﻿70 
  

  

  PEOE. 
  T. 
  G. 
  BOMTEY 
  ON" 
  TWO 
  TEAYEESES 
  OF 
  THE 
  

  

  ^ 
  i^S# 
  

  

  /3 
  ^ 
  

  

  

  ^ 
  

  

  

  / 
  

  

  /"^ 
  -x 
  ~v 
  -v 
  

  

  D 
  O 
  

  

  n 
  

  

  O 
  1 
  rtf 
  

  

  pq 
  

  

  are, 
  in 
  this 
  region, 
  generally 
  very 
  

   limited, 
  and, 
  perhaps, 
  were 
  never 
  

   very 
  extensive 
  ; 
  but 
  the 
  occurrence 
  

   of 
  the 
  Mesozoic 
  (Triassic 
  and 
  

   Jurassic) 
  in 
  many 
  isolated 
  patches 
  

   indicates 
  that 
  they 
  formerly 
  

   covered 
  the 
  greater 
  part, 
  if 
  not 
  the 
  

   whole, 
  of 
  the 
  crystalline 
  series*. 
  

  

  Restricting 
  our 
  attention 
  to 
  the 
  

   Mesozoic 
  rocks 
  only, 
  we 
  find, 
  as 
  we 
  

   proceed 
  eastward 
  from 
  Grenoble 
  

   (fig. 
  1), 
  first 
  the 
  crystalline 
  range 
  

   of 
  the 
  Belledonne, 
  then 
  the 
  fairly 
  

   broad 
  Mesozoic 
  infold, 
  traversed 
  by 
  

   the 
  Olle, 
  but 
  prolonged 
  far 
  away 
  

   northwards 
  and 
  for 
  a 
  considerable 
  

   distance 
  in 
  the 
  opposite 
  direction 
  ; 
  

   then 
  the 
  crystalline 
  range 
  of 
  the 
  

   Grandes 
  Eousses, 
  narrower 
  but 
  

   loftier 
  than 
  that 
  just 
  named, 
  which 
  

   is 
  banded 
  on 
  its 
  eastern 
  side 
  by 
  a 
  

   narrow 
  trough 
  of 
  Secondary 
  rocks, 
  

   an 
  offshoot 
  from 
  that 
  last 
  men- 
  

   tioned, 
  in 
  the 
  neighbourhood 
  of 
  St. 
  

   Jean 
  de 
  Maurienne 
  ; 
  and 
  after 
  that 
  

   comes 
  the 
  huge 
  massif 
  of 
  the 
  

   High 
  Alps 
  of 
  Dauphine, 
  fringed 
  on 
  

   the 
  north 
  by 
  the 
  same 
  Jurassic 
  

   rocks, 
  through 
  which 
  it 
  has 
  been 
  

   violently 
  forced. 
  To 
  the 
  east 
  of 
  

   the 
  region 
  just 
  described 
  comes 
  

   another 
  tract 
  of 
  crystalline 
  rock, 
  

   which 
  forms 
  the 
  watershed 
  of 
  the 
  

   chain 
  of 
  the 
  Western 
  Alps, 
  up 
  to 
  

   the 
  southern 
  end 
  of 
  the 
  Mont- 
  

   Blanc 
  range, 
  together 
  with 
  the 
  

   mountain 
  region 
  draining 
  to 
  Italy. 
  

  

  The 
  last, 
  as 
  indicated 
  by 
  a 
  geolo- 
  

   gical 
  map, 
  consists 
  almost 
  entirely 
  

   of 
  a 
  group 
  of 
  schists 
  different 
  in 
  

   character 
  from 
  those 
  already 
  men- 
  

   tioned 
  (though 
  here 
  and 
  there 
  

   tracts 
  of 
  the 
  former 
  type 
  occur, 
  

  

  * 
  For 
  further 
  remarks 
  on 
  the 
  sub- 
  

   ject 
  see 
  the 
  notice 
  by 
  Prof. 
  C. 
  Lory 
  in 
  

   " 
  Etudes 
  sur 
  les 
  schistes 
  crystallines," 
  

   read 
  at 
  the 
  Congres 
  geologique 
  interna- 
  

   tional, 
  1888 
  (Sept.), 
  and 
  three 
  lectures 
  

   given 
  by 
  myself 
  in 
  May 
  1888, 
  at 
  the 
  

   Royal 
  Institution, 
  published 
  in 
  the 
  

   ' 
  Alpine 
  Journal,' 
  1888-9. 
  

  

  