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  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  of 
  upper 
  Beekmantown 
  age 
  were 
  deposited 
  in 
  Beekmantown 
  time; 
  

   and 
  after 
  a 
  brief 
  emergence, 
  the 
  Normanskill 
  shale 
  of 
  Chazy 
  age, 
  

   which 
  in 
  its 
  turn 
  was 
  followed 
  after 
  another 
  short 
  emergence 
  by 
  

   the 
  sea 
  depositing 
  the 
  Upper 
  Normanskill 
  shale 
  with 
  the 
  Rysedorph 
  

   Hill 
  conglomerate 
  and 
  the 
  Snake 
  Hill 
  shale. 
  It 
  appears 
  that 
  this 
  

   whole 
  group 
  of 
  Ordovicic 
  seas 
  of 
  the 
  Levis 
  trough 
  invaded 
  from 
  

   the 
  north. 
  The 
  north 
  connection 
  is 
  shown 
  by 
  the 
  faunas 
  and 
  areal 
  

   distribution 
  of 
  the 
  Schaghticoke, 
  Deep 
  Kill 
  and 
  Normanskill 
  shales, 
  

   by 
  the 
  Atlantic 
  faunas 
  of 
  the 
  Rysedorph 
  Hill 
  conglomerate, 
  and 
  it 
  

   is 
  suggested 
  by 
  the 
  fauna 
  of 
  the 
  Snake 
  Hill 
  shale. 
  Some 
  of 
  these, 
  

   as 
  the 
  Deep 
  Kill 
  and 
  Normanskill 
  seas, 
  had 
  also 
  connection 
  with 
  

   the 
  Pacific 
  ocean. 
  

  

  LATER 
  PALEOZOIC 
  HISTORY 
  

  

  Withdrawal 
  of 
  marine- 
  waters 
  from 
  the 
  Saratoga 
  region 
  followed 
  

   the 
  deposit 
  of 
  the 
  Indian 
  Ladder 
  shales 
  and 
  for 
  the 
  latter 
  part 
  of 
  

   the 
  Ordovicic 
  period 
  the 
  region 
  was 
  above 
  water. 
  Then 
  followed 
  

   a 
  time 
  of 
  considerable 
  disturbance 
  and 
  uplift, 
  the 
  so-called 
  Taconic 
  

   revolution. 
  Along 
  a 
  belt 
  of 
  country 
  east 
  of 
  Saratoga 
  the 
  Ordovicic 
  

   rocks 
  were 
  folded 
  and 
  upturned. 
  About 
  Saratoga 
  this 
  disturbance 
  

   had 
  no 
  effect 
  beyond 
  giving 
  the 
  region 
  somewhat 
  increased 
  alti- 
  

   tude. 
  During 
  the 
  following 
  Paleozoic 
  periods, 
  Siluric, 
  Devonic 
  

   etc., 
  the 
  region 
  continued 
  its 
  oscillations 
  of 
  level, 
  but 
  the 
  times 
  of 
  

   depression 
  did 
  not 
  carry 
  the 
  bottoms 
  of 
  the 
  troughs 
  below 
  sea 
  

   level. 
  Paleozoic 
  rocks 
  younger 
  than 
  the 
  Ordovicic, 
  and 
  all 
  Meso- 
  

   zoic 
  rocks, 
  are 
  absent 
  from 
  the 
  western 
  trough. 
  It 
  remained 
  a 
  

   trough 
  during 
  all 
  this 
  great 
  lapse 
  of 
  time, 
  but 
  it 
  remained 
  above 
  

   the 
  level 
  of 
  the 
  sea, 
  even 
  when 
  its 
  altitude 
  was 
  the 
  lowest. 
  Siluric 
  

   and 
  Devonic 
  seas 
  came 
  into 
  southern 
  New 
  York, 
  but 
  probably 
  the 
  

   waters 
  of 
  none 
  of 
  them 
  covered 
  Saratoga. 
  

  

  Apparently, 
  however, 
  the 
  district 
  remained 
  at 
  low 
  altitude 
  dur- 
  

   ing 
  all 
  this 
  time. 
  No 
  great 
  thickness 
  of 
  Ordovicic 
  rocks 
  has 
  been 
  

   eroded 
  from 
  its 
  surface. 
  These 
  shales 
  of 
  the 
  upper 
  Ordovicic 
  are 
  

   weak 
  rocks 
  and 
  would 
  be 
  readily 
  worn 
  away 
  under 
  conditions 
  of 
  

   high 
  altitude 
  and 
  free 
  drainage. 
  That 
  they 
  remain 
  in 
  such 
  thick- 
  

   ness 
  as 
  they 
  have 
  over 
  so 
  much 
  of 
  the 
  district 
  is 
  demonstrative 
  of 
  

   small 
  erosion 
  since 
  they 
  were 
  laid 
  down. 
  

  

  It 
  is 
  quite 
  probable 
  that 
  during 
  oscillations 
  which 
  depressed 
  the 
  

   western 
  trough, 
  continental 
  deposits 
  accumulated 
  in 
  it 
  and 
  were 
  

   subsequently 
  worn 
  away 
  during 
  the 
  intervening 
  periods 
  of 
  greater 
  

   altitude, 
  It 
  is 
  also 
  possible 
  that 
  the 
  overthrust 
  shales 
  of 
  the 
  more 
  

  

  