Vol. 54.] GEAVELS IIST BEKKSHIEE AND OXFOEDSHIRE. 599 



YIII. Geneeal CoNcmsioNS. 



The Pebble-gravel has the appearance of being a relic of an 

 old marine pebble-bed, possibly re-arranged. Although it has been 

 claimed as Westleton, one might venture to ask whether it may not 

 possibly be of Diestiau age. The exact westerly limit of the sea of 

 the Lenham Beds has never been determined. At Lenham, according 

 to Mr. Clement Reid,^ there is indicated a depth of about 10 fathoms. 

 Possibly here we have the remains of deposits nearer to the shore- 

 line, but there is no evidence to warrant a positive conclusion. 



The Quartzose Gravel. — In stating the facts regarding this 

 deposit, no definite theoretical conclusion has been drawn. Its 

 pebbly nature and its westward limitation by the range of the 

 Chilterns are arguments for a marine origin. No attempt has been 

 made to discuss its suggested connexion with deposits in East Anglia. 

 That this gravel is marine at all has been disputed. 



The Quartzite-gravel is generally regarded as a fiuviatile 

 deposit, yet its connexion with the foregoing is rather close. A 

 westerly tilt, however, would convert an inlet into a river-valley. 

 If this gravel were a fluviatile accumulation the present Thames 

 Valley would have been probably at that time a chain of lakes. 



Although this gravel is characterized by the presence of pebbles 

 from the Bunter, which does not occur in situ in the district 

 drained by the present river Thames, it is not distinctly Glacial, in 

 the sense of containing angular fragments of foreign rocks, so far 

 as I have observed, until a later stage of its history, indicated by 

 the presence of such erratics at a level of about 187 feet above the 

 present surface of the Thames at Rose Hill, Caversham. 



The remarks of Prof. Bonney suggest the possibility that the 

 fragments of igneous rock, occurring in the Quartzite-gravel may be 

 derived from a somewhat definite area. The further investigation, 

 of the subject is likely to be of interest. 



My sincere thanks are due to Prof. Bonney for having been so 

 good as to examine and describe numerous specimens sent to him, 

 and also to Dr. G. J. Hinde for similar kind services. 



Plate XXVIII. 



Sketch-map of high-level gravels in the Reading District, on the scale of 



4 miles to the inch. 



Discussiojsr. 



Mr. MoNCKTON complimented the Author on his careful work in 

 the district, and acknowledged his indebtedness to him for many 

 facts. He asked why the gravels on Green moor Hill should be 

 called ' Goring Gap Gravels,' the hill being at an elevation much 

 above the valley of the Thames, in which Goring stands. 



The speaker remarked that Prestwich characterized his Westleton 



1 Mem. Geol. Surv. 1890, 'The Pliocene Deposits of Britain,' p. 69. 



