﻿10 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  logic 
  map 
  as 
  such. 
  Occurrences 
  of 
  this 
  kind 
  will 
  be 
  described 
  

   later. 
  

  

  One 
  of 
  the 
  strongest 
  proofs 
  of 
  the 
  sedimentary 
  origin 
  of 
  the 
  

   Grenville 
  is 
  the 
  presence 
  of 
  limestone 
  beds 
  in 
  the 
  formation. 
  

   Such 
  limestones 
  have 
  been 
  described 
  by 
  Smyth^ 
  in 
  the 
  Diana- 
  

   Pitcairn 
  area 
  some 
  30 
  miles 
  northward 
  and 
  also 
  at 
  the 
  Ful- 
  

   ton 
  chain 
  of 
  lakes 
  some 
  25 
  miles 
  eastward. 
  A 
  little 
  has 
  been 
  

   found 
  by 
  Mr 
  D. 
  H. 
  Newland 
  in 
  the 
  Little 
  Falls 
  district 
  and 
  

   also 
  on 
  Moose 
  river 
  a 
  few 
  miles 
  east 
  of 
  the 
  Port 
  Ley 
  den 
  quad- 
  

   rangle. 
  The 
  latter 
  occurrence 
  is 
  the 
  closest 
  to 
  the 
  Port 
  Leyden 
  

   quadrangle 
  so 
  far 
  known. 
  The 
  writer 
  has 
  found 
  no 
  actual 
  lime- 
  

   stone 
  on 
  either 
  the 
  Remsen 
  or 
  the 
  Port 
  Leyden 
  sheet 
  although 
  

   certain 
  gneisses 
  usually 
  associated 
  with 
  the 
  limestone 
  are 
  pres- 
  

   ent. 
  The 
  statement 
  may 
  be 
  repeated 
  that, 
  whereas 
  Grenville 
  

   limestone 
  is 
  common 
  along 
  the 
  northwestern 
  Adirondacks, 
  it 
  is 
  

   only 
  sparingly 
  represented 
  along 
  the 
  southwestern 
  border. 
  

  

  The 
  fact 
  that 
  commonly 
  the 
  Grenville 
  rocks 
  here 
  and 
  else- 
  

   where 
  are 
  in 
  alternating 
  layers 
  which 
  stand 
  out 
  in 
  sharp 
  con- 
  

   trast 
  because 
  of 
  marked 
  differences 
  in 
  composition 
  and 
  color 
  

   leads 
  to 
  the 
  belief 
  that 
  these 
  bands 
  are 
  due 
  to 
  dififerences 
  in 
  

   original 
  sedimentation. 
  At 
  times 
  the 
  gneiss 
  is 
  composed 
  of 
  

   almost 
  pure 
  quartz 
  and 
  could 
  scarcely 
  be 
  of 
  igneous 
  origin. 
  

  

  Graphite 
  is 
  a 
  form 
  of 
  crystallized 
  carbon 
  and 
  of 
  organic 
  origin. 
  

   Its 
  presence 
  as 
  flakes 
  in 
  certain 
  of 
  the 
  Grenville 
  gneisses, 
  in- 
  

   cluding 
  some 
  within 
  this 
  quadrangle, 
  affords 
  a 
  strong 
  argument 
  

   in 
  favor 
  of 
  the 
  sedimentary 
  origin 
  of 
  those 
  gneisses. 
  Garnet 
  is 
  

   frequently 
  present, 
  often 
  in 
  great 
  abundance, 
  and 
  it 
  is 
  rather 
  

   more 
  common 
  in 
  metamorphosed 
  sediments. 
  

  

  Of 
  the 
  three 
  areas 
  above 
  mentioned, 
  each 
  has 
  certain 
  dis- 
  

   tinctive 
  features 
  and 
  hence 
  thc}^ 
  will 
  be 
  separately 
  described. 
  

   Thus 
  in 
  the 
  Kosterville 
  area 
  the 
  rocks 
  are 
  mostly 
  quartz-silli- 
  

   manite 
  gneisses 
  in 
  thin 
  layers 
  and 
  weathering 
  to 
  a 
  rusty 
  brown. 
  

   They 
  are 
  not 
  sharply 
  separated 
  from 
  the 
  neighboring 
  rocks 
  and 
  

   some 
  feldspar-garnet 
  gneisses 
  appear 
  near 
  the 
  northern 
  border 
  

   of 
  the 
  area 
  and 
  along 
  the 
  river 
  below 
  Shuetown. 
  The 
  dip 
  of 
  

   the 
  foliation 
  is 
  northward 
  while 
  the 
  strike 
  is 
  about 
  n. 
  60° 
  e. 
  

   which 
  is 
  the 
  same 
  as 
  for 
  the 
  surrounding 
  rocks. 
  The 
  specimens 
  

   here 
  described 
  were 
  taken 
  from 
  the 
  fine 
  exposures 
  just 
  below 
  

  

  the 
  bridge 
  across 
  Moose 
  river. 
  Microscopic 
  study 
  shows 
  one 
  

  

  _ 
  — 
  ____ 
  — 
  — 
  

  

  1 
  Crystalline 
  Rocks 
  of 
  the 
  Western 
  Adirondack 
  Region. 
  N. 
  Y. 
  State 
  

   Mus. 
  51st 
  An. 
  Rep't. 
  1897. 
  2:469-97. 
  

  

  