﻿Vol. 6 1.] SEQUENCE IN THE BRISTOL AEEA. 231 



(ii) Isolated Exposures in the Bristol Area. 

 (A) In the Clifton-Clevedon Bidge. 

 I. Between the Clifton and Failand Areas. 



(1) Near Cadbury Camp (3 miles east of Clevedon Railway-Station). 



(a) The upper Zaphrentis-Zone is seen in small exposures, at 



the side of the road which runs along the crest of the ridge. 

 Zaphrentis is abundant, associated with the same brachio- 

 pods as in the Clevedon area, and it is this abundance 

 that immediately fixes the horizon. 



(b) The lower laminosa-mbzone (the ' laminosa-dolomite ') is 



well shown in a quarry on the southern flank of the ridge, 

 north-west of Tiekenham (halfway between Cadbury 

 Camp and East Clevedon). 

 Bands of Ghonetes aff. papilionacea and Ortliotetes crenistria 

 fix the horizon. 



(c) Horizon 3 (the ' JBelhroj)hon-Beds ') is splendidly displayed 



in a quarry a little north-west of Tiekenham, on the 

 north side of the Clevedon road, at the western end of 

 the village of Middletown. This quarry is cut into the 

 southern side of a lower ridge, which runs parallel to 

 the main ridge on its south side, and is separated from the 

 main ridge by a depression. This depression is doubt- 

 less caused by the more rapid denudation of the thick 

 ' lammasa-dolomites,' of the ' Caninia-0 olite/ and of 

 a thin series of the superjacent ' Canmia-J) olomites.' 

 Erom this quarry I have obtained : — 



1 Chatties' tumidus. identical with that at Horizon d, 



Cyathophyllum (p. Eailand, and cf. var. Kellii). 



byrmgopora sp. 



Syringothyris aff. cuspidata. 



Syringothyris aff. Laminosa. 



Semimda spp. 



(Athyris) sp. 



Orthotetes crenistria (a mutation 



Productus sp. (cf. Productus 6). 



Productus aff. semireticulatus (niut.). 



Reticularia sp. 



Dielasma sp. 



Bellerophon sp. (cf. costatus). 



Euomphalus sp. 



The above list leaves no doubt as to the identity of the horizon. 

 (d) Clapton-in-Grordano. — Clapton lies nearly 6 miles 

 west (slightly north) of the Clifton Suspension-Bridge. 

 The quarry occurs in an isolated mass of Carboniferous 

 Limestone which lies just north of the road from Port- 

 bury to Clevedon, about a quarter of a mile east of Clapton 

 Church. This mass of limestone comes into contact with 

 the Pennant Series on the south, but on all other sides 

 it is surrounded by Triassic rocks. There are several 

 other smaller masses x of Carboniferous Limestone in the 



1 In the Geological Survey Memoir (' Geology of East Somerset & the Bristol 

 Coalfields ' 1876, p. 21) these small, isolated masses are merely mentioned, 

 with the remark that it is difficult to account for their presence. They are 

 accounted for by Prof. Lloyd Morgan as the result of a 'flat-lying fault' which 

 sliced and heaved the Carboniferous Limestone, subsequent denudation pro- 

 ducing the isolated patches, Proc. Bristol Nat. Soc. n. s. yol. v (1885-88) p. 15. 



