818 EXPERIMENT STATION RECORD. 



Kussia. The Russian rivors, with the exception of some which flow 

 through mountainous regions, overflow regularly in the spring. The 

 alluviums which they deposit consist of sands, clays, and sandy or 

 marly clays, containing some limonite, peat, vivianite, etc. 



The prairie vegetation which springs up after the water has receded 

 results in an accumulation in the upper horizon (soil proper) of 

 varying <|uantities of humus. 



The petrographic character of these soils approaches that of the 

 soils from which the alluvium is derived — in northern Russia the 

 podzols, in southern the chernozems. 



