﻿IS 
  2 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  If 
  the 
  lava 
  solidified 
  where 
  it 
  now 
  rests, 
  the 
  only 
  possible 
  con- 
  

   ception 
  of 
  the 
  occurrence 
  which 
  at 
  all 
  fits 
  the 
  facts 
  of 
  the 
  case 
  is 
  

   that 
  it 
  is 
  a 
  volcanic 
  neck. 
  But 
  volcanic 
  necks 
  are 
  usually 
  nearly 
  

   vertical, 
  instead 
  of 
  quite 
  inclined, 
  as 
  in 
  this 
  case; 
  they 
  usually 
  cut 
  

   across 
  the 
  bedding 
  instead 
  of 
  following 
  it; 
  and 
  they 
  are 
  usually 
  

   filled 
  with 
  agglomerate, 
  tuff 
  or 
  solid 
  lava. 
  We 
  do 
  not 
  recall 
  any 
  

   account 
  of 
  a 
  volcanic 
  neck 
  filled 
  with 
  material 
  such 
  as 
  that 
  at 
  

   Stark's 
  knob. 
  The 
  usual 
  filling 
  is 
  generally 
  much 
  more 
  distinctly 
  

   fragmental 
  in 
  type 
  and 
  more 
  diversified 
  in 
  character. 
  On 
  the 
  

   other 
  hand, 
  we 
  know 
  of 
  no 
  reason 
  why 
  such 
  material 
  might 
  not 
  

   accumulate 
  in 
  a 
  neck. 
  

  

  Many 
  features 
  of 
  the 
  rock 
  of 
  the 
  knob 
  recall 
  very 
  forcibly 
  

   the 
  characters 
  of 
  pillow 
  lavas, 
  characters 
  produced 
  (in 
  many 
  in- 
  

   stances 
  at 
  least) 
  in 
  surface 
  lavas 
  when 
  poured 
  out 
  so 
  that 
  they 
  

   mingle 
  with 
  surface 
  waters. 
  Spheroidal 
  masses 
  of 
  lava, 
  production 
  

   of 
  glass, 
  and 
  explosive 
  mixture 
  with 
  fragmental 
  material 
  from 
  

   beneath, 
  are 
  the 
  prominent 
  characters 
  of 
  such 
  lava 
  flows. 
  A 
  great 
  

   number 
  of 
  shrinkage 
  cracks 
  through 
  the 
  lava 
  pillows 
  is 
  another 
  

   feature 
  possessed 
  in 
  common. 
  

  

  At 
  Stark's 
  knob 
  there 
  is 
  no 
  sign 
  of 
  the 
  basal 
  admixture 
  with 
  

   fragmental 
  material, 
  such 
  as 
  is 
  found 
  in 
  many 
  pillow 
  lavas, 
  unless 
  

   indeed 
  the 
  shear 
  zone 
  material 
  at 
  the 
  base 
  may 
  represent 
  it, 
  crushed 
  

   beyond 
  recognition, 
  as 
  an 
  analysis 
  perhaps 
  suggests. 
  Nor 
  is 
  the 
  

   lava 
  as 
  highly 
  altered 
  as 
  most 
  pillow 
  lavas 
  are; 
  yet 
  this 
  difference 
  

   may 
  be 
  more 
  apparent 
  than 
  real. 
  Most 
  such 
  have 
  been 
  described 
  

   from 
  natural 
  exposures, 
  and 
  exteriorly 
  the 
  rock 
  at 
  the 
  knob 
  was 
  

   highly 
  altered. 
  The 
  fresh 
  material 
  is 
  due 
  to 
  quarrying 
  and 
  comes 
  

   from 
  many 
  feet 
  below 
  the 
  original 
  surface. 
  

  

  Nor 
  is 
  the 
  structure 
  exactly 
  comparable 
  with 
  that 
  of 
  pillow 
  

   lavas, 
  the 
  chief 
  difference 
  being 
  in 
  the 
  greater 
  quantity 
  of 
  inter 
  

   vening 
  material 
  at 
  the 
  knob. 
  We 
  have 
  seen 
  that 
  shearing 
  has 
  prob- 
  

   ably 
  increased 
  the 
  apparent 
  amount 
  of 
  this, 
  the 
  outer 
  portions 
  

   of 
  the 
  balls 
  cracking 
  and 
  shearing 
  away, 
  especially 
  where 
  com- 
  

   posed 
  of 
  glass. 
  But 
  when 
  every 
  allowance 
  has 
  been 
  made 
  for 
  

   this 
  it 
  remains 
  doubtful 
  whether 
  the 
  balls 
  were 
  ever 
  as 
  closely 
  

   packed 
  and 
  close 
  fitting 
  as 
  in 
  most 
  pillow 
  lavas. 
  

  

  In 
  weighing 
  the 
  evidence 
  for 
  or 
  against 
  the 
  lava 
  being 
  in 
  place, 
  

   with 
  part 
  of 
  the 
  evidence 
  seeming 
  to 
  point 
  one 
  way 
  and 
  part 
  the 
  

   other, 
  we 
  must 
  confess 
  our 
  inability 
  to 
  come 
  to 
  any 
  definite 
  con- 
  

   clusion 
  in 
  the 
  matter. 
  The 
  overthrusting 
  seems 
  a 
  priori 
  so 
  un- 
  

   likely 
  that 
  our 
  sympathies 
  are 
  entirely 
  with 
  the 
  other 
  view. 
  But 
  

  

  