494 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 2, 



as far as Burford, whence it strikes southwards for several miles. 

 The line then extends westward to within a mile or two south of 

 Cirencester, — being indicated by the occurrence of quartz-pebbles ; 

 and is finally lost beneath the newer oolitic gravels which I have 

 arranged under the head of the Estuarine Deposits (see Map, fig. 1, 

 p. 479). 



The drift has evidently been carried along the Moreton Valley, and 

 swept over the high grounds to the south, which are not only lower 

 than the Cotteswold Hills to the west, but also do not present to their 

 progress a precipitous barrier. 



Transported fragments diminish numerically the farther south we 

 proceed from the Moreton Valley. They have been strewn over 

 hills and valleys, quite independently of the form of the ground ; and 

 it is possible that shore-ice was to some extent an agent in raising the 

 fragments from lower to higher levels, after the manner described by 

 Mr. Darwin. 



From the knowledge we now possess of the nature and position 

 of the estuarine deposits, we have an index to the distribution of land 

 and sea over our district during the period of their deposition. This 

 ancient sea swept around the western flanks of the Cotteswolds, 

 extending in the form of long bays and reaches far into the inte- 

 rior of the country. Ebrington Hill was an island, separated from 

 the mainland by Mickleton Strait, and the waters spread over the 

 Vale of Gloucester to the flanks of the Malverns. This was " the 

 ancient Strait of Malvern," and above its waters the Islands of Bredon, 

 Dumbleton, Oxenton, Churchdown, and Robins Wood stood forth 

 unsubmerged'''. The sea also covered the Vale of Moreton, the 

 eastern escarpment forming a coast-line, though much less bold and 

 lofty than that on the western side, and thence extended southward 

 over the Oolitic hills from Burford to Cirencester, and as far south 

 as the escarpment of the Chalk. 



Conclusions. — It would appear that, in order to explain all the 

 phsenomena of the denudation and the post-tertiary or pleistocene 

 accumulations of the district, it is necessary to suppose the following 

 vertical movements of the land : — A first elevation ; dating, perhaps, 

 as far back as the commencement of the Tertiary epoch, during which 

 the more marked physical features were produced, accompanied with 

 an enormous destruction of Secondary rocks. This was followed by 

 a submersion, which appears to have been only partial, during which 

 the Northern Drift, with ice-transported boulders, was spread over 

 the area under water. Next, a second elevation ; towards the close 

 of which the estuarine mammaliferous gravels were formed along the 

 valleys, and round the flanks of the hills. During this latter eleva- 

 tion the relative positions of land and sea occurred which have been 

 described above, the period finally terminating with the introduction 

 of the present physical features of the country f. 



* Mr. Howell informs me, that he found no drift on Bredon Hill, nor did I 

 observe any on the outliers between Bredon and the Oolitic escarpment. 



t If it can be proved that the " Warp-Drift " is in reality a deposit of trans- 



