746 PROF. REYNOLDS AND MR. VAUGHAN ON THE __[ Nov. 1902, 
from the White-Oolite Series below to the beds of the Upper Great 
Oolite. On the other hand, the Upper Great Oolites are cha- 
racterized throughout by very uniform assemblages of fossils. We 
may note, however, a gradual increase in the forms characteristic 
of the Bradford Clay as we pass upward in the series. In Group D 
(see vertical section below) the brachiopods are represented by 
typical transverse specimens of Terebratula maaillata, large Rhyn- 
chonella obsoleta, and an occasional example of Waldheimia cardium. 
At the horizon E, though 7’. mavillata still occurs of the typical form, 
it is largely replaced by a form, more elongate, less maxillated, and 
with a beak so truncated that the margin of the perforation lies in a 
plane sloping backward. Waldhemia digona enters this horizon, 
and is not uncommon. Rhynchonella obsoletau is very common, and 
Waldheimia cardium occurs sparingly (large specimens of Lima 
carduforms abound at this horizon). At the top of Group F, 
Terebratula bradfordensis occurs of quite typical character, and it 1s 
associated, as at Bradford-on-Avon, with Waldheimia digona. Here 
also Avicula costata is quite as abundant as at Bradford-on-Avon. 
It is important to note that we have been unable to find any 
specimens of Dictyothyris coarctata and of Aptocrinus ; but, with 
this reservation, it would be utterly impossible to separate the top 
beds of the Upper Great Oolite from the Bradford Clay, on paleeonto- 
logical grounds. On account of the perfectly continuous faunal 
sequence, we have found it impossible to separate a ‘ Bradford-Clay ’ 
horizon, and have consequently grouped the whole of the upper 
series of beds under the title of ‘Upper Great Oolite,’ being content 
to point out that the uppermost beds are homotaxial with the clay 
at Bradford-on-Avon. 
GENERALIZED VERTICAL SECTION OF THE GREAT OoLite AND Forest MARBLE EAST 
oF THE TUNNEL (NEAR ACTON TURVILLE). 
Thickness in feet. 
Shales and clays containing 
; : Avicula costata especially to to 
two thick limestone-bands. } = Pp 
| Waldheimia digona and 
fi ; | abundant towards the of section. 
(Forrest MArsue.) : 
itl base. 
a . ; rhynchonella ohsoleta. 
F. Massive wedge-bedded lime- T ine me Be. 
ae ; Pe erebratula brad fordensis, about 
stones, with lenticular sandy - Wa lascisiiance 2 
Sane | MANEIUA HUGond. a) 
aes Avicula costata, 
{ Lima cardiiforinis. \ 
: f l. Phanehonelimne, 
EAE, f Sand, withsandy | Ehynchonella ohsoleta. ; | 
~. { Dying out or ea Terebratula aff. bradfordensis | about 
Bes limestone-bed. 4 7, . a : 
| eastward. ) oo dy clay | 7. macxillata. 6 
te a ee | Waldheimia digona. | 
\ W. cardium. ) 
: - Lima cardiiforiis 
. Mass redge-bedd ime- 77 
D pi TE a eee ho ee ae Terebratula maxillata. about 
Ss S 7 sever: ane 
‘ Soe ares an en) Rhynchonella obsoleta. 24. 
aha eae : Waldheimia cardiun. 
Thin sandy parting, variable in thickness ..............-s2sseceeeeeere 1 
C.. White oolitic limestone, with few fossils... ----.-. ae eee eee a 
B. Lenticularsandy band, of very variable { Pholadomya deltotdea, 3 
thickness. ' abundant. 
A. Massive white oolitic limestone, with few fossils ........ . to base of section. 
