Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/314

 hazel and other trees, was discovered to lie under the bed of indurated mud, that forms the surface of that peninsula.

These data throw much light on the natural operations that were going on, between the period of the last retreat of the diluvian waters, and that at which sea walls began to be erected against the rising waters of the Thames. The substratum of clay and gravel mentioned by Capt. Perry, formed the first surface of the valley uncovered by mud or water, and lying at a small elevation above the then existing high water level of the river. The sediments of the river gradually raised its bed, and caused its waters to spread laterally over the adjacent low lands; first converting to marsh by inundations at high tides, and at length completely burying, by its daily sediment of mud, those tracts which in the early periods of the rise of the bed of Thames, had been quite dry and covered with extensive forests. The horns of stags that inhabited them lie on the surface of the moor log, which appears to be the wreck of these ancient forests, first converted to swamps as the water began to reach their level, at length wholly destroyed by the constant inundation of the ground on which they grew, and still affording evidence of their position and extent, in the roots and trunks that lie buried on the surface and in the mass of the moor log, and over which a bed of mud has subsequently been deposited by those gradually rising waters which caused the destruction of the forest.