﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I907 
  1 
  5 
  

  

  beds. 
  Only 
  one 
  of 
  these 
  has 
  commonly 
  been 
  recognized 
  by 
  other 
  

   investigators. 
  At 
  Cystid 
  point 
  a 
  reef 
  is 
  shown 
  and 
  its 
  extinction 
  

   and 
  the 
  deposit 
  of 
  sediment 
  over 
  it 
  is 
  clearly 
  to 
  be 
  seen. 
  Five 
  

   meters 
  down 
  from 
  this 
  horizon 
  and 
  300 
  meters 
  to 
  the 
  north 
  is 
  

   another. 
  Twenty-three 
  meters 
  down 
  and 
  1000 
  meters 
  to 
  the 
  north 
  

   comes 
  the 
  more 
  massive 
  one 
  which 
  forms 
  the 
  " 
  dove 
  color 
  " 
  of 
  

   Tiger 
  point. 
  Reef 
  material 
  is 
  found 
  again 
  from 
  400 
  to 
  500 
  meters 
  

   north 
  of 
  this 
  and 
  at 
  a 
  horizon 
  70 
  meters 
  below 
  the 
  surface 
  at 
  

   Cystid 
  point. 
  This 
  reef 
  is 
  as 
  large 
  as 
  the 
  Tiger 
  point 
  reef 
  and 
  

   in 
  many 
  respects 
  resembles 
  it. 
  The 
  shore 
  is 
  of 
  a 
  deeper 
  blue 
  dove 
  

   color 
  on 
  the 
  whole, 
  yet 
  this 
  darker 
  dove 
  color 
  may 
  also 
  be 
  found 
  in 
  

   the 
  Tiger 
  point 
  reef. 
  The 
  rock 
  abounds 
  in 
  cephalopods 
  and 
  the 
  

   trilobite 
  Glaphurus 
  pustulosus. 
  The 
  rocks 
  of 
  Sloop 
  

   island 
  (which 
  show 
  a 
  pure 
  dove 
  colored 
  rock 
  as 
  light 
  as 
  that 
  of 
  

   Tiger 
  point) 
  seem 
  by 
  their 
  position 
  to 
  belong 
  to 
  this 
  reef. 
  One 
  of 
  

   the 
  reefs 
  noted 
  belongs 
  to 
  the 
  upper 
  Chazy, 
  the 
  other 
  47 
  meters 
  

   below 
  it, 
  is 
  in 
  the 
  middle 
  Chazy. 
  

  

  The 
  fault 
  system 
  of 
  the 
  region 
  is 
  of 
  interest 
  and 
  corrections 
  have 
  

   been 
  made 
  of 
  the 
  location 
  of 
  the 
  faults 
  mapped 
  by 
  others 
  and 
  also 
  

   data 
  on 
  new 
  faults 
  acquired. 
  A 
  preliminary 
  map 
  of 
  the 
  intricate 
  

   fault 
  system 
  of 
  the 
  Plattsburg 
  region 
  has 
  been 
  made 
  and 
  the 
  fact 
  

   brought 
  forward 
  that 
  the 
  form 
  of 
  Lake 
  Champlain 
  is 
  the 
  outward 
  

   expression 
  of 
  some 
  of 
  the 
  more 
  extended 
  of 
  these 
  faults. 
  Enough 
  

   evidence 
  has 
  been 
  acquired 
  to 
  show 
  the 
  presence 
  of 
  two 
  widely 
  

   different 
  systems 
  and 
  that 
  correlation 
  of 
  the 
  scattered 
  observations 
  

   is 
  at 
  least 
  in 
  part, 
  possible. 
  The 
  north 
  and 
  south 
  system 
  appears 
  

   to 
  be 
  the 
  younger, 
  or 
  at 
  least 
  has 
  suffered 
  the 
  most 
  recent 
  additions 
  

   to 
  its 
  displacements. 
  

  

  A 
  number 
  of 
  interesting 
  observations 
  have 
  been 
  made 
  on 
  the 
  

   island, 
  bearing 
  on 
  the 
  glacial 
  history 
  of 
  the 
  region 
  and 
  on 
  the 
  

   striae 
  of 
  the 
  glacial 
  boulders. 
  An 
  enormous 
  amount 
  of 
  the 
  energy 
  

   of 
  a 
  moving 
  glacial 
  sheet 
  is 
  spent 
  in 
  reducing 
  its 
  ground 
  moraine 
  

   to 
  powder. 
  The 
  sheet 
  of 
  till 
  in 
  actual 
  contact 
  with 
  the 
  bed 
  rock 
  

   does 
  not 
  move 
  so 
  rapidly 
  as 
  the 
  sheets 
  lying 
  over 
  this. 
  As 
  a 
  conse- 
  

   quence 
  comparatively 
  few 
  stones 
  of 
  the 
  till 
  are 
  found 
  with 
  surfaces 
  

   ground 
  by 
  contact 
  with 
  bed 
  rock, 
  for 
  such 
  a 
  grinding 
  produces 
  a 
  

   flat 
  face 
  with 
  hundreds 
  of 
  parallel 
  lines 
  as 
  may 
  be 
  seen 
  in 
  the 
  adjoin- 
  

   ing 
  photograph 
  ; 
  on 
  the 
  contrary 
  curved 
  outlines 
  predominate 
  caused 
  

   by 
  contact 
  with 
  each 
  other. 
  

  

  Highlands 
  of 
  the 
  Hudson. 
  Geological 
  fieldwork 
  in 
  the 
  High- 
  

   lands 
  was 
  continued 
  by 
  Dr 
  Charles 
  *P. 
  Berkey 
  during 
  a 
  part 
  of 
  the 
  

  

  