﻿10 
  GEOLOGICAL 
  MEMOIES. 
  

  

  it 
  is 
  the 
  important 
  fact 
  that 
  there 
  exists 
  near 
  Egeln, 
  in 
  Northern 
  

   Germany, 
  a 
  formation 
  contemporaneous 
  with 
  the 
  Belgian 
  Lower 
  

   Tongrian, 
  where 
  the 
  equivalents 
  of 
  the 
  younger 
  Limburg 
  beds 
  were 
  

   afterwards 
  deposited. 
  

  

  Professor 
  Beyrich 
  accordingly 
  considers 
  his 
  classification 
  of 
  the 
  Oli- 
  

   gocene 
  beds 
  to 
  hold 
  good. 
  In 
  his 
  Lower 
  Oligocene 
  he 
  includes 
  all 
  the 
  

   beds 
  of 
  the 
  age 
  of 
  Dumont's 
  " 
  Systeme 
  Tongrien 
  inferieur," 
  and 
  also 
  

   the 
  strata 
  which 
  occur 
  betweenjthe 
  Sandstones 
  of 
  Beauchamp 
  and 
  the 
  

   Fontainebleau 
  Sands, 
  that 
  is 
  to 
  say, 
  the 
  Paris 
  Gypsum 
  and 
  its 
  equi- 
  

   valents, 
  whether 
  they 
  represent 
  the 
  whole 
  or 
  only 
  a 
  part 
  of 
  that 
  

   formation. 
  In 
  Northern 
  Germany, 
  to 
  this 
  division 
  belong 
  the 
  

   Egeln 
  beds, 
  as 
  well 
  as 
  the 
  underlying 
  Brown 
  Coal 
  ; 
  because 
  there 
  is, 
  

   as 
  yet, 
  no 
  evidence 
  of 
  a 
  freshwater 
  formation 
  in 
  Germany 
  contem- 
  

   poraneous 
  with 
  the 
  Calcaire 
  grossier, 
  and 
  also 
  because, 
  according 
  to 
  

   Dumont, 
  the 
  manner 
  in 
  which 
  the 
  Belgian 
  beds 
  are 
  spread 
  out 
  on 
  

   those 
  beneath 
  them 
  bears 
  evidence 
  of 
  a 
  gap, 
  which 
  is 
  elsewhere 
  filled 
  

   by 
  still 
  older 
  formations. 
  

  

  The 
  large 
  number 
  of 
  species 
  (amounting 
  to 
  at 
  least 
  50) 
  common 
  

   to 
  the 
  Belgian 
  Oligocene 
  and 
  the 
  English 
  so-called 
  Eocene 
  is 
  also 
  

   advanced 
  by 
  Professor 
  Beyrich 
  as 
  a 
  further 
  justification 
  of 
  his 
  classi- 
  

   fication. 
  About 
  one-half 
  of 
  these 
  species 
  occur 
  in 
  the 
  Middle 
  and 
  

   Upper 
  Limburg 
  beds, 
  while 
  the 
  rest, 
  even 
  if 
  not 
  found 
  in 
  those 
  

   strata, 
  occur 
  in 
  the 
  Lower 
  Tongrian. 
  In 
  this 
  numerical 
  relation 
  the 
  

   author 
  also 
  finds 
  a 
  support 
  to 
  the 
  conclusion 
  already 
  arrived 
  at, 
  that 
  

   the 
  proper 
  position 
  of 
  the 
  Belgian 
  Lower 
  Oligocene 
  is 
  between 
  the 
  

   Fontainebleau 
  Sands 
  and 
  the 
  Barton 
  Clay, 
  or 
  the 
  Sable 
  de 
  Beau- 
  

   champ, 
  close 
  to 
  the 
  Gypsum 
  of 
  Montmartre. 
  

  

  After 
  remarking 
  that 
  M. 
  Hebert's 
  hypothesis 
  of 
  a 
  general 
  cata- 
  

   strophe 
  is 
  not 
  supported 
  by 
  facts, 
  as 
  numerous 
  species 
  of 
  the 
  youngest 
  

   English 
  Eocene 
  occur 
  in 
  association 
  with 
  many 
  characteristic 
  forms 
  

   of 
  newer 
  strata, 
  Professor 
  Beyrich 
  proceeds 
  to 
  describe 
  the 
  geogra- 
  

   phical 
  distribution 
  of 
  the 
  Oligocene 
  strata. 
  The 
  lowermost 
  Oligocene 
  

   strata, 
  occurring 
  in 
  Northern 
  Germany 
  and 
  containing 
  many 
  Eocene 
  

   species, 
  are 
  older 
  than 
  the 
  Fontainebleau 
  Sands, 
  and 
  do 
  not 
  occur 
  

   in 
  districts 
  south 
  of 
  the 
  Hartz. 
  On 
  the 
  other 
  hand, 
  the 
  marine 
  beds 
  

   of 
  Alzey, 
  the 
  oldest 
  Middle 
  -Oligocene 
  German 
  equivalents 
  of 
  the 
  

   Fontainebleau 
  Sands, 
  scarcely 
  extend 
  beyond 
  the 
  banks 
  of 
  the 
  Rhine 
  ; 
  

   they 
  do 
  not 
  occur 
  in 
  Central 
  and 
  Northern 
  Germany, 
  but, 
  with 
  the 
  

   corresponding 
  Swiss 
  beds, 
  are 
  more 
  probably 
  in 
  connexion 
  with 
  the 
  

   strata 
  in 
  the 
  neighbourhood 
  of 
  Orleans 
  than 
  with 
  those 
  of 
  Tongres 
  

   and 
  Maestricht. 
  These 
  strata 
  are 
  succeeded 
  in 
  Germany 
  by 
  an 
  ex- 
  

   tended 
  series 
  of 
  brackish- 
  and 
  fresh-water 
  beds, 
  which 
  are 
  overlain, 
  

   near 
  Cassel, 
  by 
  the 
  equivalent 
  of 
  the 
  youngest 
  Belgian 
  Oligocene 
  

   series 
  — 
  the 
  Clay 
  of 
  Boom, 
  this 
  formation 
  being 
  widely 
  distributed 
  

   in 
  Northern 
  Germany. 
  

  

  Professor 
  Beyrich 
  then 
  notices 
  the 
  important 
  memoir 
  by 
  MM. 
  He- 
  

   bert 
  and 
  Benevier 
  *, 
  in 
  which 
  they 
  endeavour 
  to 
  show 
  that 
  the 
  Upper 
  

  

  * 
  " 
  Description 
  des 
  fossiles 
  du 
  terrain 
  nummulitique 
  superieur 
  des 
  environs 
  de 
  

   Gap, 
  des 
  Diablerets, 
  et 
  de 
  quelques 
  localities 
  de 
  la 
  Savoie," 
  Bull. 
  Soc. 
  Statistique 
  

   du 
  Dep. 
  de 
  l'lsere, 
  Grenoble, 
  1854. 
  

  

  