of the Ural Mountains. 131 



and magnetic iron, the latter in so hard and crystalline a state that 

 it is not worthy of extraction and manufacture. The most pro- 

 ductive masses of magnetic iron are at the Government establish- 

 ment of Mount Blagodat, and that of Nijny Tagilsk, belonging to 

 M. Anatole Demidoft'. In both these cases the ordinary varieties of 

 iron occur in great masses, occasionally with chromate of iron*, in 

 contact with rocks of igneous origin, in which serpentine, compact 

 felspar, greenstone, porphyry, &c. are apparent. At Nijny Tagilsk 

 the chief intrusive rock (greenstone) is coated by prodigious masses 

 of the iron ore, which is worked in open quarries, and is most mag- 

 netic where it is in contact with greenstone. Copper ores also 

 abound at this spot, and some of them are associated with Silurian 

 limestone, often highly mineralized, but in which large Pentameri 

 and other fossils are observed ; also with a bedded trappean rock or 

 schaalstein, which is in parts highly cupriferous. It is from such 

 ancient rocks that copper solutions are supposed to have flowed, in 

 very remote periods, into the adjacent low countries on the west, 

 then under the sea, and to have impregnated the sandstones and 

 grits of Perm during their formation. The malachites of this place 

 have long been celebrated, and, from their structure as well as their 

 position, in cavities of the rock, they are supposed to have been 

 formed by ancient stalactitic depositions. The ores of platinum, 

 though hitherto found in alluvia only, always occur near the pro- 

 trusive igneous rocks. Magnetic iron ore and copper ore are stated 

 to occur at many other localities, and always under similar circum- 

 stances. 



Gold Ores. — Though the great supply of gold which the Ural 

 mountains afford, is derived from alluvia, the ore has been found in 

 veins which are slightly worked at Berosofsk, near Ekaterinburg, 

 and were formerly near Miask f. Wherever gold veins or gold 

 alluvia have been discovered, the auriferous matter is flanked by 

 rocks of intrusive origin, and these are very frequently serpentine. 

 It has however been shown by Humboldt and Rose, who, in the first 

 volume of their recent work, have described twenty-seven sites 

 of gold alluvia in these mountains, that the auriferous detritus 

 rests upon a great variety of rocks, viz. talcose, chloritic, siliceous, 

 argillaceous schists and encrinite limestone, as well as upon 

 granite, greenstone and serpentine, though most frequently on the 

 last-mentioned rock. An observation also of these authors is im- 

 portant, as bearing upon the relative date of the origin of gold, 

 viz. that the veins containing it have been seen by them to cut 

 through not only the schists and the beresite (according to them 



* The largest masses of chromate of iron occur in the South Ural, near 

 the mines of Polikofski, south of Miask, and from whence from 6000 to 7000 

 " pouds " per annum have recently been sent to Moscow. 



f In the tracts around Miask and Zlataoust the authors were most 

 cordially and judiciously assisted by General Anosof, an officer highly 

 distinguished for the metallurgic processes and the manufacture of small- 

 arms which he directs. His assistant, Major Lissenko, who has prepared 

 a mineralogical map of the surrounding country, was also kindly serviceable 

 to them. 



K2 



