450 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JunC 5, 



chalk-fliiit gravel, the latter was found to have penetrated from above 

 and filled up the fissures of the roof and sides down to the floor. 



On Farleigh Down, a higher portion of the same range, hanging 

 immediately over the Avon, and nearly 1-^ mile further south, Mr. 

 Weston discovered not only a few flints scattered on the summit of 

 the hill, but also small quantities of chalk-flint mixed up with the 

 debris of the oolitic rocks, and partially converted by the infiltration 

 of water charged with carbonate of lime into a conglomerate or breccia. 

 This deposit is about 629 feet above the river, and consequently 84 feet 

 higher than that on Kingsdown. There was also a strong ferrugi- 

 nous tmt imparted to the upper surface of the oolitic rocks where no 

 superincumbent clay and gravel existed. The superficial tint extend- 

 ing over the Great Oolite on the western side of the Box Valley of 

 denudation and eastward towards the chalk range over the forest 

 marble of Wilts, noticed by Conybeare and Phillips *, appears to be 

 the rem.ains of the same diluvium which has to a greater extent been 

 presented at Kingsdown, 



]Mr. Weston describes the dilm-ium occupying the valley of the 

 Avon as consisting of a few chalk flints, fragments of greensand, 

 oolite, lias, carboniferous limestone, millstone grit, and old red sand- 

 stone ; indeed, to use Mr. Lonsdale's words t, "of every formation 

 from the Wiltshire Downs to the INIendip Hills ; " the great mass, 

 however, of this gravel consists of oolitic debris ; the chalk-flints are 

 \ery rare, and, if the Kingsdown diluvium were described as com- 

 posed of chalk-flints exclusively, the valley diluvium might with 

 nearly equal truth be said to consist of almost everything except 

 chalk-flint. 



This valley drift may be traced on both sides of the Avon ; some 

 of its beds being not far above the level of the river, and others at 

 considerable elevations. Fossil remains of Elephas and Rhinoceros 

 have been found in the gravel on both sides of the valley ; the other 

 organic remains found in this deposit are of Sus, Equus, Bos, and 

 Vrsus ? X 



The section of this gravel made by the railway cutting near the 

 Hampton rocks exhibits beds of fine gravel and coarse sand, having 

 a horizontal stratification ; the pebbles generally being arranged upon 

 the subjacent lias according to their size and weight. In the bed 

 nearer the river the gravel is less regularly disposed, the larger and 

 smaller pebbles being confusedly mingled together. 



Mr. Weston remarks that the chalk-flmt diift was probably depo- 

 sited over the oolitic district prior to the excavation of the existing 

 valleys, and during, perhaps, the earlier part of the eocene period ; 

 that its source must have been the chalk hills near Denizes ; and the 

 cause of its production the westerly currents resulting from the ele- 

 vation of the northern anticlinal axis of the south-east of England, 

 viz. that of the valleys of Kingsclere, Ham, and Pusey. 



* Outlines of the Geology of England and Wales, 

 t Trans. Geol. Soc. vol. iii. pt 2. 2nd Ser. p. 271. 

 X Lonsdale, loc. cit. p. 271. 



