﻿144 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  large 
  thickness 
  of 
  continental 
  deposits. 
  There 
  is 
  no 
  vestige 
  of 
  

   such 
  deposits 
  in 
  the 
  lower 
  Mohawk 
  trough, 
  and 
  no 
  direct 
  evidence 
  

   that 
  they 
  were 
  ever 
  deposited 
  there. 
  That 
  a 
  small 
  thickness 
  of 
  such 
  

   material 
  may 
  have 
  been 
  laid 
  down 
  in 
  the 
  trough 
  at 
  this 
  date 
  is 
  

   by 
  no 
  means 
  unlikely. 
  The 
  lower 
  Mohawk 
  trough, 
  throughout 
  its 
  

   history, 
  has 
  had 
  a 
  tendency 
  to 
  sag, 
  as 
  contrasted 
  with 
  the 
  territory 
  

   east 
  and 
  west 
  of 
  it. 
  It 
  would 
  not 
  be 
  forced 
  or 
  unnatural 
  to 
  

   assume 
  that 
  it 
  participated 
  somewhat 
  in 
  the 
  sagging 
  tendency 
  which 
  

   was 
  so 
  prominently 
  manifest 
  in 
  some 
  neighboring 
  troughs 
  to 
  the 
  

   east 
  and 
  south 
  at 
  this 
  time. 
  But 
  if 
  such 
  deposits 
  were 
  formed 
  

   here 
  they 
  were 
  in 
  such 
  slight 
  thickness 
  that 
  every 
  vestige 
  of 
  them 
  

   has 
  since 
  been 
  removed 
  by 
  erosion. 
  

  

  When 
  were 
  the 
  great 
  faults 
  of 
  the 
  eastern 
  Adirondack 
  region 
  

   formed? 
  And 
  was 
  the 
  faulting 
  wholly 
  done 
  during 
  one 
  single 
  

   period 
  of 
  disturbance, 
  or 
  has 
  repeated 
  dislocation 
  occurred 
  along 
  

   them 
  since 
  they 
  were 
  first 
  formed? 
  

  

  The 
  repeated 
  sags 
  of 
  the 
  western 
  trough 
  would 
  tend, 
  to 
  form 
  

   fault 
  breaks 
  along 
  its 
  margins, 
  separating 
  it 
  from 
  the 
  adjacent 
  dis- 
  

   tricts, 
  the 
  Adirondack 
  region 
  on 
  the 
  west 
  for 
  example, 
  whose 
  

   tendency 
  has 
  been 
  to 
  rise 
  rather 
  than 
  to 
  sag. 
  It 
  is 
  therefore 
  quite 
  

   possible 
  that 
  faulting 
  began 
  in 
  the 
  district 
  early 
  in 
  the 
  Paleozoic. 
  

   With 
  every 
  notable 
  succeeding 
  oscillation 
  of 
  level 
  of 
  the 
  region 
  

   it 
  is 
  highly 
  probable 
  that 
  renewed 
  faulting 
  would 
  take 
  place 
  along 
  

   the 
  breaks 
  already 
  in 
  existence. 
  Such 
  an 
  oscillation 
  as 
  that 
  which 
  

   brought 
  the 
  Paleozoic 
  to 
  a 
  close 
  would 
  be 
  sure 
  to 
  be 
  accompanied 
  

   by 
  renewed 
  movement 
  along 
  the 
  fault 
  planes. 
  

  

  The 
  early 
  Mesozoic 
  rocks 
  of 
  the 
  easterly 
  Appalachian 
  troughs 
  

   have 
  been 
  greatly 
  faulted 
  since 
  they 
  were 
  laid 
  down. 
  Obviously 
  

   this 
  faulting 
  must 
  be 
  of 
  later 
  date 
  than 
  the 
  deposition 
  of 
  the 
  rocks. 
  

   Most 
  probably 
  also 
  this 
  faulting 
  was 
  not 
  confined 
  to 
  the 
  mere 
  

   troughs 
  of 
  deposit, 
  but 
  affected 
  the 
  adjacent 
  territory 
  also. 
  It 
  

   seems 
  in 
  the 
  highest 
  degree 
  likely 
  that 
  further 
  faulting 
  occurred 
  

   in 
  the 
  Champlain 
  region 
  at 
  this 
  time. 
  The 
  faults 
  of 
  the 
  eastern 
  

   Adirondack 
  region 
  are 
  normal 
  with 
  nearly 
  vertical 
  fault 
  planes, 
  

   and 
  these 
  certain 
  Mesozoic 
  faults 
  are 
  of 
  similar 
  type. 
  

  

  On 
  the 
  other 
  hand, 
  the 
  great 
  overthrusts 
  which 
  have 
  carried 
  the 
  

   rocks 
  of 
  the 
  eastern 
  basin 
  west 
  to 
  their 
  present 
  position, 
  covering 
  

   much 
  of 
  the 
  Schuylerville 
  quadrangle, 
  are 
  faults 
  of 
  an 
  entirely 
  

   different 
  type. 
  The 
  question 
  arises 
  as 
  to 
  the 
  relative 
  age 
  of 
  the 
  

   two 
  types 
  of 
  faulting. 
  If 
  the 
  thrust 
  faulting 
  occurred 
  before 
  the 
  

   normal 
  faulting 
  it 
  would 
  seem 
  that 
  the 
  thrust-faulted 
  territory 
  

  

  