4am 
European Russia is a feature of great importance, in explaining 
the difference between the mineral basin to the north and that to 
the south of it. The carboniferous system, the most widely extended 
deposit of Northern Russia, has now been subdivided into stages, 
_ each characterised by its fossils; and it has been clearly shown, that 
the most productive of the coal-bearing strata in the Russian em- 
pire, viz. those of the southern steppes, are associated with the 
mountain limestone ; whilst the uppermost member of the system, 
or coal-measures, which is so rich in coal in Western Europe, if 
indeed it exists, is nearly unpreductive in Russia. 
The next great group of rocks in ascending order, is that which 
has been elaborated in considerable detail under the name of the 
Permian system, and which, as already shown, is to be considered 
as a vastly expanded equivalent of the zechstein and associated beds 
of Germany and the magnesian limestone of the British Isles. This 
system is rendered much more important by its fossil contents in 
Russia than by any remains which have been discovered: in it in 
other parts of Europe ; for not only does it contain, like the zech- 
stein of Germany and the magnesian limestone of England, the re- 
mains of thecodont saurians and certain fishes (Paleonisci), but 
also a fauna much more copious in other classes, and a flora in- 
finitely more rich than any which had been previously made known 
as pertaining to recks of this age. This flora is shown to be of in- 
termediate characters between that of the carboniferous system 
and the plants which have been published as typical of the trias. 
The Permian system is also of high interest in setting before us 
the example of wide accumulations impregnated throughout great 
thicknesses with copper, and as this matter has manifestly been de- 
rived from the mineral masses of the adjacent Ural, so is it inferred 
that these mountains constituted dry land on which the plants in 
question grew, and that the latter having been washed down into these 
Permian deposits were there rendered the nuclei of the copper ores 
which are arranged around them. The thin layer of kupfer schiefer 
of Germany may be considered as the miniature representative of this 
great metallifercus deposit, whilst in its large masses of gypsum, the 
Permian deposits exceed even the zechstein on the south of the Hartz’. 
The Jurassic system of Russia reposes on the Permian and older 
rocks without clear evidence of the existence of any part of the 
Triassic group, there being no traces of the muschelkalk limestone 
nor yet of the keuper ; and it is with doubt even that the authors 
refer any portion of certain red strata which partly overlie the Per- 
mian rocks to the “‘bunter sandstein,’ or new red sandstone of 
geologists. 
True lias has not vet been seen, but the Jurassic system is clearly 
divisible into upper and lower formations, and is followed by the 
cretaceous and tertiary systems, the latter including eocene, mio- 
* The authors use the term “‘ Permian”’ in reference to Russian deposits 
only, and they by no means seek to interfere with the general use of the 
word ‘ Zechstein,”’ which has = so long sanctioned by the highest Ger- 
man authorities. : 
