ORGANIC REMAINS OF THE CARBONIFEROUS SYSTEM. 
133 
strict scrutiny, prove to be distinct varieties. If, indeed, the Leptana sarcinulata 
(Hupsch), which is very prevalent in the carboniferous strata of Russia, should 
eventually be pronounced to be the same species as the Leptcena lata, so typical of 
the Silurian rocks of Britain — an opinion which is already entertained by no less 
an authority than M. L. Von Buch, and also by one of us 1 — it offers a very puz- 
zling problem in the distribution of marine remains, for of this shell there is not a 
trace in the well-examined Silurian deposits, nor even in the Devonian deposits 
of Russia ; whilst, on the other hand, as will be shown in the sequel, it has in 
these regions been first brought into existence in the carboniferous age, and has 
been continued into its uppermost members. Such a striking anomaly as is offered 
by this singular exception, may therefore render us cautious in identifying all species 
by their external forms. 
W ithout, however, dwelling upon a solitary exception, we invite attention to 
the remarkable proofs which Russia affords, of an almost completely new creation 
of species in the carboniferous epoch ; a fact which is the more remarkable, when 
we know, that by far the larger portion of the vast area under review has not, 
during these ancient epochs, been the theatre of any violent catastrophes ; but that, 
on the contrary, the deposits have there succeeded to each other in the most tranquil 
manner. Enormous tracts, however, it must be admitted have been periodically 
raised from beneath the sea by grand oscillations, of which the central dome of 
Devonian rocks (p. 53) is a striking example ; and parts of the bottom of the car- 
boniferous sea have then been added to this continent, to form, in their turn, the 
shores of newer accumulations, which will hereafter be described under the name 
of the Permian system. 
The Carboniferous rocks of Russia are rich in characteristic organic remains, 
and though the lists which we have to offer are not so copious as those which 
have been derived from the more diligently explored rocks of similar age, in other 
parts of Europe, they completely answer the views of the geologist. In a word, 
tnany well-known species represent exactly the fauna of this epoch, and serve 
as a sound basis for reasoning, which future discoveries may slightly modify, but 
cannot destroy. 
Of ichthyolites, so remarkably abundant in the Devonian epoch, there are very 
few traces in the carboniferous limestone ; a fact which may be theoretically ex- 
1 M. de Verneuil. See the reasoning on this point in Part III. 
T 
