Ch. III.] OF SUCCESSIVE FORMATIONS. 27 



largest portion of the whole, is either suffering degradation, 

 or remaining stationary without loss or increment. The reader 

 will assent at once to this proposition, when he reflects that 

 the dry land is, for the most part, wasting by the action of 

 rain, rivers, and torrents, while the effects of vegetation have, 

 as we have shown, only a conservative tendency, being very 

 rarely instrumental in adding new masses of mineral matter 

 to the surface of emerged lands ; and when he also reflects that 

 part of the bed of the sea is exposed to the excavating action 

 of currents, while the greater part, remote from continents 

 and islands, probably receives no new deposits whatever, being 

 covered for ages with the clear blue waters uncharged with 

 sediment. Here the relics of organic beings, lying in the ooze 

 of the deep, may decompose like the leaves of the forest in 

 autumn, arid leave no wreck behind, but merely supply 

 nourishment, by their decomposition, to succeeding races of 

 marine animals and plants. 



The other part of the terraqueous surface is the receptacle 

 of new deposits, and in this portion alone, as we pointed out in 

 the last volume, the remains of animals and plants become 

 fossilized. Now the position of this area, where new forma- 

 tions are in progress, and where alone any memorials of the 

 state of organic life are preserved, is always varying, and must 

 for ever continue to vary ; and, for the same reason, that por- 

 tion of the terraqueous globe which is undergoing waste, also 

 shifts its position, and these fluctuations depend partly on the 

 action of aqueous, and partly of igneous causes. 



In illustration of these positions we may observe, that the 

 sediment of the Rhone, which is thrown into the lake of Ge- 

 neva, is now conveyed to a spot a mile and a half distant from 

 that where it accumulated in the tenth century, and six miles 

 from the point where the delta began originally to form. We 

 may look forward to the period when the lake will be filled up, 

 and then a sudden change will take place in the distribution 

 of the transported matter ; for the mud and sand brought 

 down from the Alps will thenceforth, instead of being deposited 



