132 Mr. Murchison on the Geological Structure 



a felspathic granite), but also the serpentine ; thus seeming to prove 

 that the gold veins have resulted from one of the very last changes 

 which have affected this region. (Rose, vol. i. p. 422.) 



It is stated, that as the alluvia containing gold are purely of local 

 origin, or derived from the adjacent hills, theip accumulation can 

 have no reference to the actual period, and present rivulets or 

 waters, for the deposits lie at considerable heights above their beds, 

 contain bones of mammoths, the extinct rhinoceros, and, in some 

 instances, are even traceable over small ridges of intrusive and altered 

 rocks from veins whence the detritus was doubtless derived, and ac- 

 cumulated in its present state at the period when the large mammals 

 were destroyed. Numerous sections are given at Berosofsk, Soi- 

 manofski Zavod, and notably from the environs of Miask and Cos- 

 satchi Datchi, all of which tend to establish these views, as well as 

 those of the alteration, mineralization and crystallization of the 

 palaeozoic strata by the intrusion of igneous matter, and prove that 

 the alluvia were collected anterior to the existing epoch. Some 

 of the gold alluvia are exclusively composed of carboniferous lime- 

 stone replete with fossils (Cossatchi Datchi). 



In concluding this sketch of the Ural mountains, the authors ad- 

 vert to the remarkable fact, that all the superficial detritus is local, 

 and that no large boulders or blocks transported from afar are 

 visible either in the chain or in the low countries on its flanks; and 

 they also state, that they nowhere observed among the higher por- 

 tions of the mountains any traces of those scratches or polishings of 

 the rock which are common in some parts of Europe, and which 

 are supposed to have been produced by glacial action. 



Original maps and sections of the districts around the mining 

 establishments of Bogoslofsk, Turinsk and Blagod at Ekaterinburg, 

 Soimanofsk, Zlataoust and Miask, prepared by the officers of the 

 Imperial School of Mines, were exhibited, as well as a map of the 

 North Ural to 65° N. lat., drawn by Strajefski, together with a most 

 elaborate geographical map of the South Ural, executed by orders 

 of General Perovski, under the superintendence of the officers of 

 the staff of his government, directed by General Rakosofski*. From 

 all these documents and others published in the volumes of the 

 ' Journal of the School of Mines,' combined with their own ob- 

 servations, the authors have coloured geologically the map of Hum- 

 boldt, a reduction of the chief features of which will appear in a 

 map now in progress, which will accompany their forthcoming work 

 on Russia and the Ural mountains. 



General Conclusions. — In greatly extending the knowledge which 

 they had previously acquired, the survey of last year has enabled 

 the authors to modify their earlier views concerning the equivalents 

 of some of the strata of Russia in Europe. With respect to their 

 former account of the great tripartite palaeozoic series of beds 

 which covers such large portions of Northern Russia, they have 



* This map is illustrated by a description of the physical features of 

 South Ural from the pen of M. Khanikof, which Mr. Murchison has com- 

 piunicated to the Royal Geographical Society of London. 



