﻿Notes 
  upon 
  the 
  Lithology 
  of 
  the 
  Adikondacks. 
  109 
  

  

  present 
  in 
  them, 
  its 
  quantity 
  is 
  too 
  small 
  to 
  form 
  the 
  more 
  

   acidic 
  varieties 
  of 
  plagioclase 
  feldspars. 
  

  

  IV. 
  The 
  alkalies 
  are 
  notably 
  deficient, 
  potash 
  being 
  present 
  

   in 
  minute 
  quantities 
  and 
  potash 
  feldspars 
  wanting. 
  The 
  rela- 
  

   tive 
  preponderance 
  of 
  earthy 
  bases 
  is 
  further 
  shown 
  by 
  the 
  

   multitudes 
  of 
  iron-lime-alumina 
  garnets, 
  the 
  most 
  abundant 
  

   associated 
  mineral. 
  Also 
  by 
  the 
  iron-holding 
  hypersthenes 
  

   and 
  diallages, 
  and 
  the 
  general 
  occurrence 
  of 
  magnetite. 
  

  

  Y. 
  Menaccanite 
  is 
  found 
  universally 
  in 
  both 
  the 
  labradorites 
  

   and 
  pyroxenes 
  — 
  a 
  peculiarity 
  noticed 
  wherever 
  the 
  norites 
  have 
  

   been 
  investigated, 
  and 
  which 
  probably 
  will 
  be 
  found 
  universal. 
  

  

  VI. 
  In 
  the 
  menaccanite 
  of 
  certain 
  localities, 
  over 
  one 
  per 
  

   cent 
  of 
  chromite 
  has 
  been 
  found 
  — 
  an 
  association 
  apparently 
  not 
  

   hitherto 
  observed. 
  

  

  Stevens' 
  Institute 
  of 
  Technology, 
  

   March 
  1st, 
  1877. 
  

  

  