558 
TCHORNOZEM OR BLACK EARTH OF RUSSIA. 
central and southern parts of that region. Although we met with it occasionally 
in the low gorges of the chain, and in the Bashkir country on both flanks of the 
southern Ural (in plateaux more than 1000 feet above the sea), and also in the 
steppes of the Kirghis, we did not see it in the plains near Orenburg, nor to the 
south of that city. We know, indeed, that it does not exist in the flat southern 
steppes extending to beyond Illetzkaya Zastchita and between that place and the 
mouth of the Volga ; for there the surface is strewed with fine submarine detritus 
containing numerous shells of the same species as those which now inhabit the 
adjacent Caspian. In short, we apprehend, that the true black earth occupies 
small tracts only of the area once overspread by the great Caspian of former 
epochs (see p. 299). Nor did we meet with any black earth to the south of 
Tzaritzin on the Volga, in the steppes of the Kalmucks between that place and 
the mouth of the Don ; nor indeed, except in very limited patches, along the Sea 
of Azof, or in other words, on the southern face of that elevation between the 
Dnieper and the Don, which constitutes what is commonly called the granitic 
steppe. It occurs, however, in great thickness on the plateaux on the northern 
side of that axis, where, as it really surmounts the carboniferous limestone with 
many seams of coal, a geologist who had not observed it in other places might, at 
first sight, be led to suppose, that the black matter was due to the decomposition 
of the subjacent carbonaceous strata 1 . It lies, however, upon rocks of all ages, 
and the greatest masses are included in the territories thus roughly defined. 
Geologically considered, therefore, the tchornozem occupies the centre of a trough, 
large as an European empire, having the detritus of the crystalline and older rocks 
for its northern, and the low granitic steppes and Caspian deposits for its southern 
limits. 
It is found at all levels in European Russia, sometimes on plateaux, as on the 
right bank of the Volga, high above the adjacent plains, in various parallels, from 
56^° north latitude to the high grounds extending to Saratof, and at heights of not 
less than 400 feet above the valleys ; in other places on undulations, and often in 
broad valleys, where the rivers, having cut through the deposit, expose its thick- 
ness on their banks. In the country where the southern limits of the northern sub- 
aqueous drift are traceable, it is interesting to observe, that the northern materials, 
reduced to small size and mixed with local debris, are succeeded if not overlapped 
by the black earth. In one spot, however, near Voroneje, we observed northern 
1 For description of these coal-fields see p. 92 et seq., and PL I. 
