﻿144 
  II. 
  E. 
  Gregory 
  — 
  la 
  Paz 
  (Bolivia) 
  Gorge. 
  

  

  localities 
  studied 
  by 
  the 
  writer, 
  clay 
  is 
  relatively 
  small 
  in 
  

   amount, 
  the 
  larger 
  beds 
  being 
  100 
  to 
  200 
  feet 
  in 
  length 
  and 
  of 
  

   inconsiderable 
  thickness. 
  (4) 
  Carbonaceous 
  shale 
  and 
  two 
  

  

  Fig. 
  3. 
  

  

  Fig. 
  3. 
  View 
  of 
  deposits 
  in 
  La 
  Paz 
  gorge, 
  about 
  one 
  mile 
  west 
  of 
  the 
  

   American 
  Institute. 
  

  

  layers 
  or 
  lenses 
  of 
  impure 
  lignite 
  three 
  to 
  six 
  inches 
  thick, 
  

   composed 
  of 
  comminuted 
  plant 
  remains 
  too 
  fragmentary 
  for 
  

   determination. 
  (5) 
  Volcanic 
  ash, 
  eight 
  to 
  fifteen 
  (at 
  one 
  point 
  

   twenty 
  or 
  more) 
  feet 
  thick, 
  extending 
  as 
  a 
  continuous 
  white 
  

  

  