﻿1864.] 
  BIGSBY 
  MISSING 
  SEDIMENTARY 
  FORMATIONS. 
  207 
  

  

  basin, 
  and 
  in 
  that 
  of 
  the 
  Pyrenees; 
  but 
  the 
  Upper 
  Greensand 
  

   occurs 
  in 
  both 
  regions. 
  

  

  The 
  transgressive 
  and 
  ever-varying 
  relations 
  of 
  some 
  deposits 
  are 
  

   finely 
  illustrated 
  by 
  the 
  Upper 
  Greensand. 
  It 
  lies 
  on 
  Portland 
  Stone 
  

   near 
  St. 
  Jean 
  d'Angilly 
  ; 
  on 
  Kimmeridge 
  Clay 
  at 
  Cap 
  la 
  Heve 
  

   (Normandy) 
  * 
  ; 
  on 
  Coral 
  Rag 
  at 
  Ecommoy 
  ; 
  on 
  Oxford 
  Clay 
  at 
  

   Dinas 
  ; 
  on 
  Kelloway 
  Rock 
  at 
  Ballon, 
  and 
  on 
  the 
  Great 
  Oolite. 
  At 
  

   Tournay 
  this 
  rock 
  covers 
  Coal-measures 
  ; 
  at 
  Tonvois, 
  and 
  in 
  La 
  

   Vendee, 
  we 
  find 
  it 
  on 
  Azoic 
  beds 
  t. 
  

  

  Prof. 
  Cook, 
  from 
  surveys 
  and 
  borings, 
  has 
  published 
  J 
  some 
  ap- 
  

   parently 
  accurate 
  details 
  on 
  the 
  true 
  stratigraphical 
  relations 
  of 
  the 
  

   Greensand 
  of 
  New 
  Jersey 
  (North 
  America) 
  ; 
  and 
  he 
  announces 
  that 
  

   it 
  is 
  in 
  direct 
  and 
  discordant 
  superposition 
  to 
  Laurentian 
  gneiss. 
  

  

  Neither 
  of 
  these 
  beds 
  is 
  seen 
  on 
  the 
  north 
  flank 
  of 
  the 
  Pyrenees, 
  

   nor 
  on 
  the 
  Lower 
  Pyrenees, 
  in 
  the 
  Landes 
  on 
  the 
  north-west, 
  nor 
  

   on 
  the 
  opposite 
  border 
  of 
  the 
  Cretaceous 
  sea, 
  in 
  the 
  Perigord, 
  the 
  

   Angoumais, 
  the 
  Saintonge, 
  and 
  finally 
  in 
  the 
  basin 
  of 
  the 
  Loire 
  — 
  

   and 
  the 
  result 
  is 
  a 
  proportionately 
  great 
  gap. 
  Dr. 
  Geinitz 
  does 
  not 
  

   admit 
  the 
  presence 
  of 
  Gault 
  in 
  the 
  valley 
  of 
  the 
  Elbe 
  §. 
  

  

  c. 
  Gault 
  and 
  Neocomian. 
  — 
  I 
  have 
  under 
  this 
  head 
  only 
  to 
  men- 
  

   tion 
  that 
  M. 
  Lory 
  || 
  has 
  recognized 
  Neocomian 
  strata 
  resting 
  on 
  

   Oxfordian 
  limestones 
  in 
  the 
  Departments 
  of 
  the 
  Drome 
  and 
  the 
  Isere, 
  

   north-west 
  of 
  the 
  town 
  of 
  Gap. 
  

  

  4. 
  With 
  a 
  Jurassic 
  Roof, 
  — 
  I 
  shall 
  be 
  rather 
  minute 
  in 
  treating 
  

   of 
  the 
  omitted 
  portions 
  of 
  the 
  Jurassic 
  strata, 
  partly 
  because 
  we 
  

   meet 
  with 
  good 
  matter, 
  and 
  partly 
  to 
  show 
  what 
  the 
  other 
  periods 
  

   would 
  disclose 
  if 
  treated 
  with 
  equal 
  fulness. 
  

  

  We 
  shall 
  find 
  here 
  denudation 
  in 
  general 
  and 
  intense 
  activity, 
  and 
  

   suspension 
  of 
  the 
  processes 
  of 
  deposit. 
  We 
  shall 
  sometimes 
  find 
  

   much 
  of 
  the 
  formation 
  absent, 
  and 
  often 
  notice 
  its 
  fragmentary 
  

   occurrence, 
  as 
  well 
  as 
  its 
  disguise 
  by 
  metamorphism 
  ; 
  that 
  process, 
  

   however, 
  from 
  time 
  to 
  time 
  relaxing 
  in 
  force, 
  and 
  then 
  not 
  destroy- 
  

   ing 
  the 
  characteristic 
  fossils. 
  

  

  Rarely, 
  if 
  ever, 
  is 
  the 
  Jurassic 
  series 
  complete. 
  Generally 
  we 
  

   find 
  only 
  one 
  of 
  the 
  four 
  principal 
  members 
  %. 
  The 
  most 
  constant, 
  

   if 
  we 
  are 
  to 
  judge 
  from 
  organic 
  remains, 
  is 
  the 
  Oxford 
  Clay 
  ; 
  then 
  the 
  

   Lias 
  ; 
  thirdly, 
  the 
  Lower 
  Jurassic 
  ; 
  and 
  fourthly, 
  the 
  Upper 
  Oolite, 
  

   the 
  smallest 
  of 
  them 
  all, 
  and 
  not 
  seen 
  out 
  of 
  Western 
  and 
  Central 
  

   Europe. 
  A 
  glance 
  at 
  Dumont's 
  large 
  geological 
  map 
  of 
  Europe 
  

   will 
  show 
  us 
  very 
  well 
  the 
  superficial 
  extent 
  of 
  the 
  European 
  Ju- 
  

   rassic 
  formation. 
  It 
  appears 
  to 
  cross 
  the 
  English 
  Channel 
  from 
  

   Dorsetshire 
  into 
  Western 
  Normandy, 
  and 
  to 
  proceed 
  to 
  near 
  Angers 
  

   (Department 
  of 
  Maine 
  and 
  Loire), 
  and 
  so 
  on, 
  in 
  two 
  principal 
  masses, 
  

   both 
  directed 
  E.N.E., 
  into 
  the 
  Departments 
  of 
  Yienne, 
  Cher, 
  the 
  

  

  * 
  D'Orbigny, 
  ' 
  Cours 
  de 
  Paleontologie,' 
  vol. 
  ii. 
  p. 
  610. 
  

  

  f 
  Lory, 
  Bull. 
  Soc. 
  G-eol. 
  de 
  France, 
  2 
  e 
  serie, 
  vol. 
  xi. 
  p. 
  782. 
  

  

  % 
  Boundary 
  Report, 
  Mexico, 
  vol. 
  i. 
  p. 
  128. 
  

  

  § 
  D'Archiac, 
  ' 
  Histoire 
  des 
  Progres,' 
  vol. 
  v. 
  pp. 
  46, 
  277. 
  

  

  || 
  Bull. 
  Soc. 
  Geol. 
  2 
  e 
  serie, 
  vol. 
  xi. 
  p. 
  782. 
  

  

  *[[ 
  D'Archiac, 
  ' 
  Histoire 
  des 
  Progres,' 
  vol. 
  vii. 
  p. 
  699. 
  

  

  