70 DIVISIONS OF THE CARBONIFEROUS LIMESTONE — LOWER DIVISION. 
In sketching the features of this great expanse of calcareous matter, we shall follow 
the same course as that adopted in the preceding chapter, by resuming the account, 
in the ascending order, Irom the strata of the preceding system, with which the 
beds under consideration are in contact. We first, therefore, describe the lower 
members on the Msta and the Priutchka, and then follow them in their extension 
to the north-east, south-west, and south-east. The description of the southern 
carboniferous tract, so important from its mineral contents, will occupy the next 
chapter. 
In our last year’s survey we were led to divide the chief calcareous mass of this 
system into three subformations, each typified by characteristic fossils. When, 
however, fully developed (as on the western flank of the Ural Mountains), the 
limestones are surmounted by a peculiar group charged with Goniatites, and made 
up of grits, flagstones and conglomerates (see Tabular view and Chapter VII.) . 
The attention of the reader is now called to the lower or great calcareous 
masses only ; and these, constituting the whole Carboniferous system of northern, 
central and southern Russia, consist in ascending order of— 
1 . Lower limestone, with Productus giganteus ; for the most part dark grey and 
bituminous, and which is associated with sands and a little coal. 
2. Middle or white Moscow limestone, with Spirifer Mosquensis (Choristites, 
Fisch.). This portion is void of carbonaceous matter in the northern or central 
governments, but in the southern steppes contains coal of good quality. 
3. Upper limestone, with Fusulina cylindrica (Fisch.), without coal in the north 
or upon the Volga, but in the south containing a little. 
Lower Limestone, fyc. in the Valdai Hills. — The lower limestone may here he 
detected at many places along the southern and eastern edge of the Devonian rocks, 
which it immediately surmounts. Its bottom beds consist of sand and shale, 
which, however slight may be their commercial value in any tract yet explored, are 
unquestionably of the same age, and occupy the same geological position as the 
productive British coal-field, which on the banks of the Tweed rises out from 
beneath the great mass of the mountain limestone of Northumberland 1 . 
In the natural sections of the Msta and its tributary the Priutchka in the eastern 
part of the Valdai Hills, the lowest carboniferous beds, or those immediately above 
1 See Transactions of the Nat. Hist. Soc. of Ncwcastlc-on-Tyne, vol. i. ; in which the memoirs 
of Mr. N. Wood, Mr. Winch, and particularly a paper by Mr. Witham, show the position of this coal- 
field. Having revisited the coast near Berwick since our return from Russia, we must say, that this coal- 
field, so very low in the series, is worthy of being described in greater detail. 
