THEIE GEOLOGICAL AGE. 199 



as yet seen no well-marked remain of Loxodon prisons from 

 these beds, which. I regard, from the mammalian contents, 

 as being 1 of the same age as the Snb-Apennine Pliocene 

 alluvia. 



The next Elephant-yielding bed which I shall notice is 

 the ' mud-deposit ' of Brackelsham Bay and Pagham Harbour, 

 described by Mr. Dixon, and ably investigated lately by Mr. 

 God win- Austen. It consists of a fine dark-coloured sandy 

 mud, of great firmness and tenacity, lying upon the Eocene 

 blue clay, and in some places attaining a thickness which Mr. 

 Austen estimates at eighteen or twenty feet. He enumerates 

 thirty-eight species of marine Testacea, and 'the character of 

 the whole assemblage,' he states, ' is essentially southern and 

 western.' He considers that the ' mud-bed ' is either an old 

 estuary or an ' enclosed salt-water lagon ' deposit, formed 

 under conditions of comparatively high temperature. The 

 only mammalian remains which it was supposed to yield 

 were those of Elephas primigenius. But during a late visit to 

 Brackelsham Bay, in company with Sir Charles Lyell and Mr. 

 Godwin- Austen, the Eev. Robert Everest and myself, after a 

 few minutes' search, picked up a well-marked tibia of a small 

 Eqmis and another bone. The dark-coloured bones are not 

 obvious in the dark mud, and the attention of the local col- 

 lectors has been habitually so much directed to looking out for 

 fine specimens of Pholas and Lutraria, that the bone-remains 

 have been to a great extent overlooked. When a closer 

 search is instituted abundant mammalian remains may be 

 expected. A considerable collection of Elephant-grinders 

 from the ' mud-deposit ' exist in the Chichester Museum. 

 They are mostly in fine preservation, and after a careful ex- 

 amination the whole of them proved to be of Euelephas anti- 

 quus (pp. 181-4). I found no teeth of the Mammoth among 

 them. In this case the mammalian evidence, so far as it 

 goes, agrees with the shells in indicating the ' mud-deposit ' 

 to be of the Sub-Apennine age, and it may prove to be one 

 of the oldest Pliocene beds in England. 



I shall next consider the fluviatile deposits of the Valley of 

 the Thames, in relation to their Elephantine remains. These 

 freshwater strata occur at various points along the valley, 

 such as Brentford, Grays Thurrock in Essex, and other 

 localities. ' They consist of sand, gravel, and loam, from 

 60 to 100 feet thick, and often form a terrace on each side of 

 the valley, rising to a much higher level than a vast bed of 

 more modern gravel.' 1 This ochreous gravel, says Sir Charles 

 Lyell, whose description I quote, extends from east to west, 



1 Annals of Nat. Hist. 1836, vol. ix. p. 261. 



