375 



This operation is carried on upon all broken and 

 sandy banks, from the lowest to the highest; but it 

 may be seen and observed, to the best advantage, upon 

 high perpendicular banks, such as prevail higher upon 

 the Mississippi and other rivers, in the Mississippi 

 territory. 



Here the wind, in crossing the river, either oblique- 

 ly or at right angles, strikes forcibly against the bank, 

 and is immediately elevated with its dust and sand 

 into the air ; in passing over the bank, it forms an arch 

 of about one hundred and twenty degrees of a circle, 

 before it is brought into the general current of air, so ae 

 to sweep along the surface of the ground again. Be- 

 neath this arch, or current of air, is a kind of eddy, 

 into which the sand and dust, that is suspended and 

 floating over the banks, is let fall, in the same manner, 

 as alluvion is deposited by a current, that falls into an 

 eddy 



It is in this way and by this process, that the allu- 

 vial banks of almost all rivers, have been raised and 

 kept higher than the land at a distance from the river ; 

 and it is, doubtless, to this source that we may look for 

 the cause, in part, of the elevation of the banks of the 

 alluvial region under consideration. 



Should any doubts exist of the correctness of this 

 view, a more satisfactory and a more beautiful illustra- 

 tion of the fact may be witnessed, almost every winter, 

 by the drifting of snow : in which all the phenomena 

 are regulated by the same laws, and governed by the 

 same principles. 



