136 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DcC. 19. 



clinal before spoken of, extensive beds of angular gravel prevail, 

 containing sometimes eocene pebbles, and, more especially as we 

 approach the Downs, forming the " supracretaceous " zone of drift 

 I have elsewhere described as mantling round the nucleus of the 

 Weald. 



These drifts have been so well described by Sir R. Murchison in 

 his paper* on the flint-drift of Sussex, that I need not enter into 

 further detail respecting them. The great occasional mixture of 

 these angular gravels with the shingle-beds of the eocene has escaped 

 the notice of Sir Roderick. This mixture is very remarkable about 

 Boxgrove and Crocker Hill on the Chichester road, and at Halnaker, 

 and indeed is common to all districts where relics of the lowest ter- 

 tiaries are to be found. 



Much stress has been laid on the colour and general appearance 

 of these gravels, the white being considered as of the newest order. 

 The flints that are found mixed up with chalk-rubble have a white 

 coat, and the angular gravel that is mixed up with ferruginous sand 

 or brick-earth is brown. 



I consider these as accidental circumstances ; and, although the 

 gravel arising from the earliest chalk-denudations may exhibit a 

 browner colour and greater marks of antiquity, whilst that which 

 was last produced, when the denuding forces were in operation, ap- 

 pears to be more recent, yet there seems to be no ground for the 

 belief that they belong to distinct eras or other agencies than are 

 common to both. 



[The above notice of the geology of part of Western Sussex com- 

 prised the written portion of the communication made by Mr. Martin, 

 and was preliminary to the verbal exposition of the author's views on 

 the relations of the boulder-deposits of Bracklesham and the neigh- 

 bourhood with the older tertiary and cretaceous strata, on the one 

 hand, and with the superficial gravels and brick-earth on the other ; 

 a subject closely connected with the author's previous researches in 

 the geological history of Sussex and the Wealden district f. 



A paper by Mr. Martin, illustrative of this subject, was unfortu- 

 nately mislaid after having been read before the Geological Society 

 in 1840, and not found again until about 1848. The author was 

 subsequently enabled to publish it in the * Philosophical Magazine ' 

 (see Mr. Martin's "Memoir on the Anticlinal Line," &c. 1851) with 

 additional observations ; and, at the request of the President, who 

 took advantage of the opportunity to express the Society's regret for 

 the temporary loss of Mr. Martin's memoir above referred to, Mr. 

 Martin favoured the Meeting with a general exposition of his views 

 on the Wealden denudation, as far as time allowed, on the occasion 

 of his reading the paper now printed. 



In this communication the author assigned the boulder-drift lately 



* Quart. Journ. Geol. Soc. vol. vii. p. 347. 



t See Mr. P. J. Martin's Memoir on the Anticlinal Line of the London and 

 Hampshire Basins (8vo, 1851) and Supplement, 1854 ; in which also his previous 

 writings on the subject are referred to. 



