Vol.  49,] 
OF  THE  SHERBORNE  DISTRICT. 
511 
From  what  he  called  ‘  Gryphite-grit ’  of  Frith  Quarry  and  of 
Rodborough  Hill,  near  Stroud,  the  late  Mr.  ]&.  Witchell,  F.G.S., 
obtained  Ammonites  of  the  genera  Hyjperliocercis ,  Sonninia ,  and 
Stejphanoceras .  The  particular  species  of  these  genera  found  are  all 
known  as  characteristic  of  the  4  concavum- zone  ’  of  Bradford  Abbas, 
and  with  such  I  therefore  correlated  the  Cotteswold  Gryphite- 
grit.1  However,  for  the  greater  precision  aimed  at  in  the  present 
paper,  such  a  correlation  is  not  sufficiently  exact.  The  question 
now  is  whether  these  strata  were  deposited  during  the  concavi 
hemera,  or  the  discitce  hem  era,  or  both. 
The  species  of  Hgperlioceras  indicate  that  these  strata  were  laid 
down  during  the  discitce  hemera,  and  the  absence  of  any  species 
of  the  abundant  Lioceras  concavurn-tjge  makes  it  appear  very 
improbable  that  we  have  as  yet  detected  any  Cotteswold  strata 
which  were  deposited  during  the  concavi  hemera. 
On  correlating  the  so-called  4  Gryphite-grit  ’  of  Frith  Quarry 
with  the  Lower  Trigonia-  and  Gryphite- grits  of  Leckhampton,  I 
was  forced  to  the  conclusion  that  Witchell’s  application  of  the  term 
4  Gryphite-grit’ to  the  Frith  bed  cannot  be  maintained.  In  litho¬ 
logical  composition,  in  the  relative  paucity  of  the  Qryphcea ,  in  the 
possession  of  several  Trigonice  and  numerous  other  lamellibranchiata 
it  agreed  exactly  with  the  strata  called  4  Lower  Trigonia-g rit  ’  at 
Leckhampton.2  Further,  I  found  in  the  true  Gryphite-grit  of  Leck¬ 
hampton  Ammonites  of  the  hemera  above  discites ,  viz.,  that  of 
Witchellia  sp. 
This  becomes  very  important.  The  identification  of,  and  the 
distinction  between,  Lower  Trigonia-  and  Gryphite-grits  must  be 
rigidly  exact.  It  is  not,  as  has  usually  been  taught,  the  Lower 
Trigonia-gr it,  but  it  is  the  Gryphite-grit  which  is  absent  from  Frith 
Quarry,  if  anything  is  wanting.  Further,  by  the  identification  of 
WitchelTs  Gryphite-grit =  concavum-zone,  and  the  superjacent  Upper 
Trig onia-grit= Par Jc'insoni- zone ,  the  Cotteswolds  were  supposed  to 
be  deficient  in  any  strata  equivalent  to  the  typical  Normandy 
Bajocian ;  but  as  the  true  Gryphite-grit  was  deposited  during  the 
hemera  of  Witchellia  sp.,  strata  equal  to  the  commencement  of  the 
Bajocian,  strictly  so-called,  are  developed  in  the  Cotteswolds. 
As  this  is  an  important  matter  in  regard  to  correlation,  I  give  the 
following  section  of  what  are  called  the  4  Ragstones  ’  of  Leck¬ 
hampton. 
Section  XIX. — The  4  Ragstones  ’  of  Leckhampton  Hill. 
Feet.  Inches. 
Garantiance  ?  1.  ‘Upper  Trigonia-g.  rit.’  Hard  shelly  lime¬ 
stone.  Terebratula  globata,  Sow.,  Bhyn- 
chonella  subtetrahedra,  J)av.,  Zeilleria 
Hughesi  (Walker).  The  lower  bed,  some 
10  inches  thick,  is  called  by  the  workmen 
the  ‘  Middle  Bed  ’ .  5  0 
1  ‘  Inferior  Oolite  Ammonites,’  p.  91,  Palreont  Soc.  vol.  xiii.  1889. 
2  Wright,  ‘  Lias  Ammonites,’  p.  151,  Pakeont.  Soc.  vol.  xxxiii.  1879. 
Q.  J.  G.  S.  Xo.  196.  2  m 
