﻿226 
  NEW 
  YOIiK 
  STATE 
  MUSEUM 
  

  

  rocks 
  which 
  adjoin, 
  or 
  are 
  intercalated 
  with, 
  the 
  crystalline 
  lime- 
  

   stone. 
  It 
  is 
  found 
  in 
  stegregated 
  masses 
  of 
  yarying 
  sizes 
  from 
  

   (fhat 
  of 
  a 
  pigeon's 
  egg 
  to 
  a 
  diameter 
  of 
  20 
  feet. 
  It 
  is 
  commer- 
  

   cially 
  cliasisified 
  as 
  massive 
  garnet, 
  shell 
  garnet 
  and 
  pocket 
  gar- 
  

   net, 
  the 
  former 
  being 
  impure 
  from 
  the 
  admixture 
  of 
  other 
  miner- 
  

   als. 
  The 
  shell 
  garnet 
  is 
  almost 
  entirely 
  pure 
  and 
  the 
  mo-st 
  valu- 
  

   aible 
  for 
  industrial 
  purposes. 
  The 
  pocket 
  gairnet 
  is 
  that 
  w'hich 
  

   occurs 
  in 
  small 
  segregations 
  or 
  incipient 
  crystals 
  in 
  the 
  gneiss. 
  

   This 
  garnet 
  is 
  used 
  almost 
  exclusiyely 
  in 
  the 
  manufacture 
  of 
  

   sandpaper, 
  or 
  garnet-paper, 
  as 
  it 
  is 
  called, 
  which 
  is 
  employed 
  

   extensively 
  for 
  abrasive 
  purposes 
  in 
  the 
  manufacture 
  of 
  boots 
  

   and 
  shoes. 
  It 
  is 
  also 
  employed 
  to 
  some 
  extent 
  in 
  the 
  wood 
  

   manufacturing 
  industry. 
  For 
  metals 
  garnet 
  is 
  niot 
  as 
  good 
  as 
  

   emery, 
  although 
  some 
  satisfactory 
  results 
  have 
  been 
  obtained 
  

   from 
  its 
  use 
  o^n 
  brass. 
  It 
  has 
  been 
  experimentally 
  mixed 
  with 
  

   emery 
  in 
  the 
  manufacture 
  of 
  emery-wheels 
  but 
  without 
  very 
  

   eiatisfactoTy 
  results. 
  

  

  Emery 
  

  

  The 
  variety 
  of 
  Corundum 
  known 
  as 
  emery 
  is 
  quarried 
  at 
  many 
  

   points 
  in 
  Cortlandt 
  township, 
  Westchester 
  county, 
  from 
  deposits 
  

   which 
  occur 
  in 
  the 
  eruptive 
  rocks 
  known 
  as 
  the 
  * 
  Cortlandt 
  series.' 
  

   It 
  is 
  used 
  by 
  the 
  New 
  York 
  Emery 
  Company 
  at 
  Peekskill. 
  

  

  DiATOMACEous 
  Earth 
  — 
  Infusorial 
  Earth 
  

  

  This 
  material 
  consists 
  of 
  hydrated 
  silica, 
  and 
  is 
  the 
  accumu- 
  

   lation 
  of 
  the 
  minute 
  skeletons 
  of 
  microscopic 
  forms 
  of 
  vegetable 
  

   life 
  known 
  as 
  diatoms. 
  It 
  accumulates 
  in 
  the 
  bottom 
  of 
  ponds 
  

   and 
  lakes, 
  and 
  is 
  found 
  in 
  recent 
  as 
  well 
  as 
  Tertiary 
  and 
  Cretace- 
  

   ous 
  formations. 
  While 
  the 
  living 
  diatoms 
  are 
  found 
  in 
  all 
  the 
  

   waters 
  of 
  the 
  state, 
  deposits 
  of 
  diatomaceous 
  earth 
  have 
  been 
  

   reported 
  from 
  only 
  two 
  localities. 
  One 
  of 
  these 
  is 
  in 
  White 
  

   lake, 
  town 
  of 
  Wilmurt, 
  Herkimer 
  county, 
  and 
  the 
  other 
  is 
  on 
  the 
  

   shore 
  of 
  Cold 
  Spring 
  Harbor, 
  Long 
  Island, 
  on 
  the 
  property 
  of 
  

   Dr. 
  Oliver 
  Jones. 
  The 
  latter 
  is 
  a 
  fossil 
  deposit 
  in 
  beds 
  probably 
  

   of 
  Tertiary 
  age. 
  The 
  White 
  lake 
  deposit 
  is 
  the 
  only 
  one 
  in 
  use 
  

  

  