464 
ORIGINAL STRUCTURE OF THE URAL CONTINUED. 
words, as the moving agent was fluid plutonic matter, we may naturally imagine 
that it was connected with deeply-seated lateral sheets of similarly molten mate- 
rials, which flowing towards the central line to fill up the space previously occupied 
by the elevated axis, may have caused the cavities in question. In suggesting 
this hypothesis lor consideration, we shall further illustrate it in the Appendix. 
II some persons be disposed to think, that certain of the Uralian crystalline rocks, 
particularly those which appear on various parallels on the Asiatic side of the axis, 
may, like the azoic rocks of Sweden (Chap. I.), have been formed during a period 
anterior to that to which the term palaeozoic ought to be applied, we are at once at 
issue with them. The cases are, in truth, wholly dissimilar. In Scandinavia, as 
has been shown, there exist, at intervals, true Loiver Silurian rocks, containing a 
copious list of the organic remains belonging to the earliest ascertained sera of 
animal creation, which are there seen to repose Mnconformably upon crystalline 
stratified rocks of an entirely distinct character, and with completely discrepant 
lines of bearing — anterior, therefore, to the lowest known palaeozoic sediments. 
In the Ural, on the contrary, though Carboniferous, Devonian and Upper Silurian 
strata, either succeed each other regularly, as on the western side, or appear in 
oases on the eastern, where they have been torn into fragments by bands of erup- 
tive matter, it is at one or two spots only, that any traces of Lower Silurian beds 
can be detected. That such have existed, however, is proved by these very ex- 
ceptions, and we, therefore, believe that along the central crest, where igneous out- 
bursts have been most intense, and where, therefore, the lowest sediments have been 
most upheaved, inverted and altered, limestones, sandstones and schists, which at 
one period may have resembled those of the Lower Silurian of Sweden and of 
the government of St. Petersburgh, have been converted into crystalline limestone, 
chloritic and micaceous schists and quartz rocks. We draw this inference, not 
only because the quartz rock and the chlorite schist are seen to graduate into and 
inclose subordinate calcareous masses, which still present traces of organic remains, 
but also because throughout the chain, the whole series of rocks, from the most 
unaltered carboniferous deposits on the western flank, to the most highly altered 
Silurians, as well as the crystalline metamorphic rocks of the axis, are all parallel 
to each other, — all so graduate into each other, and are, in short, so interlinked, 
that we can nowhere, as in Sweden, obtain a definite base-line which exhibits the 
lowest stages of animal life as completely separated from an anterior state of things. 
On the contrary, in the Ural Mountains, when we try to reach Lower Silurian ves- 
