552 W. F. Hume — Notes on Russian Geology. 



South Central tract under consideration, we may now examine the 

 conditions prevalent at Kharkoff, the capital of Little Russia. The 

 town, though situated between and on the banks of two important 

 tributaries of the Donetz, has. nevertheless, higher ground both on 

 the N. and W., and a casual inspection shows that Loess here plays 

 an important part. This is especially well seen in a ravine, at the 

 foot of the low hill on which the Technological Institute is situated. 

 The base-rock is composed of a greenish, sandy rock, which is very 

 unfossiliferous, having only yielded a few Bryozoa. It is regarded 

 as Oligocene by Professor Barbot-de-Marny. This rock has been 

 denuded in many places, the hollows being completely filled up 

 with a brown-red Loess deposit. At some points, indeed, on one 

 side of the ravine the escarpment appears to be entirely of green- 

 sand rock, while on the other the red clay alone is visible. A closer 

 inspection of this clay shows it to possess a very perfect capillary 

 structure, the tubes being filled inside with a carbonate of lime 

 coating, and being evidently originally caused by similar root fibres 

 to those which still penetrate the soil in all directions. Further up 

 the gully, the colour changes from red to white, the transformation 

 being due to the presence of calcareous concretions, aggregated in 

 such large quantities that they simulate a bed of rubbly chalk. In 

 reality, however, this is merely an exaggerated case of an occui'rence 

 which is very frequent, and indeed general in the Loess of Southern 

 Eussia, and thus brings it into line with similar deposits occurring 

 on the Ehine, in Austria, and in China. Another variety is dis- 

 played here, which demands special attention, as throwing some 

 light on the origin of the Black Earth. A close examination enables 

 us to trace a gradual transition from the ordinary yellow-red sandy 

 G\&.y, through a Loess moderately rich in humus materials, to a 

 small, but distinctly-marked layer of Black Earth, which forms the 

 surface-layer in the cliff-face. 



A similar relationship on a far larger scale was observed by me 

 while visiting the Bielgorod district. Here, in a small cutting, or 

 quarry on the Steppe, are to be observed some five feet of ordinary 

 Loess, rich in quartz-grains, surmounted by four feet of dark-brown 

 "Black Earth" (this is scarcely ever truly black, being more usually 

 of a dark-brown colour). The latter also contained an innumerable 

 quantity of fair-sized (one-eighth of an inch in diameter) grains of 

 quartz, which glittered brilliantly in the strong sunlight. Close to 

 the point of junction, no sharp demarcation line could be drawn, 

 little seams, or folia, of Black Earth having been formed in the 

 Loess itself. Such inter-bedding, frequently observed, has led me 

 to the conclusion that Black Earth is really a humus-rich modifica- 

 tion of Loess, and other facts tend to confirm this view. 



In this connection also an interesting section at Kharkofi" may be 

 mentioned. It consists of a hollow in the greensand rock, which 

 has been since filled up by very varying materials. Thus at the 

 base is a soft sandstone, following the slope of the little basin. 

 Above it lies a ferruginous sand, which in turn is covered by true 

 Loess. The upper part becomes very rich in humus, and finally 



