﻿212 
  PROCEEDINGS 
  OE 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  species 
  ; 
  they 
  are 
  so 
  important 
  stratigraphically 
  that 
  I 
  name 
  them 
  

   — 
  A. 
  alternans, 
  A. 
  auritulus, 
  A. 
  Bdkerice, 
  A. 
  Baugieri, 
  A. 
  Comptoni, 
  

   A. 
  convolutus, 
  A. 
  Eugenii, 
  A. 
  flexicostatus, 
  A.jluctuosus, 
  A. 
  goliatlius, 
  

   A. 
  Henrici, 
  A. 
  Lalandianus, 
  A. 
  Lonsdcdei, 
  A. 
  ocidatus, 
  A. 
  planxda, 
  

   A. 
  tatricus, 
  A. 
  raricostatus, 
  A. 
  Vernoni. 
  These 
  18 
  species 
  are 
  en- 
  

   tirely 
  confined 
  to 
  the 
  Oxford 
  Clay. 
  The 
  4 
  species 
  that 
  pass 
  to 
  the 
  

   Kimineridge 
  Clay 
  are 
  A. 
  longispinus, 
  A. 
  Lamherti, 
  A. 
  annularis, 
  

   and 
  A. 
  anc&ps. 
  Yery 
  few 
  species 
  occur 
  in 
  the 
  Oxford 
  Clay 
  of 
  

   Yorkshire 
  ; 
  they 
  mostly 
  occur 
  in 
  Wiltshire, 
  Huntingdonshire, 
  Lin- 
  

   colnshire, 
  Oxfordshire, 
  and 
  Western 
  Scotland. 
  The 
  groups 
  repre- 
  

   sented 
  in 
  the 
  Oxford 
  Clay 
  are 
  the 
  Dentati, 
  Flexuosi, 
  and 
  Ornati 
  

   (species 
  of 
  Cosmoeeras), 
  the 
  Armati 
  (Aspidoeeras 
  longispinum 
  and 
  

   perarmatum), 
  the 
  AmaltJiei 
  through 
  A. 
  eordatus, 
  A. 
  Lamherti, 
  and 
  the 
  

   Macrocepliali 
  thioMs^iSteplianoceras 
  macrocejihalum. 
  Twenty 
  Oxford- 
  

   Clay 
  species 
  occur 
  in 
  the 
  Western 
  Isles 
  (Scotland), 
  in 
  which 
  the 
  

   groups 
  Dentati, 
  Ornati, 
  and 
  Flexuosi 
  are 
  conspicuous, 
  species 
  of 
  the 
  

   genera 
  Cosmoceras 
  and 
  Aspidoeeras 
  prevailing*. 
  

  

  Ancyloceras. 
  — 
  Ancyloceras 
  calloviense 
  is 
  the 
  only 
  form 
  occurring, 
  

   though 
  sparingly. 
  It 
  is 
  chiefly 
  Callovian. 
  

  

  Nautili. 
  — 
  None 
  known. 
  

  

  Belemnites. 
  — 
  13 
  species 
  have 
  been 
  described, 
  but 
  probably 
  only 
  

   10 
  occur, 
  and 
  3 
  varieties 
  of 
  the 
  species 
  B. 
  Owenii. 
  Since 
  the 
  

   Inferior 
  Oolite, 
  which 
  yielded 
  16 
  species, 
  there 
  has 
  been 
  no 
  such 
  

   illustration 
  of 
  the 
  genus. 
  The 
  Fuller's 
  Earth 
  has 
  only 
  3 
  species, 
  the 
  

   Great 
  Oolite 
  3, 
  Forest 
  Marble 
  none, 
  Cornbrash 
  none, 
  Kellaways 
  Eock 
  

   3, 
  and 
  the 
  Oxford 
  Clay 
  under 
  notice 
  13. 
  They 
  decline 
  again 
  in 
  

   the 
  two 
  next 
  horizons. 
  The 
  Corallian 
  beds 
  possess 
  only 
  4, 
  the 
  

   Kimmeridge 
  Clay 
  8, 
  and 
  the 
  Portland 
  beds 
  none. 
  The 
  varieties 
  of 
  B. 
  

   Owenii 
  are 
  B. 
  Puzosianus, 
  B. 
  verrucosus, 
  and 
  B. 
  tomatilis. 
  Admit- 
  

   ting 
  these 
  to 
  be 
  varieties 
  of 
  that 
  species, 
  the 
  number 
  may 
  be 
  reduced 
  

   to 
  10. 
  Only 
  1 
  species 
  (B. 
  abbreviatus) 
  passes 
  to 
  the 
  Corallian 
  series 
  

   and 
  Kimmeridge 
  Clay; 
  B. 
  eoccentricus 
  may 
  be 
  only 
  a 
  var. 
  of 
  B. 
  

   abbreviatus. 
  Only 
  6 
  of 
  the 
  13 
  species 
  are 
  confined 
  to 
  the 
  Oxford 
  

   Clay, 
  viz. 
  B. 
  Beaumontianus, 
  B. 
  excentricus, 
  B. 
  obeliscus, 
  B. 
  spicu- 
  

   laris, 
  B. 
  strigosus, 
  and 
  B. 
  sulcatus. 
  These 
  13 
  forms, 
  with 
  the 
  one 
  

   exception, 
  are 
  all 
  Middle 
  Oolitic, 
  none 
  appearing 
  below 
  the 
  Kellaways 
  

   Hock 
  or 
  above 
  the 
  Corallian 
  beds. 
  3 
  species 
  pass 
  to 
  the 
  Corallian 
  

   rocks, 
  viz. 
  B. 
  abbreviatus 
  and 
  var. 
  excentricus, 
  and 
  B. 
  hastatus. 
  B. 
  

   abbreviatus 
  also 
  ranges 
  to 
  the 
  Kimmeridge 
  Clay 
  or 
  the 
  Upper 
  Oolite. 
  

   B. 
  hastatus 
  and 
  B. 
  Owenii 
  are 
  the 
  only 
  two 
  species 
  that 
  come 
  up 
  

   from 
  the 
  Kellaways 
  below. 
  

  

  Teuihidce. 
  — 
  Acanthoteutliis 
  antiquus 
  and 
  Geoteuthis 
  brevispinus 
  

   illustrate 
  this 
  family 
  ; 
  they 
  are 
  associated 
  with 
  the 
  great 
  series 
  of 
  

  

  * 
  To 
  enter 
  into 
  the 
  distribution 
  of 
  the 
  Middle 
  Oolite 
  Ammonites 
  according 
  

   to 
  their 
  groups 
  and 
  new 
  genera 
  would 
  alone 
  constitute 
  an 
  entire 
  address; 
  the 
  

   difficulty 
  is 
  to 
  reduce 
  any 
  history 
  of 
  this 
  group 
  to 
  moderate 
  limits. 
  D'Orbigny 
  

   in 
  this 
  division 
  of 
  the 
  Jurassic 
  rocks 
  (Oxfordian) 
  enumerates 
  no 
  less 
  than 
  43 
  

   species 
  of 
  Ammonites, 
  12 
  Belemnites, 
  and 
  4 
  Nautili. 
  

  

  