THE LOWEE LIAS OF KEYNSHAM. 
35 
The highest hard bed in the section represents the lower 
Semicostatus beds and contains Am. ohliqueco status in 
profusion ; good specimens showing the characteristic 
smooth central whorls can be seen in great numbers, but 
the sparry infilling of their interior renders them almost 
impossible to extract from the hard matrix. 
Exposure 10. A disused quarry practically filled up. 
The only bed still accessible is the hard Ohliquecostatus 
bed, which is extremely rich in fossils. Am. ohliquecostatus 
occurs in abundance in it, and Avicula inequivalvis and the 
Radstock type of Eh. lineata are also common in this bed. 
Large Limas extend up into the Bisulcatus beds and, in fact, 
the faunal sequence is transitional between that of the 
Keynsham and that of the Radstock area. 
Exposure 11. A disused quarry. 
The beds in this exposure are confined to the lowest zone 
of the Lower Lias, viz. the Ostrea liassica zone. Capping a 
few feet of thin White Lias, is a thick bed (The Sun Bed) 
and, above this, about 2| feet of thin limestones and clays, 
belonging to the sub-ammonite section. The position of 
these uppermost beds is well fixed by the presence of Lima 
valoniensis. Pinna hartmanni and Pholadomya glabra are 
not uncommon, but all the fossils are badly preserved. 
IV. Exposure at Kelston Station (Exposure 12). 
The east face of the Midland Railway cutting, just south 
of Kelston station. 
The Sun Bed is here seen capping a considerable thickness 
of typical White Lias. The base of this series is not seen 
but the Gotham marble is almost certainly present, since it 
was recorded by Sanders in the neighbouring cutting on the 
G.W.R. line at Saltford.^ The upper surface of the Sun 
Bed shows numerous borings. (This character was stated by 
Moore to be a general feature of this bed in all districts, and 
^ Loe. gU, 
