721 
should be so clear. The superior value, however, of the Russian 
sections of this division of the Paleozoic rocks over those in every 
other part of Europe, consists in the conjunction before adverted 
to and so generally observed in Russia, of Heloptychius and other 
fishes of the old red sandstone of Scotland and England, with the 
fossil shells characteristic of South Devon, the Boulonnais, and the 
Kifel *. 
Carboniferous Limestone and Coal.—The lowest beds of the car- 
boniferous system in Russia are, as previously stated (ante, p. 401), 
sands and shale with thin seams of coal, Stigmaria ficoides, &c. The 
authors examined a considerable tract occupied by these beds to the 
south of Tula and Kaluga, where many additional natural outcrops 
have been discovered by Colonel Olivieri, the mineral having the 
lignite or impure character of the beds of coal described last year in 
a similar position in the Waldai Hills, These strata are, the authors 
conceive, of the same geological age as those of the great pro- 
ductive coal-field of Berwickshire, which equally underlies the 
mountain limestone. 
By their recent labours the authors have divided the carbonife- 
rous limestone of Russia into three members. The lowest of these, 
generally a dark-coloured rock, is characterized by the presence of 
Productus giganteus and P. Waldaicus (near to P. anomala, Sowerby, 
&c.). The central mass is the well-known white limestone of Mos-_ 
cow, containing Spzrifer Mosquensis, S. resupinatus, S. glaber, the 
Chetetes radians, Euomphalus pentangulatus, and many other fossils, 
some of which (such as Productus antiquatus, P. comotdes) are found 
also in the lower division. Beds of compact, yellow, magnesian 
limestone occur in this central part of the carboniferous system, as 
well as bands of red and greenish shale or marl, and thin beds of 
_pure siliceous flint graduating into ordinary limestone chert. 
The third caicareous division is one which is not seen in the Wal- 
dai or Moscow district, but which seems to surmount the before- 
mentioned divisions on their eastern flank at Velikovo and Kosrof, 
on the river Kliasma. Again, the lofty cliffs which occupy the 
banks of the Volga between Stavropol and Samara are almost ex- 
clusively composed of this member of the carboniferous limestone, 
which is there made up of myriads of Fusuline (the fossil bodies 
mentioned by Pallas as resembling grains of wheat), associated 
with Ewomphalus pentangulatus, Cyathophylli, &c. 
In a part of the coal region between the Dnieper and the Don, 
the authors detected a band of this fusulzna limestone, in the same 
relative position which had been assigned to it in other parts of 
Russia, namely, in the upper part of the calcareous strata. 
Carboniferous Region between the Dnieper and the Don, or Coal- 
field of the Donetz.—Whilst the central member of the carbonife- 
rous limestone of the northern parts of Russia (Moscow basin) con- 
tains no coal, and the upper beds on the Volga are equally void of 
* The large scales of Holoptychius Nobilissimus were found by the authors 
at a locality called Kipet between Lichwia and Bielef. 
VOL. III, PART II. 3M 
