Reconquest of the Water 
No doubt at every flood the “ white” water deposits 
a minute film of sediment all over Hylaea, and in pro- 
cess of time this may perhaps become a rich and fertile 
pampas like that of the Argentine. 
It is this last great country which is perhaps the most 
striking example of the geological importance of the 
plant world. From Buenos Ayres on the Atlantic, the 
express train which starts for the Pacific Coast passes 
over one flat, illimitable, scarcely undulating plain, until 
at Mendoza, some 1047 kilometres (655 miles) away, it 
reaches the Andine foot-hills. 
The flatness and monotony of this Pampas is only 
perhaps really interesting at sunrise or sunset, to which 
the enormous horizon gives spaciousness and dignity. 
But even the most casual traveller is struck by its 
fertility. Vigorous alfalfa, rich crops of wheat and 
Indian corn luxuriate in a soil which is for the most 
part rich alluvial silt, mixed with the lime and other salts 
brought down from the Cordillera of the Andes. 
The whole country was once the Pampean sea, whose 
waters extended to the eastern slopes of the Andes. 
Then it became a land of lagoons and morasses with 
sluggish silt-laden and winding rivers, and now it is the 
Argentine Pampas. Unfortunately there is not enough 
rain from the Atlantic to sufficiently supply more than 
the eastern edges of the Argentine, but there can be no 
doubt that it is all the work of plants, especially of 
reed-thickets and brakes of trees, such as have been 
described in this chapter. 
The importance of this process of valley-land forma- 
tion has not yet been appreciated either by geographers, 
geologists, or men of business. Still less have any 
practical steps been taken to assist or stimulate this im- 
portant work. On the contrary, it is in most places 
delayed as much as possible by the pernicious habit of 
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