PROCEEDINGS  OP  THE  GEOLOGICAL  SOCIETY. 
1 16 
[May  1893, 
which  present  themselves  for  solution  is  to  ascertain  the  meaning 
of  this  attenuation,  and  also  the  meaning  of  the  attenuation  of  the 
Red  Chalk,  as  a  whole,  by  comparison  with  the  synchronous  Gault. 
Messrs.  Jukes-Browne  and  Hill  are  rather  disposed  to  explain  these 
facts  on  the  assumption  of  deeper  water.  Undoubtedly  there  is  less 
terrigenous  sediment,  which  would  at  first  sight  seem  to  imply 
greater  distance  from  land.  This,  however,  will  not  altogether 
explain  the  gieat  diminution  in  the  actual  amount  of  calcareous 
matter  ;  for  we  should  bear  in  mind  that  there  is  many  more  times 
the  amount  of  carbonate  of  lime  in  such  a  formation  as  the  Upper 
Gault  of  Folkestone  than  exists  in  the  whole  of  the  Bed  Chalk  of 
Hunstanton.  The  phenomena  in  connexion  with  the  equivalent  of 
the  Bed  Chalk  at  the  north-western  corner  of  the  Yorkshire  Wolds, 
where  its  outcrop  reposes  on  a  denuded  ridge  of  Jurassic  rocks  600 
xeet  above  sea-level,  seem  to  supply  a  clue.  Even  according  to  the 
views  of  Messrs.  Jukes-Browne  and  Hill  there  was  an  approximation 
to  the  western  margin  of  the  Cretaceous  sea  at  that  spot.  With 
this  appi  oximation  to  land  we  have  a  minimum  of  deposit,  yet  we 
aie  asked  to  believe  that  the  scanty  deposit  at  Hunstanton  was  due 
to  distance  from  land  and  deepening  water. 
I  would  venture  to  suggest  that  the  Bed  Chalk,  as  a  whole, 
is  not  a  deep-water  deposit,  but  that  it  was  formed  where 
powerful  currents  limited  the  amount  of  sediment  thrown 
down.  The  number  of  small  siliceous  stones  found  in  it  serves 
to  bear  out  this  view.  There  can  be  no  doubt  that  such  was  the 
case  throughout  the  major  part  of  what  is  now  the  Wold  outcrop  ; 
less  so,  perhaps,  in  Lincolnshire,  but  likely  enough  at  Hunstanton, 
where  some  irregularity  in  the  sea-bottom,  of  the  nature  of  an 
old  ridge,  may  have  caused  currents  unfavourable  to  a  bulky 
deposit.  Clearly,  this  must  have  been  the  case  at  the  north-western 
corner  of  the  Wolds.  At  Speeton,  on  the  other  hand,  materials 
swept  from  the  shallower  and  more  troubled  portions  of  the  sea, 
possibly  in  part  from  the  old  Jurassic  ridge  before  it  was 
completely  covered  up,  were  deposited  in  calmer  and  perhaps 
rather  deeper  water. 
Lower  Cretaceous.— The  relations  of  the  Lincolnshire  Carstone 
were  described  by  Mr.  Strahan  in  a  paper  where  he  showed  that 
this  formation  rests  on  different  members  of  the  Tealby  group, 
presenting  a  strong  contrast  to  them  in  lithological  character, 
and  in  being,  except  for  the  derived  fauna,  entirely  unfossiliferous. 
He  seemed  disposed  to  associate  it  more  or  less  with  the  Bed  Chalk, 
