﻿TtfE 
  EPICENTRAL 
  TRACT. 
  &45 
  

  

  been 
  altered, 
  Large 
  areas 
  have 
  been 
  permanently 
  flooded, 
  but 
  the 
  

   boundaries 
  of 
  the 
  flooded 
  areas 
  are 
  irregular 
  and 
  principally 
  deter- 
  

   mined 
  by 
  the 
  original 
  inequalities 
  of 
  the 
  surface 
  of 
  the 
  ground. 
  

  

  Having 
  described 
  the 
  course 
  of 
  this 
  fault 
  in 
  detail 
  there 
  are 
  

   certain 
  aspects 
  of 
  it, 
  as 
  a 
  whole, 
  which 
  require 
  notice. 
  Firstly, 
  

   although 
  the 
  throw 
  of 
  the 
  fault 
  varies 
  from 
  over 
  35 
  feet 
  to 
  nothing, 
  yet, 
  

   wherever 
  there 
  is 
  any 
  perceptible 
  throw, 
  the 
  upthrow 
  is 
  always 
  on 
  

   the 
  east 
  and 
  the 
  downthrow 
  on 
  the 
  west. 
  Secondly, 
  I 
  was 
  unable 
  

   to 
  detect 
  any 
  pronounced 
  horizontal 
  movement 
  of 
  one 
  side 
  with 
  

   reference 
  to 
  the 
  other, 
  in 
  other 
  words, 
  the 
  displacement 
  appears 
  

   to 
  have 
  been 
  simply 
  up 
  or 
  down, 
  so 
  that 
  the 
  fault 
  is 
  a 
  fault 
  pure 
  

   and 
  simple, 
  and 
  not 
  a 
  heave. 
  Thirdly, 
  wherever 
  the 
  plane 
  of 
  the 
  

   f-^ 
  alt 
  could 
  be 
  seen 
  in 
  rock 
  it 
  was 
  practically 
  vertical, 
  with 
  no 
  pro* 
  

   nounced 
  hade 
  in 
  either 
  direction. 
  Fourthly, 
  the 
  displacement 
  appears 
  

   to 
  have 
  been 
  principally, 
  if 
  not 
  entirely, 
  an 
  elevation 
  of 
  the 
  upthrow 
  

   side 
  and 
  not 
  a 
  depression 
  of 
  the 
  downthrow 
  side 
  of 
  the 
  fault. 
  

  

  With 
  reg 
  : 
  d 
  to 
  the 
  last 
  mentioned 
  point 
  it 
  is 
  not 
  possible 
  to 
  

   speak 
  with 
  the 
  same 
  positiveness 
  as 
  on 
  the 
  first 
  three, 
  for 
  the 
  only 
  

   measurements 
  that 
  can 
  be 
  made 
  with 
  certainty 
  are 
  differential 
  ones; 
  

   that 
  is, 
  the 
  present 
  difference 
  of 
  level 
  of 
  two 
  points 
  which 
  were 
  

   formerly 
  on 
  the 
  same 
  level 
  can 
  be 
  measured, 
  but 
  it 
  is 
  not 
  possible 
  to 
  

   determine 
  whether 
  one 
  has 
  gone 
  up 
  or 
  the 
  other 
  down. 
  There 
  are, 
  

   however, 
  some 
  considerations 
  which 
  bear 
  out 
  the 
  conclusion 
  for- 
  

   mulated 
  above. 
  The 
  two 
  large 
  pools, 
  which 
  correspond 
  in 
  position 
  

   to 
  what 
  may 
  be 
  called 
  the 
  nodes 
  of 
  the 
  fault, 
  that 
  is, 
  the 
  places 
  

   where 
  the 
  throw 
  becomes 
  nil, 
  are, 
  as 
  has 
  been 
  explained, 
  due 
  to 
  

   the 
  raising 
  of 
  a 
  barrier 
  across 
  the 
  river 
  channel 
  whereby 
  it 
  was 
  

   given 
  a 
  reverse 
  slope. 
  Now 
  it 
  is 
  conceivable 
  that 
  this 
  might 
  be 
  

   due 
  to 
  a 
  general 
  and 
  uniform 
  subsidence 
  on 
  the 
  downthrow 
  side, 
  

   and 
  an 
  unequal 
  subsidence 
  on 
  the 
  upthrow 
  side, 
  whereby 
  certain 
  

   parts 
  retained 
  their 
  original 
  level 
  while 
  in 
  others 
  the 
  subsidence 
  

   .was 
  equal 
  to 
  that 
  of 
  the 
  downthrow 
  side 
  of 
  the 
  fault. 
  In 
  this 
  way 
  

   hollows 
  would 
  be 
  formed 
  on 
  the 
  upthrow 
  side 
  in 
  which 
  water 
  

   would 
  accumulate, 
  

  

  L 
  I 
  '45 
  ) 
  

  

  