172 



apparently of subsidence, and overlaid by Oolitic drift, which covert 

 all the superior deposits. About 25 feet of these Shales are exposed, 

 distinguished by their well-marked character, no less than by the 

 Liassic Cephalopoda, portions of which are abundant. The Shales are 

 overlaid by the " Sands," a series of alternating micaceous Sands and 

 Sandstones, from 60 to 80 feet thick, which appeared to be wholly 

 unfossiliferous. To these " Sands" succeeds the Inferior Oolite rock, 

 about 25 feet in thickness, and exhibiting the following succession 

 of beds, which will be found to be remarkably persistent in character 

 and extent throughout the Bath district : 



1. Basement led. A hard rock, full of fossils, and \ 

 especially characterised by the prevalence of Tri- > 4 to 5 feet, 

 gonia costata and Rhynchonella spinosa ) 



2. Coarse Bastard Freestones. Bubbly in their ) _. f 

 upper portions slightly fossiliferous. j 



Now, the point to which I particularly desire to invite attention, 

 is to the fact of the Trigonia and Spinosa Beds, forming the base of 

 the series, and to their being surmounted by 20 feet of freestones ; thus 

 apparently inverting the order of sequence exhibited in the Cottes- 

 wold sections, and I shall endeavour to show that this relationship 

 holds good throughout the Bath district, extending even to Dundry 

 Hill, where I found similar conditions prevailing. 



INFERIOR OOLITE BEDS AT LYMPLEY STOKE. 



On the line of railway between Bath and Bradford, and about 

 three miles from the latter town, is the pretty village of Lympley 

 Stoke, looking down upon the Valley of the Avon, whose green ex- 

 panse is diversified by the frequent windings of the stream, and by 

 the Trowbridge Canal, which traced along the foot of the hills 

 forming the opposite boundary of the valley, is flanked for probably 

 two miles of its course by the beds of the Inferior Oolite, which, 

 emerging from beneath the clays of the Fuller's Earth, present a 

 mural escarpment of extreme regularity until eventually lost beneath 

 the overlying beds, under which they dip at a scarcely appreciable 

 angle within a short distance of the town of Bradford. The extent 

 and regularity of this section render it extremely valuable for the 

 study of the Inferior Oolite series in this district, and it will be 

 found to present characters in all respects similar to those exhibited 

 by the same beds at Charlcombe. 



The Canal is at this point hollowed out of the " Sands" a sub- 

 soil one would imagine, not very well adapted for the retention of 

 water, and about two or three feet of the sands are exposed above 

 the level of the Canal. Besting on these sands is the " basement-bed " 

 of the Inferior Oolite, about three feet in thickness, charged with 

 fossils, amongst which Trigonia costata and Rhynchonella spinosa are 

 abundant. The texture of the rock is extremely hard and intract- 

 able, which renders it difficult to extract fossils in good condition. 

 Trigonia costata is most frequently present in the shape of casts ; 



