THE LOWEE LIAS OE KEYNSHAM. 
31 
which Am. geometriciis^ Am. planicosta, and Eh. semicostati 
{v.i.) are extremely abundant. 
The shales just above this band are rich in Bel. acMtus and 
its mutations. 
Exposure 4. A quarry in work. 
The lowest beds exposed are the thick clay and a few feet 
of the hard beds below. These beds are shown in a recent 
opening in the floor of the quarry. The upper part of the 
clay is crowded with the spines and fragments of the test of 
a small Pseudodiadeina {v.i.\ associated with Modiola hil- 
lanoides and small smooth Pectens. Large Limas are 
abundant below and above the clay. 
The Calcicosta beds are extremely well shown in the face 
of the quarry furthest from the river, and since this face has 
been exposed to the action of the air for a very considerable 
time, the fossils in the beds are beautifully weathered out 
(see above). 
The Bisulcatus beds are also shown in this face and con- 
tain abundant large ammonites and a few large nautili. 
The shale at the base of these beds, just above the top block 
of the Calcicosta series, is very rich in fossils and contains 
numerous fragments of Pentacrinus. 
The beds in this quarry show a dip of to the south-east 
The lower portion of our vertical section (up to the top of 
the Calcicosta series) was constructed mainly from data sup- 
plied by exposure 4. 
Exposure 5. A quarry in work. 
All the beds, from the base of the Calcicosta series up to 
the Oxynotus clay, are finely exhibited. The most interesting 
feature is the very perfect shale, crowded with Avicula 
inequivalvis and containing, at the top, fragments of fish. 
In the hard bed, above this shale. Am. ohliqueco status is very 
abundant and, in the shales above, Am. yeometricus occiirs 
plentifully, but always crushed. 
