620 [AprU 30. 



Although in Norway, therefore, there is a consecutive succession 

 from lower Silurian through upper Silurian to the Old Red 

 Sandstone inclusive, the continents of Sweden and Russia (at 

 least that central portion of Sweden which I examined), are 

 void of any true upper Silurian strata ; the latter being confined, 

 as far as I now know, to the Isle of Gothland on the one side, and 

 the isles of Dago and Oesel on the other. These facts can, it ap- 

 pears to me, be best explained by supposing that these continental 

 areas were elevated above the waters after the completion of 

 the lower Silurian beds, which were thus placed beyond the in- 

 fluence of the depository action under which the rocks of the Baltic 

 Isles and of Norway were accumulated ; and also that after their 

 accumulation, the Swedish continent remaining stable, the Russian 

 masses were subjected to a broad, equable, and general depression 

 beneath the sea, whereby the Devonian strata were conformably 

 superposed to the Lower Silurian. 



At the same time it is difficult to conceive that such extensive 

 operations of upheaval and depression could have taken place with- 

 out occasioning some dislocations. In describing Sweden I have 

 already adverted to such, proving that, although the lower Silurian 

 rocks of that region are for the most part horizontal, stiU there are 

 tracts wherein they have been considerably deranged. And even 

 in the Baltic provinces of Russia, which lie at so low a level above 

 the sea, and in which no intrusive rocks are visible, there are 

 transverse dislocations, the importance of which must not be passed 

 over in coming to a right conclusion on this subject. I will there- 

 fore give a brief description of the nature of the junction of the 

 Silurian strata, along their northern or Finnish and Lappish 

 frontier, and after referring to the eruptions by which they have 

 been there affected, will show how such operations and their ac- 

 companying elevations have extended their influence by producing 

 transverse dislocations in the slightly consolidated lower Silurian 

 rocks of the Baltic governments of Russia. 



"When viewing the great features of the earth, the geologist who 

 compares the northern frontier of the palaeozoic deposits of Scan- 

 dinavia and Russia with that of British North America, recently 

 described before this Society by Captain Bayfield*, cannot avoid 

 being struck with the great similarity of succession in these two 

 vast regions. In both the general range of the rocks is from S. W. 

 to N.E., in both the same type of lower Silurian deposits occurs, 

 and rests upon more ancient crystalline rocks ; and in both are 

 these strata succeeded in similar ascending order by upper Silu- 

 rian, Devonian, and Carboniferous deposits. We may still further 

 pursue the analogy by stating that in both regions great sheets of 

 water range more or less along the older frontier line, and lastly, 

 that in both large quantities of erratic blocks have been transported 

 from N. to S., or from N.N.W. to S.S.E. 



* See ant^, p. 584. 



