﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  

  

  3j 
  

  

  the 
  next 
  50 
  feet 
  sandstone 
  and 
  calcareous 
  sandstone 
  alternate, 
  with 
  

   an 
  occasional 
  bed 
  of 
  blue, 
  sandy 
  dolomite 
  in 
  addition. 
  The 
  upper 
  

   100 
  feet 
  consists 
  of 
  alternations 
  of 
  all 
  three. 
  This 
  we 
  definitely 
  

   assign 
  to 
  the 
  Theresa 
  formation. 
  The 
  lower 
  100 
  feet 
  we 
  assign 
  

   to 
  the 
  Potsdam, 
  notwithstanding 
  the 
  presence 
  of 
  an 
  occasional 
  

   dolomite 
  bed. 
  There 
  is 
  never 
  any 
  sharp 
  boundary 
  between 
  the 
  two 
  

   formations. 
  

  

  THERESA 
  FORMATION 
  

  

  Everywhere 
  in 
  New 
  York 
  where 
  the 
  Potsdam 
  sandstone 
  occurs, 
  

   it 
  is 
  united 
  with 
  the 
  formation 
  next 
  above, 
  usually 
  a 
  dolomite 
  

   formation, 
  by 
  a 
  series 
  of 
  intermediate 
  or 
  passage 
  beds 
  which 
  con- 
  

   sist 
  of 
  alternating 
  sandstone, 
  calcareous 
  sandstone 
  and 
  dolomite. 
  

   These 
  passage 
  beds 
  differ 
  from 
  the 
  sandstone 
  beneath 
  and 
  the 
  

   dolomite 
  above, 
  are 
  sufficiently 
  thick 
  to 
  require 
  mapping 
  as 
  a 
  

   separate 
  formation, 
  as 
  such 
  require 
  a 
  name, 
  and 
  we 
  are 
  calling 
  

   them 
  the 
  Theresa 
  formation. 
  1 
  The 
  sandstone 
  is 
  in 
  excess 
  in 
  the 
  

   lower 
  part 
  of 
  the 
  formation, 
  and 
  the 
  dolomite 
  in 
  the 
  upper. 
  Deposi- 
  

   tion 
  was 
  apparently 
  continuous 
  but 
  physical 
  conditions 
  slowly 
  

   changed, 
  the 
  sand 
  supply 
  from 
  the 
  Adirondack 
  land 
  slowly 
  dimin- 
  

   ishing 
  and 
  finally 
  being 
  entirely 
  cut 
  off. 
  Because 
  of 
  this 
  it 
  is 
  

   impossible 
  sharply 
  to 
  delimit 
  the 
  formation, 
  either 
  at 
  base 
  or 
  sum- 
  

   mit. 
  In 
  what 
  we 
  here 
  class 
  as 
  upper 
  Potsdam 
  there 
  is 
  an 
  occasional 
  

   bed 
  of 
  dolomite, 
  and 
  a 
  few 
  stray 
  beds 
  of 
  sandstone 
  run 
  well 
  up 
  

   into 
  the 
  overlying 
  dolomite 
  formation. 
  Nevertheless 
  there 
  is 
  a 
  

   sufficient 
  thickness 
  of 
  mingled 
  sandstone 
  and 
  dolomite, 
  about 
  which 
  

   there 
  could 
  be 
  no 
  possible 
  difference 
  of 
  opinion, 
  to 
  justify 
  its 
  sepa- 
  

   rateness 
  as 
  a 
  formation. 
  

  

  In 
  the 
  general 
  region 
  the 
  Theresa 
  formation 
  has 
  a 
  thickness 
  of 
  

   from 
  150 
  to 
  200 
  feet. 
  Thus 
  Miller 
  gives 
  its 
  thickness 
  as 
  200 
  feet 
  

   on 
  the 
  Broadalbin 
  quadrangle, 
  while 
  our 
  measured 
  sections 
  at 
  

   Whitehall 
  and 
  at 
  Ticonderoga 
  show 
  a 
  thickness 
  of 
  at 
  least 
  150 
  feet. 
  

   There 
  is 
  at 
  least 
  150 
  feet 
  of 
  it 
  in 
  the 
  section 
  south 
  of 
  East 
  Galway, 
  

   on 
  the 
  Saratoga 
  quadrangle, 
  and 
  the 
  full 
  thickness 
  is 
  not 
  there 
  

   exposed. 
  In 
  all 
  these 
  localities 
  the 
  formation 
  consists 
  of 
  alter- 
  

   nating 
  beds 
  of 
  hard, 
  vitreous 
  sandstone, 
  weak 
  calcareous 
  sandstone 
  

   and 
  sandy 
  blue 
  dolomite, 
  with 
  Lingulella 
  acuminata 
  as 
  

   its 
  most 
  abundant 
  and 
  characteristic 
  fossil. 
  

  

  West 
  and 
  northwest 
  of 
  Saratoga, 
  in 
  Greenfield 
  township, 
  the 
  

   section 
  differs. 
  Instead 
  of 
  a 
  thickness 
  of 
  150 
  to 
  200 
  feet, 
  the 
  

  

  N. 
  Y. 
  State 
  Mus. 
  Bui. 
  145. 
  P- 
  64-66. 
  

  

  