﻿CLAYS 
  OF 
  NEW 
  YORK 
  835 
  

  

  sandstones 
  become 
  more 
  prominent, 
  but 
  to 
  the 
  west 
  the 
  shales 
  in- 
  

   crease 
  and 
  predominate, 
  so 
  that 
  along 
  Lake 
  Erie, 
  " 
  the 
  O^shaqua 
  

   shale 
  is 
  succeeded 
  by 
  a 
  thick 
  mass 
  of 
  black 
  shale, 
  and 
  this 
  again 
  by 
  

   alternations 
  of 
  green 
  and 
  black 
  shales 
  ", 
  which 
  aggregate 
  several 
  

   hundred 
  feet 
  in 
  thickness. 
  

  

  Angola^ 
  Erie 
  co. 
  The 
  Portage 
  shale 
  is 
  used 
  by 
  J. 
  Lyth 
  & 
  Sons 
  

   at 
  this 
  locality 
  for 
  the 
  manufacture 
  of 
  sewer 
  pipe, 
  fireproofing, 
  

   drain 
  tile 
  and 
  terra 
  cotta. 
  The 
  clay 
  is 
  somewhat 
  less 
  gritty 
  thkn 
  

   that 
  at 
  JamestOAvn. 
  It 
  is 
  a 
  grayish, 
  moderately 
  coarse-grained 
  

   shale 
  and 
  contains 
  scattered 
  streaks 
  of 
  bituminous 
  matter. 
  

  

  When 
  ground 
  to 
  30 
  mesh 
  it 
  required 
  21.4^ 
  of 
  water 
  to 
  work 
  it 
  

   up, 
  giving 
  a 
  moderately 
  plastic 
  mass. 
  The 
  air 
  shrinkage 
  was 
  

   and 
  the 
  fire 
  shrinkage 
  10^. 
  The 
  air-dried 
  briquets 
  had 
  an 
  

   average 
  tensile 
  strength 
  of 
  92 
  pounds 
  a 
  square 
  inch, 
  and 
  a 
  maxi- 
  

   mum 
  of 
  95 
  pounds 
  a 
  square 
  inch. 
  Incipient 
  fusion 
  occurs 
  at 
  

   cone 
  . 
  06, 
  vitrification 
  at 
  cone 
  . 
  01 
  and 
  viscosity 
  at 
  cone 
  4. 
  

   The 
  analysis 
  of 
  the 
  clay 
  is 
  as 
  follows 
  •} 
  

  

  Silica 
  65.15 
  

  

  Alumina 
  15 
  . 
  29 
  

  

  Ferric 
  oxid 
  6.16 
  

  

  Lime 
  3 
  . 
  50 
  

  

  Magnesia 
  1 
  . 
  57 
  

  

  Alkalis 
  5 
  . 
  71 
  

  

  97.38 
  

   Total 
  fluxing 
  impurities 
  16 
  . 
  94 
  

  

  In 
  general 
  composition 
  it 
  resembles 
  a 
  Carboniferous 
  shale 
  used 
  

   for 
  paving 
  brick 
  at 
  Kansas 
  City, 
  Mo.^ 
  This 
  shows 
  the 
  following 
  

   analysis 
  : 
  

  

  Silica 
  64.37 
  

  

  Alumina 
  19.73 
  

  

  ' 
  Bulletin 
  New 
  York 
  state 
  museum, 
  no. 
  12, 
  v. 
  8, 
  p. 
  228. 
  

   ' 
  Clay 
  worker, 
  December 
  1893. 
  

  

  