Vol.  49.]  ANNIVERSARY  ADDRESS  OF  THE  PRESIDENT*  1 25 
So  far  the  resemblance  holds  fairly  well  ;  but  when  we  come  to 
consider  the  equivalents  of  what  used  to  be  called  the  Upper  Oolite 
in  this  country,  viz.  the  Kimeridge  Clay  and  Portland  Beds,  there 
is  found  to  be  a  very  considerable  difference  of  development  which 
renders  correlation  more  difficult.  Thus  it  is  not  easy  to  parallel 
the  4  Calcaire  a  Nerinees  ’  with  anything  in  England.  These  beds 
are  very  rich,  containing  192  species,  of  which  28  only  are  recognized 
as  British.  The  series  corresponds  approximately  in  position  with 
a  group  of  beds  I  once  ventured  to  name  4  Upper  Corallian ?  or 
j'  Supra-coralline,’  and  of  which  the  curious  little  reef  in  Bingstead 
Bay  is  a  notable  example.  This  4  Calcaire  a  Nerinees  ’  is  rich  in 
species  of  corals.  Indeed,  one  of  the  most  striking  differences 
between  the  fauna  of  the  British  Corallian  reefs  and  those  of  the 
Jura  is  the  large  number  of  species  of  corals  in  the  latter.  I  can 
hardly  think  that  the  difference  of  climate  can  have  been  so  great 
as  to  account  for  the  whole  of  this  peculiarity,  which  may  in  part 
have  been  due  to  deeper  and  clearer  water. 
The  next  thing  to  consider  is  how  far  the  Kimeridge  Clay  proper 
is  represented  in  the  Swiss  Jura,  and  here  we  must  remember 
that  we  are  for  the  most  part  comparing  clays  with  limestones. 
In  this  case  also  the  beds  are  characteristically  developed  in  the 
Southern  as  well  as  in  the  Northern  Jura.  We  can  hardly  find 
fault  with  Mr.  Roberts  for  grouping  the  Ostrea  deltoiclea  and  Astarte 
supracorallina- clays  with  the  Swiss  Astartian  ;  at  least  they  occupy 
approximately  the  same  relative  position,  and  contain  a  few  of 
the  same  fossils.  It  is  more  difficult  to  point  out  the  actual  time- 
equivalents  of  the  Pteroceriau  in  our  English  beds.  Mr.  Roberts 
considered  the  Pteroceriau  to  be  perhaps  the  most  important  stage  in 
•  the  whole  Upper  Jurassic  Series,  since  it  forms  by  far  the  greater 
portion  of  the  high  ground  in  parts  of  the  Jura  (southern  district), 
where  it  consists  of  limestones  with  some  marls.  It  should  be 
noted  that  Pteroceras  Oceani  occurs  at  Boulogne  on  a  higher  horizon 
than  is  usually  assigned  to  the  Pterocerian,  viz.  in  the  so-called 
Lower  Portlandian,  the  Bolonian  of  Blake. 
Next  come  the  clays  with  Eccogyra  virgula ,  and  these  we  have  not 
much  difficulty  in  correlating  with  the  Yirgulian,  which,  however, 
is  somewhat  irregularly  developed,  even  in  the  northern  district  of 
the  Swiss  Jura,  whilst  in  the  southern  district  it  has  only  been 
recognized  at  one  or  two  spots.  These  beds  take  us  to  the  top  of  the 
Lower  Kimeridge,  above  which,  on  the  present  occasion,  I  do  not 
propose  to  go,  since  the  investigation  of  the  various  interpretations 
