﻿CLAYS 
  OF 
  NEW 
  YORK 
  837 
  

  

  often 
  the 
  predominating 
  rock, 
  though 
  from 
  weathering 
  to 
  an 
  olive 
  

   •color 
  it 
  does 
  not 
  always 
  appear 
  as 
  distinctly 
  ". 
  

  

  ^^ 
  In 
  the 
  ravines 
  in 
  Chautauqua 
  co., 
  extending 
  toward 
  Lake 
  

   Erie, 
  the 
  shale 
  still 
  retains 
  its 
  green 
  color 
  ". 
  

  

  Jamestown, 
  Chautauqua 
  co. 
  This 
  sample 
  of 
  shale 
  came 
  from 
  

   the 
  hank 
  of 
  the 
  Jamestown 
  shale 
  paving 
  brick 
  co. 
  

  

  This 
  was 
  a 
  rather 
  gritty 
  shale, 
  which 
  required 
  18.5^ 
  of 
  water 
  to 
  

   make 
  a 
  workable 
  paste 
  ; 
  plasticity, 
  lean. 
  The 
  paste 
  shrunk 
  4.5,^ 
  in 
  

   drying, 
  and 
  an 
  additional 
  7.5^ 
  in 
  burning, 
  making 
  a 
  total 
  shrink- 
  

   age 
  of 
  12^. 
  Air-dried 
  briquettes 
  made 
  of 
  this 
  mud 
  had 
  an 
  average 
  

   tensile 
  strength 
  of 
  16 
  pounds 
  a 
  square 
  inch, 
  and 
  a 
  maximum 
  of 
  20 
  

   pounds 
  a 
  square 
  inch. 
  This 
  low 
  tensile 
  strength 
  was 
  due 
  to 
  the 
  

   silicious 
  character 
  of 
  the 
  shale 
  which, 
  however, 
  permitted 
  rapid 
  

   drying. 
  

  

  Incipient 
  fusion 
  occurred 
  at 
  cone 
  .04, 
  vitrification 
  at 
  cone 
  .01 
  

   and 
  viscosity 
  at 
  cone 
  3. 
  The 
  clay 
  burns 
  to 
  a 
  deep 
  red 
  and 
  dense 
  

   body. 
  

  

  A 
  sample 
  collected 
  by 
  the 
  writer 
  a 
  year 
  later, 
  representing 
  an 
  

   average 
  of 
  the 
  material 
  used, 
  gave: 
  water 
  required 
  tO' 
  mix 
  up, 
  17/^; 
  

   tensile 
  strength, 
  45-69 
  pounds; 
  plasticity, 
  lean; 
  incipient 
  fusion 
  

   cone 
  .06, 
  with 
  5^ 
  shrinkage; 
  vitrification 
  .01, 
  with 
  10^ 
  shrinkage; 
  

   viscosity 
  at 
  cone 
  2. 
  When 
  vitrified 
  the 
  clay 
  bums 
  deep 
  red. 
  Sol- 
  

   uble 
  salts 
  .55^. 
  

  

  Alfred 
  center, 
  Allegany 
  co. 
  Chemung 
  shale 
  is 
  used 
  at 
  this 
  

   locality 
  for 
  the 
  manufacture 
  of 
  roofing 
  tile. 
  The 
  shale 
  is 
  some- 
  

   what 
  argillaceous, 
  and 
  moderately 
  fine-grained. 
  

  

  It 
  requires 
  20^ 
  of 
  water 
  to 
  make 
  a 
  workable 
  mass, 
  which 
  is 
  

   slightly 
  plastic. 
  The 
  shrinkage 
  of 
  this 
  paste 
  in 
  drying 
  is 
  4^ 
  and 
  

   in 
  burning 
  9^. 
  The 
  tensile 
  strength 
  of 
  air-dried 
  briquettes 
  was, 
  

   on 
  the 
  average, 
  61 
  pounds 
  a 
  square 
  inch, 
  with 
  a 
  maximum 
  of 
  62 
  

   pounds 
  a 
  square 
  inch. 
  

  

  Incipient 
  fusion 
  occurs 
  at 
  cone 
  .06, 
  vitrification 
  at 
  cone 
  .01, 
  and 
  

   viscosity 
  at 
  cone 
  3. 
  

  

  