east, near Boscombe, the level is about 120 feet; midway between that spot and Hengistbury Head, the height of the gravel is 90 feet; at High Cliff, 84 feet; at Hordwell, where implements abound, a short distance inland, 60 feet; and about midway along the northern shore of the Solent, 50 feet. The surface of the ground is, of course, much cut up by the numerous streams coming in from the north; but the general fall of the gravel from west to east is perfectly in accordance with its having been deposited in the valley of an ancient river running in this direction, the whole of the southern side of which has since been carried away by the sea. Whether the old river had become tidal so far west as Hurst Castle, when first it was intercepted by the sea to the south, does not appear to me to be a matter of importance, inasmuch as no doubt a valley was already formed, along the course of which the encroachments of the sea would be more rapid than where the cliffs were higher, and more solid matter had to be removed. That the valley, in which is now Southampton Water, was also originally, for the most part, scooped out by the rivers coming from the north, which in remote times flowed into the old River Solent, is, I think, beyond all reasonable doubt. The increased volume of the ancient river, after receiving so important an affluent, is evinced by the widening of the channel, from Calshot Castle eastward by Spithead, to a full third more than it is to the west, along what is now the Solent Sea.
As to the character of the gravels at Bournemouth, it is, as already observed, hard to distinguish those presumably of fluviatile origin from the older and probably marine beds. In the railway-cutting between Bournemouth and Christchurch, I thought, however, that in places I could trace the superposition of the one upon the other. The more recent deposits contain waterworn fragments of quartz, granite, and porphyry, as was noticed long ago by Mr. Godwin-Austen,[1] who, from this circumstance, saw reason for connecting them with the gravels capping the tabular hills of Devon and Dorset to the west.
It is, of course, evident that at the period when the river ran at this high level, past the spot where now is Bournemouth, all the land to the immediate west must have been far higher than it is at present, and that Poole Harbour could not have existed. In attempting to reconstruct the map of a country, the shores of which have been much wasted by the sea, in order to show what
- ↑ Q. J. G. S., vol. xiii. p. 45.
