Vol.  49.] 
OF  THE  SHERBORNE  DISTRICT. 
505 
neighbourhood  of  Frogden  the  place  where,  so  far  as  we  know 
yet,  most  deposit  accumulated ;  during  the  Witchellice  hemera  the 
molluscan  headquarters  had  shifted  to  Sandford  Lane,  and  the 
most  sediment  was  collected  at  Milborne  Wick ;  during  the  Hum - 
pliriesiani  and  niortensis  hemerse  the  mollusca  evidently  congregated 
at  Frogden,  and  in  that  case,  considering  the  conditions  found  to 
ha,ve  obtained  during  previous  henrerae,  the  maximum  deposit  of 
sediment  should  be  looked  for  eastward  or  south-eastward  of 
Milborne  Port. 
Now,  however,  came  a  very  great  change  ;  and  it  is  noticeable 
that  this  change  almost  coincides  with  the  commencement  of  the 
Bathonian,  as  advocated  by  some  French  authors.  During  the 
Garantiance  hemera  the  maximum  deposit  is  found  to  have  moved 
hack  westward — it  is  in  the  neighbourhood  of  Clatcombe.  The 
fossils  are  not  there  in  any  great  numbers,  nor  are  they  very 
numerous  at  Halfway  House  or  Bradford  Abbas,  where  the  deposit 
was  so  small ;  perhaps  they  lie  unseen  between  Halfway  House  and 
Sherborne — the  area  of  no  openings.  This  is  not  unlikely,  for, 
rather  later,  in  the  Truellii  hemera,  mollusca  were  plentiful  at 
Halfway  House,  in  the  ;  Fossil  Bed  ’ ;  and  this  means  a  decided 
westerly  faunal  migration. 
During  the  succeeding  hemerae,  however,  the  westerly  faunal 
migration,  followed  by  westerly  movement  of  deposit,  is  still  more 
remarkable.  The  deposit  at  Halfway  House  is  very  great  in  the 
4  top  beds  ’ ;  but  the  mollusca  left  the  district  altogether  before 
such  an  accumulation  of  sediment.  It  is  necessary  to  go  nearly 
11  miles  W.S.W.  from  Halfway  House,  in  fact  to  Crewkerne 
Station,  before  the  mollusca  are  found  sufficiently  numerous  to 
constitute  a  ‘  fossil-bed.’ 
In  order  to  bring  these  variations  of  deposit  more  clearly  into  view, 
I  have  constructed  a  tabular  analysis  of  the  various  sections  (Table  I„ 
p.  506).  The  localities  are  arranged  from  east  to  west  in  their 
order,  with  regard  to  a  line  from  Stoford  to  Milborne  Wick,  those 
off  the  line  being  placed  in  the  position  where  they  would  meet  the 
line  at  right  angles. 
The  maxima  of  deposit  given  in  the  last  column  are  certainly  in¬ 
structive,  for  they  show  that  the  ‘  Inferior  Oolite  ’  of  the  district 
is  really  very  much  thicker  than  was  supposed  to  be  the  case. 
When  the  various  maxima  are  added  together,  a  result  of  150  feet 
is  obtained.  -  Putting  Marston  Boad,  Sandford  Lane,  Combe,  and 
Clatcombe  together  as  exposures  in  a  limited  area,  showing  nearly 
the  full  sequence,  we  obtain  72  feet  6  inches  as  possibly  to  be  found 
in  one  section  in  the  neighbourhood  ;  and  adding  to  this,  say 
20  feet,  for  the  top  beds,  which  have  been  denuded,  and  which  pro¬ 
bably  lie  on  the  dip  under  Sherborne,  a  possible  92  feet  is  obtained. 
The  results  of  the  analysis  of  the  deposits  I  have  shown  diagram- 
matically  in  Table  II.  (facing  p.  508)  ;  and  very  interesting  these 
results  are.  This  Table  must  be  read  in  conjunction  with  Table  I., 
and  some  of  the  measurements  are  necessarily  not  of  absolute  accu¬ 
racy,  owing  to  incompleteness  of  exposures  ;  but  the  chief  deficiencies 
