as indicated in the results of' Geognosy* 119 
through which it has passed ; and contributes to fill up the 
ocean, by forming land on its borders. The flat ground at the 
mouth of the Ganges, the Nile, and the Rhine, have derived 
their origin from this source, as well as the carses of Falkirk 
and Gowrie, in Scotland. If the attention is turned from the 
sea to inland lakes, we observe the same process of upjillmg go- 
ing on, with the assistance of other circumstances connected 
with their condition. Mud is constantly poured into them by 
the rivulets ; the testaceous animals separate lime from the wa- 
ter, for their shells, which ultimately go to the formation of 
marl. Aquatic plants multiply ; and, by their annual decay, 
form layers of peat. The whole mass of foreign matter, by de- 
grees, acquires the altitude of the mouth of the lake, passes into 
the state of a marsh ; and, by the wearing away of the rocks at 
the outlet, is in part drained, becomes fit for grazing, and, final- 
ly, suitable for cultivation. The rivulets, now prevented from 
precipitating their suspended contents in the lake, carry them to 
some lower pool, or farther on to the sea. Numerous plains, 
meadows, and peat-bogs, indicate the former operations of this 
process ; and, in every lake at present, similar changes may be 
observed taking place. 
This obvious tendency of the present order of things, to wear 
down eminences, and fill up hollows, has not been confined to 
the period of the formation of the alluvial strata, but has exert- 
ed its influence during the period of the formation of all those 
rocks in which organic remains are imbedded. Thus, when the 
position of the beds of the transition rocks are examined in the 
great scale, they are found to occupy immense hollows in the 
primitive rocks. The old red sandstone fills up the hollows of 
the transition, and occasionally of the primitive rocks. The in- 
. dependent coal formation is found occupying the hollows of the 
preceding groups. The hollows of these different formations 
have been still farther filled up, by the numerous series of beds 
connected with chalk and gypsum ; and, at last, we come to the 
alluvial deposits, which at present are contributing to fill up ex- 
isting inequalities. 
These changes which have taken place, have every where di- 
minished the height of mountains, filled up lakes, and increased 
the quantity of dry land. We may therefore safely draw the 
