Vol.  49.] 
BOEINGS  IN  EAST  LINCOLNSHIRE. 
477 
nishes,  at  any  rate,  strong  confirmatory  evidence  of  the  existence 
of  this  anticlinal. 
It  is  indeed  very  probable  that  the  outcrops  of  the  strata  below 
the  Chalk  are  prolonged  north-westward  beneath  the  Drift  as  far 
as  Claythorpe  and  Belleau,  and  into  the  transverse  valley  which 
traverses  the  Wolds  by  Calceby  and  South  Thoresby.  This  valley 
is  filled  with  Glacial  clays  and  gravels  to  a  depth  of  at  least  30 
or  40  feet.  On  the  northern  side  the  basal  Red  Chalk  is  exposed 
at  a  level  of  about  80  feet,1  while  that  of  the  stream  in  the  valley 
is  only  50  feet.  On  the  southern  side,  at  South  Thoresby,  there  is 
a  quarry  with  Lower  Chalk  dipping  south-west,  and  bringing  in  the 
base  of  the  Middle  Chalk  at  a  level  of  about  100  feet.  Assuming 
the  Lower  Chalk  to  be  75  feet  thick,  the  base  would  be  reached  at  a 
level  of  25  feet  above  O.D.  under  the  Drift  to  the  north-east,  even  if 
there  were  no  dip  to  the  south-west.  Row,  the  surface  of  the 
ground  falls  in  that  direction  to  less  than  50  feet,  while  at  Claythorpe 
Station,  where  the  surface  is  54  feet,  a  boring  is  said  to  be  66  feet 
deep,  finding  water  in  gravel  at  that  depth.  There  must  therefore 
be  a  large  area  near  Claythorpe  where  the  Drift  rests  on  beds 
older  than  the  Chalk,  and  there  is  nothing  to  prevent  this  area  from 
being  united  to  that  near  Alford. 
The  result  of  the  information  thus  obtained  makes  it  probable  that 
the  Chalk  tract  which  lies  to  the  S.E.  of  the  Calceby  valley  is  com¬ 
pletely  isolated  from  the  rest  of  the  Chalk  area,  being  separated 
from  the  Chalk  under  the  marshland  by  the  anticlinal  above  men¬ 
tioned,  and  cut  off  from  the  more  northern  Wolds  by  the  Lower 
Cretaceous  outcrops  along  the  Calceby  valley. 
Postscript. — Since  the  above  was  written,  my  colleague,  Mr. 
A.  Strahan,  was  instructed  to  visit  some  of  the  localities  in  this 
district.  He  confirms  Mr.  Ililfs  identification  of  the  basement  Red 
Chalk  in  the  small  pit  east  of  Swaby,  and  has  drawn  its  outcrop  on 
the  6-inch  map  for  the  short  distance  along  which  it  is  visible,  as 
well  as  its  probable  continuation  beneath  the  Drift  along  the  north¬ 
eastern  side  of  the  Calceby  valley. 
Discussion. 
The  President  said  that  the  lesson  of  the  paper  was  that  it  was 
never  safe  to  take  anything  for  granted  when  one  had  to  deal  with 
Boulder  Clay.' 
Mr.  Strahan  remarked  that  the  tract  referred  to  in  this  paper 
was  one  that  could  be  mapped  only  by  the  aid  of  wells  and  bore¬ 
holes.  The  records  of  a  great  number  of  these  had  been  collected 
by  Mr.  Jukes-Browne  and  tabulated  in  the  Memoir,  their  positions 
being  noted  on  a  copy  of  the  Map  kept  in  the  Geological  Survey 
1  In  a  quarry  near  Swaby.  In  the  Survey  Memoir,  ‘  Geol.  of  E.  Lineolnsh.’ 
p.  53,  the  Red  Chalk  seen  here  was  referred  by  me  to  the  higher  beds,  but 
information  supplied  by  Mr.  William  Hill,  F.C.S.,  who  visited  the  place  in 
1887,  has  convinced  me  that  the  section  is  really  in  the  basement-beds. 
