﻿396 Trof. Milne — Acro88 Europe and Asia. 



The line of highest elevation, which has a general north and south 

 direction along the summit of the Urals, is about 1500 (?) feet above 

 the town. 



On either side of this line, and more or less at right angles to it, 

 the rocks dip away in a generally east and west direction. This 

 dip is, however, by no means distinctly marked in the neighbour- 

 hood of Tagil, as the rocks are often so fractured, metamorphosed, 

 and altogether altered, that they would require to be very carefully 

 examined before it would be possible to speak of them with any 

 certainty. The rocks along the highest line are for the most part 

 Silurian, as is indicated by the presence of Orthis and other fossils. 

 These rocks are made up of limestone, clay-slate, and sandstone. 

 Eunning parallel to this Silurian band, but nearer to Tagil, there is a 

 broad band of rock called diorite. The general character of this rock, 

 from what I saw, was that of a highly chloritic and much, altered 

 stone, which was generally very soft, sometimes talcose, and some- 

 times calcareous. In one place it is dark red, and ten feet away it 

 is dark green. Where its structure can be made out, it is seen to be 

 somewhat laminated. In places this appearance gave rise to the 

 suspicion that it might be only an altered Silurian slate. 



It is along this band of diorite that the greater number of gold 

 washings are situated. Here and there, cropping up through this 

 band, are patches of a fine green serpentine, and it is to the surface 

 of the country marked by the outcrop of this latter rock that most 

 of the platinum works are confined. 



Still farther to the east, and parallel to both the Silurian rocks 

 and the diorite, there is a band which is generally felspathic. In 

 the neighbourhood of Tagil, however, a patch of limestone seems to 

 have been intercalated. This, from the evidence of a single fossil 

 found at the time of my arrival, would appear to be of Silurian age, 

 and probably the remnant of a fold of the rocks of similar age, 

 which I have just described as forming the higher ground farther 

 to the west. It is in this limestone, and on the border ground 

 between it and the neighbouring dioritic and felsitic rocks, that 

 the copper-mines are situated. Continuing still farther to the east, 

 bands of diorite, serpentine, and limestone lie approximately 

 parallel to each other and to those which I have just described. 

 These repetitions of parallel bands of similar rocks suggest the idea 

 that they are probably sections produced by denudation of foldings 

 and crumplings of strata once horizontal. 



All these rocks are traversed by numerous faults running about 

 15° W. of N., a direction to which but very few are counter. These 

 faults, which are waved rather than straight lines along their out- 

 crop, sometimes intersect at an acute angle. They are filled with 

 a yellow ochreous clay, in which malachite occurs imbedded in 

 nodular and other forms. It is upon a deposit of this sort that the 

 great copper-mine of Nijni Tagil has been sunk. I believe Murchi- 

 son described this mine as being in two faults, which lay between 

 diorite and limestone, and which at the surface was marked by a 

 worn-out hollow filled with alluvium and boulders. 



