﻿GEOLOGY. 
  213 
  

  

  the 
  subject, 
  I 
  shall 
  proceed 
  to 
  give 
  a 
  detailed 
  statement 
  

   of 
  the 
  rocks 
  and 
  minerals 
  that 
  have 
  been 
  observed, 
  with 
  

   reference 
  to 
  their 
  character 
  and 
  position. 
  

  

  LOESS, 
  OR 
  LOAM. 
  

  

  A 
  prominent 
  and 
  interesting 
  feature, 
  which 
  distin- 
  

   guishes 
  the 
  counties 
  bordering 
  upon 
  the 
  Mississippi 
  

   below 
  the 
  Yazoo, 
  is 
  found 
  in 
  that 
  considerable 
  deposit 
  

   superimposed 
  on 
  the 
  diluvial 
  gravel, 
  and 
  which 
  enters 
  

   into 
  the 
  more 
  easterly 
  range 
  of 
  counties 
  only 
  along 
  the 
  

   margins 
  of 
  the 
  Homochitto, 
  Big 
  Black, 
  and 
  Yazoo 
  Elvers. 
  

   Its 
  average 
  width, 
  on 
  the 
  east 
  side 
  of 
  the 
  Mississippi, 
  

   does 
  not 
  exceed 
  twelve 
  miles, 
  and 
  it 
  is 
  not 
  met 
  with 
  at 
  

   all 
  on 
  the 
  western 
  side, 
  at 
  least 
  below 
  the 
  high 
  lands 
  of 
  

   Arkansas. 
  

  

  In 
  the 
  escarpment 
  of 
  the 
  Mississippi 
  Bluffs, 
  and 
  in 
  

   other 
  natural 
  sections, 
  it 
  is 
  seen 
  frequently 
  of 
  the 
  thick- 
  

   ness 
  of 
  fifty 
  or 
  sixty 
  feet, 
  thinning 
  out 
  as 
  you 
  recede 
  

   from 
  the 
  river, 
  until 
  it 
  is 
  lost, 
  and 
  the 
  red 
  sands 
  and 
  

   pebbles 
  on 
  which 
  it 
  rests, 
  appear 
  upon 
  the 
  surface. 
  

  

  European 
  geologists 
  describe 
  it, 
  under 
  the 
  name 
  of 
  

   Loess, 
  or 
  Lehm, 
  "as 
  an 
  alluvial 
  tertiary, 
  sedimentary 
  

   deposit, 
  consisting 
  of 
  very 
  fine, 
  well-washed, 
  yellow, 
  

   calcareous 
  loam, 
  occurring 
  over 
  considerable 
  tracts, 
  and 
  

   found 
  reposing 
  on 
  every 
  rock 
  from 
  the 
  granite 
  of 
  Heidel- 
  

   berg 
  to 
  the 
  gravel 
  on 
  the 
  plains 
  of 
  the 
  Rhine." 
  

  

  Here 
  it 
  has 
  not 
  the 
  character 
  of 
  a 
  local 
  alluvium, 
  and 
  

   is 
  probably 
  due 
  to 
  the 
  same 
  causes 
  that 
  have 
  spread 
  the 
  

   gravel 
  and 
  pebble 
  deposits 
  so 
  widely 
  over 
  our 
  surface. 
  

  

  In 
  March, 
  1846, 
  being 
  desirous 
  of 
  drawing 
  the 
  atten- 
  

   tion 
  of 
  Mr. 
  L^^ell, 
  then 
  on 
  a 
  visit 
  to 
  this 
  State, 
  to 
  this 
  

   peculiar 
  and 
  interesting 
  deposit, 
  he 
  accompanied 
  me 
  on 
  

  

  