J. S. Gardner — Oscillations of Level on S. Coast. 147 



course of which a thick plank with a bolt was discovered, showing 

 that this part of the bank had no great antiquity. An artesian well 

 has also been made to supply Block-house Fort, which for the first 

 60 feet exhibits nothing but clean shingle, and then a layer of sandy 

 clay full of common oyster-shells, another example of the great 

 changes in the ancient coast and sea-bottom.^ We may also refer to 

 the well-known tradition that Shanklin Down could not formerly be 

 seen from St. Catherine's Down, There can be no doubt that the 

 river Lym found its outlet to the sea at Freshwater Gate when the 

 Mammoth lived, and that not only has the Solent broken through 

 since then, but an elevation causes the Yar to flow the reverse way, 

 though still occupying the old channel. There is a submerged forest 

 at Bournemouth below low-water mark under the pier, and I have 

 seen at times stumps of trees partly exposed, and large lumps of 

 tangled root and heather partly pyritized, thrown up by the sea on 

 these occasions. The land at Poole, it is well known, is gaining ground 

 on the sea, part of the town now occupying ground where seventy 

 years ago was deep water. In a street a furlong from the sea a 

 stake and post were found buried 6 feet below the present level and 

 evidently forming part of an old embankment. Beds of peat prove 

 that elevation and depressions have taken place in recent times on 

 the shores of Poole Harbour, at the very edge and even in the water 

 itself. Mr. Clarke mentions in his paper, in the Quarterly Journal 

 of the Geological Society, that the sand dunes advanced half a mile 

 between the years 1785 and 1829, and that the new series on the 

 south side were formed in five years. Bourne Vallej'- contains beds 

 of peat ten to twenty feet thick, with huge trees of oak, hazel, beech, 

 etc., none of which would have grown in an undrained swamp. A 

 Eoman via now terminates at half a mile from the north head of 

 Hole's Bay, in what is now a marsh and extensive peat bog, having 

 probably originally terminated in a landing-place. Such examples 

 on both sides of the Channel are endless, and are referred to in 

 scores of works ; but I will pass on to Devonshire itself. 



The ancient alluvium of the Dart shows that it formerly flowed at a 

 much greater elevation above the sea. Pengelly records the remains 

 of boring mollusca 200 feet above the present sea-level at Kent's 

 Hole. Could anything in fact be more eloquent of changes in level 

 and denudation, since the period of man, than this Kent's Hole, 

 perched on a hill, and jjreserving to us a fragment of a water-course 

 where no water could possibly flow now ? Mr. J. A. Colenso 

 communicated to the Eoyal Cornwall Geological Society the occur- 

 rence under deposits of gravel and mud, of both marine and fresh- 

 water deposition, of trunks of trees in sitii, 34 feet below lowest 

 spring-tide low-water mark, and 12 feet higher, occurred a piece 

 of wood worked by man. 



At Pentuan human remains were found 40 feet below the surface 

 and 34 feet below high- water ; at Garnon they were found at a depth 

 of 58 feet and 64 feet below high- water; from 40 feet a wooden 



1 Report of Brit. Assoc, for 1848, Trans. Sections, p. 72. See also Quart. Jonru. 

 Geol. Sue. 1847, p. 249, 1870, p. 84. 



