132  PROCEEDINGS  OF  THE  GEOLOGICAL  SOCIETY.  [May  1 893, 
Kimeridge  Clay.  He  directed  attention  also  to  a  species  from  the 
Lias  of  the  Midlands,  whose  habits  suggest  a  relationship  with  the 
Tubuliporidse,  and  for  which  he  proposed  the  name  Tubulipora 
inconstans ,  in  reference  to  its  varying  modes  of  growth. 
There  are  two  papers  by  Mr.  Wethered  devoted  to  rock  structure 
and  referring  principally  to  the  Inferior  Oolite.  His  identification 
of  Girvcinella  in  the  Oolitic  rocks  had  been  previously  announced 
in  the  ‘  Geological  Magazine  ’  for  1889, 1  where  it  was  shown  that 
this  organism  was  not  confined  to  the  Silurians,  and  that,  as  an 
agent  in  the  formation  of  rocks,  it  is  of  more  importance  than  had 
been  previously  supposed.  In  that  communication  he  had  established 
a  new  species,  Girvanella  pisolitica ,  which  in  his  opinion  was 
instrumental  in  forming  the  Pea-grit  spherules  in  the  well-known 
bed  towards  the  base  of  the  Inferior  Oolite.  He  also  showed  that 
.a  much  smaller  form  built  up  the  pisolitic  spherules  which  occur  in 
the  Coralline  Oolite  near  Weymouth,  and  which  he  now  described 
under  the  title  of  Girvanella  minuta. 
In  referring  to  G.  pisolitica  he  discussed  the  views  of  Brady  and 
Hicholson  as  to  whether  the  genus  is  most  allied  to  the  ‘Challenger’ 
Poraminifer,  Hyperammina  vagans,  or  to  Syringammina  fragilissima. 
Traces  of  the  organism  occur  in  the  Clypeus-g rit,  but  none  have 
been  discovered  either  in  the  Great  Oolite  or  the  Portland  Oolite. 
Considerable  variety  is  noted  in  connexion  with  the  subject  of 
Girvanella.  Por  instance,  there  occur  (1)  spherules  with  a  loosely 
aggregated  form  of  Girvanella-tubvles  as  a  nucleus,  and  (2)  this 
form  also  occurs  in  loose  aggregations  on  surrounding  foreign 
objects:  in  such  specimens  there  can  be  little  doubt  as  to  the 
presence  of  the  organism.  Thirdly,  he  takes  the  case  of  a  spherule 
or  granule  in  which  the  nucleus  generally  consists  simply  of  calcite, 
and  the  concentric  arrangement  has  a  granular,  crystalline  ap¬ 
pearance  in  which  occasional  outlines  of  tubuli  may  be  seen.  Last 
of  all  is  the  ordinary  oolitic  granule,  with  a  clear  and  well-defmed 
concentric  arrangement  round  a  nucleus. 
There  is  something  very  fascinating  in  the  way  the  Author 
gradually  and  unconsciously,  as  it  were,  seems  to  lead  us  to  the 
conclusion  that  possibly  the  oolitic  granule  itself  has  been  fashioned 
hy  an  unseen  artificer.  It  is  true  he  did  not  claim  that  all  oolitic 
gran  ales  are  derived  from  this  one  source,  but  his  remarks  regarding 
the  last  of  his  series  plainly  show  the  tendency  of  his  thoughts. 
Viewed  through  a  microscope,  he  says,  spherules  of  this  type  would 
1  Dec.  iii.  vol.  \i.  p.  196. 
