.602 [April 30. 



red sandstone in Norway, as well as a very remarkable junction 

 between its Devonian equivalent and the lower Silurian rocks of 

 the government of St. Petersburg, I now lay the result before 

 the Society, communicating both those general views which wiU 

 appear in the forthcoming work on Russia, and also some details 

 respecting Norway and Sweden which do not appear therein. 

 The remarks which I now make on Scandinavia are, however, to 

 be simply considered as the first of a series of communications 

 which I hope to be able to continue by subsequent surveys of that 

 region, in which I have the promise of being joined by M. de 

 Verneuil. 



The present memoir is therefore to be regarded as an outline 

 sketch only of certain broad lines of demarcation to which it is 

 essential that geologists should attend when investigating similar 

 phenomena which have not yet been sufiiciently worked out. 



It will readily be understood when a few of the more prominent 

 facts of the case are laid before the reader, that in order to give a 

 history of the whole series of sedimentary deposits of Russia, we 

 must commence with a sketch of the adjacent Scandinavian regions, 

 which, chiefly occupied by highly crystalline rocks, are in many 

 places covered with patches of ancient strata containing organic 

 remains. 



The fossils, indeed, described by several writers, had shown that 

 true Silurian deposits existed in Sweden and Norway, and it was 

 therefore necessary for us to see and describe the absolute contact of 

 the lowest sedimentary strata with the crystalline rocks of that 

 region. We have come to the conclusion that the lowest of these 

 beds that are fossiliferous are the exact equivalents of the lower 

 Silurian strata of the British Isles, and that they have been formed 

 out of and rest upon slaty and other rocks which had undergone 

 crystallisation before their particles were ground up to compose 

 the earliest beds in which remains of organic life appear. We 

 apply to these crystalline masses, therefore, the term Azoic, simply 

 to express that, while as far as research has hitherto gone no ves- 

 tiges of living things have been found in them, so also from their . 

 nature they seem to have been formed under such accompanying 

 conditions of intense heat and fusion, that it is hopeless to attempt 

 to find in them traces of organisation. 



The great extent of the crystalline rocks in Scandinavia is one 

 of the features which first strikes the ordinary observer with sur- 

 prise. They occupy the great bulk of Sweden, and are at present 

 undergoing very careful examination and minute description by 

 several able mineralogists in Norway. They rise into mountains, 

 and form the flanks of troughs containing palteozoic strata, which 

 have in their turn been invaded by granitic, porphyritic, and 

 trappean rocks of another epoch. Although extremely bi'oken up 

 and diversified by various plutonic rocks, and very much dislo- 

 cated, the lower members of these ancient strata consist of quartz- 

 ose sandstone and hard slaty schists, the former visible in some 

 tracts only, as at Vigersund on the Drammen, the latter being the^ 

 well-known fucoid alum-shale of the country, and forming the 



