398 Rogers's Account of two Remarkable | 
ridge stood exactly in the place to receive the brunt of 
the impinging ice ; whose vast momentum would be derived, 
not merely from the force of the general current, but from the 
still more tremendous impulse of the great waves of trans- 
lation, generated in the rocking crust, and launched, in suc- 
cessive surges, ahead of the current itself, full against the 
opposing barrier. 
For the production of either of the boulder trains, we have 
only to conceive, then, that a large island or berg of ice, 
driven forward at the extremely rapid rate we have endeavored 
to picture, suddenly struck the top of the ridge a little below the 
actual crest. A broad, shallow, and ragged notch, or depres- 
sion in the summit of the mountain, would be the inevitable 
consequence of the tremendous collision. That part of the 
solid strata which received the blow would be broken into 
huge angular fragments; but no sooner would the blocks 
thus dislodged be sent forward into the current, than they 
would be gathered in and prevented from dispersing by the 
immense vortex or whirlpool which would naturally form e, 
the waters moved in their rapid course past the prodi- 
gious stationary block of ice thus made to impede their 
progress. ‘The whirlpool would form just over the top of the 
mountain. It would possess an excessive gyratory force com- 
mensurate with the check received by the swiftly-moving cut- 
rent; and, in virtue of this, it would exert in a high degree 
that lifting or upward-floating power, which we have seen to 
belong so conspicuously to every vortex. Winding the broken 
blocks within its narrow, whirling column, and advanbing ™ 
the direction and with the progressive speed of the general 
current in which it was rapidly spinning, it would float pen- 
dant from the surface of the water, indifferent, in a great 
measure, to the inequalities of the land beneath. Be 
forming to the onward course of the inundation, it W 
only deviate with the changes in the path of the general cur 
rent itself; and, hanging from the surface to the bottom, it 
would rise and fall with every great undulation on the bosom 
of the flood. Wherever the apex of this slender, water 
ould 
