﻿ADIRONDACK 
  MAGNETIC 
  IRON 
  ORES 
  93 
  

  

  45 
  , 
  with 
  rarely 
  one 
  to 
  the 
  west 
  of 
  north. 
  The 
  dip 
  is 
  uniformly 
  

   toward 
  the 
  west. 
  In 
  many 
  places 
  the 
  foliation 
  is 
  too 
  obscure 
  to 
  

   permit 
  determinations 
  with 
  any 
  certainty. 
  

  

  Augite 
  syenite. 
  This 
  rock 
  occupies 
  two 
  distinct 
  areas 
  at 
  least 
  

   within 
  the 
  district. 
  The 
  one 
  near 
  Ausable 
  Forks 
  already 
  mentioned 
  

   is 
  the 
  larger 
  and 
  more 
  typical 
  of 
  the 
  normal 
  character 
  of 
  the 
  syenite. 
  

   As 
  near 
  as 
  the 
  limits 
  can 
  be 
  drawn 
  it 
  forms 
  practically 
  a 
  connected 
  

   mass 
  or 
  boss, 
  the 
  surface 
  of 
  which 
  is 
  coextensive 
  with 
  that 
  of 
  the 
  

   dome-shaped 
  hills 
  lying 
  between 
  Ausable 
  Forks 
  and 
  Palmer 
  hill. 
  

   The 
  exposure 
  south 
  of 
  the 
  Ausable 
  is 
  probably 
  an 
  offshoot 
  from 
  

   this 
  mass. 
  Compared 
  with 
  the 
  gneiss 
  of 
  the 
  region 
  the 
  syenite 
  shows 
  

   marked 
  differences 
  even 
  in 
  hand 
  specimens. 
  Its 
  color 
  on 
  fresh 
  

   surfaces 
  is 
  green, 
  with 
  a 
  suggestion 
  of 
  gray 
  or 
  yellow 
  at 
  times, 
  

   while 
  the 
  fracture 
  is 
  that 
  of 
  a 
  close 
  grained 
  igneous 
  rock, 
  con- 
  

   ditioned 
  by 
  its 
  massive 
  texture. 
  Feldspar 
  and 
  magnetite 
  are 
  the 
  

   minerals 
  most 
  apparent 
  to 
  the 
  unaided 
  eye. 
  Under 
  the 
  microscope 
  

   the 
  former 
  is 
  seen 
  to 
  be 
  almost 
  entirely 
  microperthite, 
  while 
  asso- 
  

   ciated 
  with 
  it 
  are 
  augite, 
  hypersthene, 
  hornblende, 
  quartz, 
  zircon, 
  

   apatite 
  and 
  rarely 
  a 
  light 
  colored 
  garnet. 
  The 
  feldspar 
  is 
  built 
  up 
  

   in 
  stout 
  anhedra 
  between 
  the 
  interstices 
  of 
  which 
  the 
  quartz 
  occurs 
  

   in 
  irregular 
  grains. 
  On 
  the 
  borders, 
  especially 
  on 
  the 
  east 
  side 
  of 
  

   the 
  mass, 
  the 
  rock 
  is 
  apt 
  to 
  be 
  more 
  quart 
  zose 
  and 
  the 
  grains 
  attain 
  

   such 
  dimensions 
  that 
  they 
  are 
  readily 
  distinguishable. 
  

  

  The 
  second 
  occurrence 
  of 
  the 
  syenite 
  is 
  on 
  Arnold 
  hill, 
  a 
  few 
  

   hundred 
  feet 
  west 
  of 
  the 
  Nelson 
  Bush 
  mine. 
  It 
  is 
  here 
  quite 
  differ- 
  

   ent 
  in 
  appearance 
  from 
  the 
  first, 
  having 
  a 
  mottled 
  aspect 
  which 
  is 
  

   induced 
  by 
  the 
  abundant 
  hornblende 
  mixed 
  with 
  the 
  feldspar. 
  

   Plagioclase 
  constitutes 
  a 
  large 
  proportion 
  of 
  the 
  feldspar. 
  The 
  

   rock 
  is 
  to 
  be 
  regarded 
  as 
  a 
  basic 
  phase 
  of 
  the 
  syenite, 
  near 
  the 
  

   borders 
  of 
  the 
  gabbro 
  rock 
  group. 
  

  

  Gabbro. 
  The 
  only 
  intrusion 
  of 
  gabbro 
  in 
  the 
  gneiss 
  series 
  of 
  the 
  

   district 
  that 
  has 
  been 
  found 
  is 
  on 
  the 
  south 
  bank 
  of 
  the 
  Ausable, 
  a 
  

   mile 
  east 
  of 
  Ausable 
  Forks 
  along 
  the 
  Clintonville 
  road. 
  It 
  is 
  a 
  

   coarse 
  dark 
  rock 
  somewhat 
  laminated 
  but 
  with 
  the 
  peculiar 
  mot- 
  

   tling 
  that 
  is 
  so 
  often 
  associated 
  with 
  gabbroic 
  rocks. 
  The 
  constitu- 
  

   ents 
  are 
  mostly 
  hypersthene, 
  hornblende 
  and 
  labradorite. 
  The 
  

   occurrence 
  is 
  doubtless 
  to 
  be 
  ascribed 
  to 
  an 
  outlying 
  intrusion 
  from 
  

   the 
  large 
  anorthosite-gabbro 
  area 
  to 
  the 
  south. 
  

  

  Dikes. 
  Diabase 
  dikes 
  are 
  conspicuous 
  features 
  of 
  the 
  geology 
  of 
  

   the 
  ore 
  bodies. 
  They 
  intersect 
  the 
  latter 
  in 
  different 
  directions, 
  

   apparently 
  without 
  following 
  the 
  joint 
  systems 
  of 
  the 
  walls. 
  Their 
  

   thickness 
  ranges 
  up 
  to 
  15 
  feet, 
  the 
  maximum 
  reached 
  by 
  two 
  dikes 
  

  

  