400 Prof. Milne — Across Europe and Asia. 
deposition of the alluvium, which covers areas of vast extent upon 
the Siberian plains, and up to the present, they must have seen 
many cbanges and suffered much degradation, all of which has 
tended to reduce tbeir original height and bring them to their present 
form. There is only one other ränge of any importance which has 
had time to see and suffer more, and that is the line of hills in 
Scandinavia which date back to Silurian and Laurentian times. At 
times the Urals must have stood up like a ränge of islands, during 
which period Sediments were deposited like those we now see upon 
their flanks. From the beds of alluvium which I saw in and near 
Tagil, lying in thick patches high up upon their sides, they must at 
no very remote period have been almost totally, if not quite, sub- 
merged, the surrounding waters being probably fresh, and perhaps 
the same as those from which the Siberian drift was deposited. 
In Triassic times the waters were probably salt. 
But before saying anything more about these mountains, I will give 
a general geological sketch of their structure, as compiled from infor- 
mation I derived in Ekaterinburg and Tagil, which of course relates 
especially to their appearances in the vicinity of these two localities. 
If we made an ideal section across the middle portion of this ränge 
of mountains, we should see that their nucleus is granitic. This 
does not appear at all points to occupy the highest position as a 
saddle to the ränge, as for example near Nijni Tagil, where, from a 
cursory examination, a Silurian limestone seems to form the highest 
ground. Moreover, these central granitic rocks do not occur as a 
single boss, but rather appear to protrude at several points. Thus 
near Ekaterinburg, upon the eastem side of the mountains, there are 
three protrusions of granitic and porphyritic rocks. Eight and left 
of these rocks, and dipping away from them both east and west, a 
series of schiefer, gneiss, greenstone, Serpentine, limestone, and other 
crystalline rocks are seen, which, from their stratigraphical position 
and lithological characters, are regarded as being of Laurentian age. 
Above these, upon both sides of the ränge, come the Silurian rocks, 
which are in turn overlain by the Devonian and Carboniferous for- 
mations. Upon the western side of the Urals, above the last forma- 
tion, we get the Permian, and last of all the Trias, this latter resting 
horizontally upon all the older rocks, which dip away from the axis 
of the Urals, and have all suffered more or less contortion. On the 
eastern side of the Urals the Carboniferous formation is buried 
beneath horizontal Tertiaries. These latter consist of sandstones, 
whitish clay, and other rocks, in which fragments of lignite and 
small pieces of amber are sometimes found. 
If the Permian and Triassic strata are absent upon the eastern 
flanks of the Urals, we here get indications of vastly different physi- 
cal conditions having existed over portions of Europe and Asia at 
the close of the Palmozoic age. On the one side there may have 
been conditions purely terrestrial, and on the other a vast expanse 
of salt inland seas. 
From the horizontal position of the Trias, whilst all the older 
formations dip away right and left from the Ural axis, we may 
