﻿252 
  GEOLOGY. 
  

  

  Another, 
  of 
  nearly 
  half 
  the 
  extent, 
  is 
  seen 
  at 
  Natchez 
  

   Island, 
  six 
  miles 
  below 
  the 
  city. 
  

  

  On 
  a 
  bar 
  at 
  the 
  base 
  of 
  the 
  Natchez 
  Bluff, 
  and 
  on 
  

   another 
  in 
  the 
  Mississippi 
  River, 
  about 
  five 
  miles 
  below 
  

   Rodney, 
  considerable 
  deposits 
  are 
  found, 
  the 
  latter 
  only 
  

   exposed 
  at 
  low 
  water. 
  

  

  On 
  these 
  river 
  bars, 
  the 
  finest 
  and 
  largest 
  of 
  the 
  sard 
  

   agates 
  and 
  carnelians 
  have 
  been 
  obtained. 
  

  

  Many 
  other 
  extensive 
  beds 
  have 
  been 
  noticed 
  more 
  in 
  

   the 
  interior, 
  but 
  have 
  not 
  been 
  much 
  explored, 
  and 
  it 
  is 
  

   not 
  necessary 
  to 
  specify 
  others. 
  

  

  Petrified 
  wood 
  has 
  been 
  spoken 
  of 
  as 
  constituting 
  some 
  

   of 
  the 
  ingredients 
  of 
  the 
  drift. 
  I 
  would 
  not 
  be 
  under- 
  

   stood, 
  however, 
  as 
  referring 
  it 
  all 
  to 
  that 
  origin. 
  On 
  the 
  

   contrary, 
  petrified 
  wood 
  is 
  of 
  very 
  general 
  occurrence 
  

   over 
  a 
  large 
  portion 
  of 
  the 
  State, 
  and 
  will 
  be 
  further 
  

   noticed 
  under 
  the 
  head 
  of 
  Palaeontology, 
  hereafter 
  to 
  be 
  

   treated 
  of. 
  

  

  I 
  incline 
  to 
  the 
  belief, 
  however, 
  that 
  the 
  silicified 
  

   palms 
  or 
  endogenous 
  woods, 
  which 
  have 
  so 
  far 
  been 
  

   found 
  only 
  within 
  a 
  limited 
  compass, 
  not 
  exceeding 
  an 
  

   area 
  perhaps 
  of 
  ten 
  miles 
  in 
  extent, 
  are 
  derived, 
  like 
  the 
  

   boulders 
  with 
  which 
  they 
  are 
  associated, 
  from 
  a 
  foreign 
  

   source. 
  

  

  These 
  endogens 
  have 
  all, 
  more 
  or 
  less, 
  a 
  rounded 
  

   water-worn 
  character, 
  and 
  being 
  confined, 
  so 
  far 
  as 
  yet 
  

   observed, 
  to 
  a 
  single 
  locality, 
  may 
  have 
  formed 
  part 
  of 
  

   the 
  freight 
  of 
  an 
  extended 
  ice-floe, 
  which, 
  grounding 
  in 
  

   that 
  quarter, 
  discharged 
  its 
  contents 
  upon 
  the 
  surface. 
  

  

  A 
  variation 
  in 
  the 
  character 
  of 
  the 
  predominating 
  rock 
  

   or 
  fossils 
  composing 
  the 
  beds 
  of 
  drift 
  in 
  different 
  locali- 
  

   ties 
  has 
  been 
  observed, 
  suo-o-estins; 
  a 
  conclusion 
  that 
  

   separate 
  fields 
  of 
  ice, 
  starting 
  from 
  various 
  points, 
  

   charged 
  with 
  the 
  detritus 
  of 
  dissimilar 
  formations, 
  or 
  

  

  