﻿486 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  part 
  of 
  the 
  latter. 
  The 
  gabbro 
  occurs 
  quite 
  like 
  an 
  interbedded 
  

   basic 
  gneiss, 
  but 
  is 
  clearly 
  the 
  same 
  rock 
  seen 
  elsewhere 
  as 
  an 
  

   intrusive, 
  so 
  that 
  its 
  character 
  is 
  fixed 
  by 
  indirect 
  evidence. 
  

   Finally 
  as 
  to 
  garnetiferous 
  gneiss, 
  we 
  have 
  no 
  single 
  positive 
  

   piece 
  of 
  evidence 
  to 
  determine 
  its 
  nature, 
  but 
  it 
  can 
  be 
  traced 
  

   for 
  several 
  miles 
  along 
  the 
  strike, 
  appearing 
  to 
  be 
  a 
  definite 
  

   horizon 
  in 
  the 
  limestone 
  formation; 
  it 
  is 
  well 
  -banded 
  and 
  quite 
  

   variable 
  in 
  both 
  composition 
  and 
  structure; 
  it 
  does 
  not 
  at 
  all 
  re- 
  

   semble 
  in 
  its 
  appearance 
  an 
  igneous 
  rock, 
  while 
  it 
  is 
  quite 
  like 
  

   a 
  great 
  many 
  other 
  garnetiferous 
  gneisses 
  which 
  have 
  been 
  seen 
  

   in 
  the 
  region, 
  always 
  closely 
  associated 
  with 
  limestone. 
  In 
  view 
  

   of 
  all 
  of 
  these 
  facts 
  it 
  seems 
  highly 
  probable 
  that 
  this 
  garnetifer- 
  

   ous 
  gneiss 
  is 
  of 
  sedimentary 
  origin, 
  a 
  constituent 
  member 
  of 
  the 
  

   limestone 
  formation. 
  

  

  It 
  is 
  of 
  interest 
  to 
  note 
  as 
  confirmatory 
  of 
  this 
  view 
  that 
  in 
  

   thin 
  sections 
  it 
  is 
  seen 
  that 
  the 
  order 
  of 
  crystallization 
  in 
  the 
  

   gneiss 
  is 
  not 
  that 
  normally 
  present 
  in 
  igneous 
  rocks? 
  Instead 
  

   the 
  ferromagnesian 
  mineral, 
  mica, 
  was 
  the 
  last 
  to 
  form, 
  wrap- 
  

   ping 
  around 
  and 
  including 
  quartz, 
  feldspar 
  and 
  other 
  constitu- 
  

   ents. 
  The 
  mica 
  moreover 
  is 
  the 
  golden 
  brown 
  phlogophite 
  vari- 
  

   ety 
  so 
  common 
  in 
  the 
  limestone. 
  

  

  It 
  need 
  hardly 
  be 
  stated 
  that 
  no 
  great 
  reliance 
  is 
  placed 
  on 
  

   this 
  structure 
  as 
  an 
  indication 
  of 
  origin, 
  for 
  not 
  only 
  does 
  the 
  

   order 
  of 
  crystallization 
  vary, 
  but 
  in 
  a 
  region 
  of 
  intense 
  meta- 
  

   morphic 
  action 
  like 
  this 
  the 
  order 
  might 
  be 
  and 
  indeed 
  certainly 
  

   has 
  been 
  in 
  some 
  cases 
  entirely 
  changed 
  by 
  recrystallization. 
  

  

  Nevertheless 
  it 
  is 
  interesting 
  when 
  taken 
  in 
  connection 
  with 
  

   the 
  other 
  facts 
  regarding 
  the 
  gneiss 
  and 
  may 
  prove 
  of 
  value 
  if 
  

   found 
  to 
  be 
  a 
  rule. 
  Already 
  this 
  inverted 
  order 
  of 
  crystallization 
  

   has 
  been 
  noted 
  in 
  several 
  gneisses 
  which 
  like 
  the 
  present 
  one 
  

   give 
  many 
  indications 
  of 
  being 
  sedimentary. 
  

  

  PULTON 
  CHAIN 
  AND 
  RAQUETTE 
  LAKE 
  AREA 
  

  

  As 
  nearly 
  all 
  the 
  work 
  hitherto 
  done 
  in 
  the 
  western 
  half 
  of 
  the 
  

   Adirondack 
  region 
  had 
  been 
  in 
  the 
  marginal 
  portions 
  of 
  the 
  crys- 
  

   talline 
  area, 
  it 
  seemed 
  advisable 
  to 
  make 
  a 
  trip 
  into 
  the 
  heart 
  of 
  

   the 
  region 
  and 
  take 
  the 
  first 
  steps 
  toward 
  bridging 
  the 
  gap 
  that 
  

  

  