﻿122 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  consisting 
  of 
  a 
  dozen 
  such 
  grains. 
  It 
  is 
  possible 
  that 
  these 
  came 
  

   from 
  the 
  grits. 
  But 
  if 
  so, 
  it 
  is 
  surprising 
  that 
  there 
  are 
  not 
  larger 
  

   fragments 
  from 
  the 
  same 
  source, 
  since 
  these 
  grits 
  are 
  exceedingly 
  

   tough 
  and 
  well-cemented 
  rocks. 
  

  

  Structural 
  features. 
  The 
  dissection 
  of 
  the 
  knob 
  by 
  quarrying 
  

   operations 
  has 
  brought 
  to 
  light 
  some 
  new 
  structural 
  features. 
  

   Woodworth 
  described 
  two 
  faults 
  along 
  the 
  margin 
  of 
  the 
  knob, 
  

   and 
  his 
  section 
  (figure 
  9) 
  shows 
  his 
  conception 
  of 
  the 
  rela- 
  

   tions 
  of 
  lava 
  and 
  shale. 
  But 
  quarrying 
  brought 
  to 
  light 
  other 
  

   masses 
  of 
  shale, 
  involved 
  with 
  lava, 
  within 
  the 
  knob. 
  We 
  found 
  

   evidence 
  of 
  severe 
  compressive 
  disturbance 
  and 
  dislocation 
  all 
  

   through 
  the 
  lava 
  mass 
  of 
  the 
  knob, 
  suggesting 
  a 
  number 
  of 
  minor 
  

   dislocations 
  throughout 
  the 
  mass, 
  instead 
  of 
  merely 
  the 
  two 
  which 
  

  

  Slates 
  

  

  Fig. 
  12 
  Sketch 
  of 
  relations 
  of 
  shale 
  and 
  lava 
  near 
  the 
  south 
  end 
  of 
  the 
  

   knob; 
  shale 
  overlying 
  lava 
  on 
  the 
  projecting 
  point 
  at 
  the 
  left, 
  and 
  a 
  steep 
  

   shale 
  wedge 
  in 
  the 
  lava 
  midway 
  

  

  he 
  saw, 
  which 
  were 
  all 
  that 
  could 
  have 
  originally 
  been 
  recognized. 
  

   A 
  few 
  sketches, 
  and 
  a 
  comparison 
  of 
  them 
  with 
  our 
  photograph 
  

   of 
  the 
  knob 
  (plate 
  18), 
  will 
  aid 
  in 
  the 
  presentation 
  of 
  the 
  details. 
  

   Figure 
  12 
  is 
  a 
  diagram 
  of 
  the 
  south 
  end 
  of 
  the 
  quarried 
  face 
  

   of 
  the 
  knob, 
  with 
  a 
  projecting 
  point 
  on 
  the 
  left 
  which 
  remains 
  

   unquarried. 
  On 
  that 
  point, 
  slate 
  overlies 
  trap. 
  Woodworth's 
  sec- 
  

   tion, 
  in 
  which 
  trap 
  overlays 
  shale, 
  was 
  made 
  a 
  little 
  farther 
  south, 
  

   and 
  the 
  remnants 
  may 
  be 
  seen 
  just 
  over 
  the 
  roof 
  of 
  the 
  engine 
  

   house 
  in 
  plate 
  18. 
  To 
  the 
  north 
  of 
  the 
  point, 
  shown 
  in 
  the 
  sketch, 
  

   trap 
  makes 
  the 
  full 
  height 
  of 
  the 
  face 
  and 
  the 
  shale 
  has 
  pinched 
  

   out, 
  but 
  up 
  this 
  face 
  runs 
  another 
  very 
  steeply 
  inclined, 
  shale 
  

   wedge, 
  which 
  runs 
  nearly 
  to 
  the 
  top 
  before 
  pinching 
  out. 
  Because 
  

   of 
  the 
  section 
  which 
  Woodworth 
  saw 
  and 
  figured, 
  he 
  judged 
  a 
  

  

  