of the Northern and Central Beg ions of Russia, 137 



scratches, M-hich came under their notice near Petrazowodsk, on the lake 

 Onega, no such markings having any where been observed in Central 

 Russia. They then examine the applicability of the glacial theory, as 

 proposed by M. Agassiz, to the tracts of Russia under revicvi^. Starting 

 from what they conceive to be an axiom, that the advance of every mo- 

 dern glacier depends upon the superior altitude of the ground behind it, 

 they shew, that if certain parallel strice, observed by M. Botlingk, and 

 others noted by themselves, are to be taken as proofs of the overland march 

 of glaciers, such bodies must often have been propelled /rom lower to higher 

 levels. For the proofs of this they refer to the eastern sides of the Both- 

 ninn Gulf, where M. Botlingk found the striae (*' diluvial schrammen") 

 directed in common with the boulders from N. W. to S.E. ; and yet any 

 glaciers which bore these blocks must have advanced from Scandinavia, 

 across the Baltic Sea, and then have ascended the rocky tract in question. 

 Again, near Petrazowodsk, in the isles of the lake Onega, the authors ob- 

 served such strisc exactly parallel to the major axis of the lake, N.N.W. 

 and S.S.E., even from a good many feet under the clear fresh water, and 

 thence rising to the height of twenty feet above the summer. level of the 

 lake on the sloping surfaces of the roek. They then argue, that in this 

 tract there are no hills of suiRcient altitude on the N.N.W. to account 

 for the determined forward direction to the S.S.E. ; and as a still further 

 reason for rejecting the application of the "'Alpine glacial theory" to this 

 country, they add, that as the striae in one region have all a given and 

 parallel direction, so must the supposed glacier not only have moved on 

 as^ it were without a cause, but also have maintained an incredibly enor- 

 mous advancing front of many hundred miles in length ! 



Without pretending to offer a complete solution of so difficult a pro- 

 blem, and after stating that many additional and even experimental re- 

 searches are required in relation to the power of water, drift, and ice, 

 tliey cannot avoid suggesting, as a probable explanation of the chief phe- 

 nomena in the North of Russia, that currents strongly determined in given 

 directions by the elevation of the northern continental masses, might dis- 

 lodge and set in movement icefloes and detritus, which, grating upon the 

 bottom of a sea, may have produced the parallel stricv. They are the more 

 confirmed in tliis hypothesis, by the fact, that the longer axes of the lakes 

 and stony ridges of the Northern Russia have generally the same direction ; 

 so that the supposed icebergs and land detritus would necessarily be borne 

 in that direction. By adopting this view, the existence of the post-pleio- 

 cene shells of the Vaga and the Dwina, and their relations to the overly- 

 ing drift from the north, are in harmony; and whilst admitting so much 

 of the glacial theory as to allow, that in former days glaciers probably 

 advanced farther to the south and occupied many insulated tracts, and 

 to a much greater extent than at the present day, the geologist, they con- 

 ceive, is alone called upon to define and limit the area of land in Scandi- 

 navia and Lapland, once covered with solid ice, in doing which he must 

 ^f oouree exclude from such agency the vast c&untrics bow covered t>y 



