THE SCANDINAVIAN MOUNTAINS. 125 
the boulders moved towards the earth, or the earth in a direc- 
tion opposite to the masses of boulders. Such an indication 
might possibly be found. 
If, for instance, the observations on the furrows could be ex- 
tended all over the world, that is to say, if furrows are found in 
the southern in the same manner as in the northern hemisphere, 
it would no doubt enlighten us considerably in regard to the 
before-mentioned question. 
It is likewise credible, that if the boulder-masses moved 
against the earth by their own force, or still more by a vis & 
tergo, in such a case the rapidity of the boulder-masses must 
have been greater on the surface than in depth; while, on the 
contrary, the rapidity at the greatest depth must have been 
greatest, in case the earth had moved itself against the boulder- 
masses. Now, should any indication be found by which it 
could be determined whether the rapidity had been greater on 
the surface or the contrary, the answer might be given with 
some degree of certainty. A closer investigation of the moun- 
tains of West Giéthland might possibly throw some light on the 
subject. 
If the boulder-masses were moved by a vis & tergo, it would 
appear that it would be more difficult to detach large pieces 
of rock from the lee-side of the mountain, and that some differ- 
ence would present itself in the situation and character of the 
masses which lie to the leeward. 
The section also of any considerable masses of gravel and sand 
might afford some explanation ; for where the rapidity has been 
very great, the fine carth must have been washed away, and the 
gravel have remained. The effects in this respect are very re- 
markable below Avestad, where Dalelfven has cut its way 
through a bed of sand a hundred and fourteen feet thick, below 
which smooth rocks are found, which are furrowed at right 
angles to the river’s present direction. Had the boulder-flood 
been moyed by a vis a tergo, it would soon have filled the dale 
in which Dalelfven now flows, while crossing it, and the rocks 
around have been less furrowed. 
But the most important of these observations must be left to 
futurity. . 
