H. Bury — The Chines and Cliffs of Bournemouth. 75 



both here and in the Tsle of Wight/ are due to the advance of the 

 sea, I see no evidence of that advance in earlier structures. 



The difference between the hypothesis supported by Lyell and 

 others and that here advanced may be summed up as follows : 

 According to the former the chines originated in quite recent times 

 as miniature torrents in the cliff-face, and have since been growing 

 steadily longer and less steep (longitudinally) ; while in my view, 

 although the chines themselves (reserving this term for the newer 

 valleys) are recent, yet they are the remnants of an old drainage 

 system which anteceded the cliffs ; and since the growth at the 

 head is, if not absent, at any rate less rapid than the advance of 

 the sea, they must each year be growing shorter, and will (unless 

 marine erosion is permanently checked by man) ultimately disappear 

 altogether. 



II. The Cliffs. 



The suggestion (first advanced, I believe, by Mr. Carus Wilson) 

 that there has been a general increase in the steepness of the Bourne- 

 mouth cliffs in the last thirty or forty years, has been widely accepted, 

 and coupling this belief with a tradition of a marshy tract of shore. 

 Dr. Ord ^ builds up an elaborate theory of an old sea-cliff' left far 

 inland at the time of the raised beaches, and only recently reached 

 again by the sea. But before we accept such a speculative view 

 ^e must be absolutely sure of the facts on which it rests. 



As there is nothing to show that the marshy tract was anything 

 more than an extension of the valley floor of the Bourne,''' and as it 

 in any case admits of a simple explanation,^ it need not be further 

 discussed ; but the alleged change in the angle of the cliffs merits 

 closer attention. 



My own intimate acquaintance with the western part of the bay 

 (from Alum Chine to Poole Harbour) goes back fifty years, ^nd rests 

 further upon many conversations with one who had been familiar 

 with that coast for some ten or fifteen years before ; and I am quite 

 confident that, at any rate within the region named and the time 

 specified, the general angle of the cliffs has undergone no change 

 whatever. Moreover, Lyell, who visited this coast in 1830, evidently 

 found erosion going on rapidly, since, as we have seen, he attributes 

 ■the origin of the chines to falls of the cliffs. On the other hand, 

 the evidence in favour of change having occurred appears to me 

 to amount to nothing more than this, that at certain points the cliffs 

 were formerly more easily scaled than now, and for this, I think, 

 local causes can be found without postulating a wide stretch of 

 raised beach, which is entirely unsupported by evidence. 



We have seen that the chines are growing shorter, and from the 

 condition of a few of them (notably little Durley Chine) we may 



1 Quart. Journ. Geol. Soc, vol. xxvi, 1870, p. 541. 



2 Natural History of Bournemouth, pp. 234-5. 



* Lyell, op. cit., vol. ii, p. 531. 



* Mem. Geol. Surv., Bournemouth, 2nd ed., p. 66. 



