﻿GEOLOGY. 
  231 
  

  

  In 
  New 
  Jersey, 
  the 
  green-sand 
  Marls, 
  so 
  called 
  by 
  

   Professor 
  H. 
  D. 
  Rogers, 
  have 
  been 
  in 
  use 
  for 
  more 
  than 
  

   forty 
  years. 
  

  

  As 
  the 
  green-sand 
  has 
  been 
  discovered 
  to 
  exist 
  under 
  

   "various 
  geological 
  relationships," 
  besides 
  those 
  it 
  pre- 
  

   sents 
  in 
  New 
  Jersey, 
  as 
  it 
  does 
  in 
  Virginia, 
  Maryland, 
  

   and 
  Delaware, 
  and 
  having 
  recognized 
  its 
  presence 
  in 
  

   this 
  State 
  associated 
  with 
  the 
  tertiary 
  marls 
  and 
  the 
  

   sulphate 
  of 
  lime, 
  I 
  am 
  inclined 
  to 
  follow 
  the 
  example 
  of 
  

   Professor 
  Eogers, 
  in 
  his 
  report 
  on 
  the 
  Geology 
  of 
  New 
  

   Jersey, 
  and 
  to 
  embrace 
  those 
  substances 
  among 
  our 
  

   marls, 
  giving 
  the 
  term 
  a 
  wider 
  acceptation 
  than 
  that 
  to 
  

   which 
  it 
  is 
  restricted 
  by 
  Mr. 
  Ruffin, 
  as 
  not 
  only 
  locally 
  

   more 
  convenient, 
  but 
  as 
  sanctioned 
  by 
  popular 
  usage 
  

   and 
  understanding, 
  as 
  comprehending 
  all 
  those 
  mineral 
  

   substances 
  or 
  compounds, 
  commonly 
  applied 
  to 
  the 
  soil 
  

   with 
  a 
  view 
  to 
  its 
  greater 
  productiveness, 
  and 
  not 
  re- 
  

   quiring 
  previous 
  pre|)aration, 
  such 
  as 
  the 
  burning 
  to 
  

   lime 
  or 
  grinding 
  into 
  plaster. 
  

  

  I 
  propose, 
  therefore, 
  for 
  the 
  present, 
  and 
  until 
  further 
  

   researches 
  and 
  developments 
  may 
  render 
  a 
  different 
  ar- 
  

   rangement 
  expedient, 
  to 
  consider 
  our 
  Marls 
  as 
  consti- 
  

   tuting 
  the 
  following 
  varieties 
  : 
  — 
  

  

  1. 
  Lahe 
  Marl. 
  — 
  That 
  found 
  in 
  limited 
  lakelike 
  de- 
  

   pressions; 
  the 
  beds 
  of 
  former 
  lakes 
  or 
  ponds 
  of 
  an 
  

   origin 
  either 
  preceding 
  or 
  subsequent 
  to 
  the 
  diluvial 
  

   period 
  ; 
  and 
  which 
  is 
  characterized 
  by 
  the 
  fresh-water 
  

   shells, 
  described 
  under 
  the 
  head 
  of 
  Palaeontology, 
  in- 
  

   cluding 
  Planorbis, 
  Cyclas, 
  Paludinas, 
  Lymnasa, 
  &c. 
  

  

  2. 
  Diluvial 
  Marl, 
  or 
  the 
  Loess 
  ; 
  a 
  finely 
  comminuted, 
  

   pulverulent, 
  silt-like 
  loam, 
  containing 
  thirty 
  per 
  cent, 
  or 
  

   more 
  of 
  carbonate 
  of 
  lime, 
  the 
  shells, 
  which 
  are 
  nu- 
  

   merous, 
  being 
  exclusively 
  terrestrial, 
  embracing 
  many 
  

   species 
  of 
  helices 
  or 
  snails. 
  

  

  