﻿698 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  by 
  the 
  ore. 
  The 
  " 
  serpentine 
  " 
  at 
  the 
  Dixon 
  mine 
  in 
  appearance 
  

   and 
  in 
  origin 
  is 
  like 
  that 
  at 
  the 
  Old 
  Sterling. 
  

  

  In 
  the 
  Caledonia 
  mines 
  the 
  so-called 
  serpentine 
  is 
  a 
  lighter- 
  

   colored 
  rock, 
  looking 
  even 
  more 
  like 
  a 
  true 
  serpentine 
  and 
  usually 
  

   lacking 
  the 
  quartz 
  fragments. 
  It 
  has, 
  also, 
  quite 
  a 
  different 
  com- 
  

   position 
  from 
  that 
  of 
  the 
  Sterling 
  rock. 
  But 
  in 
  spite 
  of 
  these 
  

   differences 
  there 
  is 
  such 
  similarity 
  in 
  mode 
  of 
  occurrence 
  and 
  

   relation 
  to 
  the 
  ore 
  that 
  it 
  seems 
  probable 
  the 
  two 
  rocks 
  have 
  had 
  

   a 
  like 
  origin. 
  Indeed, 
  the 
  same 
  may 
  be 
  said 
  of 
  the 
  " 
  serpentine 
  " 
  

   at 
  nearly 
  all 
  of 
  the 
  mines, 
  the 
  Clark 
  and 
  Pike 
  being 
  the 
  only 
  

   clearly 
  established 
  exception. 
  There 
  the 
  "serpentine 
  " 
  is 
  decidedly 
  

   laminated 
  and 
  contorted, 
  differing 
  greatly 
  in 
  appearance 
  from 
  

   the 
  rock 
  at 
  the 
  other 
  mines. 
  The 
  microscope 
  shows 
  it 
  to 
  be 
  an 
  

   alteration 
  of 
  the 
  laminated 
  gneiss, 
  The 
  altered 
  granite 
  may 
  also 
  

   be 
  present, 
  but 
  is 
  not 
  shown 
  in 
  the 
  surface 
  exposures. 
  

  

  Although 
  this 
  highly 
  altered 
  granite 
  (or, 
  rarely, 
  gneiss) 
  is 
  a 
  

   characteristic 
  accompaniment 
  of 
  the 
  ore 
  deposits, 
  nothing 
  in 
  any 
  

   way 
  resembling 
  it 
  has 
  been 
  seen 
  elsewhere 
  in 
  the 
  region, 
  in 
  spite 
  

   of 
  the 
  fact 
  that 
  granite 
  is 
  a 
  very 
  common 
  rock. 
  Hence, 
  in 
  

   endeavoring 
  to 
  explain 
  the 
  origin 
  of 
  the 
  ore 
  it 
  becomes 
  necessary 
  

   to 
  account 
  for 
  the 
  common 
  association 
  of 
  granite 
  with 
  it 
  ; 
  and 
  as 
  

   this 
  granite 
  is 
  ahvays 
  greatly 
  altered 
  in 
  a 
  manner 
  not 
  seen 
  else- 
  

   where 
  in 
  the 
  region, 
  a 
  satisfactory 
  hypothesis 
  must 
  explain 
  the 
  

   presence 
  in 
  connection 
  with 
  the 
  ore 
  deposits, 
  and 
  nowhere 
  else, 
  

   of 
  a 
  powerful 
  chemical 
  agent 
  which 
  is 
  capable 
  of 
  producing 
  this 
  

   alteration. 
  The 
  two 
  hypotheses 
  mentioned 
  above 
  do 
  not 
  offer 
  

   sufficient 
  explanation 
  of 
  these 
  points. 
  The 
  first, 
  that 
  of 
  deriva- 
  

   tion 
  of 
  the 
  iron 
  from 
  the 
  Potsdam 
  sandstone, 
  would 
  account 
  

   neither 
  for 
  the 
  alteration 
  of 
  the 
  granite 
  nor 
  for 
  the 
  linear 
  

   arrangement 
  of 
  the 
  deposits 
  along 
  the 
  strike. 
  If 
  the 
  second 
  

   hypothesis 
  were 
  correct 
  and 
  the 
  ore 
  an 
  original 
  sedimentary 
  

   deposit, 
  why 
  (to 
  recall 
  a 
  difficulty 
  already 
  pointed 
  out) 
  should 
  so 
  

   many 
  ore 
  bodies 
  be 
  cut 
  by 
  granite, 
  and 
  what 
  agent 
  would 
  be 
  

   present 
  to 
  produce 
  such 
  great 
  alteration 
  of 
  the 
  granite 
  after 
  

   intrusion? 
  

  

  It 
  would 
  seem 
  that 
  the 
  key 
  to 
  a 
  solution 
  of 
  the 
  problem 
  must 
  

   be 
  found 
  in 
  the 
  presence 
  at 
  or 
  near 
  the 
  ore 
  deposits 
  of 
  some 
  

   sufficient 
  source 
  both 
  of 
  iron 
  and 
  of 
  a 
  powerful 
  chemical 
  agent. 
  

   That 
  such 
  a 
  source 
  is 
  at 
  hand, 
  a 
  brief 
  examination 
  suffices 
  to 
  

  

  