665 
and Moscow to the White Sea, with a vast basin of red deposits in 
the governments of Vologda and the Middle Volga, were laid down, 
T assert, for the first time, and thus established the essentially di- 
stinguishing features of subdivision of the North of Russia. 
After the application of this basis, Colonel Helmersen, to whom I 
have alluded, put together in the ensuing winter a small general map 
of Russia in Europe, in which he inserted the result of the labours 
of M. de Verneuil, the Baron A. de Meyendorf, Count Keyserling, 
Professor Blasius, and myself, acknowledging our services as well 
as those of all previous observers. The map of M. Erman which 
followed, was prepared by the Baron A. de Meyendorf and his 
companions, who extended the knowledge which they acquired with 
M. de Verneuil and myself to some of the central and southern 
parts of Russia, and thus marked a new step in the development of 
the structure of the empire. Since that time, the extended geolo- 
gical researches of the expedition in which my friends M. de Ver- 
neuil and Count Keyserling were associated with me, aided by 
Lieut. Koksharof, and an independent survey of Colonel Helmer- 
sen, have thrown a new light over the structure of various parts of 
the central, eastern, and southern regions, and have rendered ne- 
cessary considerable changes in all previous maps. As a mere pre- 
lude, therefore, to what may hereafter appear, I have, with the aid 
of my associates, coloured a small general sketch-map of the em- 
pire, including the Ural chain, which as it will shortly appear before 
you in a published form, I only mention in this place to assure you 
that it differs very essentially from all previous maps. 
Whilst on the topic of Russia, I will now state, that if on ac- 
count of the preparation of this discourse and other official duties 
I had not been greatly occupied, I might before now have present- 
ed to you some of the results of the second visit to that country. 
In the mean time, however, my colleagues, M. de Verneuil and 
Count Keyserling, have been sedulously comparing our collections 
of fossils, and reducing a vast number of barometrical observations, 
whilst with their cooperation I have already completed a general 
table of superposition of Russian deposits, which, with a section 
across Russia, and the map above alluded to, are now nearly ready 
for publication. My brother geologists will feel that a general table 
of classification ought to be the finishing stroke in illustration of 
any country previously little known, and respecting which so much 
confusion prevailed. We offer it, however, in the persuasion that 
its leading divisions will be supported by the evidences hereafter to 
be brought forward, and we simply put forth this table (which was 
drawn up at Moscow after our second journey ) to convey to the cul- 
tivators of our science the chief results of our inquiries, and to place 
them upon record as bearing date from September 1841. 
Among these results I will now merely allude to the first an- 
nouncement of some of them, in a letter of the above date, ad- 
dressed to Dr. Fischer de Waldheim at Moscow, in which the two 
points most dwelt upon were the discovery of a large central dome 
or axis of Devonian rocks, which separates Russia in Europe into 
