Yol.  49.] 
STET7CTTTBE  OF  THE  WEXLOCK  LIMESTONE. 
241 
III.  Wenloce  Limestone  at  Pttbley,  neab  West  Malyeen. 
The  late  Prof.  Phillips  observed  1  that  “  the  lower  limestone  at 
Colwell  Copse,  Winning  Farm,  and  Whitmans  Hill  abounds  in  a 
large  pisolitic  structure,  which  is  of  great  beauty.’’  Sir  E.  Murchison 
figured  one  of  the  pisolites  under  the  name  of  Stromatoporci  nummu- 
litisimilis  in  the  3rd  edition  (1859)  of  ‘  Siluria,’ 2  but  in  the  4th 
edition  (1867)  of  that  book  the  name  is  changed  to  4  Pisolite  ’  (see 
pi.  xli.  there,  and  explanation). 
In  1890  I  tried  to  find  some  of  this  pisolite,  but  all  the  quarries 
mentioned  by  Phillips,  where  he  saw  the  pisolite,  are  either  partially 
or  entirely  filled  in.  Thus  the  quarry  at  Colwell  Copse  is  now  a 
plantation,  and  only  the  upper  series,  of  Modular  Limestones,  are 
exposed.  I  was  therefore  disappointed  in  my  efforts  to  trace  the 
object  of  my  search  till  the  following  year,  when  I  found  a  small  quarry 
at  Purley,  near  West  Malvern.  I  collected  specimens  of  limestone 
for  microscopic  examination,  and  in  one  of  these  I  discovered  pisolite. 
Beturning  to  the  quarry  early  in  the  spring  of  1892,  1  was  rewarded 
by  obtaining  a  weathered  block  of  limestone  full  of  pisolites. 
The  strata  in  this  quarry  at  Purley  give  a  vertical  section  very 
similar  to  that  at  May  Hill,  but  the  three  divisions,  so  well  marked 
at  the  latter  locality,  are  not  so  clearly  defined  here.  When  1 
visited  the  quarry,  about  12  feet  of  rock  was  exposed.  At  the  base 
was  a  massive  bed  of  limestone,  which  passed  up  into  thin-bedded 
limestone,  and  then  again  into  thin-bedded  and  nodular  rock. 
Fossils  are  not  so  numerous  as  at  May  Hill,  but  such  fossils  as  there 
are  belong  to  similar  species. 
The  microscopic  examination  of  the  Massive  Bed  at  the  base  shows 
that  it  is  more  or  less  pisolitic,3  the  spherules  averaging  about 
3  millim.  in  diameter  ;  therefore  4  oolitic  ’  would  perhaps  be  the  more 
correct  term.  In  some  of  the  spherules  there  is  an  irregular  con¬ 
centric  arrangement,  in  others  simply  a  crust  around  the  nucleus. 
That  some  of  these  are  of  organic  origin  cannot  be  doubted ;  and  PI.  YI. 
fig.  5  affords  a  proof  of  it.  Of  the  great  majority  of  the  spherules, 
however,  all  that  can  be  said  is  that  there  are  in  some  indications 
of  GirvcineZla-txib'ales  (PI.  YI.  fig.  6) ;  others  are  quite  structureless 
or  show  only  a  concentric  arrangement.  Had  the  two  latter  types 
of  spherules  been  the  oifiy  spherules  found,  no  one  would  have 
ventured  to  ascribe  to  them  an  organic  origin.  But  the  fact  that  in 
some  instances  tubules  can  be  seen,  and  that  in  PI.  YI.  fig.  5  they  show 
a  decidedly  concentric  growth,  makes  one  hesitate  to  pronounce 
against  the  probability  of  organic  origin.  In  support  of  this  proba¬ 
bility  let  me  ask  the  question,  what  would  be  the  appearance  of 
the  spherule  represented  in  fig.  5,  had  not  the  tubules  been  filled  in 
with  calcite,  or  had  they  only  partially  been  filled  in  with  it  ?  All 
outline  of  the  tubules  would  be  obliterated  or  at  least  rendered  very 
obscure  ;  but  there  would  be  a  rude  concentric  arrangement  or  crust, 
1  Mem.  Geol.  Survey,  vol.  ii.  part  i.  (1848)  p.  86. 
2  PL  xli.  fig.  32. 
3  I  use  the  term  because  of  Phillips’s  reference,  mentioned  above. 
Q.  J.  G.  S.  Ho.  194. 
E 
