﻿26 
  GEOLOGICAL 
  MEMOIRS. 
  

  

  were 
  the 
  junction 
  beds 
  between 
  the 
  Triassic 
  and 
  Liassic 
  formations, 
  

   occur, 
  distinguishing 
  the 
  different 
  members 
  of 
  each 
  section 
  with 
  

   their 
  imbedded 
  fossils 
  from 
  the 
  Trias 
  upwards. 
  The 
  first 
  locality 
  

   described 
  is 
  the 
  ravine 
  of 
  Pissot, 
  which 
  descends 
  from 
  the 
  north- 
  

   east 
  extremity 
  of 
  the 
  Mont 
  d'Arvel, 
  and 
  enters 
  the 
  valley 
  of 
  the 
  

   Rhone 
  behind 
  the 
  town 
  of 
  Yilleneuve, 
  in 
  the 
  immediate 
  vicinity 
  of 
  

   which 
  place 
  the 
  lower 
  beds 
  are 
  seen 
  to 
  rise 
  towards 
  the 
  north. 
  The 
  

   other 
  localities 
  are 
  Luan, 
  Yvorne, 
  and 
  Fontanney, 
  Douvaz 
  (above 
  

   Aigle), 
  Chainees 
  (near 
  Villeneuve), 
  and 
  Taulan 
  (near 
  Montreux). 
  

  

  Then, 
  after 
  describing 
  71 
  fossil 
  species, 
  with 
  their 
  separate 
  lo- 
  

   calities 
  in 
  these 
  two 
  zones, 
  the 
  author 
  sums 
  up 
  with 
  the 
  following 
  

   conclusions 
  : 
  — 
  

  

  " 
  Upper 
  Zone. 
  — 
  Of 
  38 
  species 
  contained 
  in 
  the 
  Ostrea-irregidaris 
  

   zone 
  of 
  the 
  Yaudois 
  Alps, 
  31, 
  or 
  82 
  per 
  cent., 
  are 
  quoted 
  as 
  occurring 
  

   in 
  the 
  Infralias 
  of 
  various 
  localities; 
  5 
  of 
  these 
  last, 
  or 
  13 
  per 
  cent., 
  

   are 
  also 
  found 
  in 
  the 
  Gryphaea-limestone, 
  or 
  Sinemurien 
  formation 
  

   of 
  D'Orbigny 
  ; 
  5 
  are 
  new 
  or 
  uncertain 
  ; 
  and 
  two 
  species, 
  or 
  5 
  per 
  cent., 
  

   already 
  existed 
  in 
  the 
  Avicula-contorta 
  zone. 
  One 
  of 
  these, 
  Mytilus 
  

   semicircular 
  is, 
  occurs 
  only 
  on 
  the 
  southern 
  slope 
  of 
  the 
  Alps, 
  while 
  

   the 
  other, 
  Placunopsis 
  Schafhauili, 
  appears 
  to 
  have 
  lived 
  at 
  two 
  differ- 
  

   ent 
  epochs 
  in 
  the 
  district 
  now 
  occupied 
  by 
  the 
  Alps. 
  From 
  these 
  

   numbers 
  we 
  may 
  infer 
  that 
  the 
  beds 
  in 
  question 
  correspond 
  to 
  the 
  

   Infralias 
  properly 
  so 
  called, 
  namely, 
  to 
  the 
  zones 
  of 
  Ammonites 
  pla- 
  

   norbis 
  and 
  A. 
  angulatus. 
  The 
  greatest 
  degree 
  of 
  analogy 
  exists 
  

   with 
  the 
  Infraliassic 
  sandstone 
  of 
  Hettange, 
  and 
  the 
  upper 
  zones 
  of 
  the 
  

   Infralias 
  of 
  the 
  Cote 
  d 
  ? 
  Or, 
  which 
  together 
  contain 
  19 
  of 
  my 
  species, 
  or 
  

   50 
  per 
  cent. 
  These 
  proportions 
  may 
  be 
  slightly 
  modified 
  by 
  future 
  

   discoveries, 
  but 
  the 
  parallelism 
  which 
  I 
  have 
  mentioned 
  appears 
  to 
  

   be 
  founded 
  on 
  too 
  great 
  a 
  number 
  of 
  species 
  to 
  run 
  any 
  risk 
  of 
  being 
  

   controverted." 
  

  

  " 
  This 
  is 
  the 
  first 
  time, 
  so 
  far 
  as 
  I 
  am 
  aware, 
  that 
  the 
  Hettange 
  

   horizon 
  has 
  been 
  positively 
  pointed 
  out 
  in 
  the 
  Alps. 
  It 
  is 
  true 
  that 
  

   1SX. 
  Stoppani, 
  in 
  his 
  ' 
  Tableau 
  Synoptique 
  de 
  l'Etage 
  Infraliasien,' 
  has 
  

   paralleled 
  with 
  the 
  sandstones 
  of 
  Hettange 
  the 
  Dolomia 
  Superiore 
  

   of 
  Lombardy, 
  and 
  the 
  Dachsteinkalk 
  of 
  the 
  Austrian 
  and 
  Bavarian 
  

   Alps 
  ; 
  but 
  his 
  statement 
  is 
  not 
  supported 
  by 
  any 
  list 
  of 
  fossils, 
  and 
  

   on 
  the 
  other 
  hand 
  the 
  list 
  of 
  the 
  fossils 
  of 
  the 
  Dachsteinkalk 
  given 
  

   by 
  M. 
  Giimbel 
  (Geogr. 
  Bayr. 
  Alpen-Geb. 
  p. 
  419) 
  evidently 
  proves'that 
  

   this 
  formation 
  belongs 
  to 
  the 
  zone 
  of 
  Avicula 
  contorta, 
  and 
  not 
  to 
  the 
  

   Hettange 
  group. 
  I 
  am 
  therefore 
  disposed 
  to 
  believe 
  that 
  this 
  is 
  the 
  

   first 
  time 
  that 
  a 
  well-established 
  Alpine 
  equivalent 
  of 
  the 
  fauna 
  of 
  

   the 
  Infraliassic 
  sandstones 
  of 
  Hettange 
  has 
  been 
  pointed 
  out." 
  

  

  " 
  Lower 
  Zone. 
  — 
  Out 
  of 
  34 
  species 
  hitherto 
  recognized 
  in 
  this 
  zone, 
  

   26, 
  or 
  76 
  per 
  cent., 
  are 
  also 
  found 
  in 
  some 
  one 
  of 
  the 
  beds 
  of 
  the 
  

   Avicula-contorta 
  zone, 
  either 
  in 
  the 
  Alps 
  or 
  without. 
  Of 
  the 
  8 
  re- 
  

   maining 
  species, 
  4 
  are 
  new 
  and 
  3 
  uncertain. 
  The 
  proportion 
  is 
  not 
  

   quite 
  so 
  great 
  as 
  in 
  the 
  upper 
  zone, 
  but 
  it 
  is 
  sufficient 
  to 
  remove 
  all 
  

   doubt 
  as 
  to 
  the 
  identity 
  of 
  the 
  lower 
  zone 
  with 
  the 
  Avicula-contorta 
  

   beds 
  known 
  in 
  different 
  countries 
  under 
  the 
  names 
  of 
  Bone-bed, 
  

   Kossener 
  Schichten, 
  Infralias, 
  Upper 
  Keuper 
  or 
  Arkose, 
  The 
  principal 
  

  

  