466 ORIGINAL STRUCTURE AND ALTERATIONS OF THE URAL. 
age as those of Christiania in Norway, which have there also burst through pa- 
laeozoic deposits. 
Reverting to the probable original structure of this chain ; let not geologists be 
appalled, when we call upon them to regard the chief crystalline axis of the Ural, as 
an equivalent (for the most part) of the Silurian strata. We can assure them, that 
so tar from being a mass of too great dimensions fairly to represent such deposits, 
all the lower Uralian rocks united, are but feeble in thickness, when compared with 
the grand Silurian series of Britain ; which, as is now well understood, occupies 
the whole principality of Wales and several of the adjacent English counties. 
Instead of being compelled to call for the presence of the many thousand feet of 
Silurian sediment which there exist, in oi’der to construct the narrow central ridge 
of the Ural, the latter mountains expose at intervals, within themselves alone, abun- 
dant sedimentary materials out of which all their crystalline schists and quartz 
rocks may have been formed. In a word, by comparing different portions of this 
chain, and hy following its masses upon their strike, w T e are assured, that the same 
zone which in one tract has a mechanical aspect and is fossiliferous, graduates, in 
another parallel of latitude, into a metamorphosed crystalline condition, whereby 
not only the organic remains, but even the original impress of sedimentary origin 
are to a great degree obliterated. In this respect, therefore, the Ural may be com- 
pared with many other regions, and notably with the Cumbrian or lake region of 
the British Isles, where, as before said , the equivalent of the great mass of the 
Lower Silurian rocks is composed of crystalline slaty masses, alternating with much 
igneous matter ; all those records of the most ancient beings in the paleeozoic 
succession, which are so clearly exhibited in Wales and Siluria, being no longer 
traceable. 
We may now conclude this long chapter with a few words upon the direction of 
the chief Uralian rocks. The geologist who inspects our Map, or who has fol- 
lowed our descriptions, can scarcely have failed to perceive, that although these 
mountains have, upon the whole, what must be called a meridian direction, dif- 
ferent portions of them are subject to considerable aberrations from that line. 
Thus from the Arctic Ural, in latitude 64° to latitude 55J°, the dominant ridge 
ranges from north and by west to south and by east ; occasionally the strata on 
either flank of the axis having a strike of 25°, 30°, and even 35° west of north. In 
1 See Introductory matter. Chapter I. 
