  the 
  principal 
  constituents 
  of 
  the 
  

   cherty 
  beds. 
  

  

  The 
  finding 
  of 
  Normanskill 
  graptolites 
  in 
  the 
  white 
  beds 
  at 
  

   several 
  places 
  on 
  the 
  Schuylerville 
  sheet, 
  notably 
  in 
  a 
  small 
  creek 
  

   just 
  above 
  Coveville 
  and 
  northeast 
  of 
  Willard 
  mountain, 
  leave 
  no 
  

   doubt 
  of 
  the 
  Normanskill 
  age 
  of 
  the 
  principal 
  mass 
  of 
  the 
  cherty 
  

   beds. 
  There 
  is, 
  however, 
  no 
  doubt 
  that 
  similar 
  cherty 
  layers 
  

   occur 
  also, 
  though 
  rarely, 
  in 
  the 
  Snake 
  Hill 
  formation 
  and 
  that 
  

   all 
  transitions 
  occur 
  from 
  the 
  common 
  argillaceous 
  shales 
  through 
  

   slightly 
  more 
  siliceous 
  and 
  whitish 
  weathering 
  shales 
  to 
  the 
  thick- 
  

   bedded, 
  white-weathering 
  cherty 
  layers. 
  

  

  On 
  account 
  of 
  their 
  great 
  hardness 
  the 
  white 
  beds 
  most 
  fre- 
  

   quently 
  form 
  the 
  tops 
  of 
  ridges 
  and 
  can 
  often 
  be 
  traced 
  for 
  some 
  

   distance 
  along 
  the 
  strike 
  of 
  the 
  folded 
  beds. 
  The 
  more 
  important 
  

   outcrops 
  of 
  white 
  beds 
  have 
  been 
  indicated 
  on 
  the 
  map 
  by 
  the 
  

   blue 
  symbols. 
  These 
  show 
  that 
  the 
  principal 
  areas 
  of 
  chert 
  out- 
  

   crops 
  are 
  the 
  region 
  extending 
  from 
  Coveville 
  northward 
  to 
  Thom- 
  

   son 
  and 
  Northumberland 
  and 
  that 
  of 
  the 
  Willard 
  mountain 
  ridge 
  

   in 
  the 
  southeast 
  corner 
  of 
  the 
  quadrangle. 
  In 
  the 
  former 
  the 
  

   most 
  striking 
  chert 
  ridge 
  is 
  seen 
  iy 
  2 
  miles 
  west 
  of 
  Victory 
  Mills. 
  

   This 
  forms 
  cliffs 
  seen 
  from 
  the 
  Schuylerville 
  branch 
  of 
  the 
  Fitch- 
  

   burg 
  Railroad, 
  in 
  which 
  are 
  solid 
  beds 
  of 
  the 
  cherty 
  or 
  siliceous 
  

   rock 
  30 
  feet 
  and 
  more 
  thick. 
  Other 
  smaller 
  ridges 
  of 
  white 
  beds 
  

   protrude 
  through 
  the 
  drift 
  one-half 
  of 
  a 
  mile 
  west 
  of 
  Victory 
  Mills 
  

   and 
  on 
  the 
  water-swept 
  plateau 
  north 
  of 
  Coveville. 
  Also 
  south 
  and 
  

   north 
  of 
  the 
  Northumberland 
  plug 
  appear 
  ledges 
  of 
  the 
  harder 
  

   cherty 
  beds 
  on 
  the 
  hillsides 
  and 
  a 
  small 
  outcrop 
  of 
  very 
  thick- 
  

   bedded, 
  deep 
  black 
  chert 
  was 
  found 
  just 
  west 
  of 
  the 
  entrance 
  of 
  

   the 
  Hudson 
  river 
  bridge 
  at 
  Thomson. 
  

  

  1 
  According 
  to 
  a 
  later 
  statement 
  by 
  the 
  same 
  author 
  (1904, 
  p. 
  36) 
  the 
  

   weathering 
  white 
  of 
  the 
  chert 
  may 
  be 
  due 
  either 
  to 
  the 
  loss 
  of 
  carbon 
  or 
  to 
  

   the 
  kaolinization 
  of 
  a 
  fine 
  feldspathic 
  cement. 
  

  

  