MOUNDS OF DRIFT HAVE ACTED LIKE GLACIERS. 
553 
superjacent masses of drift have been removed from them. Such we have our- 
selves remarked on the surface of the low hills of carboniferous limestone on the 
right bank of the Rhine near Diisseldorf, where, when the superincumbent gravel 
is cleared away, the edges of the highly inclined beds are seen to have been trun- 
cated and smoothed down, as if they had been subjected to the passage of a heavy 
incumbent mass, the sand at the base of which had served as a polishing powder. 
These facts are, we repeat, nothing more than what have been detected under 
similar conditions of overlying drift throughout large, low portions of the British 
Isles ; and to bring back their application to our own immediate subject, all these 
detrital heaps are simply the equivalents of the “Osars” in Sweden, the great 
block clay and sand of Denmark, and the piles of stones, sand, clay and gravel 
which are spread out in such enormous masses over the low countries of Russia, 
Poland and Germany. A vast portion — by far the greater part — of this drift has 
therefore, we think, been transported by aqueous action, consequent on powerful 
waves of translation and currents occasioned by relative and often paroxysmal 
changes of the level of sea and land. Now that we are sustained by the reasoning 
of mathematicians, who show us, that with sudden vertical elevations, each not 
exceeding fifty feet in the case of an ocean of 300 or 400 feet in depth 1 (and might 
not corresponding depressions produce the same?), bodies of water have the power 
of hurling on enormous blocks, sand and gravel to vast distances and over con- 
siderable inequalities, we are relieved from one of the great difficulties opposed to 
the rational explanation of the position of a very large proportion of this drifted 
matter. Whatever may have been the period of their action, such aqueous deba- 
cles have probably formed many of the conglomerates of previous ages, and with 
the help of ice floes, much of that foreign drift, of which we have already treated. 
Seeing that there are no mountains whatever from which a glacier can ever have 
been propelled in southern Sweden, Finland, or north-eastern Russia, and yet that 
these regions are powerfully abraded, scored and polished, we have naturally come 
to the conclusion, that effects so extensively developed over such flat countries, 
must have resulted from the enormous masses of debris and rolled stones, which, 
always found in adjacent positions, have invariably taken the same direction as the 
1 For a mathematical application of the powers of the waves of translation, described by Mr. Scott 
Russell (Trans, of the Brit. Assoc, for the Advancement of Science for 1844), to geological dynamics, see 
the very able memoir of Mr. Hopkins “ On the elevation and denudation of the lake district of Cumber- 
land and Westmoreland” (Proc. Geol. Soc. Lond., vol. iii. p. 763). 
