﻿La 
  SALLE 
  COUNTY. 
  39 
  

  

  NOTES 
  ON 
  LA 
  SALLE 
  COUNTY. 
  

  

  LaSalle 
  is 
  one 
  of 
  the 
  most 
  interesting 
  counties 
  in 
  the 
  State, 
  not 
  

   only 
  from 
  the 
  variety 
  and 
  economic 
  value 
  of 
  its 
  mineral 
  resources, 
  

   but 
  also 
  from 
  the 
  peculiar 
  geological 
  phenomena 
  that 
  are 
  presented 
  

   within 
  its 
  borders. 
  Situated 
  on 
  the 
  northern 
  confines 
  of 
  the 
  great 
  

   coal 
  field 
  of 
  Illinois, 
  its 
  coal 
  products 
  find 
  a 
  ready 
  market 
  in 
  the 
  

   more 
  northerly 
  portions 
  of 
  this 
  and 
  the 
  adjoining 
  States 
  of 
  Wiscon- 
  

   sin 
  and 
  Minnesota, 
  where 
  no 
  productive 
  coal 
  beds 
  have 
  hitherto 
  been 
  

   found, 
  and 
  its 
  favorable 
  position 
  in 
  regard 
  to 
  the 
  iron 
  and 
  zinc 
  de- 
  

   posits 
  of 
  the 
  northwest 
  makes 
  this 
  county 
  an 
  eligible 
  location 
  for 
  

   the 
  economical 
  reduction 
  of 
  these 
  metallic 
  products. 
  

  

  Among 
  the 
  economical 
  resources 
  of 
  this 
  county, 
  bituminous 
  coal 
  

   ranks 
  first 
  in 
  importance, 
  and 
  is 
  found 
  underlying 
  nearly 
  all 
  that 
  

   portion 
  of 
  the 
  county 
  lying 
  south 
  of 
  the 
  Illinois 
  river, 
  as 
  well 
  as 
  a 
  

   limited 
  area 
  north 
  of 
  that 
  stream. 
  Four 
  coal 
  seams, 
  of 
  sufficient 
  

   thickness 
  to 
  be 
  of 
  practical 
  value 
  in 
  the 
  production 
  of 
  coal, 
  outcrop 
  

   within 
  the 
  limits 
  of 
  the 
  county, 
  and 
  are 
  the 
  representatives 
  of 
  coals 
  

   numbered 
  2, 
  4, 
  5 
  and 
  7 
  of 
  the 
  general 
  section 
  of 
  the 
  Coal 
  Measures 
  

   of 
  this 
  State. 
  

  

  Their 
  aggregate 
  thickness 
  is 
  about 
  sixteen 
  feet, 
  and 
  their 
  range 
  

   from 
  two 
  to 
  seven 
  feet, 
  and 
  they 
  will 
  be 
  described 
  further 
  on 
  in 
  in- 
  

   dicating 
  the 
  localities 
  where 
  they 
  are 
  worked. 
  

  

  An 
  anticlinal 
  axis 
  crosses 
  this 
  county 
  from 
  northwest 
  to 
  southeast, 
  

   having 
  its 
  center 
  in 
  the 
  valley 
  of 
  the 
  Illinois 
  river, 
  about 
  three 
  

   miles 
  east 
  of 
  the 
  city 
  of 
  LaSalle, 
  where 
  the 
  Lower 
  Magnesian 
  lime- 
  

   stone 
  of 
  Owen, 
  the 
  oldest 
  rock 
  in 
  the 
  State, 
  is 
  elevated 
  above 
  the 
  

   surface 
  to 
  the 
  height 
  of 
  about 
  80 
  feet. 
  The 
  Lower 
  Carboniferous, 
  

   Devonian 
  and 
  Upper 
  Silurian 
  formations 
  are 
  all 
  absent 
  in 
  this 
  por- 
  

   tion 
  of 
  the 
  State, 
  so 
  that 
  the 
  Coal 
  Measures 
  in 
  LaSalle 
  county 
  

   overlie, 
  unconformably, 
  both 
  the 
  Trenton 
  limestone 
  and 
  St. 
  Peters 
  

   sandstone 
  of 
  the 
  Lower 
  Silurian 
  series. 
  

  

  The 
  exposure 
  of 
  the 
  Lower 
  Magnesian 
  limestone 
  is 
  restricted 
  to 
  

   a 
  limited 
  area 
  in 
  the 
  valley 
  of 
  the 
  Illinois, 
  its- 
  outcrop 
  only 
  extend- 
  

   ing 
  eastward 
  from 
  Split-rock 
  [about 
  two 
  miles. 
  It 
  affords 
  the 
  best 
  

   hydraulic 
  limestone 
  in 
  the 
  State, 
  and 
  the 
  manufacture 
  of 
  hydraulic 
  

   cement 
  has 
  been 
  an 
  important 
  industry 
  at 
  Utica 
  for 
  many 
  years. 
  

  

  The 
  St. 
  Peters 
  sandstone, 
  which 
  immediately 
  overlays 
  the 
  Lower 
  

   Magnesian 
  limestone, 
  forms 
  the 
  main 
  portion 
  of 
  the 
  river 
  bluffs 
  from 
  

   near 
  Utica 
  to 
  a 
  point 
  two 
  or 
  three 
  miles 
  east 
  of 
  Ottawa, 
  and 
  on 
  Fox 
  

  

  