72 PROCEEDINGS OF WASHINGTON MEETING. 



often covered by marshes and by little lakes, sometimes round and very shallow. 

 The number of these marshes and lakes was formerly very great, but they have 

 disappeared before the eyes of the inhabitants. The brooks on these plateaus have 

 banks that are but little pronounced, and on following their courses you come upon 

 the steppe, where you can hardly trace the beginning of the brook. Beneath the 

 soil are found loessoid clays difficultly pervious to water. 



What is true of these two governments, which are now well described, is true of 

 the whole surface of chernozem Russia. Nowhere does the " black earth " prevail 

 alone ; everywhere it is interrupted by islets of sand or of gray earth with forest, 

 and everywhere the size and number of forests depend on the character of the 

 relief; and wherever the loess prevails, there we see the steppe, the steppe marshes 

 and the " black earth." All this shows that the climate of this part of Russia is as 

 favorable to forest vegetation, which is detrimental to the " black earth," as to the 

 steppe, and that there are in the soil itself certain conditions which now are more 

 favorable to the forest, now to the prairie. The steppe, despite the dryness which 

 characterizes it, seems to be less well drained than the spots where the forests pre- 

 vail ; the latter seem to augment in number in proportion as the relief is rendered 

 less regular owing to the growth of the gullies, the number of which increases 

 with exceeding rapidity with the cultivation of the soil. 



If these observations are confirmed in other provinces of Russia, we shall have 

 to suppose that we are witnessing an enormous phenomenon of drainage of southern 

 Russia, where the steppe and the formation of the " black earth " play a j)art inter- 

 mediate between the marshy, semi-lacustrine state of the postglacial epoch and the 

 forest epoch. Drained by the great rivers, the clayey and loessoid subsoils, imper- 

 vious to atmospheric water, in a climate of scanty rain, must have been covered by 

 a vegetation of herbs of semi-Alpine origin, which covered the highest points dur- 



i ing the preceding epoch. As the forest enters through the moister gullies into the 

 center of the " black earth " plateaus it transforms by its roots the soil, little per- 

 meable to water, into gray earth, which, acting as a reservoir of atmospheric water, 

 allows the forest vegetation to occupy the surface of the steppe. In other words, 

 we see here what was witnessed, according to Nathorst's theory, in Europe at a 



•more remote period, when the tundras of the postglacial epoch gave place to steppes 

 with antelopes, which in their turn were covered by forests during the historic 

 epoch. 



But, in order to be sure that this view is correct, we still need observations on 

 the postglacial deposits of Russia, those loessoid strata, poor in fossils, so widely 

 spread over the surface of southern Russia, on the appearance of which the features 

 of the morainic landscape peculiar to northern Russia disappear. Yet before these 

 researches, which already occupy much attention, are completed, I desire to call 

 your attention to the analogy existing between the soil and the character of our 

 steppes and the American prairies. So far as it was possihle to me to study the 

 American literature on the subject, winch unfortunately is but scantily represented 

 in our provincial universities, I was struck by the resemblance existing between 

 the Russian " black earth " and that of the prairies of Minnesota and Illinois. It 

 may suffice, in order to see this resemblance, to compare my list of Russian analyses 

 with the American analyses. There is close correspondence between the climates 

 of the two countries as regards temperature and rainfall. Moreover, the history of 

 the evolution of the prairie, as traced by Lesquereux (who thinks that the prairies 

 are even now in the state of transformation from the stage of inundated, lacustrine 



