72 
CARBONIFEROUS LIMESTONE IN THE VALDAI HILLS. 
sidered to represent the same member of the series as the white limestone here- 
after to be described, which is so abundant near Moscow and to the south of that 
city, for we did not detect its characteristic fossil, the Spirifer Mosquensis (Fisch.), 
in the Valdai Hills. This upper limestone of the Priutchka (twelve to fifteen feet 
thick) is milk-white, resembling the finest varieties of “ calcaire grossier,” and con- 
tains Bellerophon clatliratus { D’Orb.), Cirrus rotundatus (Sow.), = Euomphalus Dio- 
nysii (Goldf.), Pecten None (Eicliw.), Orthis arachnoides (Phill.), Productus striatus 1 
(. Mytilus , Fisch.), P. scabriculus (Sow.), Nautilus tuberculatus (Phill.), Orthoceras 
annulatum (Sow.), Cidarites Deucalionis and Pyrula monticola (Eichw.), with corals, 
including Lithostrotion jloriforme , Fenestella, &c. 
Magnesian Limestone. — Without pretending to assert that the mineral succession 
which we observed in the sides of the brooks above the Priutchka, particularly on 
the rivulet Stolobna, is to be taken as the type of the strata in other places, we may 
state, that upon the left bank of that brook, the cliffs (fifty feet high) exhibit a 
series of very varied beds inclined at 35° to 40°, and including yellowish, sandy, 
dolomitic limestones, sometimes very earthy and impure, and some remarkable 
bands of flint, as represented in the annexed woodcut. 
12 . 
a. Strong-bedded, dark purplish limestone, dislocated along the course of the rivulet Stolobna.— b. Sandy, reddish marls e. Soft white limestone.— 
<t. Red and yellowish argillaceous sands. — e. Red clay, ochreous sandstone, &c.— /. Greyish white limestone. — g. Thin-bedded ditto. — h. Bituminous 
schist.— i. Yellowish, sandy, magnesian limestone.—^. Courses of flat-bedded flint, subordinate to sandy magnesian limestone.— k. Yellow magnesian 
limestone.—/. Flint layers repeated in two courses.— in. Greyish encrinite limestone.— w, o, &c., which are not fully drawn in the woodcut, repre- 
sent in ascending order a course of flint, grey thin-bedded limestone, with greenish marlstone, white siliceous flinty band, dull greenish, earthy, impure 
limestone, and yellowish, sandy, magnesian limestone, passing upwards into other beds of impure sandy limestone. The whole, is covered by local de- 
tritus and northern blocks (/>). 
Besides displaying both magnesian and white limestone so common in the Car- 
boniferous system of Russia, this section is instructive in exposing certain bands of 
siliceous matter, which, from the durability of their fragments, when broken up, 
are permanent features in the detritus of Russia, just like the chalk flints of 
1 This shell, so characteristic of the carboniferous limestone in the most distant countries, is known 
under several synonyms. It was first named and figured by Fischer Mytilus striatus, and, believing with 
M. de Buch that it is a true Productus, we have retained the earliest specific name. It is the Pinna 
inflata (Phill.), Productus linueformis (V. Buch), and the Leptana anomala (Sow.). Yet, with these dif- 
ferent names, the shell is identically the same from Britain to Siberia. 
