﻿140 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  is, 
  however, 
  also 
  possible 
  that 
  a 
  thin 
  edge 
  of 
  the 
  Utica 
  formation 
  

   reached 
  here 
  around 
  the 
  southern 
  Adirondacks, 
  but 
  was 
  again 
  

   eroded 
  before 
  the 
  Indian 
  Ladder 
  sea 
  crept 
  over 
  this 
  region 
  from 
  

   the 
  south. 
  This 
  latter 
  formation 
  consists, 
  at 
  the 
  Indian 
  Ladder, 
  

   mainly 
  of 
  soft 
  shales 
  with 
  some 
  sandstone 
  and 
  calcareous 
  bands, 
  

   and 
  seems 
  to 
  have 
  been 
  deposited 
  in 
  a 
  slightly 
  deeper 
  sea 
  than 
  

   the 
  Schenectady 
  beds. 
  

  

  As 
  we 
  have 
  seen 
  before, 
  there 
  are 
  exposed 
  in 
  the 
  shale 
  belt 
  rocks 
  

   of 
  two 
  entirely 
  different 
  sets 
  of 
  formations 
  which 
  represent 
  sedi- 
  

  

  Fig. 
  15 
  Diagram 
  of 
  time 
  relations 
  of 
  formations 
  of 
  the 
  eastern 
  and 
  west- 
  

   ern 
  troughs 
  on 
  the 
  Saratoga-Schuylerville 
  quadrangles. 
  Shaded 
  intervals 
  

   indicate 
  probable 
  emergences 
  

  

  ments 
  deposited 
  in 
  two 
  different 
  troughs, 
  the 
  western 
  or 
  lower 
  

   Mohawk 
  trough 
  and 
  the 
  eastern 
  or 
  Levis 
  trough; 
  and 
  if 
  the 
  

   Georgian 
  beds 
  represent 
  a 
  third 
  trough 
  (see 
  above, 
  page 
  114), 
  even 
  

   sediments 
  of 
  three 
  basins. 
  

  

  