238 Geological Society : — 



the Thames is occupied with a mass of ochreous gravel, from 5 to 

 15 feet thick, and varying from 2 or 3 miles to 8 or 9 miles in 

 width. This gravel is composed of subangular chalk-flints, derived 

 from the chalk of the adjacent district, together with flint-pebbles 

 derived from the tertiary strata, and pebbles of quartz and 

 old rocks derived from the conglomerates of the New Red Sand- 

 stone. There are also a few fragments of Oolitic rocks and of the 

 Lower Greensand. Land-shells and bones of land-animals have 

 been found in this gravel at several detached localities, as at Brent- 

 ford, Kingston, London, &c. The date of the deposition of the 

 mammaliferous gravel is, in the author's opinion, probably posterior 

 to that of the boulder-clay of Norfolk and Suffolk, and necessarily 

 posterior to the gravel which caps the chalk plateau traversed by 

 the valley at Maidenhead. This latter, or " high-level," gravel is 

 very similar in its lithological character to that in the valley, or the 

 "low-level," gravel. The " low-level " gravel at Maidenhead rests on 

 chalk-rubble ; and the skull of the Musk-buffalo was found, together 

 with fragments of other bones, low down in the gravel, where it 

 begins to be mingled with the chalk-rubble. 



3. " On some Geological Features of the country between the 

 South Downs and the Sussex Coast." By P. J. Martin, Esq., F.G.S. 



In this paper the author appropriates the boulder-drift lately 

 brought to light by Mr. Godwin Austen to an outer zone of Wealden 

 drift, in addition to those which he has already descriljed as mantling 

 round the nucleus of the Weald ; the corresponding parts of this zone 

 he thinks are to be found in the valley of the Thames, and perhaps 

 yet to be discovered amongst the Grey wethers and other relics of the 

 Tertiaries found on the chalk country of Hampshire and Wilts. The 

 above-mentioned zone the author considers as the remains of the 

 boulder deposit spread over the tertiary countries of this and the 

 adjoining parts of the North of Europe, before their continuity was 

 disturbed by the upheaval of the great anticlinal of the South of 

 England. 



The country immediately under review, Mr. Martin regards as a 

 sectional part of this great anticlinal, and not to be considered apart 

 from the wide geological area to which it belongs. 



He considers that its phsenomena of arrangement and drift belong 

 to the epoch of that upheaval, and betoken the agencies of powerful 

 diluvial currents, set in motion and contemporaneously assisted by 

 the dislocations known to abound in this part of our island ; and 

 without the aid of which no satisfactory conclusion, in the author's 

 opinion, can be deduced respecting the drifts and the other phseno- 

 mena of the denudations and surface-changes here exhibited. 



Feb. 6, 1856. — W. J. Hamilton, Esq., President, in the Chair. 



The following communications were read : — 



1. "Notice of the Raised Beaches in Argyllshire." By Com- 

 mander J. E. Bedford, R.N. Communicated by Sir R. I. Mur- 

 chison, V.P.G.S. 



In June last some notes by Capt. Bedford were read on this sub- 



