ANNIVERSARY ADDRESS OF THE PRESIDENT. 157 



But Sir R. Murchison also observes, that the connexion between 

 the character of the fossils and the nature of the matrix in which 

 they are imbedded is more pointedly brought before the observer 

 who ranges over the boundless tracts of Russia, than in any other 

 country which he has examined. Notwithstanding the absence of 

 violent dislocations, the various Russian formations, though hori- 

 zontal, or so nearly so that they may be all considered conformable 

 to each other, are as distinctly separable by their included remains, 

 as in those typical and dislocated tracts where geologists first worked 

 out their order. And these observations hold good in the newer as 

 well as in the older deposits ; thus, in the regions of the Volga, green- 

 sand, ironsand, chalk, and chalk marl occur, in which the same 

 groups of fossils prevail as in the rocks of Britain and France, which 

 hold the same relative place in geological succession ; and pure white 

 chalk, containing some characteristic organic remains, extends from 

 the British Isles to the confines of Asia. 



That so vast a tract of country, unlike most other parts of Europe, 

 has been so little broken up locally by igneous eruptive rocks, may 

 perhaps with great probability be ascribed to this, that a safety-valve 

 was opened, an enormous crack or cleft was made on the east, by a 

 subsidence of the country on the west, through which the pent-up 

 elastic force and the molten matter escaped, and thus the high pres- 

 sure was taken off from under the broad expanse. The Ural Moun- 

 tains, bounding Russia in Europe on the east, are a comparatively 

 narrow ridge, made up of igneous rocks and sedimentary palaeozoic 

 deposits; and through fractures in the latter the igneous rocks were 

 erupted, after having produced in them those changes of structure 

 which we call metamorphic, that is, having caused them to change 

 their original characters, and assume a crystalline aspect ; the force 

 acting with such intensity as in many places to overturn the strata, 

 and so invert the order of superposition on the flanks. But it has 

 not been by one great fissure only that the igneous rocks have been 

 erupted ; " other parallel outbursts and upheavals have taken place 

 along the same line at subsequent epochs ;" and the authors show 

 grounds for belief that the present form of these mountains was the 

 result of more than one elevatory process, and that there was a period 

 when, as a low ridge, they formed the western shore of a great con- 

 tinent to the east, that now called Siberia, and even at so recent a 

 period as when that continent was inhabited by large quadrupeds 

 closely allied to existing species. The Urals extend from Nova 

 Zemlia to the Caspian, through nearly thirty degrees of latitude, in 

 a direction nearly north and south, but sending off branches to the 

 east and west at both extremities, one of which on the north-west, 

 the Timan range, was first explored geologically by Count Koyser- 

 ling in 1843 ; and in no part of this long line are they divided by 

 any great transverse valleys, nor does their general altitude exceed 

 from 2000 to 2500 feet. No parts of the authors' descriptions are of 

 higher geological interest than those in which they speak of the 

 Urals ; and to some of the more striking features of that chain of 

 mountains I shall afterwards more particularly refer. 



