332 JAMES GEIKIE 



no single erratic can be taken as a guide to the direction in which 

 an ice-sheet has flowed. But if by this he means that we cannot 

 decide upon the direction of ice flow from a consideration of the 

 general assemblage or facies of the stones in any given bowlder 

 clay, I cannot possibly agree with him. I am well aware of the 

 fact that every now and again erratics occur in bowlder clay, 

 whose presence would seem to indicate a different direction of 

 ice flow from that suggested by the others in their neighbor- 

 hood. In regions which have been overflowed by ice at differ- 

 ent times and in different directions, such occurrences must 

 be expected. But in the case of the bowlder clays of the 

 Cimbric peninsula it is not merely a few sporadic stones of 

 eastern derivation that we have to deal with. The whole mass 

 of the materials of the two bowlder clays which appear at the 

 surface has traveled from east and northeast, So, again, the 

 bulk of the stones in the Dutch bowlder clay have come from 

 the north. 



(2) Following De Geer, I maintain that the strong belt 

 of terminal moraines which extends from Hango Head in a 

 northeasterly direction through Finland, are contemporaneous 

 with those of the Baltic Ridge. Referring to the observations 

 of the accomplished geologists of the Geological Commission 

 of Finland, I cite the fact that two distinct systems of glacial 

 striae are apparent in that country. "The striae of the one sys- 

 tem run in parallel directions, and extend far east and southeast 

 of the terminal moraines. The other and younger system, on 

 the other hand, is bounded by these moraines — the later striae 

 crossing the older series at various angles. When striae belong- 

 ing to both systems appear on one and the same rock-surface, 

 the younger are always the fresher of the two, the older ones 

 being worn and abraded. The latter, according to Rosberg, 

 are the products of a general mer de glace, which attained so 

 great a thickness that minor inequalities of the ground had little 

 or no influence in deflecting the ice flow, which extended far 

 beyond the limits of the terminal moraines. The ice, under- 

 neath which the younger system of striae came into existence. 



