COAST OF THE KETHERLANDS. 523 



is, indeed, possible that the territory of those states would have 

 been as extensive as it now is, and, at the same time, somewhat 

 elevated above its natural level. 



The argument in favor of that method rests on the assumption 

 that all the sea-washed earth, which the tides have let fall upon 

 the shallow coast of the Netherlands, has been brought down by 

 the rivers which empty upon those shores, and could have been 

 secured by allowing those rivers to spread over the flats and de- 

 posit their sediment in still-water pools formed by cross-dikes like 

 those of Egypt. 



But we are ignorant of the proportions in which the marine 

 <ieposit8 that form the soil of the polders have been derived 

 from materials brought down by these rivers, or from other 

 more remote sources. Much of the river slime has, no doubt, 

 been transported by marine currents quite beyond the reach of 

 returning streams, and it is uncertain how far this loss has been 

 balanced by earth washed by the sea from distant shores and let 

 fall on the coasts of the l^etherlands and other neighboring 

 countries. 



We know little or nothing of the quantity of sohd matter 

 brought down by the rivers of Western Europe in early ages, but, 

 as the banks of those rivers are now generally better secured 

 against wash and abrasion than in former centuries, the sediment 

 transported by them must be less than at periods nearer the 

 removal of the primitive forests of their valleys, though cer- 

 tainly greater than it was before those forests were felled. Kloden 

 informs us that the sedimentary matter transported to the sea by 

 the Rhine would amoimt to a cubic geographical mile in five 

 thousand years.* 



The proportion of this suspended matter which, with our pres- 

 ent means, could be arrested and precipitated upon the ground, 

 is almost infinitesimal, for only the surface-water, which carries 

 much less sediment than that at the bottom of the channel, would 

 flow over the banks, and as the movement of this water, if not 

 <;hecked altogether, would be greatly retarded by the proposed 



* Erdkunde, vol. i., p. 384. The Mississippi — a. river "undercharged with 

 «ediment " — with a mean discharge of about ten times that of the Rhine, d©* 

 posits a cubic geographical mile in thirty -three years. 



