﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  59 
  

  

  These 
  are 
  on 
  the 
  same 
  line 
  with 
  one 
  another 
  and 
  also 
  about 
  on 
  line 
  

   with 
  the 
  prolongation 
  of 
  the 
  West 
  Galway 
  fault. 
  The 
  throw 
  also 
  

   is 
  much 
  the 
  same 
  so 
  far 
  as 
  can 
  be 
  judged, 
  but 
  the 
  direct 
  evidence 
  is 
  

   meager. 
  

  

  East 
  Galway 
  fault. 
  The 
  evidence 
  for 
  the 
  extension 
  of 
  this 
  fault 
  

   as 
  far 
  as 
  Middlegrove 
  is 
  fairly 
  satisfactory. 
  At 
  first 
  it 
  shows 
  Cana- 
  

   joharie 
  shales 
  on 
  the 
  downthrow 
  side. 
  Back 
  from 
  Rock 
  City 
  Falls 
  

   the 
  Amsterdam 
  and 
  the 
  Little 
  Falls 
  come 
  in. 
  On 
  the 
  upthrow 
  side 
  

   the 
  horizon 
  varies 
  but 
  little, 
  the 
  surface 
  of 
  the 
  slice 
  lying 
  very 
  flat. 
  

   Beyond 
  Middlegrove 
  it 
  runs 
  into 
  the 
  heavy 
  drift, 
  but 
  its 
  trend 
  would 
  

   be 
  with 
  the 
  axis 
  of 
  the 
  preglacial 
  valley 
  for 
  the 
  next 
  few 
  miles. 
  

   Farther 
  north 
  its 
  occurrence 
  is 
  problematical, 
  but 
  the 
  presence 
  of 
  a 
  

   fault 
  is 
  needed 
  to 
  explain 
  the 
  occurrence 
  of 
  the 
  Potsdam 
  and 
  Theresa 
  

   formations 
  at 
  and 
  south 
  of 
  Corinth, 
  which 
  are 
  wholly 
  out 
  of 
  adjust- 
  

   ment 
  with 
  the 
  same 
  formations 
  in 
  the 
  eastern 
  part 
  of 
  Greenfield 
  

   township. 
  We 
  think 
  a 
  fault 
  must 
  lie 
  here, 
  and 
  it 
  seems 
  more 
  reason- 
  

   able 
  to 
  connect 
  it 
  with 
  the 
  East 
  Galway 
  fault 
  than 
  to 
  assume 
  a 
  

   wholly 
  separate 
  break. 
  The 
  chief 
  objection 
  to 
  this 
  view 
  is 
  that 
  the 
  

   fault 
  south 
  of 
  Corinth 
  downthrows 
  to 
  the 
  west, 
  while 
  at 
  East 
  Galway 
  

   the 
  downthrow 
  is 
  to 
  the 
  east. 
  This 
  may 
  be 
  explained, 
  however, 
  by 
  

   the 
  fact 
  that 
  the 
  slice 
  of 
  territory 
  to 
  the 
  west 
  of 
  the 
  fault 
  lies 
  very 
  

   flat, 
  while 
  to 
  the 
  east 
  of 
  the 
  fault 
  the 
  rocks 
  are 
  more 
  tipped, 
  having 
  

   a 
  very 
  noticeable 
  southwest 
  dip. 
  Because 
  of 
  this 
  the 
  throw 
  steadily 
  

   diminishes 
  in 
  passing 
  north 
  as 
  far 
  as 
  a 
  point 
  southeast 
  of 
  Porter 
  

   Corners, 
  where 
  the 
  Theresa 
  formation 
  is 
  present 
  on 
  both 
  sides 
  of 
  

   the 
  fault 
  and 
  the 
  throw 
  has 
  become 
  zero. 
  To 
  the 
  northward 
  the 
  

   throw 
  reverses 
  and 
  the 
  older 
  rocks 
  are 
  present 
  on 
  the 
  east 
  side 
  of 
  

   the 
  fault 
  instead 
  of 
  on 
  the 
  west. 
  Faults 
  of 
  this 
  type, 
  called 
  

   " 
  rotatory 
  " 
  faults, 
  are 
  not 
  very 
  common, 
  which 
  is 
  the 
  cause 
  for 
  

   greater 
  regret, 
  as 
  the 
  heavy 
  drift-covering 
  makes 
  the 
  whole 
  matter 
  

   so 
  uncertain. 
  

  

  Rock 
  City 
  Falls 
  fault. 
  The 
  small 
  fault 
  at 
  Rock 
  City 
  Falls 
  has 
  

   been 
  described 
  by 
  both 
  Darton 
  and 
  Prosser. 
  It 
  is 
  well 
  exposed 
  in 
  

   the 
  creek, 
  the 
  fall 
  itself 
  being 
  practically 
  on 
  the 
  fault 
  line, 
  15 
  feet 
  

   of 
  Little 
  Falls 
  dolomite 
  underlying 
  the 
  Amsterdam 
  on 
  the 
  west 
  or 
  

   upthrow 
  side, 
  while 
  the 
  base 
  of 
  the 
  Amsterdam 
  is 
  below 
  the 
  creek 
  

   level 
  on 
  the 
  downthrow 
  side. 
  To 
  the 
  south 
  of 
  the 
  creek 
  also 
  recent 
  

   quarrying 
  of 
  the 
  Amsterdam 
  has 
  exposed 
  the 
  fault 
  line 
  excellently 
  

   for 
  a 
  short 
  distance, 
  though 
  with 
  Amsterdam 
  limestone 
  on 
  both 
  

   sides, 
  a 
  little 
  fault 
  breccia, 
  and 
  with 
  much 
  updrag 
  of 
  the 
  rock 
  on 
  

   the 
  downthrow 
  side. 
  The 
  throw 
  of 
  the 
  fault 
  is 
  only 
  25 
  to 
  30 
  feet. 
  

  

  