108 



entombed the bones of the Mammoth, Rhinoceros tichorrhinus, and 

 other great extinct quadrupeds, mixed up with gold sand and gravel. 

 Transporting ourselves to the sot\th of Russia, we find the upper 

 portion of the cliffs of the Sea of Azof composed of local detritus 

 and clay equally charged with the same remains. 



The general examination of Russia proves in the most emphatic 

 manner, that the central masses of her continent, though exempt 

 from all plutonic agency, have undergone grand but tranquil oscilla- 

 tions which have scarcely at all disturbed the physical outlines of 

 the ancient bottoms of the sea — oscillations which have operated in 

 a similar manner over this vast space from the remote Silurian age, 

 to the close of the period antecedent to the historic sera. This sur- 

 vey has also taught us, that the great Russian continent is surrounded 

 by rocks of igneous origin, the eruptions of which have corrugated 

 and diversified certain portions of the surface at different periods. 



On her eastern or Asiatic side it has been the wish of my 

 friends and myself to endeavour to read off in the Ural Mountains 

 the effects of such derangements, and to trace the sedimentary de- 

 posits of Russia through the mazes of that band of great disturb- 

 ance. Having so recently laid before you the outline of our views 

 concerning this chain, and being aware that you will soon be in 

 possession of much additional knowledge respecting it from the pen 

 of the illustrious Humboldt, I will confine myself to a single para- 

 graph, by saying that our chief object was to refer these broken and 

 altered masses to their normal types. 



We found this highly metamorphic chain, so rich in metalliferous 

 masses, to consist essentially of Silurian, Devonian and Carbonife- 

 rous rocks, the fossils of which we traced at intervals, notwithstand- 

 ing the countless ridges of igneous matter and the highly crystalline 

 structure which has been communicated by its eruption to the con- 

 tiguous sedimentary sti-ata. A short period only has elapsed, since 

 rocks having quartzose, micaceous and gneissose characters would 

 not have been admitted into the same category with strata con- 

 taining organic remains ; but the theory of metamorphism, founded 

 on patient observation and comparison, has prevailed over ancient 

 doctrines. The sedimentary rocks of the Ural being palaeozoic, 

 must, indeed, be viewed as among the most ancient of the meta- 

 morphic class. Many other crystalline chains are of much more 

 recent age, as long ago, indeed, shown by M. Leopold Von Buch 

 and other observers. Of the truth of this I will first adduce proofs 

 from the Caucasian chain which bounds the Russian Empire on 

 the south. The second illustration of metamoi'phism wall be de- 

 rived from recent researches in the Western Alps. 



Caucasian Chain. — We must now estimate the efforts of an ob- 

 servei', who, in common with Agassiz, does such honour to the little 

 canton of Neufchatel. Though the name of M. Dubois de Mont- 

 pereux has escaped the notice of my predecessors, an outline of 

 his chief labours was laid before the geologists of France, in 1837) 

 by M. Elie de Beaumont. Attention having been latterly much 

 directed towards Russia and the adjacent regions, it becomes my 



