I 
OJg THE GEOLOGY OF RUSSIA IN EUROPE. 207 
liar over a space as large as an ordinary European kingdom, put 
on many of tlie features wliicli are so well known to those who 
have studied the carboniferous limestone only in the western 
parts of Europe. 
We further learnt, that, in the absence of any deposits to re- 
present our great coal-fields, the carboniferous system was suc- 
ceeded, in ascending order, by a vast series of red and cuprife- 
rous deposits, to which we have assigned the name of Permian. 
It will not, therefore, be arrogant on our part to say, that we 
entered upon the examination of the territory of the Donetz, in 
the possession of elements of comparison which no previous tra- 
vellers had acquired. 
Knowing, from the maps and instructions furnished to us by 
the Imperial Administration of Mines*, that the major axis of 
this tract and the main direction of the strata trend from west- 
nort-west to east-south-east, we resolved, after terminating our 
researches in Southern Russia, to examine the chain of the Do- 
netz in parallel lines transverse to its general strike ; and, by 
carrying out this scheme, we arrived at the conclusion, that the 
oldest member of the series occupies its southern frontier, and 
that, after a multitude of flexures, the central strata dip under a 
limestone charged with Fusulinse, fossils which we had invariably 
found in the uppermost bands of limestone ; the whole group 
being surmounted in the valley of Bachmuth by the equivalents 
of the Permian system. One striking deficiency, however, at- 
tached to our reconnoissance, and fortunately it has been sup- 
plied by M. Le Play himself. Those members of the Geological 
Society who heard our memoirs read, will recollect the importance 
we attach to the presence of the large Productus giganteus, as uni- 
formly characterizing (over vast regions in Russia) the lowest 
beds of the carboniferous limestone : and, we now learn from 
M. Le Play, that this fossil, of which he collected many indivi- 
duals, occurs in the southern part of the region ; our idea is thus 
* The instructions of General Tcheflfkine, the works of Captain Ivanitzki, and 
a map by Colonel Olivieri. See Journal des Mines, &c. 
