350 The late Sir Joseph Presticich — The Solent River. 



roughly bedded, and contains flint implements.^ It is evident, 

 therefore, that we have here some important changes in physical 

 conditions, and that a considerable alteration in the charactex'S of 

 the drift-beds likewise commences. This has led to the belief that 

 the gravel on the coast from this point to Bournemouth and Poole 

 is the Alluvium of an old river, which, before the removal of the 

 Chalk ridge that extended across the bay of Christchurch, blocked 

 the rivers flowing southward, and diverted them into a main stream 

 flowing eastward, passing along the line of the present Solent and 

 debouching in the area now occupied by Spithead. 



I cannot agree in this view, as it is wanting in proof, though as 

 the subject is a complicated one, and would take too much time to 

 discuss at length, I will merely touch upon some of the objections 

 which occur to me. No one can doubt that the Chalk range of the 

 Isle of Wight was once continuous to the Dorset Coast in the Isle of 

 Purbeck, but it does not follow that it formed an impassable barrier 

 by which the drainage of the Frome, the Trent, the Stour, Avon, and 

 other rivers was stayed and made confluent, giving rise to the 

 " Ancient river Solent." 



There is no reason why these separate rivers should not have held 

 on their southern course and passed through the barrier as the rivers 

 on the Sussex coast do at the present day. To prove the contrary, 

 it must be shown that the gravel-beds in question are of fluviatile 

 origin, and that they contain the debris of rocks through which, the 

 supposed river and its tributaries flowed, also that the levels are 

 such as would accord with the gradients of a river of that character. 

 An able exponent of the hypothesis admits that it is hai'd to 

 distinguish between the presumed fluviatile gravels and the older 

 probably marine gravels.- First, as none of these gravels contain 

 either fresh-water or marine shells, the difficulty is easily understood.^ 

 By itself this would not be a strong objection, as we all know how 

 frequently such organisms have been removed by the percolation of 

 the surface-waters, but taken in conjunction with others, it cannot 

 be neglected. Secondly, the debris forming the gravel consists 

 almost entirely of materials derived from the high Chalk plateau to 

 the north of the coast-line. Thirdl}', there is no maintained fall of the 

 gravel from west to east. The section given by Mr. Codrington * 

 along the coast for a distance of 10 miles between Poole and Barton 

 shows the following surface-heights : — West — 126, 125, 117, 115, 

 121, 110, 120, 114, 117, 98, 126, and 114 feet— East; and so on to 

 95 feet near Lymington. East of Lymington a lower plateau 

 commences, the level of which continues at heights varying from 

 35 to 40 feet to Hill Head and Stubbington. So much, for the 

 surface-levels. Taking the levels at the base of the gravel, the 



1 Evans, Quart. Journ. Geol. Soc, vol. xx, p. 188. 



- Evans, "Ancient Stone Implements," 1872, p. 609. [See also ed. 2, 1897, 

 pp. 688-696 ; also " Geology of Isle of Wight," ed. 2, p. 249, Geol. Survey ; and 

 C. Reid, "Geology of Bournemouth," 1898, pp. 10, 11, Geol. Survey.] 



* The only fossil I have found in these gravels is a small indeterminable fragment 

 of bone in a pit near Poole Station. 



* Quart. Journ. Geol. Soc, vol. xxvi, pi. xxxvii, fig. 2. 



