26 



GEOLOOY OP TTTE AVON BASTM. 



In Buckland and Conybeare's paper before cited (p. 24C), 

 the limestone ridgo between Battery Point and the landing- 

 stage is regarded as belonging to a totally different limestone 

 axis to tliat wlu'eh forms part of the Portishead-Clevedon 

 ridge ; viz., to tlic axis of King's Weston Down and Penpolo 

 Point, on the Gloucestershire side of the Avon. "From 

 Penpole Point," they say, " the limestone ridgo points 

 exactly to Portishead Point, on the south of the conlluenco 

 of the Avon with the Severn ; and on examination, the 

 strata at that point are found to consist of Mountain 

 Limestone mantling round the ceiiti'al nucleus of Old lied 

 Sandstone. The limestone may be traced from the noi'thern 

 extremity of Portishead (Battery) Point, ranging in a 

 southerly (? — see map) direction along a woody hill, to 

 the old battery commanding Portishead (Woodhill) Bay. 

 In the north-eastern angle of the bay the lowci' strata of 

 the limestone, hero approaching to the fault of the Clapton 

 coalfield, are bent into zig-zag curves. On the south-east 

 the Old Red Sandstone emerges from beneath the limestone, 

 and forms an almost insulated hill (Wood Hill) between 

 the village of Poi'tishead and the limestone. On the north- 

 west, along the coast, particularly near to Portishead Point, 

 a covering of Dolomitic Conglomerate gi'catly conceals tlio 

 inclined strata, which are displayed at intervals only, in 

 low cliffs. At low water, however, we discover the Pennant 

 coal-grit I'oposing against the calcareous chain, and may 

 trace it nearly all the way from Portishead Point to the 

 fort ; and in the cliffs of a small cove, half way between 

 the northern capo and the fort, the crop of a coal-bed is 

 seen, having a roof of the Pennant abounding in vegetable 

 ronvaiiis. These strata arc highly elevated, and occasionally 

 vertical or even reversed in their dip. These coal measures 

 seem to indicate the existence of a yet unexploi'ed coal- basin 



