40 
TPIE LOWER LIAS OF KEYNSHAM. 
Upper 
OSTEEA 
BEDS 
(sub-ammonite 
section). 
feet 9 indies ; limestones 
with clay partings (near 
the base two conspicuous 
double beds). 
' Ostrea liassica, Pleuromya crow- 
combeia, Modiola minima^ 
AvicuJafallax, Pholadomya 
glabra^ Astarte obsoleta (f), 
Cardium rheticum, (Liassic 
mutation), Unicardium 
cardioides, Pecten j^oUux, 
Lima valoniensis. 
(Sun Bed). 
Js inches; thick, compact, 
( cream-coloured limestone. 
(Pleuromya crowcombeia^ Ostrea 
liassica, Modiola minima, 
Avicula fall ax, Cardium 
i rheticum (Liassic mutation) 
? Astarte or Cardinia, 
? Isodonta. 
\Phasianella sp. 
PALAEONTOLOGICAL SUMMAPY. 
This portion of our work will be confined, almost entirely 
to notes on the Cephalopods and Brachiopods. 
The Lamellibranchs will receive some little attention on 
account of their great stratigraphical importance; but, since 
we have in contemplation an exhaustive examination into 
the Lower Lias lamellibranchs of the whole Bristol area, no 
attempt will be made here to give a complete account of their 
mutations and relationships. 
Beptilia. 
Ichthyosaurus : vertebrae and teeth occur at the top of the 
Semicostatus zone. 
Pish. 
Fragments (chiefly scales) occur in the Fish bed, near the 
bottom of the Semicostatus zone. 
Cephalopods. 
Belemnites enter in the top bed of the Calcicosta series 
{Angulatus zone), occur sparingly throughout the Bisulcatus 
beds, but only become abundantat the top of the Semicostatus 
zone. 
