FROM MIRBEL. 287 



other, and the mould deepens. Herbs of higher nat- 

 ure, bushes, and even shrubs, take their stand on the 

 newly fertilized rock. At last, the seeds of Uees them- 

 selves, carried either by anicmls, the water, or the 

 wind, are seen to cermin^.te, probably to become the 

 first inhabitants of a forest that shall one day extend it- 

 self over vast tracts of country. 



Lichens will not grow upon sands that are set in mo- 

 tion by the wind ; but the Grasses which are nearly as 

 unformed and rude, afford some turfy species with fine 

 closely fibred roots ; by these they weave themselves 

 together and bind down the sand, which every breeze 

 had used to drive to and fro like the surge of the sea. 

 The soil once made stable, vegetables of every size 

 thrive in it. Hence the industrious inhabitant of Eu- 

 rope has been taught, to use the sea lyme-grass and 

 others of the same nature, to fix the sand of those 

 beaches which threaten to encroach on his fields near 

 the shores of the sea. 



The bottoms of the marsh and lake are gradually 

 though slowly raised by aquatic plants. The water 

 gaining in surface what it loses in depth, is sometimes 

 made to overflow at one side or the other ; and even to 

 disappear entirely, when the springs which feed it are 

 no longer able to counterbalance the waste from evapo- 

 ration, whieh increases with the surface. 



It sometimes happens that certain species, especial- 

 ly of the Bog-Moss, float themselves on marshes and 

 lakes, forming islets and small peninsulas, which are 

 increased from day to day, both in extent and depth, 

 from the accumulated wreck, and remains of the plants 

 which have grown on them. This factitious soil is 

 sometimes clothed by meadows, sometimes by shrubs, 

 and even trees : when now and then it breaks under the 



