﻿CRYSTALLINE 
  ROCKS 
  OF 
  THE 
  ALPS. 
  75 
  

  

  presence 
  of 
  the 
  slate, 
  contrast 
  curiously 
  with 
  the 
  rugged 
  crystalline 
  

   crags 
  on 
  either 
  side. 
  

  

  (y) 
  Le 
  Dauphin 
  to 
  Brianpon 
  by 
  the 
  Col 
  du 
  Lautaret. 
  

  

  The 
  crystalline 
  series 
  reappears 
  on 
  the 
  right 
  bank 
  of 
  the 
  Eomanche, 
  

   65 
  kil. 
  from 
  Grenoble 
  (10 
  miles 
  from 
  Bourg 
  d'Oisans), 
  as 
  a 
  grey, 
  

   rather 
  coarse, 
  foliated 
  gneiss, 
  like 
  some 
  of 
  that 
  in 
  the 
  Central 
  Alps. 
  

   The 
  foliation 
  in 
  several 
  places 
  exhibits 
  distinct 
  folds 
  ; 
  the 
  rock 
  here 
  

   and 
  there 
  approximates, 
  but 
  not 
  markedly, 
  to 
  an 
  " 
  Augen-gneiss" 
  in 
  

   structure. 
  About 
  one 
  kilometre 
  further 
  it 
  becomes 
  more 
  micaceous 
  

   and 
  more 
  definitely 
  banded. 
  Next, 
  at 
  about 
  the 
  same 
  distance 
  further 
  

   on, 
  we 
  come 
  to 
  huge 
  fallen 
  blocks 
  of 
  a 
  hornblende-schist, 
  sometimes 
  

   well 
  banded, 
  and 
  of 
  a 
  gabbro, 
  which, 
  as 
  it 
  includes 
  distinct 
  frag- 
  

   ments 
  of 
  the 
  hornblende-schist, 
  must 
  have 
  been 
  intruded 
  after 
  that 
  

   rock 
  had 
  attained 
  to 
  its 
  present 
  condition. 
  Beyond 
  this 
  place 
  the 
  

   scenery 
  of 
  the 
  Combe 
  de 
  Malaval 
  becomes 
  yet 
  wilder, 
  but, 
  unfortu- 
  

   nately, 
  the 
  cliffs 
  are 
  generally 
  separated 
  from 
  the 
  road 
  (right 
  bank) 
  

   by 
  great 
  slopes 
  of 
  screes. 
  The 
  blocks, 
  however, 
  so 
  far 
  as 
  I 
  could 
  

   see, 
  are 
  a 
  greyish, 
  moderately 
  banded 
  gneiss, 
  very 
  like 
  that 
  which 
  

   occurs 
  in 
  situ 
  lower 
  down 
  the 
  valley, 
  so 
  that 
  I 
  have 
  no 
  doubt 
  as 
  

   to 
  the 
  general 
  nature 
  of 
  the 
  section. 
  

  

  About 
  3 
  miles 
  below 
  La 
  Grave 
  an 
  outcrop 
  of 
  a 
  similar 
  rock 
  occurs 
  

   by 
  the 
  roadside 
  (Appendix, 
  p. 
  102). 
  In 
  short, 
  the 
  massif, 
  cut 
  by 
  this 
  

   part 
  of 
  the 
  Eomanche, 
  appears 
  to 
  me 
  mainly 
  to 
  consist 
  of 
  a 
  rock 
  

   which, 
  though 
  modified 
  by 
  subsequent 
  pressure, 
  was 
  originally 
  a 
  

   moderately 
  banded, 
  not 
  very 
  coarse 
  gneiss, 
  of 
  a 
  decidedly 
  Laurentian 
  

   type, 
  such 
  as 
  I 
  have 
  seen, 
  in 
  other 
  parts 
  of 
  the 
  Alps, 
  apparently 
  

   underlying 
  the 
  gneiss 
  of 
  the 
  Lepontine 
  type, 
  and 
  not 
  unlike 
  some 
  

   in 
  the 
  Central 
  Oberland 
  or 
  that 
  near 
  the 
  Trient 
  gorge. 
  

  

  Before 
  we 
  reached 
  the 
  little 
  village 
  of 
  La 
  Grave, 
  the 
  dark 
  Jurassic 
  

   rock 
  which, 
  though 
  generally 
  out 
  of 
  sight, 
  is 
  supported 
  by 
  the 
  cliffs 
  

   overhanging 
  the 
  Combe 
  de 
  Malaval, 
  and 
  forms 
  the 
  range 
  between 
  

   the 
  valleys 
  of 
  the 
  Eomanche 
  and 
  the 
  Arc, 
  sweeps 
  down 
  to 
  the 
  bed 
  of 
  

   the 
  river, 
  and 
  the 
  Lautaret 
  road 
  finally 
  quits 
  the 
  crystalline 
  rock. 
  

   But 
  on 
  the 
  opposite 
  side 
  of 
  the 
  valley, 
  peaks 
  and 
  ridges 
  of 
  the 
  

   latter 
  rock 
  tower 
  on 
  high. 
  "We 
  are 
  on 
  ground 
  made 
  classic 
  by 
  the 
  

   labours 
  of 
  Elie 
  de 
  Beaumont, 
  Lory, 
  and 
  others 
  ; 
  but 
  as, 
  even 
  now, 
  it 
  

   is 
  rarely 
  visited 
  by 
  our 
  countrymen, 
  I 
  shall 
  venture 
  on 
  a 
  very 
  brief 
  

   description. 
  As 
  already 
  stated, 
  the 
  principal 
  peaks 
  of 
  the 
  central 
  

   massif 
  of 
  the 
  Dauphine 
  Alps 
  are 
  roughly 
  grouped 
  in 
  a 
  horseshoe 
  curve. 
  

   Its 
  interior 
  is 
  drained 
  by 
  the 
  Yeneon, 
  a 
  river 
  fed 
  by 
  many 
  glens, 
  

   commonly 
  steep, 
  and 
  leading 
  up 
  to 
  glaciers. 
  On 
  the 
  north 
  the 
  

   massif 
  is 
  sharply 
  defined 
  by 
  the 
  narrow 
  valley 
  of 
  the 
  Eomanche 
  ; 
  

   on 
  the 
  south, 
  less 
  perfectly, 
  by 
  the 
  Yal 
  Godemar, 
  but 
  the 
  crystalline 
  

   district 
  extends 
  for 
  some 
  distance 
  further 
  in 
  this 
  direction. 
  

  

  Some 
  short 
  but 
  very 
  lofty 
  spurs 
  project 
  towards 
  the 
  east 
  from 
  the 
  

   crest 
  of 
  the 
  watershed, 
  the 
  longest 
  and 
  northernmost 
  being 
  some- 
  

   times 
  called 
  inclusively 
  the 
  Crete 
  du 
  Glacier 
  Blanc. 
  The 
  Pelvoux, 
  

   one 
  of 
  the 
  best-known 
  summits 
  of 
  Dauphine, 
  though 
  not 
  quite 
  the 
  

  

  