366 CLIMATIC CONDITIONS OF THE GLACIAL EPOCH. 



extending over that region, for the reason that the country is not suited to 

 the development of ghaciers, and because, also, there are no detrital accumu- 

 lations in that region which can be likened to moraines. He shows how, in 

 many places along the shores of the Gulf, striated siu'faces are formed at the 

 present day by stranded ice. Hence he concludes that the liA-pothesis of a 

 continuous ice sheet over the Baltic provinces need not be adopted, since 

 the facts can all be accounted for without the necessity of invoking the aid 

 of phenomena for which we find no parallel in what is now taking place.* 



Fr. Schmidt, who has also occupied himself extensively with the glacial phe- 

 nomena of the Baltic provinces, is also inclined to consider that there is great 

 probability that much of the striation and transportation of the boulders in 

 that region w\as done by icebergs. The reasons he gives for this are, the 

 great inequality in the character of the striae, and their variation in direction 

 according to local topographical conditions. He also remarks that he has had 

 abundant opportunity to observe the striating and polishing effected at the 

 present time by floating ice masses on the rocks in the lower part of the 

 valley of the Yenisei.! 



Helmersen, on the other hand, to whose elaborate work on the boulders 

 and detrital deposits of Russia reference has already been made,t concludes 

 that " at the close of the Tertiary epoch Finland and Northwestern Russia, 

 contemporaneously with Scandinavia, were covered with an immense ice 

 sheet [machtige Eisdecke], which, like the present glaciers, had an outward 

 motion, that is, from a central region towards its ljorders."§ It is not easy 

 to make out, however, whether Helmersen considers this ice sheet to have 

 been continuous with that originating in Scandinavia., or an independent one 

 movintr from the mountains of Finland as a centre. If the direction of the 

 striation is correctly represented on the map published by the Swedish Sur- 

 vey, there can be little doubt that, if there was a continuous glacial mass 



* Geologie von Liv- iind Kurlnml, mit Inbegriff eiuiger angrenzeiiden Gebiete, Aus rlem Avohiv fiir die Natur- 

 kunde Liv-, Est, uiid Kiirlands, Erster Serie, Band II. (pag. 479-774) besonders abgedrackt, Dorpat, 1861, 

 p. 103. 



t See Bulletin de I'Academie Iniperiale de St. Petersbourg, Tome VIII. 1865, pp. 339-368, also a later article 

 on the Glacial and Postglacial formations of Esthonia and Sweden, quoted in full in Helmersen's Studien iiber die 

 Wanderblbcke, 1869, pp. 5.5-59. The author in this later article inclines more strongly than in the first one to 

 adopt the theory of transportation and striation by icebergs, in preference to that of a general ice sheet comiug from 

 the Scandinavi,an Range. He also calls attention to the fact that in a part of Sweden (Gothland) the very well 

 marked striai run parallel with the coast, and do not radiate from the axis of the range. 



t See ante, p. 351. 

 § 1. c, p. 124. 



