A study of the principles of nature / by Frederick Hovenden.

  • Hovenden, Frederick.
Date:
1909
Catalogue details

Licence: In copyright

Credit: A study of the principles of nature / by Frederick Hovenden. Source: Wellcome Collection.

    20/170 page 8
    These paper-weights are partly the subject of my present lecture (figs. 2 and 3). Besides these which contain fossil shells, I show you one not so shaped (fig. 4). It is a piece of wood altered into stone. Notice how completely the grain of the wood and also the tracks of boring organisms are preserved. When running water charged with these minute particles comes into deeper and relatively quiet water, as, for instance, from a stream or river into a lake, then the fine particles fall to the bottom of the lake, and any organisms imbedded become fossils. Hence the muddy water entering the lake passes away as clear water. Not only do these deposits lie at the bottom of lakes, but also at the bottom of the sea. On the seashore the waves pound stone against stone and mould them into pebbles, such as are seen at the base of the cliff (fig. 1). I show a very pretty illustration in this large pebble of lime- stone.1 The original size of this stone was probably very large, comparable with the large masses of stone fallen from the cliffs as seen in the photograph, fig. 1. But let us try to conceive the vast time required to fashion a large mass of stone into the pebble you see on the table. Recollect this stone has been only occasionally submitted to the wear and tear of the sea, that is, during storms, and the difference in volume from the original to the present has been pounded up and finely divided, thrown into the bottom of the sea, and settled there, because these particles are insoluble in water. Thus new layers are being deposited which will one day—for reasons shown further on —be formed into stone, and rise to be layers on the surface of the earth like those 1 The pebble illustrated was a white limestone pebble, egg-shapeil, 7 inches long and 4 inches wide at the largest diameter.
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