By the Rev. John Adams. 271 



railway cutting on the west side of the town, at the base of the mottled 

 clay and a few feet above the chalk, hundreds of leaves of plants 

 " impressed as finely as on wax and with every marking preserved."^ 

 They are supposed to have belonged to trees resembling, though 

 not identical with the fig, mulberry, walnut, and other plants 

 which indicate a warm though not a tropical climate. These 

 characteristics of the strata enable us to state many of the conditions 

 under which they must have been formed ; and to imagine how 

 strangely difierent from its present aspect the face of nature around 

 us must then have been. The materials of the rivers have very 

 few affinities with the chalk, and seem to have been produced from 

 the denudation of primary rocks. We therefore infer that they 

 were brought hither by a sea turbid with the debris of mighty 

 rivers, which swept down from remote hills even then crumbling 

 with age, and now perchance buried beneath the waves. The 

 intermingling of fresh water and marine deposits in many places, 

 leads us to the conclusion that the coast must have been low and 

 swampy ; at one time enclosing lakes and lagoons behind its sand- 

 banks, and at another inundated by the sea. The organic remains 

 are of a very distinctive character, differing widely from those of 

 the chalk b'eneath, and difiering also, though in a less degree, from 

 existing organisms. Geologists have appropriately designated this 

 and the succeeding series eocene, or the dawn, because in them the 

 forms of life which now flourish around us first begin to appear. 

 About one fifth of the shells found in the Woolwich and Reading 

 beds may be classed under existing genera, though in species none 

 of them are identical with their modern analogues ; but not a 

 single specimen remains of the myriads of races which peopled 

 land and sea during the chalk epoch. 



Overlying those beds of clay and sand we find a layer of flint 

 pebbles, perfectly rounded and extremely brittle, falling to pieces 

 under a gentle blow of the hammer ; and next, in ascending order 

 come the great deposits of argillaceous strata known as the London 

 Clay and Bagshot Sands. In many parts of the Kennet district, 

 however, those beds have been entirely swept away by the floods 

 ' The Ground beneath us, p. 64. 



