CRETACEOUS DEPOSITS NEAR VORONEJE. 
271 
tertiary limestone of the steppes. To this point we shall again refer. In ascending 
the Don, we perceived that the chalk was continuous to the neighbourhood of 
Voroneje, where it overlaps the Devonian rocks before described. We would not 
unnecessarily multiply sections which exhibit merely lithological succession, but 
we beg to offer one which we made in the neighbourhood of that city, because it is 
as valuable in showing a full development of the sands, &c. beneath the white chalk 
as some of the preceding sections have been in respect to the overlying strata. The 
following ascending succession, then, is seen on the river Veduga, two versts below 
the village of Indovistye, and to the west of Voroneje. — 
V. White chalk, 20 feet. Above this the regular succession terminates, and the surface of the chalk is 
covered by the reddish alluvium or drift common to large tracts of Russia, and by black earth 
and northern blocks. 
IV. Ferruginous, siliceous, concretionary band, exactly like that of Kursk, beneath the chalk (woodcut, p.269), 
mixed with some greensand, 4 feet. 
III. Greensand, 100 feet in thickness, divided into the following courses in ascending order : — a, white and 
yellow sands alternating, and containing flaggy grit, 20 feet ; b, yellow ferruginous grit, 3 feet ; 
c, alternations of yellow and white sands, containing concretions and flags of hard grit of irregular 
surface, 20 feet; d, coarse-grained greenish sandstone spotted yellow, 40 feet; e, coarse-grained 
micaceous green sandstone, spotted grey and weathering into elongated fragments. 
II. Black schistose clay, 30 feet. 
I. Lowest beds, ferruginous sandstone, 7 feet. 
So far then we do not hesitate to place all the strata, alluded to in the preceding 
pages, in the Cretaceous system ; hut we admit we have some embarrassment in 
even rudely determining the limit between the cretaceous rocks of the south, 
and those ferruginous sands and grits between Mtzensk and Bielef, which we 
have for the present classed with the Jurassic sandstones of Moscow and Vla- 
dimir 1 . We can only state our impression, that in those regions, true cretaceous 
rocks do not extend northwards beyond the great dome of Devonian rocks which 
constitutes the axis of Russia. In the absence of fossils it is, indeed, difficult to 
form a correct opinion concerning the age of sandy deposits occurring at wide in- 
tervals only and in small patches, and which from their lithological composition 
might be considered as Jurassic, Cretaceous, or even Tertiary. We have already 
seen reason to allow, that the siliceous grits of Moscow are truly Jurassic, though 
they much resemble other grits which in the south of Russia certainly lie above 
the chalk. If the simple analogy of the mineral or external character of certain 
sands and grits to those which overlie the white chalk could be assumed as an in- 
i We leave the classification of the isolated masses which occur between the southern basin and that 
of Moscow open till the discovery of fossils. 
2 n 2 
