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I'epresent the Trias; though the fossiliferous limestone of Moate 

 Bogdo, in the steppe of Astrachan, is probably of this age. With the 

 Jurassic strata, however, which follow, and which occur at iii- 

 tervals from 65° north latitude to the countries south of the 

 Crimea, we made ourselves well acquainted. Should the word 

 Jurassic grate upon the ears of Englii^shnien, it is impossible to deny 

 that this geographical term is much more applicable to the strata 

 in question than our ovvn word " Oolitic," which implies a struc- 

 ture scai'cely ever seen in beds of this age in Russia. Whether 

 examined at Moscow or on the Lower Volga, they consist of black 

 shales and ferruginous sands, occasionally containing calcareous 

 cement-stones, and thus they present a general lithological analogy 

 to the Lias ; a formation, however, which is not represented in Russia, 

 for the fossils are all referable to the groups extending from the 

 Inferior to the Upper Oolite, and many of them are identical with 

 British species. 



I must now pass over the Cretaceous deposits which occupy 

 such broad spaces in Southei-n Russia, the Lower Tertiary beds, 

 some of which, on the Volga, might almost be mistaken for those 

 of Bognor and the London basin, and also the strata of the 

 Miocene age, which occupy wide tracts in Volhynia and Podolia, 

 merely remarking by the vvay, how the recent discovery in limestone 

 of an herbivorous Cetacean (to which I shall elsewhere allude) is a 

 very important addition to the fauna of that period. 



Superjicial Detritus — Ural Mountains, Sfc. — The discovery of ac- 

 cumulations containing recent shells of Arctic species, considerably 

 to the south of Archangel, v/as important, as showing that the great 

 northern blocks, which overlie them there, were brought to their 

 present positions during a period which differed remarkably from the 

 one preceding it, and also from that which has followed it, in the 

 very general prevalence of a colder climate over large spaces ; thus 

 enabling us very safely to infei% that the great erratics of the North 

 were transported in icebergs, which floated in an arctic sea and 

 occasionally grated along its bottom. But this operation, gigantic 

 as it was, had its well-defined southern limits, as is beautifully 

 proved by the general survey of the Russian Empire ; in the southern 

 half of which all such erratics cease, and fine black slime (tchor- 

 nozem) takes their place. Wherever the recent accumulations of 

 the steppes indicate the desiccation of brackish seas, which like 

 the present Caspian were inhabited by Mollusca requiring a warmer 

 climate, then is there also a total absence of great boulders. On 

 this point I would further beg to remind you, that in our examina- 

 tion of the Ural Mountains, even up to 60° north latitude, my com- 

 panions and myself could trace no evidence whatever of boulders 

 having been transported from these mountains to great distances 

 upon their flanks ; although the peaks rise to heights of 5000 and 

 6000 feet above the sea, and the chain extends from north to south 

 through eighteen degrees of latitude. In every portion of the Ural 

 Mountains, and on both their Asiatic and European flanks, the 

 detritus is of a purely local character ; and in it are occasionally 



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