Russia and the Ural Mountains. 527 
novel point connected with this cavern is, that several of the hard- 
est bones and teeth have been split across, and their parts relatively 
moved, as if the detrital mass had been affected by faults posterior 
to its original deposit, which movements may, Mr. Stutchbury sup- 
poses, have been connected with the operations which closed the ori- 
fice of the aperture *. 
The President now proceeds to the subjects of Geological Dynamics, 
Detrital Phenomena, Glacial Theories, Raised Beaches and Shingle Ter- 
races, Marks of Ancient Levels of the Sea ; noticing in succession the labours 
and views of Mr. Hopkins, Prof. Sedgwick, Mr. Scott Russell, Mr. Clay, 
M. Agassiz, M. Charpentier, M. Hugi, Prof. Keilhau, M. Elie de Beau- 
mont, and especially those of M. Bravais. 
Russia AND THE URAL MountTAINs. 
Having occupied your attention during the past session with me- 
moirs 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 coad- 
jutors, M. E. de Verneuil and Count A. Keyserling. Employed as we 
are in preparing a work explanatory of our views, in which we hope 
to do justice to all previous inquirers}, and to the Imperial Admi- 
nistration 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 de- 
posits 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 unequivocally 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 northern 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 fre- 
quently sub-crystalline equivalents in Western Europe and the Bri- 
tish Isles. In their small vertical dimensions they present to us, in- 
deed, a very instructive lesson, for in passing from Norway, Sweden 
and Gothland into Russia, the distinguishing strata thin out, and 
losing their divisionary lithological characters, part also with many 
of their characteristic shells. ‘ When followed from one region to 
another, deposits of all ages exhibit like contractions and expan- 
sions, dependent on the forms of the ancient bays, the nature of 
* A similar case occurred in the gravel beds of Darmstadt, where the 
Dinotherium was found. 
+ During its preparation, our general map of the Russian empire has 
been much improved in its north-eastern extremity, the country beyond 
Archangel which we did not visit, in consequence of the observations of 
the distinguished botanist M. Ruprecht. 
