﻿GEOLOGY 
  OF 
  THE 
  NORTH 
  CREEK 
  QUADRANGLE 
  79 
  

  

  of 
  a 
  mile 
  southeast 
  of 
  Holcombville 
  (Rexford's 
  mine) 
  ; 
  (3) 
  in 
  

   the 
  mixed 
  gneiss 
  area 
  just 
  south 
  of 
  Daggett 
  pond 
  (Elisha 
  Parker 
  

   farm) 
  ; 
  (4) 
  near 
  the 
  mouth 
  of 
  Mill 
  creek 
  (Sanders 
  Brothers 
  mine 
  

   now 
  in 
  operation) 
  ; 
  and 
  (5) 
  three-fourths 
  of 
  a 
  mile 
  east 
  of 
  Fuller 
  

   pond. 
  Besides 
  these 
  the 
  principal 
  garnet 
  mines 
  of 
  the 
  Adirondack 
  

   region 
  lie 
  in 
  the 
  northern 
  portion 
  of 
  the 
  adjoining 
  Thirteenth 
  lake 
  

   sheet. 
  One 
  of 
  these 
  is 
  the 
  Rogers 
  (Barton) 
  mine 
  near 
  the 
  top 
  of 
  

   Gore 
  mountain 
  and 
  the 
  other 
  is 
  the 
  Hooper 
  mine 
  on 
  the 
  west 
  side 
  

   of 
  Thirteenth 
  lake. 
  In 
  all 
  cases 
  open 
  pit 
  methods 
  of 
  mining 
  are 
  

   employed. 
  

  

  The 
  Oven 
  mountain 
  mine 
  has 
  not 
  been 
  worked 
  for 
  nearly 
  twenty 
  

   years, 
  and 
  at 
  no 
  time 
  was 
  a 
  crushing 
  plant 
  operated. 
  After 
  blasting 
  

   out 
  the 
  garnet-bearing 
  rock 
  and 
  reducing 
  it 
  in 
  size 
  by 
  means 
  of 
  

   sledge 
  hammers, 
  the 
  large 
  garnets 
  were 
  picked 
  out 
  by 
  hand. 
  The 
  

   mode 
  of 
  occurrence 
  is 
  of 
  unusual 
  interest. 
  The 
  matrix, 
  or 
  rock 
  

   carrying 
  the 
  garnets, 
  is 
  a 
  gray, 
  medium 
  grained, 
  feldspar, 
  horn- 
  

   blende, 
  biotite, 
  gneiss, 
  a 
  thin 
  section 
  showing 
  20 
  per 
  cent 
  ortho- 
  

   clase 
  ; 
  25 
  per 
  cent 
  oligoclase 
  to 
  labradorite 
  ; 
  50 
  per 
  cent 
  hornblende 
  ; 
  

   2 
  per 
  cent 
  biotite 
  ; 
  2 
  per 
  cent 
  magnetite 
  ; 
  together 
  with 
  a 
  little 
  pyrite, 
  

   zoisite, 
  and 
  apatite. 
  Imbedded 
  in 
  this 
  gray 
  matrix 
  are 
  numerous, 
  

   well-scattered, 
  translucent, 
  pale 
  reddish 
  brown 
  garnets 
  ranging 
  in 
  

   size 
  up 
  to 
  several 
  inches. 
  These 
  garnets 
  are 
  always 
  quite 
  well 
  granu- 
  

   lated 
  and 
  never 
  show 
  crystal 
  outlines. 
  Each 
  garnet 
  is 
  completely 
  in- 
  

   closed 
  within 
  an 
  envelop 
  of 
  pure, 
  black, 
  medium 
  grained 
  horn- 
  

   blende 
  crystals. 
  Occasionally 
  a 
  half-inch, 
  irregular 
  shaped 
  crystalline 
  

   mass 
  of 
  acid 
  plagioclase 
  or 
  biotite 
  may 
  lie 
  just 
  between 
  the 
  garnet 
  

   and 
  the 
  hornblende 
  rim. 
  These 
  reddish 
  garnets 
  completely 
  sur- 
  

   rounded 
  by 
  rims 
  of 
  black 
  hornblende, 
  which 
  are 
  in 
  turn 
  imbedded 
  

   in 
  the 
  gray 
  gneiss 
  matrix, 
  present 
  a 
  very 
  striking 
  appearance. 
  As 
  

   shown 
  on 
  the 
  geologic 
  map, 
  this 
  garnet-bearing 
  rock 
  occurs 
  as 
  

   a 
  long, 
  narrow 
  inclusion 
  of 
  Grenville 
  gneiss 
  within 
  the 
  Oven 
  moun- 
  

   tain 
  granite. 
  

  

  At 
  the 
  Rexford 
  mine 
  there 
  are 
  several 
  large 
  openings 
  but 
  none 
  

   have 
  been 
  worked 
  for 
  about 
  fifteen 
  years. 
  The 
  mode 
  of 
  occurrence 
  

   is 
  almost 
  exactly 
  like 
  that 
  in 
  Oven 
  mountain, 
  only 
  here 
  there 
  appear 
  

   to 
  be 
  several 
  (smaller) 
  inclusions 
  of 
  the 
  garnet-bearing 
  hornblende 
  

   gneiss 
  instead 
  of 
  one, 
  and 
  the 
  country 
  rock 
  is 
  a 
  very 
  gneissoid 
  

   syenite. 
  Garnets 
  up 
  to 
  5 
  inches 
  across 
  and 
  always 
  with 
  hornblende 
  

   rims 
  occur 
  here. 
  

  

  By 
  way 
  of 
  comparison 
  with 
  the 
  Oven 
  mountain 
  and 
  Rexford 
  

   mines, 
  the 
  Rogers 
  mine 
  on 
  Gore 
  mountain 
  should 
  be 
  mentioned 
  as 
  

   of 
  exactly 
  the 
  same 
  type 
  of 
  occurrence 
  but 
  with 
  garnets 
  generally 
  

  

  