TRANSACTIONS OF THE SECTIONS. 109 
rous limestone without the intervention of any other strata,—a fact of 
great theoretical interest to geologists, and of practical importance to 
the Russian empire. 
6. Ferruginous Sands.—The shales of the oolitic series are covered 
by ferruginous sands, which here and there contain large flattened con- 
cretions of grit, which, near Moscow, are used for millstones ; but never 
having observed fossils in this rock, the authors are unwilling to hazard 
an opinion regarding its age. With the exception of certain very recent 
deposits, these grits are the youngest solid strata in the northern half 
of Russia in Europe. 
7. Chalk.—The cretaceous system is largely developed in the south, 
and in the Crimea; but on this occasion the authors did not extend 
their tour to the chalk districts. 
8. Tertiary Deposits.—The white shelly limestone of Crimea, and 
its relations to the underlying chalk, have already been described by one 
of the authors. Such deposits have not yet been discovered in any of 
the northern or central regions of Russia. 
9. Younger Pleiocene ( Pleistoeene).—It was formerly the general be- 
lief, that the great masses of superficial detritus, whether clays, sands 
or blocks, which cover so very large an area of the northern region, were 
all referable to an epoch (diluvian) in which the bones of the great 
extinct quadrupeds were also imbedded. The duration of their jour- 
ney was not sufficient to enable the authors to make many distinctions 
of age between these different masses ; but they have unquestionably 
commenced this division by the discovery of beds of clay and sand on 
the banks of the Dwina and Vaga, upwards of 200 miles south of the 
White Sea, which contain fifteen or sixteen species of shells, many of 
which still preserve their colours, and which, having been referred to 
Dr. Beck, of Copenhagen, have been all pronounced to be of quasi 
modern species. Mr. Lyell confirms this identification; and states, that 
they are identical with the Uddevalla group. This discovery, in which 
they were assisted by Count Kayserling, who accompanied the authors 
in a part of their tour, is conceived to be of high geological interest, as 
it demonstrates that, during the modern period, the whole of the vast flat 
country of north-eastern Russia was beneath the sea for a considerable 
time, the eastern boundary of that sea being the Ural Mountains. 
10. Drift and Erratie Blocks—Overspreading all the formations, 
and greatly obscuring them, is a vast mass of detritus, the large gra- 
nitic blocks of which have excited much attention, from the days of 
Pallas to the present time. This detritus, which has all been derived 
from the north, was shown to have been deposited under the sea, since 
it covers the above-mentioned shells. This portion of the subject was 
slightly adverted to, its consideration and that of all the superficial 
phenomena (including the parallel stria near Lake Onega, &c.) being 
deferred to a future occasion. The important work, however, of M. 
Botlingk was cited. 
In verbally illustrating this wide field of inquiry, Mr. Murchison took 
occasion to state, that he was very much encouraged to undertake 
the journey to Russia through the suggestions of M. L. von Buch, 
* M.E. de Verneuil. 
