468 Notices of Memoirs — Mr. Hudlestori's Address — 



Oolite on Dundry Hill resemble that of the neighbourhood of 

 Sherborne, both in lithology and fossils, rather than that of the 

 Cotteswolds, only a few miles distant ? 



Nine years ago Mr. Buckman offered an ingenious solution of this 

 difficulty ; ^ although his recent investigations at Dundry, and 

 especially his appreciation of the effects of contemporaneous erosion, 

 may have caused him to alter his views. Like most people who 

 wish to account for strong local differences, he placed a barrier of 

 Palaeozoic rocks between Dundry and the southern prolongation 

 of the Cotteswold escarpment. At that time it was not fully 

 realized that the Inferior Oolite in the Bath district is, for the 

 most part, limited to the Farkinsoni-zone, so that the comparison 

 ■was really being made between beds of different age as well as 

 different physical conditions. The question resolves itself into one 

 of local details, which are not suited for a general address. Still, 

 I think it may be taken for granted that, notwithstanding the east- 

 and-west barrier of the Mendip range, which acted effectually 

 previously to the Parl'tHso?u'-overlap, there was in some way 

 a communication by sea between Dundry and Dorsetshire, more 

 especially during the Soicerbyi-stage, and this most probably was 

 effected round the western flank of the Mendips. Thus, without 

 acceding to the necessity for a barrier facing the southern Cottes- 

 wolds, we may readily believe that much of the Inferior Oolite of 

 Dundry Hill is to be regarded as an outlying deposit of the Anglo- 

 Norman basin. If this be so, it is difficult to avoid the conclusion 

 that the low-lying area of the Bridgewater flats was, during part of 

 the Inferior Oolite period, occupied by a sea which was continuous 

 from Sherborne to Dundry, and that, although the barrier of the 

 Mendips was interposed, communication was effected round the west 

 flank of that chain. This would make a portion of the Bristol 

 Channel a very ancient feature. 



We must now take a wide leap in time, passing over all the rest 

 of the Jurassics, and just glancing at the Upper Cretaceous system, 

 which reposes on the planed-down surface of the older Secondary 

 rocks. The remarkable double unconformity is nowhere better 

 shown than in the south-west of England. Some of the movements 

 of the older Secondary rocks, prior to the great revolution which 

 brought the waters of the Cretaceous sea over this region, have been 

 successfully localized by Mr. Strahan, more especially in the south 

 of Dorset. 



Owing to Tertiary denudation the Chalk in this immediate 

 district has been removed, and we have no means of judging 

 the relations of the Cretaceous deposits to the Palaeozoic rocks 

 of Wales. If we may judge by results recently recorded from 

 Devonshire ^ the Lower Chalk especially undergoes important 

 changes as it is traced westwards, and, generally speaking, 

 terrigenous deposits seem more abundant in this direction. At the 



1 Proc. Cottes. Club, vol. ix (1890), p. 374. 



* Cf. Jukes-Browne and Hill, Quart. Journ. Geol. Soc, vol. lii (1896), p. 99. 



