THE EARTH. 



burst in, it must have been a long time in over- 

 whelming the branches of the fallen forest with 

 its sediments, and still longer in forming a regu- 

 lar bed of shells eleven feet over them. It must 

 have, therefore, taken an age at least to make any 

 one of these layers ; and we may conclude, that 

 it must have been many ages employed in the 

 production of them all. The land also, upon 

 being deserted, must have had time to grow com- 

 pact, to gather fresh fertility, and to be drained 

 of its waters, before it could be disposed to vege- 

 tation, or before its trees could have shot forth 

 again to maturity. 



We have instances nearer home of the same 

 kind, given us in the Philosophical Transactions ; 

 one of them by Mr Derham. An inundation 

 of the sea at Degenham, in Essex, laying bare 

 a part of the adjacent pasture, for above two 

 hundred feet wide, and, in some places, twenty 

 deep, it discovered a number of trees that had 

 lain there for many ages before ; these trees, by 

 lying long under ground, were become black 

 and hard, and their fibres so tough, that one 

 might as easily break a wire, as any of them : 

 they lay so thick in the place where they were 

 found, that in many parts he could step from 

 one to another : he conceived, also, that not 

 only all the adjacent marshes, for several hun- 

 dred acres, were covered underneath with such 

 timber, but also the marshes along the mouth 

 of the Thames, for several miles. The meeting 

 with these trees, at such depths, he ascribes to 

 the sediment of the river, and the tides, which 



