﻿208 
  Drs. 
  Smeeth 
  and 
  Watson 
  on 
  the 
  Radioactivity 
  of 
  

  

  The 
  following 
  classification 
  is 
  inserted 
  for 
  convenience 
  of 
  

   reference, 
  and 
  shows 
  the 
  order 
  of 
  succession 
  and 
  relationship 
  

   of 
  the 
  various 
  formations 
  in 
  Mysore 
  as 
  at 
  present 
  adopted 
  by 
  

   the 
  Mysore 
  Geological 
  Survey*. 
  

  

  Classification 
  of 
  Mysore 
  Rocks. 
  

  

  Possibly 
  Tertiary. 
  

   Pre-Cambrian 
  \ 
  „ 
  

   (Aniinikean) 
  J 
  

  

  1. 
  Recent 
  soils 
  and 
  gravels. 
  

  

  2. 
  Laterite. 
  Horizontal 
  sheet 
  capping 
  

  

  Mi 
  

   I 
  1 
  

  

  Dharwar 
  

   System 
  

   (probably 
  

   Keewatin). 
  

  

  Archaeans. 
  

  

  Basic 
  dykes. 
  Chiefly 
  various 
  dolerites. 
  

  

  Great 
  Eparchcean 
  Interval. 
  

  

  4. 
  Felsite 
  and 
  porphyry 
  dykes. 
  

  

  5. 
  Closepet 
  granite 
  and 
  other 
  massifs 
  of 
  corresponding 
  

  

  age. 
  

  

  6. 
  Charnockite, 
  norite, 
  and 
  pyroxenite 
  dykes. 
  

  

  7. 
  Charnockite 
  massifs. 
  (Complex.) 
  

  

  8. 
  Various 
  hornblendic 
  and 
  pyroxene-granulite 
  dykes. 
  

  

  9. 
  Peninsular 
  gneiss. 
  (Granite 
  and 
  gneissic 
  complex.) 
  

   10. 
  Champion 
  gneiss. 
  (Granite 
  porphyry, 
  micaceous 
  

  

  gneisses, 
  felsites 
  and 
  quartz 
  porphyries 
  ; 
  usually 
  con- 
  

   taining 
  opalescent 
  quartz 
  and 
  frequently 
  associated 
  

   with 
  autoplastic 
  conglomerates.) 
  

  

  Eruptive 
  Unconformity 
  . 
  

  

  ( 
  Including 
  also 
  : 
  — 
  

  

  Amphibolites, 
  peridotites, 
  &c. 
  r 
  

  

  mostly 
  intrusive. 
  

   Conglomerates 
  (autoclastic).-^^^ 
  i 
  

   Banded 
  ferruginous 
  quartzites, 
  

   origindoubtful, 
  possibly 
  igneous. 
  

   ■{ 
  Quartzites 
  and 
  quartz-schists, 
  

   mostly 
  intrusive. 
  

   Limestones, 
  probably 
  secondary. 
  

   Mica 
  schists 
  ; 
  metamorphic 
  ig- 
  

   neous. 
  

   Intrusive 
  masses 
  of 
  dioritic* 
  and 
  

   diabasic 
  character. 
  

  

  fll. 
  Upper 
  (chlori- 
  

   tic) 
  division 
  

   (greenstones 
  

   and 
  chloritic 
  

   schists). 
  

  

  ■{ 
  12. 
  Lower 
  (horn- 
  

   blendic) 
  di- 
  

   vision 
  (epi- 
  

   diorites 
  and 
  

   hornblendic 
  

   schists). 
  

  

  I 
  

  

  Unknown. 
  

  

  We 
  may 
  now 
  very 
  briefly 
  consider 
  the 
  groups 
  of 
  figures 
  

   presented 
  in 
  Table 
  I., 
  and 
  the 
  following 
  summary 
  of 
  the 
  

   results 
  will 
  help 
  to 
  bring 
  out 
  such 
  points 
  of 
  similarity 
  or 
  

   distinction 
  as 
  exist 
  amongst 
  them, 
  although 
  the 
  observations 
  

   are 
  too 
  few 
  in 
  number 
  to 
  permit 
  of 
  final 
  conclusions 
  being 
  

   drawn. 
  

  

  * 
  ' 
  Outline 
  of 
  the 
  Geological 
  History 
  of 
  Mysore,' 
  by 
  W. 
  F. 
  Smeeth, 
  

   Bulletin 
  No. 
  6 
  — 
  Department 
  of 
  Mines 
  and 
  Geology, 
  Mysore 
  State. 
  

  

  