﻿ANNIVEKSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  79 
  

  

  Formations. 
  Thickness. 
  Equivalents. 
  

  

  (1. 
  The 
  Maestricht 
  and 
  Meudon 
  

   beds 
  ? 
  or 
  Eocene 
  ? 
  

   2. 
  The 
  zone 
  of 
  Bel. 
  mucronatus. 
  

   3. 
  Middle 
  Lower 
  Chalk. 
  

  

  Upper 
  G-reensand 
  60 
  „ 
  „ 
  Cenomanian. 
  

  

  Middle 
  Oxfordian 
  very 
  considerable. 
  

  

  Great 
  unconformable 
  break. 
  

  

  Great 
  Estuarine 
  l 
  3divisions 
  850 
  f 
  ee 
  t. 
  (Lower 
  Oxfordian 
  and 
  Great 
  

  

  series 
  J 
  L 
  uoiite. 
  

  

  |" 
  1. 
  Inferior 
  Oolite, 
  zone 
  of 
  Am. 
  

  

  Parkinsoni. 
  

   1 
  2. 
  Zone 
  of 
  Am. 
  Humphriesianus. 
  

   ^3. 
  Zone 
  of 
  A. 
  Murchisonce. 
  

  

  Upper 
  Lias 
  1 
  division 
  100 
  „ 
  Upper 
  Lias 
  Clay. 
  

  

  ( 
  1. 
  Zone 
  of 
  Am. 
  spinatus 
  and 
  Am. 
  

  

  Lower 
  Oolites 
  4 
  „ 
  385 
  

  

  Middle 
  Lias 
  3 
  divisions 
  500 
  „ 
  -{2. 
  Zone 
  of 
  A. 
  Jamesoni. 
  

  

  j 
  3. 
  Zone 
  of 
  Am. 
  armatus, 
  A. 
  ibex, 
  

   \ 
  and 
  A. 
  oxynotus. 
  

  

  _ 
  _. 
  4nft 
  fl. 
  Zone 
  of 
  Am. 
  semicostatus. 
  

  

  Lower 
  Lias 
  I 
  „ 
  WU 
  „ 
  \2. 
  Zone 
  of 
  Am. 
  Bucklandi. 
  

  

  Infra 
  Lias 
  1 
  division 
  400 
  „ 
  

  

  2635 
  feet. 
  

  

  Zone 
  of 
  Am. 
  angulatus 
  and 
  Am. 
  

   planorbis. 
  

  

  The 
  accompanying 
  Table 
  (IV.) 
  exhibits 
  the 
  Ammonites 
  that 
  occur 
  

   in 
  the 
  Jurassic 
  strata 
  of 
  the 
  eastern 
  and 
  western 
  sides 
  of 
  Scotland, 
  

   and 
  in 
  the 
  patches 
  left 
  by 
  denudation. 
  This 
  Table 
  has 
  been 
  compiled 
  

   from 
  the 
  various 
  collections 
  made 
  by 
  Mr. 
  Judd 
  and 
  the 
  species 
  men- 
  

   tioned 
  in 
  his 
  paper. 
  The 
  Lower 
  Lias 
  embraces 
  12 
  species, 
  the 
  Middle 
  

   Lias 
  14, 
  the 
  Upper 
  Lias 
  5, 
  the 
  Middle 
  Oolite 
  27, 
  and 
  the 
  Upper 
  

   Ooolite 
  23 
  species 
  — 
  in 
  all 
  81 
  species. 
  Equally 
  important 
  and 
  in- 
  

   structive 
  would 
  have 
  been 
  the 
  tabulation 
  of 
  the 
  whole 
  fauna 
  of 
  these 
  

   northern 
  Jurassic 
  rocks 
  ; 
  but 
  my 
  Address 
  will 
  greatly 
  exceed 
  the 
  

   limits 
  I 
  had 
  intended, 
  and 
  tabular 
  matter 
  requires 
  long 
  explanation. 
  

   I 
  have 
  selected 
  the 
  Ammonites 
  because 
  they 
  are 
  of 
  high 
  strati- 
  

   graphical 
  importance, 
  and 
  their 
  acknowledged 
  zonal 
  value 
  carries 
  

   with 
  it 
  definite 
  ideas 
  for 
  correlation. 
  This 
  Table 
  is 
  a 
  singular 
  

   and 
  complete 
  illustration 
  and 
  confirmation 
  of 
  the 
  stratigraphical 
  

   value 
  of 
  the 
  distribution 
  of 
  the 
  Ammonites 
  in 
  time 
  and 
  space, 
  clearly 
  

   showing 
  the 
  succession 
  of 
  groups 
  of 
  species 
  through 
  the 
  long 
  conti- 
  

   nuous 
  deposition 
  of 
  the 
  sedimentary 
  matter 
  composing 
  the 
  Jurassic 
  

   rocks 
  over 
  the 
  entire 
  European 
  area. 
  

  

  In 
  addition 
  to 
  giving 
  the 
  tabular 
  distribution 
  of 
  the 
  Ammonites 
  

   only 
  in 
  the 
  patches 
  left 
  by 
  denudation 
  on 
  the 
  east 
  and 
  west 
  coasts 
  

   of 
  Scotland, 
  I 
  have 
  prepared 
  a 
  second 
  Table 
  (V.) 
  for 
  the 
  distri- 
  

   bution 
  of 
  all 
  the 
  known 
  species 
  in 
  the 
  same 
  localities, 
  arranging 
  

   them 
  stratigraphically. 
  The 
  numerical 
  development 
  and 
  distri- 
  

   bution 
  of 
  the 
  Mollusca 
  is 
  a 
  significant 
  feature 
  in 
  this 
  Table 
  ; 
  ten 
  of 
  

   the 
  fifteen 
  classes 
  are 
  scarcely 
  represented 
  ; 
  but 
  it 
  is 
  evident 
  from 
  

   the 
  associated 
  fauna 
  that 
  the 
  Jurassic 
  rocks 
  of 
  the 
  Scottish 
  area 
  have 
  

   yet 
  to 
  yield 
  a 
  rich 
  harvest 
  of 
  species. 
  The 
  genera 
  are 
  not 
  largely 
  

   represented 
  by 
  species, 
  clearly 
  showing 
  the 
  want 
  of 
  systematic 
  

  

  