﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  III 
  

  

  along 
  the 
  western 
  edge 
  of 
  the 
  Greenwich 
  plateau. 
  This 
  limestone, 
  

   which, 
  on 
  account 
  of 
  its 
  Beekmantown 
  age, 
  now 
  recognized, 
  is 
  to 
  

   be 
  considered 
  as 
  underlying 
  the 
  Snake 
  Hill 
  shale, 
  just 
  below 
  it, 
  

   may 
  indicate 
  an 
  inverted 
  order 
  below 
  the 
  Georgian, 
  although 
  there 
  

   is 
  a 
  stronger 
  probability 
  that 
  its 
  presence 
  is 
  due 
  to 
  its 
  having 
  been 
  

   brought 
  along 
  with 
  the 
  Georgian 
  along 
  the 
  trust 
  plane. 
  

  

  Our 
  observations 
  along 
  the 
  west 
  edge 
  of 
  the 
  Cambric 
  area, 
  not 
  

   only 
  on 
  the 
  Schuylerville 
  quadrangle 
  but 
  also 
  northward 
  and 
  south 
  

   of 
  it 
  in 
  Rensselaer 
  and 
  Columbia 
  counties, 
  have 
  led 
  us 
  to 
  the 
  

   conclusion 
  that 
  we 
  have 
  there 
  precisely 
  that 
  case 
  which 
  Dale 
  con- 
  

   sidered 
  as 
  not 
  an 
  ordinary 
  probability, 
  and 
  therefore 
  would 
  ex- 
  

   clude 
  from 
  his 
  working 
  hypotheses, 
  namely, 
  a 
  folded 
  thrust 
  plane, 
  

   along 
  which 
  the 
  Georgian 
  rocks 
  have 
  everywhere 
  been 
  overthrust 
  

   over 
  the 
  Ordovicic 
  rocks. 
  This 
  condition 
  is, 
  in 
  our 
  opinion, 
  a 
  

   structural 
  feature 
  of 
  the 
  first 
  magnitude 
  of 
  the 
  entire 
  plateau. 
  

   Likewise 
  the 
  underlying 
  Ordovicic 
  is 
  not 
  only 
  compressed 
  into 
  

   small 
  folds 
  from 
  the 
  east, 
  but 
  also 
  more 
  or 
  less 
  bodily 
  overthrust 
  

   over 
  the 
  series 
  of 
  rocks 
  of 
  the 
  Western 
  basin. 
  The 
  same 
  intense 
  

   pressure 
  which 
  only 
  a 
  few 
  miles 
  farther 
  east 
  caused 
  the 
  regional 
  

   metamorphism 
  of 
  all 
  these 
  shales, 
  has 
  to 
  be 
  considered 
  as 
  com- 
  

   petent 
  to 
  produce 
  the 
  folding 
  and 
  the 
  extensive 
  overthrust 
  faulting. 
  

  

  The 
  facts 
  which 
  induce 
  us 
  to 
  consider 
  the 
  entire 
  western 
  part 
  of 
  

   the 
  Cambric 
  area 
  at 
  least 
  as 
  overthrust 
  on 
  the 
  Ordovicic 
  rocks, 
  are 
  

   of 
  both 
  structural 
  and 
  topographic 
  nature. 
  The 
  strike 
  of 
  the 
  

   Ordovicic 
  rocks 
  in 
  the 
  Saratoga 
  plain 
  leads 
  these 
  rocks 
  directly 
  

   under 
  the 
  Cambric 
  rocks 
  of 
  the 
  Greenwich 
  plateau, 
  as 
  a 
  glance 
  on 
  

   the 
  Schuylerville 
  map 
  will 
  show. 
  While 
  from 
  the 
  northeast 
  corner 
  

   to 
  the 
  foot 
  of 
  Louse 
  hill 
  the 
  Snake 
  Hill 
  beds 
  pass 
  under 
  the 
  

   Georgian 
  rocks, 
  in 
  the 
  southeast 
  corner 
  of 
  the 
  quadrangle, 
  north 
  

   and 
  east 
  of 
  Willard 
  mountain, 
  the 
  Normanskill 
  rocks 
  disappear 
  

   under 
  the 
  Georgian 
  rocks. 
  In 
  several 
  localities 
  where 
  rivers 
  have 
  

   breached 
  the 
  margin 
  of 
  the 
  Cambric 
  Greenwich 
  plateau, 
  the 
  Ordo- 
  

   vicic 
  rocks 
  can 
  be 
  traced 
  upward 
  along 
  the 
  river, 
  forming 
  reentrant 
  

   angles 
  in 
  the 
  outline 
  of 
  the 
  Cambric. 
  Such 
  a 
  large 
  reentrant 
  or 
  

   embayment 
  is 
  formed 
  by 
  Moses 
  kill 
  and 
  another 
  broader 
  one 
  by 
  

   the 
  Batten 
  kill. 
  

  

  Very 
  instructive 
  are 
  the 
  cases 
  of 
  the 
  Hoosic 
  river 
  and 
  Deep 
  kill. 
  

   At 
  Schaghticoke 
  the 
  Schaghticoke 
  shale 
  (of 
  lowest 
  Ordovicic 
  age) 
  

   is 
  exposed 
  in 
  the 
  bottom 
  of 
  the 
  river, 
  while 
  the 
  hills 
  to 
  the 
  north 
  

   and 
  south 
  of 
  the 
  gorge, 
  in 
  the 
  general 
  strike 
  direction 
  of 
  the 
  rocks, 
  

  

  