﻿GEOLOGY 
  OF 
  MADAGASCAR. 
  

  

  327 
  

  

  further 
  investigation 
  by 
  future 
  travellers 
  some 
  sandstone 
  rocks 
  a 
  

   little 
  further 
  to 
  the 
  north 
  : 
  they 
  seemed 
  to 
  me, 
  from 
  a 
  very 
  cursory 
  

   examination, 
  to 
  be 
  striated 
  ; 
  but 
  of 
  this 
  I 
  am 
  by 
  no 
  means 
  certain. 
  

  

  It 
  would 
  be 
  highly 
  interesting 
  to 
  know 
  whether 
  there 
  really 
  are 
  

   any 
  signs 
  of 
  glacial 
  action 
  in 
  Madagascar, 
  and 
  therefore 
  I 
  mention 
  

   the 
  above 
  phenomena 
  in 
  the 
  hope 
  that 
  they 
  will 
  receive 
  further 
  

   attention 
  at 
  some 
  future 
  time. 
  

  

  It 
  may 
  be 
  as 
  well 
  here 
  to 
  give 
  a 
  list 
  of 
  the 
  metamorphic 
  and 
  sedi- 
  

   mentary 
  strata 
  of 
  Madagascar, 
  so 
  far 
  as 
  they 
  are 
  at 
  present 
  known, 
  

   referred 
  to 
  the 
  European 
  standard 
  of 
  geological 
  chronology 
  : 
  — 
  

  

  Post-Tertiary 
  . 
  Recent. 
  

   Tertiary 
  Eocene. 
  

  

  ( 
  Cretaceous 
  ... 
  {^P 
  61 
  "- 
  . 
  

  

  L 
  IN 
  eocomian 
  . 
  

  

  Secondary 
  ... 
  \ 
  fOxfordian 
  

  

  I 
  T 
  Lower 
  Oolite 
  (Cornbrash. 
  Bradford 
  

  

  Jurassic 
  \ 
  m 
  -*? 
  n 
  v 
  , 
  4.1 
  \ 
  

  

  ^ 
  Clay, 
  duller 
  s 
  earth). 
  

  

  (Lias. 
  

  

  -n 
  I 
  Silurian 
  ? 
  

  

  Paleozoic... 
  | 
  Cambrian? 
  

  

  Archsean. 
  

  

  Economic 
  Pkodtjcts. 
  

  

  Little 
  is 
  known 
  with 
  regard 
  to 
  the 
  metals 
  and 
  industrial 
  products 
  

   of 
  the 
  island, 
  as 
  the 
  native 
  laws 
  have 
  hitherto 
  prohibited 
  mining 
  of 
  

   every 
  description. 
  It 
  is 
  now 
  well 
  known, 
  however, 
  that 
  gold 
  has 
  

   recently 
  been 
  discovered 
  in 
  somewhat 
  large 
  quantity 
  in 
  certain 
  

   localities, 
  and, 
  judging 
  from 
  the 
  nature 
  of 
  the 
  rocks, 
  will 
  doubtless 
  

   be 
  found 
  in 
  others 
  when 
  the 
  country 
  is 
  opened 
  up. 
  The 
  Govern- 
  

   ment, 
  which 
  retains 
  the 
  monopoly 
  of 
  the 
  precious 
  metal, 
  has 
  recently 
  

   been 
  obtaining 
  it 
  from 
  Mevatanana 
  and 
  Ampasiria, 
  places 
  about 
  

   halfway 
  between 
  Antananarivo 
  and 
  Mojanga. 
  Small 
  quantities 
  

   have 
  also 
  been 
  obtained 
  from 
  the 
  bed 
  of 
  a 
  stream 
  near 
  Itompoana- 
  

   nandrariny, 
  in 
  the 
  west 
  of 
  Yalalafotsy 
  district, 
  and 
  also 
  a 
  few 
  miles 
  

   to 
  the 
  south 
  of 
  the 
  capital, 
  and 
  perhaps 
  in 
  other 
  localities 
  as 
  well. 
  

   The 
  gold 
  is 
  said 
  to 
  be 
  of 
  excellent 
  quality 
  ; 
  at 
  present, 
  however, 
  the 
  

   laws 
  forbid 
  both 
  the 
  search 
  for 
  it 
  and 
  the 
  sale 
  of 
  it, 
  although 
  by 
  no 
  

   means 
  all 
  finds 
  its 
  way 
  into 
  the 
  national 
  treasury. 
  Silver, 
  as 
  yet, 
  

   does 
  not 
  seem 
  to 
  have 
  been 
  discovered. 
  Galena 
  is 
  found 
  abundantly 
  

   somewhere 
  in 
  the 
  neighbourhood 
  of 
  Ankaratra, 
  and 
  silver, 
  it 
  is 
  said, 
  

   is 
  being 
  extracted 
  from 
  it. 
  The 
  natives 
  obtain 
  their 
  lead, 
  which 
  is 
  

   used 
  chiefly 
  for 
  bullets, 
  principally, 
  if 
  not 
  entirely, 
  from 
  this 
  galena. 
  

   Tin 
  is 
  said 
  to 
  occur 
  in 
  the 
  district 
  of 
  Yakin' 
  Ankaratra, 
  but 
  this 
  

   requires 
  verifying. 
  Copper 
  exists 
  apparently 
  in 
  great 
  quantity 
  also 
  

   in 
  Yakin' 
  Ankaratra. 
  Iron 
  is 
  found, 
  as 
  has 
  already 
  been 
  stated, 
  in 
  

   abundance 
  as 
  magnetite, 
  also 
  as 
  haematite 
  and 
  ironstone. 
  Sulphur 
  

   occurs 
  in 
  beds 
  near 
  Antsirabe, 
  in 
  the 
  neighbourhood 
  of 
  extinct 
  vol- 
  

   canoes, 
  and 
  at 
  Madera 
  (?) 
  to 
  the 
  north-west 
  of 
  Ankaratra. 
  It 
  is 
  

   brought 
  to 
  Imerina, 
  where 
  (after 
  being 
  separated 
  from 
  its 
  impuri- 
  

  

  