﻿340 
  ON 
  THE 
  GEOLOGY 
  OF 
  A 
  PART 
  OF 
  COSTA 
  RICA. 
  

  

  Discussion. 
  

  

  Mr. 
  Batterman 
  expressed 
  his 
  sense 
  of 
  the 
  value 
  of 
  a 
  section 
  

   made 
  in 
  a 
  little-known 
  country. 
  It 
  was 
  an 
  interesting 
  question, 
  

   looking 
  at 
  the 
  comparatively 
  modern 
  date 
  of 
  the 
  igneous 
  rock 
  de- 
  

   scribed 
  and 
  the 
  absence 
  of 
  schistose 
  rock, 
  whether 
  the 
  seas 
  had 
  

   previously 
  communicated. 
  As 
  for 
  the 
  condition 
  of 
  the 
  transformed 
  

   masses 
  of 
  rock 
  containing 
  minerals, 
  he 
  was 
  glad 
  to 
  find 
  Mr. 
  Attwood 
  

   had 
  observed 
  it 
  ; 
  for 
  he 
  had 
  noticed 
  the 
  same 
  thing 
  in 
  Spain 
  and 
  

   North 
  America, 
  and 
  thought 
  that 
  it 
  had 
  been 
  too 
  often 
  overlooked 
  

   in 
  the 
  search 
  for 
  lodes. 
  

  

  Mr. 
  Warington 
  Smyth 
  said 
  he 
  should 
  like 
  to 
  ask 
  Mr. 
  Attwood 
  

   on 
  what 
  grounds 
  he 
  stated 
  that 
  there 
  were 
  no 
  more 
  ancient 
  rocks 
  

   than 
  those 
  which 
  he 
  had 
  seen. 
  Had 
  not 
  vegetation 
  possibly 
  masked 
  

   them, 
  and 
  might 
  not 
  there 
  be 
  granitic 
  rocks 
  to 
  furnish 
  the 
  kaolin 
  ? 
  

   Was 
  the 
  coal 
  merely 
  carbonized 
  stems 
  or 
  a 
  true 
  lignite 
  ? 
  Was 
  the 
  

   entire 
  run 
  of 
  the 
  veins 
  metalliferous 
  ? 
  

  

  Mr. 
  Attwood 
  said 
  that 
  he 
  had 
  not 
  himself 
  seen 
  any 
  other 
  case 
  of 
  

   metalliferous 
  rock 
  like 
  those 
  which 
  he 
  had 
  described. 
  Yery 
  likely 
  

   the 
  oceans 
  had 
  once 
  communicated. 
  He 
  saw 
  no 
  signs 
  of 
  granite 
  in 
  

   the 
  country. 
  As 
  for 
  the 
  vein-matter 
  in 
  the 
  lodes, 
  he 
  thought 
  that 
  

   the 
  augite-andesite 
  and 
  the 
  fissures 
  in 
  which 
  these 
  lodes 
  occurred 
  

   were 
  of 
  about 
  the 
  same 
  age. 
  The 
  coal 
  was 
  only 
  limited 
  in 
  area, 
  but 
  

   varied 
  from 
  partly 
  carbonized 
  matter 
  to 
  true 
  lignite. 
  The 
  sandstones, 
  

   like 
  the 
  coal, 
  were 
  only 
  found 
  in 
  the 
  ravines 
  near 
  the 
  volcanoes, 
  

   and 
  were 
  of 
  small 
  area. 
  

  

  