ON THE GEOLOGY OF RUSSIA IN EUROPE. 
205 
carboniferous and crystalline rocks, and also of the overlying 
secondary and tertiary deposits are given, M. Le Play has grouped 
under darker colours such parts of the tract as are known to be 
productive of coal, to distinguish them from those in which the 
mineral has not yet been discovered. This method, doubtless' 
carries with it a certain amount of information, but it is deficient 
in stratigraphical meaning, for some of the beds so marked are 
higher than others ; in some the coal is interlaced with limestone 
and in others it is almost entirely subordinate to sandstone and 
shale ; in one tract anthracite exclusively prevails, in another 
bituminous coal. By reference, however, to the explanation, 
and to a series of tables, this defect is obviated. These tables 
are, in fact, perfect models for the practical mining engineer ; 
they give at one view the direction, inclination, thickness and 
quality of the coals at each locality, also the characters of the 
associated strata, as well as the state of the works, and their 
produce at each mine. To these is added another set of tables, 
in which the chemical analysis of the coals from forty-three 
different places is given by M. Malivaud, another agent of 
M. Demidoff. 
Into such details, valuable as they are, it was not our province 
to enter, and I will now, therefore, merely offer a few remarks 
explanatory of those points in which the geological conclusions 
of my friends and self either agree or are at varience with those 
of M. Le Play. 
Certain fosssils which he had brought to France, and which 
we inspected before our journeys to Russia (1840), first led us 
to believe, that these coal-beds are subordinate to the carbonife- 
rous limestone. Of this, indeed, there could be no doubt, for 
the species were, to a great extent, the very same as those with 
which we were familiar in rocks of that age in western Europe. 
On interrogating M. Le Play, however, we could not ascertain 
that he had arrived at any defined idea of a succession of strata, 
derived either from the stratigraphical order of mineral masses. 
