IGNEOUS ORIGIN OF MAGNETIC IRON IN THE KATCHKANAR. 
though apparently thrown about in confusion, when viewed from below, are found 
to be regularly bedded and traversed by two sets of joints, the one striking from 
north-west to south-east, the other from north-east to south-west. Courses of 
hard and pure magnetic iron ore, from one to a few inches thick, line the first- 
mentioned joints. This mineral is also so diffused through the body of the rock, 
that wherever we placed ourselves, the needles of our compasses vibrated in all di- 
rections, and we were only enabled to decide upon the true direction of the joints 
by the place of the sun, and the relative position of distant points of the chain. 
Whilst gold alluvia have been derived from veins in the adjacent rocks both on 
the west and on the east, detritus containing platinum occurs at various points 
near the central ridge. Similar alluvia have been described by Humboldt and his 
associates at Vissimo-Shaitansk, near the crest of the Ural, in the parallel of Nijny 
Tagilsk, where the platinum is associated with greenstone and hornblende rock 
containing chromate of iron. From this association it has been inferred, that these 
liornblendic igneous rocks with magnetic iron, are probably the sources from whence 
the platinum has been derived. On this point we now merely note, by the way, 
that the igneous rocks of Katchkanar seem to have played the same part as those of 
Vissimo-Shaitansk, and to have produced like results. Considerable accumulations 
of platinum have indeed been found all around the base of this mountain, particu- 
larly in the adjacent river valleys. 
If we had known nothing of observations in other parts of these mountains, to some 
of which we have already alluded', the examination of the Katchkanar alone would 
have led us to adopt the opinion, that magnetic iron ore is of igneous origin. But 
now that M. Rose and M. Le Play have observed crystals of this mineral in ig- 
neously formed rocks, and also in the metamorphic strata in contact with them, 
and that the latter author and Colonel Helmersen have shown that masses mainly 
composed of it have traversed other rocks in the form of dykes, the inference 
becomes irresistible. Partaking of the character of the igneous rock of which it 
forms a part, the magnetic iron ore of the Katchkanar is so hard and crystalline as 
to be very intractable, not only to the quarryman, but also to the smelter. This 
circumstance, coupled with the great distance to which it was necessary to trans- 
port the material, either to the east or to the west, has led to the abandonment of 
works formerly commenced. Unless that trial had been made, even our solitary 
■ See Rose, vol. i. pp. 125, 172 et sey . ; and Le Play, Comptes Rendus, October 21, 1844-, 
