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  88 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Fig. 
  29 
  A 
  horst 
  (after 
  Haug) 
  

  

  two 
  systems 
  of 
  parallel 
  faults 
  that 
  both 
  hade 
  in 
  the 
  same 
  direction 
  

   (southeast). 
  It 
  might 
  therefore 
  be 
  considered 
  to 
  be 
  more 
  of 
  the 
  

   character 
  of 
  an 
  overthrust 
  wedge 
  [see 
  below] 
  than 
  of 
  the 
  

   horst, 
  in 
  which, 
  when 
  typically 
  developed, 
  the 
  faults 
  incline 
  away 
  

   from 
  each 
  other. 
  It 
  is, 
  however, 
  apparent 
  that 
  in 
  the 
  general 
  

   sense 
  of 
  a 
  horst, 
  as 
  now 
  understood 
  in 
  Europe, 
  as 
  a 
  fault 
  block, 
  

   that 
  is 
  on 
  the 
  upthrow 
  side 
  with 
  reference 
  to 
  all 
  the 
  area 
  around 
  

   it 
  [see 
  text 
  fig. 
  29], 
  the 
  Highlands 
  fulfill 
  all 
  conditions 
  of 
  this 
  type 
  

   of 
  structure. 
  

  

  c 
  Branching 
  fault 
  inliers. 
  A 
  

   small 
  division 
  of 
  raised 
  blocks, 
  

   appearing 
  as 
  inliers 
  is 
  formed 
  by 
  

   branching 
  faults, 
  where 
  a 
  triangu- 
  

   lar 
  block 
  remains 
  standing 
  between 
  

   tiie 
  branches. 
  The 
  Mohawk 
  val- 
  

   ley 
  furnishes 
  again 
  a 
  few 
  good 
  

   examples 
  of 
  this 
  group 
  [see 
  text 
  

   fig. 
  25] 
  of 
  inliers, 
  that 
  are 
  mostly 
  recognized 
  by 
  their 
  sub- 
  

   triangular 
  outline. 
  Below 
  St 
  Johnsville 
  we 
  find 
  a 
  triangular 
  out- 
  

   lier 
  of 
  Beekmantovvm 
  with 
  a 
  surrounding 
  band 
  of 
  Trenton 
  emerg- 
  

   ing 
  from 
  the 
  Utica 
  shale, 
  and 
  the 
  Noses 
  fault 
  (below 
  Sprakers) 
  

   with 
  its 
  branch, 
  the 
  Ephratah 
  branch 
  fault, 
  forms 
  another 
  triang- 
  

   ular 
  Beekmantown 
  inlier. 
  

  

  d 
  Wedge 
  inliers. 
  As 
  wedge 
  inliers 
  or 
  " 
  wedges 
  " 
  we 
  designate 
  

   here 
  infiers 
  that 
  are 
  found 
  between 
  two 
  overthrusts. 
  There 
  is 
  no 
  

   doubt 
  that 
  many 
  such 
  wedges 
  exist 
  in 
  our 
  eastern, 
  much 
  over- 
  

   thrust 
  slate 
  belt, 
  but 
  the 
  close 
  isoclinal 
  folding 
  of 
  the 
  belt 
  ob- 
  

   scures 
  the 
  faulted 
  structure 
  there 
  to- 
  such 
  an 
  extent, 
  that 
  it 
  is 
  

   preferable 
  to 
  select 
  typical 
  examples 
  from 
  less 
  disturbed 
  areas. 
  

   The 
  Appalachians 
  furnish 
  many 
  clear 
  cases 
  of 
  this 
  structure, 
  of 
  

   which 
  we 
  select, 
  on 
  account 
  of 
  the 
  great 
  difference 
  in 
  age 
  of 
  the 
  

   adjoining 
  rocks, 
  one 
  from 
  the 
  Briceville 
  folio, 
  Tenn. 
  [Geol. 
  Atlas 
  

   of 
  the 
  United 
  States, 
  1896]. 
  It 
  will 
  be 
  seen 
  in 
  the 
  section 
  [see 
  

   text 
  fig. 
  30] 
  that 
  five 
  overthrust 
  faults 
  are 
  there 
  recognizable 
  be- 
  

   tween 
  them 
  containing 
  three 
  wedges 
  of 
  Siluric 
  rocks, 
  which 
  on 
  the 
  

   surface 
  form 
  narrow, 
  bandlike 
  inliers 
  in 
  Carboniferous 
  rocks, 
  

   sometimes 
  flanked 
  by 
  a 
  narrow 
  strip 
  of 
  Devonic 
  rocks. 
  

  

  e 
  Overthrust 
  inliers. 
  We 
  designate 
  as 
  overthrust 
  inliers 
  those 
  

   v^hich 
  result 
  from 
  the 
  extensive 
  transportation 
  of 
  older 
  rocks 
  over 
  

   younger 
  oeies 
  along 
  more 
  or 
  less 
  horizontal 
  thrust 
  planes, 
  resulting 
  

   from 
  overturned 
  anticlines 
  (" 
  fold 
  thrusts 
  " 
  of 
  Willis) 
  and 
  from 
  

  

  