The Black Earth. 307 



reason to modify the propositions submitted more than a year 

 ago (Geol. Mag. December, 1892), These are : I. That the Russian 

 Loess was originally the fine mud derived by the triturating action 

 of the ancient glacier. This view has been still more strongly- 

 urged by Prof. Dokoutchaieflf. II. That it was deposited by slowly- 

 moving waters (this would embrace the aspect adopted by Prof. 

 Arniachevsky), and was distributed by rivers in flood. This latter 

 action would account for the great southward extension of the 

 Loess along the valleys of the Dnieper and the Don, and would 

 by inference suggest that the general courses of these two great 

 streams were already marked out. The thick deposits in the Danube 

 and Rhine valleys may be explained in the same way. Here, let 

 me say, seems to be the time for considering that mighty diluvial 

 change, the Deluge, which has left its mark on the old historical 

 records and traditions of so many nations. Sir H. Howorth 

 weakens his argument by introducing prime causes, which, it is 

 to be feared, he will have great difficulty in proving; but as one 

 deeply interested in modern as well as ancient history, I should 

 be delighted if he could bring our geological data and the monu- 

 mental references into perfect accord. Only by a frank acceptance 

 of a Glacial period in some limited form, will he be able to attack 

 the serried ranks of the Uniformitarians with some hope of success, 

 but combining the results due to its melting, and the changes in 

 the mountain-structure of E. Europe, he may yet hope to carry on 

 a not unsuccessful warfare. III. The glacial and diluvial actions 

 were mainly restricted to the earlier periods of post-Glacial histor}'^, 

 and determined the general geographical relationships of the Loess ; 

 but it was not long ere the wind became the redistributive factoi', 

 and, acting through long years, established those numerous charac- 

 teristic features which can only be explained by means of an asolian 

 theory of origin. 



Having now briefly reconsidered some of the theories with regard 

 to the origin of the Loess, let us now turn to the study of the Black 

 Earth as it is developed in S. Russia. It has long attracted the 

 attention of geological observers, not only on account of its striking 

 appearance, but also because of its rich fertility as a soil. Its wide 

 distribution has been specially noted by Sir R. Murchison ("Russia 

 and the Urals," p. 557), where he says: "Its N. limit is a waving 

 line, passing from near Kieff to Tchernigov, a little to the S. of Lichvin 

 along the 54° latitude line, then advances E. to 57° N. latitude, and 

 occupies the left bank of the Volga between Nijni Novgorod and 

 Kazan. It is also abundant on the Kama and Ufa." Its wide 

 occurrence in Siberia is then noted, as also its presence on plateaux 

 more than 1000 feet above sea-level in the Bashkir country, and on 

 both flanks of the S. Urals. " It does not occur much in the space 

 occupied by the Aralo-Gaspian beds, nor is it found S. of the 

 granitic axis. It lies on rocks of all ages and is found at very different 

 levels. The northern drift is succeeded, if not actually overlapped, 

 by the Black Earth." It has, in reality, a far greater western 

 extension than has been ascribed to it in the above lines, and I 



