Notes on the Phenomena of the Quaternary Period in the Isle of Portland and around Weymouth

Abstract

I n their well-known paper on the Geology of Weymouth, Buckland and De la Beche* give but a very brief notice of the Quaternary beds of the district. They observe that there are no very “extensive and continuous beds of gravel,” and that “the largest deposit of diluvium we have noticed is at Upway Street, four miles north of Weymouth; but in smaller quantities and irregular patches it is disposed over the whole surface of the country, on the summits and slopes of the hills as well as in the valleys.” These scattered drift-beds are all referred, as usual at the time, to one great inundation, which excavated the valleys and overspread the country with patches of diluvial gravel. Mr. Bristow, in 1850† recorded the presence on the top of the cliff at Portland Bill of a recent conglomerate, which Mr. Weston in 1852‡ described as a “marine shingle,” consisting “of beachpebbles (with a few chalk flints);” and in 1860 Mr. R. Damon § mentioned that it contained in places “numerous shells of species now living in the neighbouring sea.” Mr. Whitaker ∥ was the first to give, in 1869, a more particular account of this beach, and to specify the occurrence of Littorina litorea, L. littoralis, Patella vulgata , and Purpura lapillus , extending on the east side of the Bill for a distance of half a mile northward. Over the beach Mr. Whitaker noticed near “Cave Hole” the presence “of a head” (the waste of Purbeck and Potland beds) consisting of