﻿102 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  two 
  latter 
  rocks 
  being 
  at 
  times 
  somewhat 
  garnetiferous. 
  The 
  writer 
  

   is 
  fully 
  convinced 
  that 
  this 
  transition 
  zone 
  (wall 
  rock) 
  has 
  been 
  

   formed 
  by 
  assimilation 
  or 
  actual 
  melting 
  or 
  fusing 
  together 
  of 
  

   the 
  syenite 
  and 
  the 
  border 
  of 
  the 
  great 
  inclusion 
  at 
  the 
  time 
  of 
  

   the 
  intrusion. 
  

  

  TABLE 
  SHOWING 
  THE 
  MINERALOGICAL 
  COMPOSITION 
  OF 
  THE 
  MATRIX 
  OF 
  THE 
  GARNET-BEARING 
  ROCK 
  

   IN 
  THE 
  ROGERS 
  AND 
  HOOPER 
  MINES 
  * 
  

  

  

  

  h 
  

  

  

  £13 
  

  

  

  

  a 
  

  

  

  s 
  

  

  .-§ 
  

  

  s- 
  

  

  d 
  

  

  

  

  

  

  Z£ 
  

  

  Plagioclase 
  

  

  £« 
  

  

  

  

  

  eJ-43 
  

  

  'I 
  

  

  « 
  

  

  >» 
  

  

  lH 
  

  

  

  

  O 
  <■> 
  

  

  

  H 
  J3 
  

  

  « 
  

  

  

  S 
  

  

  N 
  

  

  <: 
  

  

  Pn 
  

  

  tSJ 
  

  

  Rogers 
  mine 
  

  

  I 
  

  

  20 
  

  

  Lab. 
  20 
  

  

  40 
  

  

  3 
  

  

  15 
  

  

  1 
  

  

  I 
  

  

  

  

  

  

  2 
  

  

  30 
  

  

  01. 
  -an. 
  30 
  

  

  36 
  

  

  

  

  1 
  

  

  2 
  

  

  little 
  

  

  1 
  

  

  

  

  3 
  

  

  50 
  

  

  And. 
  25 
  

  

  24 
  

  

  

  

  

  I 
  

  

  little 
  

  

  

  

  Hooper 
  mine 
  

  

  4 
  

  

  42 
  

  

  01. 
  -and. 
  20 
  

  

  30 
  

  

  5 
  

  

  2 
  

  

  

  h 
  

  

  

  

  4 
  

  

  

  S 
  

  

  30 
  

  

  Ol.-and. 
  35 
  

  

  33 
  

  

  4 
  

  

  + 
  

  

  1 
  

  

  

  

  

  little 
  

  

  

  6 
  

  

  40 
  

  

  01. 
  -and. 
  20 
  

  

  35 
  

  

  

  4 
  

  

  1 
  

  

  

  

  

  

  2 
  A 
  close 
  approximation 
  to 
  percentage 
  by 
  volume 
  only 
  is 
  intended. 
  

  

  As 
  shown 
  in 
  the 
  field, 
  in 
  hand 
  specimens, 
  and 
  in 
  thin-sections 
  the 
  

   garnet 
  rock 
  (Nos. 
  4, 
  5, 
  and 
  6 
  of 
  the 
  table) 
  at 
  the 
  Hooper 
  mine 
  is 
  

   almost 
  exactly 
  like 
  the 
  wall 
  or 
  transition 
  rock 
  of 
  the 
  Rogers 
  mine, 
  

   and 
  it 
  also 
  appears 
  to 
  grade 
  into 
  the 
  country 
  rock. 
  In 
  each 
  case 
  the 
  

   garnets 
  never 
  show 
  reaction 
  rims 
  of 
  hornblende 
  and 
  the 
  garnets 
  

   often 
  show 
  good 
  crystal 
  outlines. 
  In 
  the 
  Hooper 
  mine 
  this 
  tran- 
  

   sition 
  or 
  intermediate 
  rock 
  makes 
  up 
  practically 
  the 
  whole 
  mass 
  

   ■which 
  is 
  mined 
  and 
  is 
  thus 
  much 
  more 
  extensive 
  than 
  at 
  the 
  

   Rogers 
  mine. 
  All 
  evidence 
  points 
  to 
  the 
  origin 
  of 
  the 
  Hooper 
  

   mine 
  rock 
  as 
  due 
  to 
  rather 
  thorough 
  melting 
  of 
  an 
  admixture 
  

   •of 
  syenite 
  and 
  Grenville 
  sediment 
  where 
  the 
  Grenville 
  inclusion 
  

   ■was 
  perhaps 
  deeper 
  down 
  in 
  the 
  magma 
  and 
  hence 
  subjected 
  to 
  

   much 
  greater 
  heat, 
  or 
  possibly 
  a 
  number 
  of 
  smaller 
  hornblende 
  

   gneiss 
  inclusions, 
  perhaps 
  with 
  some 
  limestone, 
  were 
  assimilated 
  

   by 
  the 
  molten 
  syenite. 
  

  

  BIBLIOGRAPHY 
  

  

  Merrill, 
  F. 
  J. 
  H. 
  Mineral 
  Resources 
  of 
  New 
  York. 
  N. 
  Y. 
  State 
  Mus. 
  Bui. 
  

  

  15- 
  i895 
  

   Kemp, 
  J. 
  F. 
  and 
  Newland, 
  D. 
  H. 
  17th 
  An. 
  Rep. 
  N. 
  Y. 
  State 
  Geol., 
  pages 
  

  

  548-49- 
  1897. 
  

   Hooper, 
  F. 
  C. 
  The 
  American 
  Garnet 
  Industry. 
  Mineral 
  Industry, 
  v. 
  6. 
  

  

  1897 
  

   Magnus, 
  H. 
  C. 
  Abrasives 
  of 
  New 
  York 
  State. 
  N. 
  Y. 
  State 
  Geol., 
  23d 
  An. 
  

  

  Rep. 
  1904 
  

   Newland, 
  D. 
  H. 
  Mining 
  and 
  Quarry 
  Industry 
  of 
  New 
  York 
  State. 
  N. 
  Y. 
  

  

  State 
  Mus. 
  Bui. 
  102, 
  pages 
  70-73, 
  and 
  later 
  annual 
  reports 
  on 
  the 
  

  

  mines 
  and 
  quarries 
  of 
  the 
  State. 
  1906 
  

  

  