﻿292 
  GEOLOGY. 
  

  

  Indurated 
  Marl, 
  or 
  the 
  Rotten 
  Limestone 
  of 
  the 
  Prairies, 
  according 
  to 
  

  

  Dr. 
  Troost. 
  

  

  Carbonate 
  of 
  lime 
  ....... 
  51.00 
  

  

  Earthy 
  matter, 
  insoluble 
  in 
  water, 
  composed 
  of 
  green- 
  

   sand 
  and 
  particles 
  of 
  white 
  silvery 
  mica 
  . 
  . 
  34.00 
  

   Carbonaceous 
  matter 
  ...... 
  2.00 
  

  

  Alumina, 
  water, 
  and 
  loss 
  . 
  . 
  . 
  . 
  . 
  13 
  00 
  

  

  100.00 
  

   "The 
  particles 
  of 
  green-sand 
  are 
  very 
  minute, 
  and 
  

   are 
  only 
  perceptible 
  with 
  the 
  aid 
  of 
  the 
  microscope." 
  

  

  Composition 
  of 
  the 
  Green-sand 
  Mai-l 
  of 
  New 
  Jersey. 
  

   By 
  Prof. 
  H. 
  D. 
  Rogers. 
  

  

  Silex 
  51.00 
  

  

  Protoxide 
  of 
  iron 
  ....... 
  25.10 
  

  

  Alumina 
  . 
  7.50 
  

  

  Potash 
  9.30 
  

  

  Water 
  6.50 
  

  

  Lime 
  ......... 
  a 
  trace 
  

  

  99.40 
  

   '^In 
  a 
  few 
  instances, 
  the 
  deposits 
  are 
  a 
  pure 
  green- 
  

   sand. 
  The 
  composition 
  of 
  the 
  marl 
  in 
  a 
  great 
  number 
  

   of 
  instances 
  is 
  green-sand, 
  clay, 
  and 
  quartzose 
  sand 
  ; 
  the 
  

   green-sand 
  varying 
  from 
  35 
  to 
  95 
  per 
  cent." 
  

  

  100.00 
  100.00 
  100.00 
  

  

  The 
  foregoing 
  analyses 
  of 
  the 
  green-sand 
  of 
  Tennes- 
  

   see 
  will 
  probably 
  be 
  found 
  to 
  assimilate 
  more 
  nearly 
  to 
  

   the 
  lower 
  green-sands 
  of 
  Mississippi. 
  

  

  