46 ME. H. W. MONCKTON ON THE GRAVELS SOUTH OE 



One of them was said to be bleached, which pointed to the action 

 of peat. 



Mr. W. Whitakee. said that the paper was an outcome of that 

 lately read to the Society by Prof. Prestwich, which he thought was 

 a highly suggestive one, and likely to lead to such good supple- 

 mentary work as this. The sudden way in which a gravel that 

 contains a large number of northern stones gives way to another 

 that contains hardly any such, but a large number of southern ones, 

 is remarkable, especially as the two gravels occupy like positions and 

 at like levels. 



He regarded the small quartz-boulders as coming from the 

 Plateau-gravel, as there seemed to be nothing else from which they 

 could come ; moreover, one of them seemed to have come from the 

 bottom of the deposit, one side having the dark colour of the gravel, 

 and the other side being of a light colour, as if it had rested on the 

 Bagshot Sand. 



Whether the Author was altogether right in referring all the 

 gravels to river-origin was perhaps questionable. Many of them 

 contained no trace of any organisms ; but though this was the case 

 with those classed as Westleton Beds, it should be remembered that 

 where the pebbly gravels of that age did contain fossils, these were 

 decidedly marine. 



He wished to state that the classification, by the Geological 

 Survey, of various high-lying gravels as Plateau-gravels was often 

 akin to a confession of ignorance. In the absence of evidence that 

 can settle their age, it is useful to have a class for the reception of 

 such doubtful beds, which, whilst not pledging one as to age, clearly 

 indicates position. 



Dr. Hicks suggested that some of the boulders referred to may 

 have been deposited by floating ice in a lake formed by the damming 

 up of some part of the Thames Yalley by ice and drift. The recent 

 discovery of chalky Boulder Clay at a low level in the Thames Yalley 

 proves conclusively that parts at least of the Yalley had, as he had 

 previously contended, been scooped out before the close of the 

 Glacial period. 



Mr. P. S. Heeeies thought there was no reason to suppose that 

 the various sheets of Plateau-gravel on either side of the Blackwater 

 had ever been continuous. That being so, he thought their elon- 

 gated shape was evidence of their fluviatile origin. The materials 

 of which they were composed strengthened this opinion. The 

 Westleton shingles were very different, and more likely marine. 



Prof. Geenville Cole pointed out, in reference to Mr. Monckton's 

 discovery of pebbles of chalk in the Beading Gravels, how in some 

 areas, as at Headley in Surrey, decayed flints may easily be mistaken 

 in the field for chalk. 



Mr. MoNCKToisr, in reply, said that he had worked on the lines 

 laid down by Prof. Prestwich, and had attempted to fill in details. 

 He agreed with what Mr. Whitaker had said as to the existence of 

 a bleached bed at the top of the gravels, and he compared it to the 

 '^ top sand " described by Mr. Hudleston at Walton Heath. He 



