of the Northern and Central liegiom of Ruma, 135 



&c. Among the fossils from Moscow are Ammonites of many species, 

 some of which arc figured by Fischer, others are described by Professor 

 Phillips, for this memoir. Belemnites absolutus {B. sulcatuSj Miller) ; 

 Serpula tetragona, Sow ; Amphidesma ? donaciforme, Phill. ; Lima pro- 

 boscidea ? Sow. ; Pecten Fisherii, N. S., Inoceramus duhius, Sow. ; (P. 

 riigosus, Fischer) Terchratula serrata, Sow. ; T. acuta, Phill. These forms 

 characterize the lower oolite and lias of the British Isles. 



Ferruginous Sand. — The shales of the oolitic series are covered by 

 ferruginous sands, occasionally green, which contain large flattened con- 

 cretions of grit (the Moscow millstones) ; but never having observed 

 fossils in this rock, the authors are unwilling as yet to hazard an opinion 

 regarding its age. With the exception of certain very recent deposits, 

 these grits are the youngest solid strata in the northern half of Russia in 

 Europe. 



Chalk. — The cretaceous system is largely developed in the south, near 

 Simbirsk, and in the Crimea : but on this occasion the authors did not 

 extend their tour to the chalk districts. 



Tertiary Deposits. — The white shelly limestone of Crimea, and its re- 

 lations to the underlying chalk, have already been described by one of the 

 authors.""' Such deposits have not yet been discovered in any of the 

 northern or central regions of Russia. 



Post Pleiocene {Pleistocene). — It was formerly the general belief that 

 the great masses of superficial detritus, whether clays, sands, or blocks, 

 which cover so very large an area of the northern region, were all refer- 

 able to one epoch (diluvian), in which the bones of great extinct quadru- 

 peds were also imbedded. The duration of their journey was not suffi- 

 cient to enable the authors to make many distinctions of age between 

 these different masses ; but they have commenced this division by the 

 discovery of beds of clay and sand on the banks of the Dwina and Vaga, 

 upwards of 200 miles south of the White Sea, which contain twenty-two 

 species of shells, many of which still preserve their colours, and which, 

 having been referred to Dr Beck of Copenhagen, have been pronounced 

 by him to be all of modern northern species. Mr Lyell states that they 

 are identical with the Uddevalla group described by him in Sweden. 

 Mr Smith adds, that these shells are nearly all the same as those which he 

 has found in various ancient elevated sea-bottoms around the coast of Scot- 

 land. In referring twenty of these to modern arctic species, Mr G. Sowerby 

 doubts if a certain Mya has ever been found recent, and states that a 

 Cardium, approaching to C. ciliatum, is different from any northern form 

 he is acquainted with, and near to certain Australian types. This disco- 

 very, in which they were assisted hy Count Keyserling, who accompanied 

 the authors in their tour to Archangel, is conceived to be of high geologi- 

 cal interest, as it demonstrates that during the quasi modem period, the 

 whole of the vast flat country of north-eastern Russia was beneath th« 



* M. E, de Vemouil. 



