Yol.  49.]  ANNIVERSARY  ADDRESS  OF  THE  PRESIDENT.  99 
subtropical  Mollusca,  and  almost  with  the  extinction  of  Nummulites 
in  our  area.  There  is  less  difficulty  about  the  upper  limit  of  the 
Barton  Series,  which  is  drawn  at  the  base  of  the  Lower  Headon, 
where  the  brackish-water  fauna  gives  place  to  one  of  freshwater 
origin. 
A  considerable  portion  of  the  paper  is  then  devoted  to  a  detailed 
description  of  the  Earton  Series  as  developed  in  Christchurch  Bay, 
an  ascending  section  being  given,  and  the  measurements  compared 
with  those  of  previous  observers,  such  as  Prestwich,  Bristow,  and 
Wright.  The  zone  of  Nummulites  elegans  is  taken  to  be  somewhere 
about  the  base  of  the  Lower  Barton  Beds.  I  may  mention,  by  the 
way,  that  a  paper  was  read  before  the  Society  by  Prof.  Bupert  J ones 
in  1886,  where  it  was  shown  that  Sowerby’s  labelled  specimens  of 
‘  Nummularia  ’  elegans  are  really  the  same  as  the  var.  Prestwichiana 
of  Nummulites  planulatus .  We  may  believe,  then,  that  the  Nummu- 
lina  Prestwichiana ,  auct.,  is  really  the  same  thing  as  Nummulites 
elegans ,  Sow.  Since  this  line  is  to  be  taken  as  the  base  of  the  Upper 
Eocene,  it  is  at  least  important  that  the  synonymy  of  the  name-giving 
Nummulite  should  be  settled. 
The  Lower  Barton  or  Highcliff  Beds  are  estimated  at  about  50 
feet,  consisting  mainly  in  their  lower  parts  of  stiff  drab-coloured 
clay,  which  higher  up  becomes  filled  with  sand  drifts  full  of  fossils, 
the  uppermost  portion  being  known  as  the  Highcliff  Sands ;  this 
part  of  the  series  terminates  with  the  Plioladomya- bed.  Its  fauna 
comprises  many  Bracklesham  species,  which  range  no  higher  up, 
and  it  also  contains  a  large  number  of  peculiar  species.  The  base¬ 
line  fixed  for  the  Middle  Barton,  or  Barton  Clay  proper,  is  the  lowest 
of  several  bands  of  septaria,  which  distinguish  the  50  feet  of  drab- 
coloured  clays  comprised  in  it,  and  this  last  division  terminates  in  a 
very  remarkable  formation,  known  as  the  Shell-bed,  which,  although 
only  a  foot  or  two  thick  at  Highcliff,  increases  towards  the  east.  The 
fauna  of  the  middle  division  of  the  Bartons  is  nearly  as  rich  as  that 
of  the  lower,  and  far  more  characteristic.  Some  of  the  grandest 
species,  such  as  Postellaria  ampla ,  Fusus  longcevus ,  and  Murex 
minax ,  range  from  the  Bracklesham  right  through  the  Barton,  but 
attain  their  finest  development  here.  Others,  such  as  Cassiclaria 
nodosa,  Ficula  nexilis,  Triton  argutum,  and  Fusus  regularis,  pass 
upwards  from  the  Bracklesham,  but  do  not  range  beyond  the  limit 
of  this  division.  The  finest  specimens  of  the  strictly  Barton  fossils, 
Voluta  luctatrix ,  Crassatella  sulcata,  and  Limopsis  scalaris,  are 
obtained  here,  while  others,  such  as  Voluta  ambigua  and  Pleurotoma 
