GRANITE AND CRYSTALLINE ROCKS OF THE SOUTHERN STEPPES. 91 
In the sequel we shall necessarily advert to the general relations of this crystalline 
chain, the direction of which is so exactly parallel to that of the Caucasus and the 
Crimea. In the present chapter, however, we shall confine ourselves to showing, 
that eruptions and elevations along the same line have powerfully affected the con- 
tiguous strata of the Kalmiuss and the Donetz. 
Stratified crystalline rocks are instructively displayed upon the banks of the 
rivers Voltchia and Kalmiuss. The former of these streams runs to the west of 
all the carboniferous strata. Along its banks to the south of Paulograd, and be- 
tween that town and Alexandrofsk, the rocks consist of varieties of felspathic and 
quartzose gneiss, passing into grey compact quartz, which alternates with very 
thin laminae of greenish talc, rarely micaceous. Some of these beds, a few versts 
east of the river, are so much charged with iron as to oxidize, or decompose into 
courses of hydrate of iron. Other layers consist of yellowish, coarse-grained mica 
schist, with irregular grains of garnet, alternating with thin beds, two to three 
inches thick, of a highly granitoid gneiss, in which the flesh-coloured felspar is 
beautifully laminated with red-coloured quartz, mica, and traces of steatite. 
These variegated, crystalline rocks are very striking to those who have been long 
wandering amid the unconsolidated deposits of Central Russia. They occupy low 
hillocks only, and their prevalent direction is north-north-west and south- south-east. 
Their strike along the banks of the Voltchia is nearly parallel to the course of that 
stream, or about 15° west of north, whilst their ordinary dip is at a high angle to 
the east, and they are often vertical. This strike is, it will be observed, trans- 
verse to the main direction of the chain of the Donetz. For some distance to the 
east of the Voltchia these crystalline rocks are obscured by blown sand, and on 
this frontier it is difficult to mark their boundary, though by borings directed 
some years ago by Colonel Olivieri, it would appear, that thin patches o f poor coal 
set on, at intervals, a very little to the east of the river. 
The granitoid rocks of the Kalmiuss consist, chiefly, of flesh-coloured and pink 
felspar, often laminated with grains and crystals of dark-coloured quartz. These 
materials are sometimes so arranged as to approach to the character of graphic 
granite ; other parts resemble the coarser varieties of Cornish granite. 
But besides the granitic rocks of the Dnieper, the Voltchia and the Kalmiuss, 
other crystalline masses of very different characters advance to the Kalmiuss, and 
there pierce the gneiss and granite in dykes, at many places to the south of 
Karakuba and between that place and Sartana, just as the porphyries and elvans 
