212 Proceediiigs of Philosophical Societies. [March, 



been drifted south-westward, probably from Lincolnshire, over 

 the plains of Leicestershire, subjacent to the great oohte 

 escarpment. It is certain the quartzose pebbles cannot have 

 been drifted from any part of England south-east of the escarp- 

 ment, since there is no stratum in this portion of the island from 

 which they could possibly have been derived. It is stated that 

 these quartzose pebbles, which were derived primarily from the 

 Lickey quartz rock, received their rounded form at a period pre- 

 ceding the deposition of the young red sandstone strata, from 

 which they were again torn up and mixed with fragments of 

 other rocks, and scattered over the surface of all formations that 

 lay in the course of the latest diluvian currents that have affected 

 the earth. The completely rounded flint pebbles of Blackheath 

 and of the Hertfordshire pudding-stone are also stated to have 

 received their attrition at a period intermediate between the 

 deposition of the chalk and plastic clay formations, and long 

 anterior to the action of the last great diluvian waters. 



And both these pebble beds of ancient origin have shared the 

 common fate of all formations in being torn up by the waters of 

 the last great deluge, and mixed up with the less perfectly rolled 

 fragments of rocks that have undergone no further attrition than 

 that to which they were submitted in being washed by it from 

 their native station to the gravel beds they now occupy. 



An examination of the compound character of the gravel beds 

 of Kensington and the valley of Oxford is brought forward in 

 proof of the statements above advanced. 



At Kensington, we have the ancient pebbles which existed as 

 such in the regular strata of Warwickshire and Blackheath 

 mixed up with the angular and imperfectly rolled chalk flints 

 which constitute the mass of that gravel, and have been sub- 

 mitted only to the action of the last great deluge. 



And at Oxford we have the same Warwickshire pebbles mixed 

 with the angular and slightly rolled fragments of oolite and other 

 rocks which form the hills intermediate between Warwickshire 

 and Oxford. Argmnents are also adduced to show that the 

 lower trunks of the valleys of the Thames and Even-lode, i. e. 

 those portions of them which lie between the table lands that 

 flank the course, did not exist at the time of the first advance of 

 the diluvian waters which brought the pebbles from Warwick- 

 shire, but were excavated by the denuding agency which they 

 exercised during the period of their retreat. 



Dec. 17. — The conclusion of a paper was read, which had 

 been beo"un last session, " On the Coal Fields adjacent to the 

 Severn," by Prof. Buckland and the Eev. W. D. Conybeare. 



Of these coal fields the first selected for description is that 

 which they have termed the Somerset and South Gloster Basin. 

 It is called a basin only with reference to the general position of 

 the strata, comprising its interior, since these strata are affected 

 by many minor undulations which at first sight appear to divide 



