﻿130 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  PoRTLANDIAN. 
  

  

  1. 
  Zone 
  of 
  Cyrena 
  rugosa, 
  with 
  3 
  subdivisions. 
  

  

  2. 
  Zone 
  of 
  Cyprina 
  Brongniarti, 
  with 
  3 
  subdivisions. 
  

  

  3. 
  Zone 
  of 
  Ammonites 
  gigas, 
  with 
  4 
  divisions. 
  

  

  a. 
  Bure 
  Oolite. 
  

  

  b. 
  Limestone 
  with 
  Am. 
  irrms. 
  

  

  c. 
  Marls 
  with 
  Hcmicidaris 
  purbecJcensis. 
  

  

  d. 
  Lithographic 
  Limestone 
  with 
  Amm. 
  rotundus. 
  

  

  KlMMERIDGIAX. 
  

  

  1. 
  Zone 
  of 
  Amm. 
  caletanits 
  = 
  Virgulian, 
  with 
  2 
  subdivisions. 
  

  

  a. 
  Alternations 
  with 
  Am. 
  erinus. 
  

  

  b. 
  Marls 
  with 
  Am. 
  eumelus. 
  

  

  2. 
  Zone 
  of 
  Amm. 
  orthocera 
  =Pterocerian, 
  with 
  6 
  subdivisions. 
  

  

  a. 
  Perforated 
  Limestone. 
  

  

  b. 
  Marly 
  Limestone 
  with 
  Dysaster 
  granulosus. 
  

  

  c. 
  Limestone 
  with 
  Isocardia 
  striata. 
  

  

  d. 
  Marls 
  with 
  Bhabdocidaris 
  Orbignyana. 
  

  

  e. 
  Marls 
  with 
  Ceromya 
  excentrica. 
  

  

  f. 
  Perforated 
  Limestone 
  with 
  Ptcrocera. 
  

  

  CORALLIAX 
  OR 
  Sequ.VNIAN. 
  

  

  1 
  . 
  Second 
  zone 
  of 
  Terebratula 
  hiemeralis, 
  Astartian 
  Limestone. 
  

  

  2. 
  ,, 
  „ 
  Cardium 
  corallinum, 
  La-Mo 
  the 
  Oolite. 
  

  

  3. 
  First 
  „ 
  Terebratula 
  humeralis, 
  with 
  6 
  subdivisions. 
  

  

  a. 
  Lithographic 
  Limestone. 
  

  

  b. 
  Saucourt 
  Oolite. 
  

  

  c. 
  Limestones 
  with 
  Nautilus 
  giganteus. 
  

  

  d. 
  Upper 
  Bubbly 
  Limestone 
  with 
  Cidaris 
  flori- 
  

  

  gemma. 
  

  

  e. 
  Limestone 
  with 
  Am. 
  achilles. 
  

  

  f. 
  Limestone 
  with 
  Am. 
  bimammatus. 
  

  

  4. 
  First 
  zone 
  of 
  Cardium 
  corallinum 
  and 
  zone 
  of 
  Hemicidaris 
  crenularis. 
  

  

  a. 
  Upper 
  Marls 
  without 
  fossils. 
  

  

  b. 
  Diceras-Oolites 
  and 
  lower 
  rubbly 
  Limestones 
  

  

  with 
  Cid. 
  florigemma. 
  

  

  c. 
  Lower 
  Marls 
  without 
  fossils. 
  

  

  OXFORDIAN. 
  

  

  Zone 
  of 
  Amm. 
  transversarius. 
  

  

  a. 
  Beds 
  with 
  Amm. 
  Henrici 
  and 
  Am. 
  oculatus. 
  

  

  b. 
  „ 
  „ 
  „ 
  Babeanus. 
  

  

  c. 
  „ 
  „ 
  „ 
  Martelli. 
  

  

  I 
  feel 
  bound 
  to 
  give 
  this 
  complicated 
  classification 
  on 
  account 
  of 
  

   the 
  minute 
  manner 
  in 
  which 
  the 
  typical 
  or 
  characteristic 
  fossils 
  are 
  

   assigned 
  to 
  their 
  respective 
  horizons, 
  for 
  comparison 
  with 
  our 
  English 
  

   Upper 
  and 
  Middle 
  Jurassic 
  rocks, 
  and 
  also 
  to 
  show 
  the 
  method 
  of 
  

   work 
  adopted 
  by 
  some 
  continental 
  authors. 
  

  

  Department 
  oe 
  the 
  Atjbe. 
  — 
  Leymerie, 
  as 
  far 
  back 
  as 
  1846, 
  ad- 
  

   mirably 
  described 
  the 
  geology 
  of 
  this 
  department 
  *. 
  He 
  classified 
  

   the 
  rocks 
  as 
  follows 
  : 
  — 
  

  

  Upper 
  Jurassic. 
  

  

  1. 
  Portland 
  Limestone, 
  330 
  feet. 
  

  

  2. 
  Marls 
  and 
  Limestones 
  with 
  Exogyra 
  virgula, 
  250 
  feet. 
  

  

  * 
  Leymerie, 
  ' 
  Statistique 
  du 
  Departement 
  de 
  TAube,' 
  1846. 
  

  

  