. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Ch. XIX] ; 373 the removing power, especially in those cases where well-rounded pebbles washed out of Eocene strata are likewise found broken, some- times with sharp edges, and often with irregular pieces chipped out of them as if by a smart blow. Such fractured pebbles occur not un- frequently in the drift of the valley of the Thames. In explanation I may remark that, in the Blackheath and other Eocene shingle-beds, hard egg-shaped flint-pebbles ma
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Ch. XIX] ; 373 the removing power, especially in those cases where well-rounded pebbles washed out of Eocene strata are likewise found broken, some- times with sharp edges, and often with irregular pieces chipped out of them as if by a smart blow. Such fractured pebbles occur not un- frequently in the drift of the valley of the Thames. In explanation I may remark that, in the Blackheath and other Eocene shingle-beds, hard egg-shaped flint-pebbles may be found in such a state of decom- position as to break in the same manner on the application of a mod- erate blow, such as stones might encounter in the bed of a swollen river or on a sea-coast. Angular flint-breccia is not confined to the "Weald, nor to the trans- verse gorges in the chalk, but extends along the neighboring coast from Brighton to Rottingdean, where it was called by Dr. Mantell " the elephant-bed," because the bones of the mammoth, E. primigenius, abound in it with those of the horse, and, more rarely, the rhinoceros, R. tickorhinus. The following is a section of this formation as it ap- pears in the Brighton clirl* Fig. A. Chalk with layers of flint dipping slightly to the south. b. Ancient beach, consisting of fine sand, from one to four feet thick, covered by shingle from five to eight feet thick of pebbles of chalk-flint, granite, and other rocks, -with broken shells of recent marine species, and bones of cetacea. c Elephant-bed, abont fifty feet thick, consisting of layers of white chalk rubble, with broken chalk-flints, often more confusedly stratified than is represented in this drawing, in which deposit are found bones of ox, deer, horse, and mammoth. <l. Sand and shingle of modern beach. To explain this section we must suppose that, after the excavation of the cliff A, the beach of sand and shingle b was formed by the long-co
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