into the northwest? As the poet says:

". . . Will these trees,
That have outlived the eagle, page thy steps
And skip, when thou point'st out?"

{p. 27}

But if the point of elevation was whisked away from east to west, how
could an ice-sheet a mile thick instantaneously adapt itself to the
change? For all these markings took place in the interval between the
time when the external force, whatever it was, struck the rocks, and
the time when a sufficient body of "till" had been laid down to
shield the rocks and prevent further wear and tear. Neither is it
possible to suppose an ice-sheet, a mile in thickness, moving in two
diametrically opposite directions at the same time.

Again: the ice-sheet theory requires an elevation in the north and a
descent southwardly; and it is this descent southwardly which is
supposed to have given the momentum and movement by which the weight
of the superincumbent mass of ice tore up, plowed up, ground up, and
smashed up the face of the surface-rocks, and thus formed the Drift
and made the _striæ_.

But, unfortunately, when we come to apply this theory to the facts,
we find that it is the _north_ sides of the hills and mountains that
are striated, while the _south sides have gone scot-free!_ Surely, if
weight and motion made the Drift, then the groovings, caused by
weight and motion, must have been more distinct upon a declivity than
upon an ascent. The school-boy toils patiently and slowly up the hill