﻿REPORT 
  OF 
  THE 
  DIRECTOR 
  igi2 
  

  

  97 
  

  

  irregular 
  mass 
  of 
  acid 
  plagioclase 
  or 
  a 
  crystal 
  of 
  biotite 
  may 
  lie 
  

   between 
  the 
  garnet 
  and 
  the 
  hornblende 
  rim. 
  As 
  a 
  rule 
  the 
  horn- 
  

   blende 
  rims 
  increase 
  in 
  width 
  with 
  the 
  size 
  of 
  the 
  garnets, 
  some 
  

   rims 
  being 
  as 
  much 
  as 
  two 
  or 
  three 
  inches 
  wide. 
  These 
  reddish-' 
  

   brown 
  garnets, 
  completely 
  surrounded 
  by 
  the 
  black 
  hornblende 
  

   rims 
  which 
  are, 
  in 
  turn, 
  imbedded 
  in 
  the 
  gray 
  gneiss 
  matrix, 
  pre- 
  

   sent 
  a 
  striking 
  appearance 
  in 
  the 
  walls 
  of 
  the 
  great 
  mine 
  pits. 
  

  

  T~[ 
  Syenite 
  -Granite 
  5eries 
  

  

  |^»-| 
  Garnet* 
  Deposits 
  

   — 
  — 
  — 
  Faulta 
  

  

  Scale 
  of 
  Mile9 
  

  

  Geologic 
  and 
  topographic 
  sketch 
  map 
  of 
  portions 
  of 
  the 
  North 
  Creek 
  

   and 
  Thirteenth 
  Lake 
  (U. 
  S. 
  G. 
  S.) 
  sheets, 
  showing 
  the 
  mode 
  of 
  occurrence 
  

   of 
  those 
  garnet 
  deposits 
  which 
  are 
  lenslike 
  inclusions 
  in 
  the 
  syenite 
  or 
  

   granite. 
  

  

  This 
  garnet-bearing 
  rock 
  clearly 
  occurs 
  as 
  a 
  long, 
  narrow, 
  lens- 
  

   like 
  inclusion 
  of 
  Grenville 
  gneiss 
  in 
  the 
  great 
  mass 
  of 
  Gore 
  moun- 
  

   tain 
  syenite. 
  The 
  inclusion 
  is 
  fully 
  three-fourths 
  of 
  a 
  mile 
  long, 
  

   with 
  nearly 
  east-west 
  strike. 
  Several 
  large 
  openings 
  have 
  been 
  

   made 
  in 
  it 
  and, 
  in 
  the 
  very 
  large 
  more 
  easterly 
  pit, 
  the 
  width 
  of 
  

   the 
  inclusion 
  is 
  more 
  than 
  one 
  hundred 
  feet. 
  The 
  garnet 
  rock 
  is 
  

   removed 
  by 
  blasting 
  and 
  reduced 
  by 
  sledge 
  hammers 
  after 
  which 
  

   the 
  garnets 
  are 
  picked 
  out 
  by 
  hand. 
  

  

  2 
  In 
  the 
  Oven 
  mountain 
  mine 
  the 
  mode 
  of 
  occurrence 
  is 
  pre- 
  

   cisely 
  like 
  that 
  in 
  the 
  Rogers 
  mine. 
  In 
  thin 
  section 
  the 
  matrix 
  

  

  