﻿208 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Mar. 
  9, 
  

  

  Cote 
  d'Or, 
  the 
  Doubs, 
  and 
  the 
  Jura. 
  From 
  thence 
  it 
  proceeds 
  

   E.N.E. 
  by 
  Schaffhausen 
  and 
  parts 
  of 
  Wiirtemberg, 
  to 
  near 
  Ratisbon 
  

   (Bavaria), 
  and 
  then 
  is 
  not 
  visible 
  eastwards 
  nntil 
  we 
  reach 
  Prussian 
  

   Poland, 
  where 
  it 
  shows 
  itself 
  in 
  two 
  basins, 
  near 
  Oppeln, 
  and 
  in 
  

   Sandomir, 
  respectively. 
  North-east 
  from 
  this, 
  the 
  Jurassic 
  series 
  does 
  

   not 
  come 
  into 
  view 
  until 
  we 
  arrive 
  in 
  the 
  Russian 
  Governments 
  of 
  

   Smolensko 
  and 
  Kalouga. 
  Prom 
  thence 
  it 
  spreads 
  in 
  broad 
  sheets 
  

   to 
  near 
  Moscow, 
  where, 
  with 
  increased 
  width, 
  it 
  occupies 
  great 
  spaces 
  

   on 
  the 
  west 
  side 
  of 
  the 
  Oural, 
  and 
  as 
  far 
  north 
  as 
  the 
  Icy 
  Sea. 
  It 
  

   extends 
  from 
  near 
  Moscow 
  in 
  a 
  south-easterly 
  direction 
  to 
  Astrakan, 
  

   and 
  to 
  the 
  Caspian, 
  Aral, 
  and 
  Black 
  Seas. 
  

  

  The 
  Alps 
  of 
  Mid-Europe 
  abound 
  in 
  Jurassic 
  rocks, 
  in 
  several 
  very 
  

   interesting 
  forms, 
  which 
  run 
  down 
  much 
  of 
  Italy 
  in 
  two 
  long 
  and 
  

   narrow 
  strips. 
  

  

  Of 
  the 
  Jurassic 
  strata 
  of 
  America 
  and 
  of 
  the 
  remaining 
  quarters 
  

   of 
  the 
  globe 
  no 
  notice 
  will 
  be 
  taken 
  here, 
  because 
  they 
  are 
  too 
  im- 
  

   perfectly 
  known 
  to 
  answer 
  our 
  present 
  purpose. 
  

  

  The 
  facts 
  now 
  to 
  be 
  brought 
  forward 
  will 
  place 
  in 
  a 
  very 
  strong 
  

   light 
  the 
  flitting 
  nature 
  of 
  the 
  process 
  of 
  deposition, 
  its 
  rapid 
  

   changes 
  from 
  the 
  accumulation 
  of 
  vast 
  masses 
  to 
  absolute 
  ces- 
  

   sation, 
  causing 
  the 
  loss 
  of 
  important 
  stages. 
  We 
  may 
  consider, 
  

   says 
  D'Archiac*, 
  that 
  the 
  chain 
  of 
  the 
  Jura 
  and 
  its 
  ramifi- 
  

   cations 
  occupy 
  the 
  zone 
  of 
  the 
  greatest 
  normal 
  development 
  of 
  this 
  

   formation. 
  Escher 
  von 
  der 
  Linth 
  also 
  remarks 
  that 
  in 
  the 
  Western 
  

   Jura 
  of 
  Switzerland, 
  as 
  far 
  as 
  Lucerne, 
  no 
  violent 
  dislocation 
  has 
  taken 
  

   place 
  between 
  the 
  Jurassic 
  period 
  and 
  that 
  of 
  the 
  Chalk 
  f. 
  In 
  the 
  

   valley 
  of 
  the 
  Saone 
  hard 
  by, 
  about 
  Macon 
  and 
  other 
  parts, 
  nearly 
  the 
  

   whole 
  series 
  of 
  stages 
  is 
  frequently 
  present 
  t. 
  But 
  even 
  here, 
  among 
  

   the 
  mountain-ranges 
  between 
  the 
  Rhone 
  and 
  the 
  Rhine, 
  the 
  lower 
  

   of 
  the 
  three 
  Oolites 
  is 
  very 
  feebly 
  developed, 
  and 
  the 
  beds 
  are 
  con- 
  

   stantly 
  varying 
  by 
  absence 
  or 
  by 
  presence, 
  in 
  extent, 
  thickness, 
  and 
  

   contents, 
  everywhere. 
  The 
  occasional 
  coarseness 
  of 
  the 
  beds 
  shows 
  

   that 
  they 
  then 
  must 
  have 
  been 
  within 
  the 
  influence 
  of 
  wave 
  -action. 
  

   To 
  go 
  now 
  to 
  the 
  Alps, 
  Sir 
  R. 
  I. 
  Murchison§ 
  concludes, 
  as 
  one 
  result 
  

   of 
  his 
  investigations, 
  " 
  that 
  the 
  Jurassic 
  system 
  of 
  the 
  Alps 
  and 
  

   Apennines 
  is 
  made 
  up 
  of 
  two 
  distinct 
  calcareous 
  formations, 
  the 
  

   inferior 
  representing 
  the 
  Lias 
  and 
  Lower 
  Oolites, 
  the 
  superior 
  the 
  

   Oxfordian 
  group." 
  

  

  Here 
  are 
  important 
  gaps 
  ; 
  and 
  we 
  know 
  that 
  none 
  of 
  the 
  sections, 
  

   north 
  and 
  south 
  of 
  these 
  mountains, 
  are 
  comparable 
  with 
  each 
  other. 
  

   Some 
  member 
  or 
  other 
  is 
  absent 
  from 
  one, 
  though 
  present 
  elsewhere. 
  

   This 
  irregularity 
  and 
  want 
  of 
  persistence 
  in 
  stages 
  occasionally 
  

   well 
  characterized, 
  and 
  the 
  sudden 
  appearance 
  and 
  extreme 
  thick- 
  

   ness 
  of 
  some 
  which 
  are 
  either 
  altogether 
  missing 
  or 
  very 
  thin 
  a 
  

   few 
  leagues 
  off, 
  are 
  equally 
  common 
  and 
  puzzling. 
  Then, 
  again, 
  

  

  * 
  D'Archiac, 
  ' 
  Histoire 
  des 
  Progres,' 
  toI. 
  vii. 
  p. 
  600. 
  

   t 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xi. 
  part 
  2. 
  p. 
  21. 
  

  

  I 
  Berthand 
  and 
  Tombach, 
  Bull. 
  Soc. 
  Geol. 
  de 
  France, 
  2 
  e 
  serie, 
  vol. 
  x. 
  p. 
  269 
  ; 
  

   Thiolliere, 
  ibid., 
  2 
  e 
  serie, 
  vol. 
  v. 
  p. 
  34. 
  

   § 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  v. 
  p 
  307. 
  

  

  