Page:Quarterly Journal of the Geological Society of London, vol. 31.djvu/76

30 Neale subsequently sent to the Society other bones, and amongst them the tooth of an elephant.

About twelve years ago, in making the deep dry moat (60 to 70 feet deep) on the south side of the Verne Fort, numerous large fissures, some open at bottom but closed at top, and some entirely filled with debris, were met with, traversing the Portland stone in a direction nearly north and south; and in the open ones, amongst a talus of broken fragments of rock, there were found numerous bones belonging to wild boar (a very large species), ox (a large species), deer, horse, wolf, sheep, and several small animals. In addition to these there were in the collection, when I visited it, a skull and bones of red deer, a metacarpal bone of Cervus megaceros (?), skull of Bos longifrons, and skull of dog. All the bones are rather light, white, and do not adhere to the tongue. There is reason to believe that they are all of comparatively recent date, and have fallen into the crevices while they were open to the surface. Mr. Damon also notices the occurrence of gravel with teeth and bones of the mammoth at Radipole, and of a drift with land and marine shells in the cliff, 10 to 12 feet above high watermark, at the mouth of the Preston valley.

This, I believe, embraces all the information we have on the superficial deposits of this district. I had visited Portland in 1863, when, in consequence of some extensive quarrying which had been temporarily carried on to the west side of the Bill, some remarkable sections of the raised beach, varying considerably from the better-known portions on the east side, had then been recently laid open. A visit I made last autumn of a few weeks to Weymouth has enabled me to examine it more in detail, and to notice other phenomena connected with the Quaternary deposits, which I think of sufficient interest to lay before the Society.

The general features of the district are well known. The bold chalk escarpment, 500 to 600 feet in height, of the Isle of Purbeck, ranges to the coast at Lulworth, passes westward, four miles north of Weymouth, to near the sea at Abbotsbury, where it turns inland and northward. A lower undulating triangular tract of Jurassic strata stretches from the base of the last half of this line southward to Portland (see Map, Pl. I.). At a short distance from its southern extremity stands Weymouth. None of this tract rises higher than from 250 to 300 feet, while near Weymouth the hills are generally not more than from 50 to 100 feet in height, and the narrow neck of land connecting Portland with the mainland would be on the sea-level, were it not for the Chesil beach, which rests on it and rises 40 feet above that level. At the end of the narrow neck of land the Isle of Portland rises abruptly to the height of 500 feet at the Verne, from which point it forms a gradual incline to the Bill, a distance of four miles, where the cliff ends with a height of 25 feet.