﻿NEWTON 
  : 
  GEOLOGICAL 
  ZONKS 
  AND 
  THEIR 
  MOLLUSCA. 
  285 
  

  

  on 
  the 
  lines 
  of 
  modern 
  zoning 
  work 
  with 
  its 
  index-fossils, 
  was 
  never- 
  

   theless 
  Aery 
  detailed 
  and 
  analytical 
  in 
  its 
  scope.' 
  

  

  Barrande 
  recognized 
  that 
  shells 
  andother 
  invertebrates 
  were 
  associated 
  

   in 
  ' 
  colonies 
  ' 
  or 
  provinces, 
  and 
  that 
  they 
  could 
  be 
  traced 
  over 
  distant 
  

   localities, 
  representing, 
  therefore, 
  separate 
  faunas 
  of 
  different 
  marine 
  

   areas. 
  He 
  was 
  of 
  opinion 
  that 
  there 
  were 
  " 
  three 
  distinct 
  faunas 
  in 
  

   the 
  Bohemian 
  strata 
  " 
  below 
  the 
  Devonian. 
  The 
  first 
  or 
  oldest 
  fauna 
  

   he 
  called 
  the 
  ' 
  Primordial 
  zone 
  ' 
  or 
  Etage 
  C, 
  the 
  equivalent 
  of 
  the 
  

   Cambrian 
  ; 
  the 
  second 
  fauna 
  was 
  grouped 
  as 
  Etage 
  D, 
  and 
  represented 
  

   the 
  Lower 
  Silurian 
  of 
  ^lurchison 
  ; 
  the 
  third 
  fauna 
  included 
  Etages 
  

   E, 
  E, 
  G, 
  or 
  the 
  Upper 
  Silurian, 
  as 
  also 
  defined 
  by 
  Murchison. 
  

  

  It 
  is 
  not 
  until 
  Carboniferous 
  times 
  are 
  reached 
  that 
  molluscan 
  

   organisms, 
  especially 
  in 
  this 
  countiy, 
  appear 
  to 
  take 
  a 
  more 
  prominent 
  

   part 
  in 
  the 
  history 
  of 
  stratification. 
  In 
  connection 
  with 
  the 
  assemblage 
  

   of 
  shells, 
  rather 
  than 
  with 
  actual 
  zonal 
  forms, 
  Dr. 
  Wheelton 
  Hind,^ 
  

   writing 
  " 
  On 
  the 
  Subdivisions 
  of 
  the 
  Carboniferous 
  Series 
  in 
  Great 
  

   Britain 
  ", 
  mentioned 
  that 
  the 
  various 
  Mollusca 
  of 
  the 
  Yoredale 
  rocks 
  

   of 
  Yorkshire, 
  as 
  originally 
  described 
  by 
  John 
  Pliillips, 
  were 
  equivalent 
  

   to 
  those 
  characterizing 
  the 
  Carboniferous 
  Limestone 
  of 
  Derbyshire. 
  

   In 
  his 
  subdivisions 
  of 
  the 
  Carboniferous 
  System 
  Dr. 
  Hind 
  recognized 
  

   three 
  distinct 
  faunas, 
  which 
  were 
  tabulated 
  in 
  descending 
  order 
  as 
  — 
  

  

  (1) 
  The 
  Coal-measure 
  fauna, 
  ricli 
  in 
  fish-remains 
  and 
  the 
  freshwater 
  

   Pelecypod 
  genera 
  Carhonicola, 
  Anthracomya, 
  and 
  Naiadites. 
  

  

  (2) 
  The 
  Lower 
  Coal-measures 
  and 
  Grit 
  fauna, 
  the 
  Gannister 
  and 
  

   Grit 
  Series 
  ; 
  largely 
  marine, 
  but 
  littoral, 
  containing 
  Aviculopecten 
  and 
  

   Posiclo7iieHa 
  as 
  Pelecypod 
  genera, 
  Goniatites, 
  Orthoceras, 
  and 
  Nautilus 
  

   as 
  Cephalopoda, 
  and 
  some 
  peculiar 
  Gastropoda. 
  

  

  (3) 
  The 
  Limestone 
  fauna, 
  essentially 
  marine, 
  rich 
  in 
  Corals, 
  

   Brachiopods, 
  and 
  Mollusca. 
  Many 
  genera 
  of 
  Pelecypoda, 
  such 
  as 
  

   Peden, 
  Axicula^ 
  Edmondia, 
  Smigumolites, 
  etc., 
  as 
  well 
  as 
  Gastropoda, 
  

   including 
  Euomphalus 
  , 
  Pleurotomaroid 
  genera, 
  Murchkonia^ 
  Loxonema, 
  

   etc., 
  and 
  Cephalopoda. 
  

  

  During 
  the 
  following 
  year 
  the 
  same 
  author^ 
  proposed 
  a 
  slightly 
  more 
  

   analytical 
  scheme 
  for 
  subdividing 
  the 
  Carboniferous 
  Series 
  of 
  England, 
  

   Scotland, 
  and 
  Ireland, 
  based 
  upon 
  certain 
  species 
  of 
  the 
  Pelecypoda, 
  

   Cephalopoda, 
  and 
  Brachiopoda, 
  which 
  he 
  termed 
  zones, 
  and 
  which 
  

   may 
  be 
  thus 
  enumerated: 
  — 
  

   Zones 
  of 
  — 
  

  

  (1) 
  Anthracomya 
  PhilUpsi 
  . 
  . 
  . 
  Upper 
  Coal-measures. 
  

  

  (2) 
  Naiadites 
  modiolaris 
  and 
  Anthra- 
  Middle 
  Coal-measures. 
  

  

  comya 
  modiolaris. 
  

  

  (3) 
  Aviculopecten 
  papyraceiis, 
  Gastric- 
  Lower 
  Coal-measures 
  : 
  Ganister 
  

  

  ceras 
  carbonarium, 
  Posidoniella 
  Series, 
  Millstone 
  Grit, 
  and 
  Shales 
  

  

  IcBvis 
  and 
  minor. 
  below 
  Millstone 
  Grit. 
  

  

  (4) 
  Producttis 
  giganteus 
  and 
  P. 
  cora 
  . 
  Carboniferous 
  Limestone 
  Series. 
  

  

  (5) 
  Modiola 
  Macadami 
  . 
  . 
  . 
  Lower 
  Limestone 
  Shales, 
  Calciferous 
  

  

  Sandstone 
  Series, 
  etc. 
  

  

  ' 
  It 
  should 
  be 
  mentioned 
  that 
  the 
  molluscan 
  names, 
  as 
  well 
  as 
  all 
  horizonal 
  

   terms 
  employed 
  in 
  this 
  account 
  of 
  the 
  geological 
  zones, 
  are 
  those 
  of 
  the 
  

   different 
  authors 
  who 
  have 
  written 
  upon 
  this 
  subject, 
  no 
  attempt 
  having 
  

   been 
  made 
  by 
  the 
  present 
  writer 
  to 
  place 
  them 
  on 
  a 
  more 
  up-to-date 
  basis. 
  

  

  ' 
  Geological 
  Magazine, 
  1897, 
  p. 
  205. 
  ^ 
  Ibid., 
  1898, 
  p. 
  61. 
  

  

  