204 8ir S. H. Soivorth — Surface Geology of N. Europe. 



it that it did not scour and move away all the sand and brickearth, 

 and carry them down to its lower reaches, instead of laying them 

 down along their whole course ? All torrential rivers known to 

 me have clean-washed, stony, and gravelly beds, with deltas or 

 reaches lower down, formed of the lighter materials of denudation. 



But in bespeaking torrential rivers of this kind in Sweden we 

 are postulating a virtual impossibility. The level of Sweden is too 

 low and too flat to afibrd such rivers. To get rapid rivers we must 

 have steep slopes in their beds. Of course we have a rapid flow- 

 enough at places like Trollhattan, on the Gota river, and in other 

 gorges where we have rapids like we have in the gorges of the 

 Ehine ; but there is no deposit like an asar deposit in these gorges 

 now. We cannot conceive any deposit of any kind long remaining 

 in such places, nor does it seem possible that these gorges existed 

 when the asar were made. Elsewhere than at these gorges the 

 rivers of Sweden are quiet and slow-moving, and deposit, not great 

 masses of huge boulders, but sand and silt and mud. They must 

 have been slower and less efiicient as dynamical instruments when 

 the level of the country was much lower, as apparently was the case 

 in Sweden in so-called Glacial times. Again, the rivers of Sweden 

 naturally flow from west to east, or N.W. to S.E., in channels in 

 which they drain the upper plateau by running downhill to the sea, 

 while, as we have said, the asar run from north to south, right 

 across the present river-channels and right across the lines of 

 drainage of the country. 



Again, rivers make deltas. When they have run their course, 

 and get on to fairly level ground, they deposit fan-like stretches of 

 mud and clay. There are no similar phenomena in the case of the 

 asar, which do not terminate as deltas at all, the flat spreads of 

 gravel sometimes occurring in connection with them being torrential, 

 and not like river deltas. 



Kivers naturally have wider and wider channels as we move 

 away from their sources to their mouths, and as their supply of 

 water increases from their several feeders, and consequently as their 

 loads of debris increase. This mleans that their beds become 

 wider and deeper as we proceed downwards along their course. 

 They are thus quite different to the more or less uniform ramparts 

 called asar, which chiefly differ in bulk in the fact that they are 

 bigger at their initial stage than later on. 



It seems absolutely impossible to correlate the asar of Dalecarlia 

 and those of Finland, some of which actually cross one another, 

 and others are united by cross pieces, with any river-beds, whether 

 subaerial or subglacial. Again, rivers of any size generally contain 

 fresh-water shells or other debris. The asar, on the contrary, when 

 they contain shells at all, contain marine shells only. Rivers do 

 not deposit marine shells. 



Lastly, we must not forget that although we are considering the 

 asar as substantive phenomena apart altogether from other deposits, 

 it is only for convenience of treatment. We cannot, in fact, separate 

 the asar and their contents from the sporadic and other deposits of 



