A general Review of the Geology of Russia. 155 
._M. de Verneuil then called the attention of the Society to the 
immense development of the Devonian system in Russia. ap- 
pears, on one side, extending nearly to Voronez, and thus separates 
the carboniferous formation of Donetz from that of central Rus- 
sia; on the other side it reaches towards the Teman Mountains, 
the basin of the Petchora and the Frozen Ocean. In these 
northern regions it presents nearly the same character which. it 
has on the Baltic and the province of Valdai, and not the type 
which it exhibits in the Ural Mountains. — It appears to be divis- 
ible into two epochs sufficiently distinct; viz., into the upper or 
fish-bearing red marls above, and the goneatite limestones and 
schists beneath, perfectly analogous to those of Nassau or Grund 
in the Hartz. 
The carboniferous system is divisible in Russia into two nat- 
ural regions. In the north and the centre of the country it is 
omposed of horizontal beds of friable freestone, and black argil- 
laceous beds, containing, here and there, a little coal surmounted 
by light colored limestone, sometimes magnesian. In the south, 
on the contrary, i. e., in the country of Donetz, it is much dislo- 
cated, and affords, as in the north of England, beds of good com- 
bustible coal, which alternate with gray, compact limestone, charg- 
ed with marine fossils. 
Above the carboniferous system is displayed a vast and power- 
ful assemblage of deposits, (Permean system,) which occupy, 1D 
the government of Perm and the neighboring governments, an 
fore their deposition and about the termination of the Carbon- 
iferous epoch. ‘Their mineral composition varies along the line 
of observation. In every part of the Ural which forms a portion 
of the shore of the Permean sea, and one hundred and twenty- 
five to one hundred and fifty miles to the west of that chain, the 
predominating rock. is the conglomerate of the red sandstone 
With minerals containing carbonate of copper disseminated. ‘The 
copper is often concentrated in the beds charged with fossil wood. 
In the centre of the basin as well as towards its southern and 
western limit, the freestone is replaced by red marls. Beds of 
gypsum are intercalated at different levels in this immense SysS- 
tem, as well as salt, along with calcareous, marly, and magnesian 
beds. In general ihe limestone and gypsum are at the base ; the 
freestone conglomerate and marl at the upper part. These de 
posits appear, both from their stratigraphical position and organic 
contents, to fill. up the interval between the coal formation and 
the triassic formation. It embraces those groups known in west- 
ern Europe under the names of Rothetodte liegende, Kupfer- 
