374 GEOLOGICAL MEMOIRS. 



clay, the whole the produce of high northern latitudes, must have 

 formed a series of successive deposits on the bed of an ocean. The 

 fossils of the brown coal, the masses of cretaceous rock, the thick 

 argillaceous layers of the boulder clay, are all opposed to the pos- 

 sibility of such an idea, since they all appear on the other hand to 

 have been derived from the immediate neighbourhood, and in no 

 case to have been transported from a distance. The littoral cha- 

 racter of the boulder sand is also very clearly indicated by its 

 fossils, whereas icebergs are transported only in deep water, while 

 the stratification of the boulder sand and the relations of the rolled 

 blocks it contains with those of the boulder clay are not less op- 

 posed to the admissibility of this theory. 



The theory of Sefstrom agrees no better with the phenomena of 

 the boulder clay as observed in Denmark than jthat of Agassiz. 

 The mere length of time required is indeed a sufficient objection 

 to the notion of a single deluge, for it is not to be imagined that a 

 flood could last throughout the whole tertiary period. The neces- 

 sity of the former existence of an almost tropical climate in which 

 the cretaceous coral reefs might be formed, afterwards of a Medi- 

 terranean climate for the brown coal, and then finally the fact of 

 a deposit having gone on in a deep northern sea, in which the 

 Cyprina clay might be formed, and this deep sea gradually chang- 

 ing to shallow water over sand-banks in the same sea, are quite 

 incompatible with the conditions required for this diluvial theory. 



But. if an universal deluge cannot have been the cause of our 

 Danish Aosar, neither can it explain those of Sweden. I hope, 

 however, to be able to show that a partial flood has produced im- 

 portant results during the deposit of the newest part of the boulder 

 formation, but this flood was not immediately connected with 

 the cause of the scratches and furrows on the rocks of the Scandi- 

 navian mountains. 



The theory of Agassiz, according to which the diluvial scratches 

 were produced by the movement of great glaciers, finds but little 

 support when applied to the phenomena of the earth's surface in 

 Northern Europe, and almost all who have examined the appear- 

 ances in those countries seem rather to prefer the idea of transport 

 by the agency of water, even if they do not altogether agree with 

 the theory of Sefstrom. The phenomena of erratic blocks as they 

 are observed in Scandinavia have indeed been so often described, 

 and their analogies with those of Switzerland so frequently pointed 

 out, that I have little to add on this head. The level rocks, or 

 crags, called Heller, are ground down and partially polished on 

 their inclined side (in Sweden this is generally on the north side), 

 and on this side are seen occasionally broad well-marked furrows, 

 and yet more commonly fine parallel scratches. On the whole the 

 furrows and scratches are in the same direction, and the furrows 

 are besides very often striated. In point of dimensions the fur- 

 rows are about two feet long and from eight to ten inches deep, 

 the scratches being seldom more than a line or two in depth, but 

 the two sets of markings pass by insensible gradations one into 



