﻿40 
  

  

  REMAEKS 
  ON 
  DR. 
  DALL'S 
  PAPER. 
  

  

  B}' 
  11. 
  Bdllen 
  jS^ewton, 
  F.G.S. 
  

  

  Bead 
  10th 
  December, 
  1915. 
  

  

  In 
  til 
  is 
  paper 
  Dr. 
  Dall 
  replies 
  to 
  a 
  criticism 
  made 
  by 
  M. 
  Cossmann 
  

   {Revue 
  Critique 
  de 
  Paleozoologie, 
  1915, 
  p. 
  119) 
  on 
  his 
  " 
  Moiiofjrapli 
  of 
  

   the 
  MoUuscan 
  Fauna 
  of 
  the 
  Orthaulax 
  pugnax 
  zone 
  of 
  the 
  Oligocene 
  

   of 
  Tampa, 
  Florida", 
  M. 
  Cossmann 
  being 
  in 
  favour 
  of 
  regarding 
  the 
  

   Tampa 
  beds 
  as 
  of 
  Miocene 
  instead 
  of 
  Oligocene 
  age. 
  Both 
  authors 
  

   agree, 
  however, 
  that 
  they 
  belong 
  to 
  the 
  Aquitanian 
  stage 
  of 
  the 
  

   Tertiary 
  series, 
  so 
  that 
  the 
  chief 
  point 
  for 
  discussion 
  is 
  whether 
  

   the 
  Aquitanian 
  horizon 
  is 
  to 
  be 
  correlated 
  with 
  the 
  Oligocene 
  or 
  the 
  

   Miocene. 
  M. 
  Cossmann 
  urges 
  that 
  the 
  absence 
  of 
  Megatylotiis 
  

   crassatina 
  in 
  the 
  Tampa 
  beds 
  is 
  against 
  their 
  being 
  referred 
  to 
  the 
  

   Oligocene, 
  although 
  in 
  support 
  of 
  this 
  view 
  a 
  better 
  reason, 
  I 
  think, 
  

   might 
  have 
  been 
  advanced 
  from 
  the 
  fact 
  that 
  no 
  Nummulites 
  are 
  

   found 
  in 
  those 
  deposits. 
  It 
  has 
  been 
  long 
  recognized 
  that 
  Nummu- 
  

   lites 
  died 
  out 
  at 
  the 
  end 
  of 
  Oligocene 
  times, 
  being 
  replaced 
  by 
  

   Lepidocycline 
  Foraminifera 
  in 
  the 
  succeeding 
  Aquitanian 
  and 
  later 
  

   stages 
  of 
  the 
  Miocene 
  period, 
  and 
  hence 
  European 
  stratigraphists 
  

   liave 
  favoured 
  the 
  Aquitanian 
  being 
  regarded 
  as 
  the 
  oldest 
  Miocene. 
  

   Dr. 
  Dall 
  appears 
  to 
  have 
  misunderstood 
  the 
  true 
  horizon 
  of 
  the 
  

   naticoid 
  shell 
  referred 
  to 
  by 
  M. 
  Cossmann 
  as 
  Megatylotus 
  crassatifia, 
  

   which 
  is 
  essentially 
  Oligocene, 
  and 
  not 
  known 
  either 
  in 
  the 
  Eocene 
  

   or 
  Miocene 
  deposits 
  of 
  Europe. 
  This 
  mollusc 
  is 
  more 
  particularly 
  

   characteristic 
  of 
  the 
  Stampian 
  or 
  upper 
  part 
  of 
  the 
  Oligocene, 
  being 
  

   typical 
  of 
  certain 
  beds 
  of 
  the 
  Paris 
  Basin 
  known 
  as 
  the 
  " 
  Sables 
  

   Superieurs 
  " 
  ; 
  the 
  species 
  likewise 
  occurs 
  in 
  similar 
  deposits 
  of 
  

   England, 
  having 
  been 
  recorded 
  from 
  the 
  Hempstead 
  Beds 
  of 
  the 
  Isle 
  

   of 
  Wight 
  (B. 
  B. 
  Newton, 
  Syst. 
  List 
  British 
  Oligocene 
  and 
  Eocene 
  

   Mollusca, 
  British 
  Museum, 
  1891, 
  p. 
  241). 
  

  

  It 
  is 
  to 
  be 
  regretted, 
  as 
  pointed 
  out 
  by 
  Dr. 
  Dall, 
  that 
  M. 
  Cossmann 
  

   is 
  against 
  the 
  adoption 
  of 
  Boltenian 
  names, 
  which 
  are 
  now 
  so 
  widely 
  

   accepted 
  by 
  conchologists. 
  

  

  