pressed
upon them extend toward every point of the compass. They stream north
and south from the summits of the Pyrenees, from the peaks of the
Caucasus, and down the valleys of the Himalayas. It must be
remembered, however, that these conclusions are based upon an average
of the bearings of the groove in each instance, and that these are
infinitely varied by the construction and irregularity of the land.
Thus,
over great portions of the world, we find the rocks furrowed, polished,
and striated, in long, frequently deep and rectilinear grooves, which
lie in groups and series identical in direction and pointing to
associated highlands or distant continental mountain ranges as the
source of whatever strange and inexorable instrumentalities have
produced them.
In
the White Mountains, the sides of the mountains, the valleys, the top
of Mount Washington at 5,000 feet above the sea, are all cut with these
strange furrows, the rocks polished, and the whole country bearing
these evidences of past erosion wherever the naked rock meets the eye.
Over Maine the same phenomena present themselves in endless succession,
the grooves crossing the country and losing themselves in the sea along
the coast, while they corrugate the borders of innumerable bays and
the walls of the deep fords that indent the shores.
These
furrows can be traced for miles across the country, cutting the three
ranges that lie between Bangor and the sea almost at right angles,
traversing these highlands as though they were level surfaces, dipping
beneath the sea and reappearing upon the sides of Mount Desert, to be
again lost in the waters of the Atlantic. Unquestionably, over that sea
floor, could we follow their course, the same furrows continue to the
verge of the continent which lies miles out to sea, where the steep
edge of the land falls precipitately to the true bottom of the ocean.
Over the west, throughout Canada and upon the ancient rocks of the
Great Lakes, these evidences of past erosion exist upon an enormous
scale. As a rule, these striae indicate a planing surface advancing
from the
