120  PROCEEDINGS  OF  THE  GEOLOGICAL  SOCIETY.  [May  1893, 
Neocomian  beds  by  the  side  of  those  which  are  developed  in  the 
underlying  Jurassics.  It  is  this  fauna,  especially  as  noted  in  the 
upper  beds  of  the  zone,  which  characterizes  a  deposit  of  intermediate 
age.  He  thinks,  however,  that  a  detailed  study  of  the  entire  fauna 
will  show  that  its  affinities  incline  to  the  Jurassic  rather  than  to  the 
Cretaceous.  Moreover,  he  observes  that  perhaps  the  later alis-ume 
naturally  divides  into  two  parts.  The  upper  portion  in  all  proba¬ 
bility  is  that  which  contains  the  large  and  numerous  species  of 
Polypjtychites ,  referred  by  Leckenby  to  the  Coronati;  in  Lincoln¬ 
shire  this  is  represented  by  the  Claxby  Ironstone.  On  the  other 
hand,  some  very  fragmentary  specimens  of  smaller  forms  of  Olco- 
stephanus ,  belonging  to  the  section  Craspedites,  are  held  to  mark 
the  lower  division,  which  is  correlated  with  the  Spilsby  Sandstone. 
This  twofold  division  of  the  lateralis- zone  seems  to  be  more  obvious 
in  Lincolnshire  than  at  Speeton,  supposing  the  above  correlations  to 
be  correct,  and  it  may  have  been  partly  suggested  in  order  to  bring 
the  sequence  into  harmony  with  that  which  appears  to  obtain  in 
Eastern  Europe.  When  we  come  to  consider  the  Russian  equivalents 
en  bloc,  the  upper  division  of  the  lateralis- zone  is  said  to  correspond 
with  the  4  Petchorien,’  and  the  lower  division  with  the  4  Etag’e 
superieur  de  Rouillier/  the  latter  being  a  sort  of  provisional 
arrangement  for  beds  of  the  Russian  Jura  situated  immediately 
above  the  undoubted  Portlandian.  In  the  Alpine  region  the  whole 
might  be  held  to  correspond  with  the  Upper  Tithonian,  and,  as 
regards  period  of  deposition,  with  the  Purbecks  of  the  South  of 
England  1  and  possibly  somewhat  higher  beds. 
The  remainder  of  Mr.  Lamplugh’s  paper  deals  with  beds  which 
are  undoubtedly  Jurassic,  and  are  therefore  only  indirectly  connected 
with  the  subject  of  Lower  Cretaceous  geology.  Considering  for  a 
moment  the  Speeton  section  as  a  whole,  the  bituminous  shales  of 
the  Upper  Kimeridge  call  for  no  especial  remark,  the  first  point  of 
interest  being  the  4  Coprolite-bed,’  which  our  Author  regards  as  the 
base  of  the  overlying  clays  of  the  lateralis- zone.  This  4  Coprolite- 
bed,’  he  says,  is  undoubtedly  a  most  important  horizon  in  the  series, 
both  stratigraphically  and  palseontoiogically.  There  is  a  marked 
change  in  the  character  of  the  deposits  almost  immediately  above  it, 
and  also  in  the  fauna.  Of  the  few  Jurassic  forms  that  pass  it,  the 
doubtful  Lingula  ovalis  is  the  only  species  yet  found  in  the  bitumi¬ 
nous  shales.  Here  then  is  a  well-recognized  break  in  the  great 
argillaceous  series  of  Speeton,  and  it  is  not  easy  to  say  how  long  a 
1  Pavlow,  op.  cit.  pp.  213  and  546  (sep.  cop.  pp.  35,  188). 
