﻿H. 
  E. 
  Gregory 
  — 
  La 
  Paz 
  (Bolivia) 
  Gorge. 
  

  

  145 
  

  

  band 
  for 
  over 
  two 
  miles 
  on 
  the 
  west 
  side 
  of 
  the 
  valley 
  and 
  

   reappearing 
  on 
  the 
  east 
  side 
  at 
  an 
  elevation 
  of 
  about 
  12,600 
  

   feet. 
  Microscopic 
  examination 
  shows 
  the 
  ash 
  to 
  be 
  dacitic. 
  

  

  Fig. 
  4. 
  

  

  Fig. 
  4. 
  View 
  of 
  deposits 
  in 
  La 
  Paz 
  gorge, 
  about 
  one 
  and 
  one-half 
  miles 
  

   west 
  of 
  the 
  American 
  Institute. 
  

  

  The 
  general 
  appearance 
  of 
  the 
  deposits 
  and 
  the 
  arrangement 
  

   and 
  alternation 
  of 
  strata 
  are 
  shown 
  in 
  tigs. 
  3 
  and 
  4, 
  with 
  which, 
  

   for 
  purposes 
  of 
  comparison, 
  is 
  inserted 
  a 
  typical 
  view 
  of 
  the 
  

   Dakota 
  bad 
  lands 
  (fig. 
  5). 
  

  

  