﻿NKWTON^: 
  GEOLOGICAL 
  ZONES 
  AND 
  THEIR 
  MOLLUSCA. 
  

  

  295 
  

  

  Belenmites 
  lateralis 
  as 
  representing 
  passage 
  beds 
  from 
  Jurassic 
  to 
  

   Lower 
  Cretaceous 
  or 
  Neocomian. 
  

  

  The 
  zonal 
  subdivisions 
  and 
  their 
  MoUusca 
  were 
  as 
  follows: 
  — 
  

  

  Age 
  of 
  Deposits. 
  

  

  [Albian.] 
  

  

  Marls 
  f 
  or 
  m 
  i 
  n 
  g 
  Zone 
  of 
  Belemn 
  ites 
  

  

  minimus 
  (= 
  uppermost 
  beds 
  

  

  of 
  the 
  Speeton 
  Clay 
  and 
  with 
  

  

  affinities 
  to 
  the 
  ' 
  lied 
  Chalk'). 
  

  

  [Aptian 
  ] 
  

  

  Zone 
  of 
  Belenmites 
  semi- 
  

   canaliculatu^ 
  (?) 
  { 
  = 
  Belenmites 
  

   Brunsricensis 
  of 
  Strombeck, 
  

   according 
  to 
  Judd, 
  see 
  p. 
  611 
  

   of 
  Lampliigh's 
  paper). 
  

  

  Neocomian 
  

   (Zone 
  of 
  Belenmites 
  jaculum] 
  

  

  Zone 
  of 
  Belemnites 
  lateralis. 
  

   (In 
  this 
  zone 
  the 
  author 
  

   found 
  the 
  'Portlandian 
  beds' 
  

   of 
  Leckenby/ 
  the 
  fossils 
  

   showing 
  marked 
  Jurassic 
  

   affinities.) 
  

  

  Characteristic 
  Mollusca. 
  

  

  Cephalopoda 
  : 
  Belenmites 
  miniinus, 
  

   attefmafus, 
  ultimtis. 
  Pelecypoda 
  : 
  

   Inoceranms 
  concentriciis, 
  sidcatus 
  

   var. 
  (?) 
  ; 
  Ostrea 
  sp. 
  ; 
  Avicula 
  

   Jiauliniana(?) 
  ; 
  JViicidapectinatai?). 
  

  

  Cephalopoda 
  : 
  Beletmiites 
  semicanali- 
  

   cnlatus 
  (?), 
  jaculum 
  ; 
  Atnmo7iites 
  

   Beshat/esi, 
  nucleus 
  ; 
  Crioceras 
  ; 
  

   Ancyloceras.GastiLO])oda:Bostellaria 
  

   Bhillipsi, 
  candidula, 
  hicarinala. 
  

   Pelecypoda 
  : 
  Exogyra 
  sinuata, 
  

   Pecten 
  orbicularis, 
  Pinna 
  tetragona, 
  

   CucullcBa 
  securis, 
  Nucida 
  impressa, 
  

   Panopma 
  neocomiensis, 
  Pholadomya 
  

   Martini. 
  

  

  Cephalopoda 
  : 
  Belemnites 
  jacidiim, 
  

   semicanalicidatus 
  ; 
  Crioceras 
  [Ancg- 
  

   loceras); 
  Crioceras 
  Durali, 
  pxmo- 
  

   sianum 
  ; 
  Ammonites 
  marginatus, 
  

   Speetonensis, 
  astierianus, 
  nucleus, 
  

   rotula^noricus. 
  Gastropoda: 
  Pleuro- 
  

   tomaria 
  sp. 
  ; 
  Troclms 
  pidcherrimtis, 
  

   Cerithiiim 
  acideatum. 
  Pelecypoda: 
  

   Exogyra 
  simiata, 
  Pecten 
  ci^ictiis, 
  

   Isocardia 
  angiilata, 
  Inoceranms 
  

   vemistidus, 
  Thracia 
  Phillipsi. 
  

  

  Cephalopoda 
  : 
  Belemnites 
  lateralis 
  ; 
  

   Ammonites 
  noricus, 
  Gravesiamis. 
  

   Pelecypoda 
  : 
  Avicula 
  inrnquivalvis 
  ; 
  

   Pecten 
  lens 
  var. 
  Morini, 
  cinctiis 
  ; 
  

   Exogyra 
  sinuata 
  var. 
  ; 
  Astarte 
  

   senecta 
  ; 
  Ifucula 
  ?]). 
  

  

  Professor 
  A. 
  Pavlov 
  and 
  Mr. 
  Lamplugh 
  ^ 
  contributed 
  a 
  joint 
  memoir 
  

   in 
  1892 
  on. 
  the 
  " 
  Argiles 
  de 
  Speeton 
  et 
  leurs 
  equivalents", 
  and 
  sub- 
  

   divided 
  the 
  beds 
  according 
  to 
  Belemnite 
  characters 
  as 
  originally 
  

   proposed 
  by 
  Mr. 
  Laraplugh, 
  in 
  which 
  the 
  following 
  zones 
  and 
  their 
  

   characteristic 
  Mollusca 
  were 
  given 
  as 
  — 
  

  

  Albian 
  (zone 
  of 
  Belemnites 
  mifiimus). 
  Cephalopoda: 
  Belemnites 
  

   minimus, 
  attemiatus, 
  ultimus. 
  Pelecypoda 
  : 
  hioceranms 
  concen- 
  

   tricus, 
  Nucida 
  pectinata. 
  

  

  1 
  "Note 
  on 
  the 
  Speeton 
  Clay 
  of 
  Yorkshire" 
  (Geologist, 
  1859, 
  p. 
  9), 
  and 
  in 
  

   Dr. 
  Wright's 
  British 
  Fossil 
  Cretaceous 
  Echinodermata 
  (Mon. 
  Pal. 
  Soc, 
  

   1864, 
  p. 
  9). 
  

  

  '■^ 
  Bull. 
  Soc. 
  Imp. 
  Nat. 
  Moscou, 
  Nos. 
  3, 
  4, 
  pis. 
  iv-viii, 
  xiii-xviii, 
  pp. 
  181-276, 
  

   445-570, 
  1891. 
  

  

  