558 W. F. Hume — JVotes on Russian Geology. 



in favour of mountains able to cut off the rain-laden winds such as 

 are demanded by Richthofen. On the whole, S. Russia does not 

 seem to satify the conditions favourable to the origin of a true wind- 

 blown Loess. If such elevation did, indeed, take place, it would be 

 sufficient to convert the region between the ice-sheet and the sea 

 into one vast tundra or series of tundras. Even without such 

 elevation, the effect of the presence of the ice-sheet upon the river- 

 drainage would perhaps be of such a character that we at the present 

 day might be filmost unable to grasp its full significance. 



2nd. Leaving these speculative ideas, let me ask what are the 

 actual phj'sical agencies which are at work during the course of a 

 year, and what light, if any, they throw on the points under dis- 

 cussion. The autumn may be taken as a convenient starting-point. 

 Immediately the summer heats are over, rain becomes more frequent, 

 thoroughly saturating the porous soil, which during the early frosts 

 is rent in all directions owing to the freezing of the contained 

 moisture. The winter snows which follow, protect the land for 

 four or five long months from further denudation, whilst overhead 

 they are whirled into a fierce blinding metiel by the piercing east 

 wind. It is not till March that the denuding forces are again let 

 loose. 



With the return of warmer weather, ice and snow begin to melt. 

 Every small stream becomes a rolling torrent, every river spreads 

 out on both sides into a vast lake area. The flood-gates are opened, 

 and the denuding action that takes place in the upper reaches is 

 only equalled by the deposition which must occur in the lower parts 

 of the river-basins. 



One or two examples may show the energy which is thus un- 

 locked at this period. I have seen trickling streamlets which 

 could be crossed at one step in summer converted into rushing 

 torrents 30 feet wide, and some 20 feet deep, bearing away in their 

 mad rush the remains of the wooden bridges which had been 

 thrown over them higher up the stream. Sometimes during summer 

 very curious contrasts may be witnessed. Thus, at the village of 

 Mandreekin, near Hughesevo, three great wooden ice-breakers were 

 standing in a dry bed, whilst near by rose up two massive stone 

 abutments, the sole remnants of what had once been a solidly-built 

 bridge. The only trace of the river consisted of two stagnant pools, 

 separated by a considerable distance of marsh and dry dusty land. 

 This, indeed, is the summer condition of the minor Russian rivers. 

 One more example will sutfice. In spring the Psiol regularly 

 overflows its banks, and rowing is indulged in to a great extent by 

 neighbouring landowners (whose property is often to a large extent 

 under water), the only danger being due to the trees which are 

 sometimes completely hidden under the flood-waters. This flooding, 

 again, is the rule with all the Russian streams. 



It is remarkable with what rapidity the waters disappear as 

 soon as the summer sun attains its full power. Roads previously 

 impassable become tracks deep in sand, and the wind or the air- 

 currents caused by differences of temperature have abundant material 



