﻿UNDESCRIBED 
  CRATER 
  OF 
  FIOLLONGE 
  — 
  SINGULAR 
  FLUIDITY 
  OF 
  LAVA. 
  31 
  

  

  tinued 
  longer 
  than 
  I 
  expected, 
  as 
  we 
  scrambled 
  with 
  some 
  difficulty 
  along 
  the 
  

   bank 
  of 
  the 
  river. 
  I 
  carefully 
  marked 
  here, 
  as 
  elsewhere, 
  every 
  patch 
  of 
  lava 
  

   upon 
  Cassini's 
  map. 
  The 
  disappearance 
  of 
  the 
  lava 
  in 
  this 
  place 
  is 
  no 
  doubt 
  

   due 
  to 
  the 
  steepness 
  and 
  narrowness 
  of 
  the 
  channel, 
  which 
  left 
  few 
  points 
  of 
  

   lodgment 
  for 
  the 
  lava, 
  and 
  which 
  gave 
  an 
  increased 
  force 
  to 
  the 
  eroding 
  power 
  

   of 
  water. 
  

  

  We 
  passed 
  successively 
  the 
  hamlets 
  of 
  Lespereyres 
  and 
  Chabron 
  ; 
  and 
  after 
  

   the 
  last 
  we 
  kept 
  in 
  the 
  hollow 
  of 
  the 
  valley, 
  and 
  soon 
  got 
  a 
  sight 
  of 
  a 
  great 
  lava 
  

   cliff, 
  betokening 
  our 
  approach 
  to 
  the 
  crater. 
  Clambering 
  high 
  above 
  the 
  left 
  

   bank 
  of 
  the 
  stream 
  (which 
  we 
  crossed 
  above 
  Chabron) 
  to 
  avoid 
  precipices, 
  we 
  at 
  

   length, 
  after 
  a 
  fatiguing 
  walk 
  of 
  three 
  hours 
  from 
  Burzet, 
  obtained 
  a 
  view 
  of 
  a 
  

   very 
  remarkable 
  cascade, 
  which 
  descends 
  from 
  near 
  the 
  crater 
  which 
  formed 
  the 
  

   object 
  of 
  our 
  search, 
  which, 
  from 
  a 
  cottage 
  occupying 
  its 
  centre, 
  I 
  called 
  the 
  

   Crater 
  of 
  Fiollonge. 
  The 
  cascade 
  is 
  called 
  Raipis 
  ; 
  and 
  the 
  water 
  falls 
  by 
  several 
  

   steps 
  over 
  a 
  mass 
  of 
  beautifully 
  columnar 
  lava 
  several 
  hundred 
  feet 
  high. 
  These 
  

   interesting 
  objects 
  more 
  than 
  rewarded 
  our 
  perseverance. 
  They 
  are 
  described, 
  

   so 
  far 
  as 
  I 
  am 
  aware, 
  by 
  no 
  previous 
  writer, 
  and 
  were 
  probably 
  seen 
  by 
  a 
  geolo- 
  

   gist 
  then 
  for 
  the 
  first 
  time. 
  Plate 
  VI. 
  , 
  fig. 
  4, 
  gives 
  a 
  view 
  of 
  the 
  cascade. 
  

  

  The 
  crater 
  presents, 
  as 
  usual, 
  an 
  insulated 
  cone 
  of 
  scoriae, 
  touching 
  the 
  

   granite 
  in 
  its 
  whole 
  circumference, 
  except 
  on 
  the 
  side 
  next 
  the 
  valley, 
  where 
  a 
  

   flood 
  of 
  lava 
  has 
  made 
  its 
  escape, 
  damming 
  the 
  lateral 
  stream, 
  and 
  forming 
  the 
  

   great 
  cascade. 
  In 
  the 
  slag 
  adjoining 
  the 
  cascade 
  are 
  immense 
  masses 
  of 
  im- 
  

   bedded 
  granite 
  ; 
  which 
  give 
  additional 
  countenance 
  to 
  the 
  notion 
  of 
  the 
  meta- 
  

   morphic 
  origin 
  of 
  the 
  olivine 
  nodules 
  which 
  so 
  remarkably 
  characterize 
  this 
  lava 
  

   in 
  all 
  its 
  extent. 
  The 
  columnar 
  formation 
  at 
  the 
  cascade, 
  though 
  far 
  from 
  the 
  

   most 
  extensive, 
  is 
  probably 
  the 
  most 
  curious 
  and 
  complex 
  in 
  its 
  forms 
  of 
  aggre- 
  

   gation 
  of 
  any 
  in 
  the 
  Vivarais. 
  

  

  If 
  we 
  now 
  consider 
  the 
  operations 
  of 
  this 
  volcano, 
  we 
  shall 
  find 
  the 
  extreme 
  

   length 
  of 
  its 
  lava-produce 
  to 
  be 
  really 
  surprising. 
  Although, 
  by 
  the 
  map, 
  the 
  

   distance 
  of 
  the 
  crater 
  from 
  Burzet 
  may 
  not 
  appear 
  to 
  be 
  more 
  than 
  4 
  or 
  5 
  miles, 
  

   the 
  contortions 
  of 
  the 
  bed 
  of 
  the 
  stream 
  are 
  such, 
  that 
  it 
  is 
  probably 
  double 
  that 
  

   distance 
  ; 
  and, 
  indeed, 
  can 
  hardly 
  be 
  less 
  than 
  8 
  miles, 
  since 
  we 
  were 
  3 
  hours 
  

   on 
  the 
  way 
  (steep 
  and 
  rough 
  as 
  it 
  was). 
  To 
  the 
  junction 
  with 
  the 
  lava 
  of 
  the 
  

   Gravenne, 
  in 
  the 
  valley 
  of 
  Montpezat, 
  is 
  therefore 
  more 
  than 
  12 
  miles 
  ; 
  and 
  if 
  

   it 
  be 
  the 
  same 
  lava 
  (as 
  Mr 
  Scrope 
  supposes, 
  and 
  as 
  there 
  is 
  some 
  reason 
  to 
  

   think) 
  which 
  continues 
  to 
  the 
  Pont 
  de 
  la 
  Beaume, 
  the 
  distance 
  will 
  be 
  16 
  miles. 
  

   Yet 
  the 
  whole 
  valley 
  of 
  Burzet 
  is 
  a 
  ravine 
  so 
  narrow 
  and 
  crooked, 
  that 
  the 
  lava 
  

   appears 
  like 
  a 
  thread 
  winding 
  through 
  it 
  ; 
  and 
  we 
  are 
  amazed 
  that 
  it 
  should 
  not 
  

   have 
  become 
  solidified 
  by 
  the 
  contact 
  with 
  the 
  cold 
  granite, 
  before 
  it 
  had 
  per- 
  

   formed 
  one-fourth 
  of 
  the 
  distance. 
  I 
  apprehend 
  that 
  there 
  is 
  no 
  lava 
  known, 
  

   ancient 
  or 
  modern, 
  which 
  has 
  formed 
  so 
  attenuated 
  a 
  stream. 
  This 
  is 
  only 
  to 
  be 
  

   accounted 
  for 
  by 
  its 
  excessive 
  fluidity, 
  of 
  which 
  we 
  have 
  additional 
  evidence, 
  (1.) 
  

  

  