ON THE GEOLOGY OF RUSSIA IN EUROPE. 
201 
MEMOIR S. 
On the Geology of Russia and the Ural Mountains. 
By E. I. MuRCHisoN, Esq, F.G.S. 
Having occupied mucli attention during tlie past season with 
memoirs on the Geological Structure of so large a portion of the 
earth as the Russian empire, I must make a few allusions to a 
subject which has to a great extent engrossed my thoughts and 
those of my coadjutors, M. E. de Verneuil and Count A. Key- 
serling. Employed as we are in preparing a work explanatory 
of our views, in which we hope to do justice to all previous in- 
quirers*, and to the Imperial Administration of Mines which 
supported us, I will not on this occasion venture to occupy more 
time than will be sufficient to touch upon some of the most 
striking geological features of that empire, which either sustain 
or enlarge our views of classification and comparison. 
Silurian Rocks. — The Silurian, Devonian and Carboniferous 
deposits of Russia, are each characterized by distinct organic 
remains ; and these rock systems are very clearly separated from 
each other over enormous spaces. Occupying (including the 
Baltic islands) a tract as large as the principality of Wales, the 
Silurian rocks, like those of Norway and Sweden, are unequivo- 
cally the oldest fossiliferous strata, since they are seen to repose 
upon the primary crystalline masses of Finland and Lapland. 
Little elevated above the Baltic Sea and the rivers of the north- 
ern watershed of Russia, these Silurian rocks constitute low 
plateaus only of limestone, clay and sandstone, often incoherent, 
and on the Whole of very small thickness ; thus exhibiting the 
most obvious contrast to their mountainous and frequently sub- 
* During its preparation, our general map of the Russian Empire "has been 
much improved in its north-eastern extremity, the country beyond Archangle 
which we did not visit, in consequence of the observations of the distinguished 
botanist Mr. Ruprecht, 
VOL. II — NO. XVIII 
