﻿228 
  

  

  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  Table 
  XLY1. 
  — 
  Number 
  of 
  Genera 
  and 
  Species 
  occurring 
  in 
  the 
  whole 
  

   of 
  the 
  Jurassic 
  Rocks 
  arranged 
  stratigraphically 
  , 
  or 
  from 
  the 
  

   Lower 
  Lias 
  to 
  the 
  close 
  of 
  the 
  Portland 
  Oolite. 
  

  

  Formations. 
  

  

  i 
  

  

  s 
  

  

  8 
  

  

  3 
  

  

  00 
  

  

  .2 
  

  

  'S 
  

   a 
  

  

  &« 
  

   CO 
  

  

  

  226 
  

  

  137 
  

  

  111 
  

  

  213 
  

  

  51 
  

  

  229 
  

  

  65 
  

  

  92 
  

  

  52 
  

  

  73 
  

  

  116 
  

  

  103 
  

  

  63 
  

  

  1081 
  

   563 
  

   418 
  

  

  1000 
  

   110 
  

   820 
  

   136 
  

   244 
  

   168 
  

   194 
  

   334 
  

   263 
  

   128 
  

  

  Middle 
  Lias 
  

  

  Upper 
  Lias 
  

  

  Inferior 
  Oolite 
  

  

  Fuller's 
  Earth 
  

  

  Great 
  Oolite 
  

  

  Forest 
  Marble 
  

  

  Corn 
  brash 
  

  

  Kellaways 
  Rock 
  

  

  Oxford 
  Clay 
  

  

  Corallian 
  beds 
  

  

  Kimmeridge 
  Clay 
  

  

  Portland 
  Oolite 
  

  

  

  

  1531 
  

  

  5459 
  

  

  § 
  14. 
  The 
  Modern 
  Classification 
  of 
  Ammonites. 
  

   The 
  modern 
  classification 
  of 
  the 
  Ammonitidae 
  is 
  by 
  no 
  means 
  an 
  

   easy 
  one 
  to 
  elaborate 
  after 
  the 
  long 
  usage 
  of 
  the 
  present 
  nomencla- 
  

   ture. 
  Yon 
  Buch* 
  attempted 
  a 
  better 
  arrangement 
  than 
  had 
  before 
  

   appeared, 
  based 
  upon 
  the 
  definite 
  ramificatioDS 
  and 
  foliations 
  of 
  the 
  

   suture 
  or 
  lobe-line, 
  which 
  is 
  traceable 
  beneath 
  the 
  shell 
  or 
  upon 
  the 
  

   mould, 
  the 
  characters 
  of 
  the 
  lobes 
  and 
  saddles 
  formed 
  by 
  them, 
  

   the 
  position 
  and 
  structure 
  of 
  the 
  siphuncle, 
  and 
  the 
  form 
  of 
  the 
  

   spiral 
  of 
  the 
  shell. 
  Upon 
  these 
  elements 
  he 
  constructed 
  his 
  21 
  

   groups 
  of 
  the 
  Ammonitidae, 
  which 
  for 
  years 
  have 
  been 
  the 
  foun- 
  

   dation 
  of 
  all 
  attempts 
  at 
  the 
  classification 
  of 
  the 
  Ammonites. 
  D'Or- 
  

   bigny, 
  Qucnstedt, 
  and 
  others 
  enlarged 
  upon 
  the 
  method 
  of 
  Yon 
  

   Buch. 
  Professor 
  Suess 
  f 
  , 
  Dr. 
  W. 
  Waagen 
  J, 
  Prof. 
  Hyatt, 
  of 
  America 
  §, 
  

   M. 
  E. 
  Favre 
  ||, 
  Prof. 
  Neumayer 
  ^[, 
  Dr. 
  Mojsisovics 
  •*, 
  Prof. 
  Zittel, 
  

   Dr. 
  Laube, 
  and 
  others, 
  however, 
  have 
  all 
  carried 
  out 
  the 
  views 
  and 
  

   classification 
  of 
  the 
  Yienna 
  school. 
  The 
  characters 
  upon 
  which 
  the 
  

   genera 
  are 
  established 
  are 
  : 
  — 
  1st, 
  the 
  structure 
  of 
  the 
  lobes 
  and 
  saddles; 
  

   2nd, 
  the 
  form 
  of 
  the 
  aperture 
  of 
  the 
  shell 
  and 
  the 
  development 
  of 
  the 
  

   mouth-border 
  ; 
  3rd, 
  the 
  length 
  of 
  the 
  body 
  -chamber 
  ; 
  4th, 
  the 
  amount 
  

  

  * 
  ' 
  Die 
  Ammoniten 
  in 
  den 
  alteren 
  Gebirgs-Schichten,' 
  1830. 
  

  

  t 
  " 
  Ueber 
  Ammoniten," 
  Erste 
  Abth., 
  Sitzungsber. 
  der 
  Math.-nat. 
  Classe 
  der 
  

   Wiener 
  Akad. 
  1865, 
  Band 
  lii. 
  Abth. 
  1. 
  

  

  | 
  " 
  Ueber 
  die 
  Ansatzstelle 
  der 
  Haftmuskeln 
  beim 
  Nautilus 
  und 
  den 
  Ammoni- 
  

   den," 
  Palseontographica, 
  Band 
  xvii. 
  Abth. 
  5, 
  p. 
  197 
  (1867-70). 
  

  

  § 
  Bulletin 
  of 
  the 
  Mus. 
  of 
  Comp. 
  Anatomy, 
  Harvard 
  Coll., 
  Cambridge, 
  Mass., 
  

   vol. 
  i. 
  no. 
  5 
  (1866). 
  

  

  || 
  " 
  Sur 
  la 
  Classif. 
  des 
  Ammonites," 
  Bull 
  de 
  la 
  Soc. 
  Geol. 
  de 
  France, 
  3 
  C 
  series, 
  

   tome 
  1 
  (1873). 
  

  

  ^[ 
  Zeitschrift 
  der 
  deutschen 
  geologischen 
  Gesellschaft, 
  p. 
  854, 
  Jahrgang 
  

   1875 
  ; 
  und 
  Die 
  Ammoniten 
  der 
  Kreise 
  und 
  die 
  Systematik 
  der 
  Ammonitiden. 
  

  

  ** 
  Das 
  Gebirge 
  urn 
  Hallstatt 
  (Wien, 
  1875). 
  

  

  