TF. F. Hmne — Notes on Russian Geology. 559 



upon which to exert a redistrlbutive action. On the Ekaterinoslav 

 Steppes on a hot day, we have observed as many as ten or twelve 

 dust-clonds (resembling water-spouts when seen at a distance), 

 rushing along over the vast plains, unimpeded by any obstacles, and 

 frequently attaining a height of from 30 to 40 feet. 



What the force of the wind sometimes is may be judged from the 

 fact that on some rare occasions the waters of the river Don have 

 been driven back under its influence for a distance of over eight 

 miles, the ships remaining high and dry, while the Sea of Azov is 

 then evidently seen to lie in a saucer-like depression. Such a force 

 is evidently one by no means to be ignored in considering the 

 physical activities which are at present altering the earth's 

 surface. 



It is especially interesting in the more hilly districts to see the 

 clouds of dust being driven up the long slopes, shewing the means 

 by which high elevations may be covered with Loess. Thus in the 

 annual cycle the principal physical forces coming into play are — 

 1. Kain. 2. Frost. 3. Elvers in Flood. 4. Wind. With the 

 greater differences of temperature which previously existed, the 

 first three would probably be far more active, that is to say, if the 

 river-beds were defined as they are now. 



It will be noticed that our area is now drained by three important 

 rivers, the Dnieper, Donetz, and Don, whose basins separate higher 

 plateaux lands. Thus on the W. of the Dnieper is a Sub-Carpathian 

 table-land, between the Dnieper and the Don is a Central table-land. 

 Finally, to the E. is the Yolga table-land. All these exceed 500 feet 

 in height, while the river-basins between them never reach that 

 level. It is very remarkable to notice that each of these rivers is 

 pressing oh the eastern edges of the plateaux which abut against them 

 as steep escarpments. Von Buch considered this westward advance 

 of the river- valleys as being due to the rotation of the earth. 



The Loess occupies the upper summit of many of these escarp- 

 ments, and it has seemed to me that the river Dnieper must have cut 

 out its present valley since the Loess period. The matter is one that 

 seems to call for further study. It is remarkable, for instance, that 

 the Dnieper for a long distance follows the line of the Archaean axis, 

 yet having a thin band of gneisses on the left bank. Below 

 Ekaterinoslav it cuts straight across the Archgean rocks, giving rise 

 to the famous cataracts which render the river useless for navigation 

 below the town of Ekaterinoslav. It seems probable that the 

 Dnieper once ran at the point of surface junction between the gneisses 

 and some softer beds, but that now the latter have been denuded 

 and the river has cut its bed deep into the underlying gneisses. 



I cannot refrain from further calling attention to the present 

 physical geography of S. Eussia. The Crimea elevation with its 

 volcanic hills appears to have served as a barrier against which the 

 land has been piled up, separating the Sea of Azov from the Western 

 tongue of the Black Sea. But this does not explain the striking 

 parallelism between the course of the three southern rivers. It may 

 be only a coincidence, but it may be also that some deeper cause 



