te and other sedimentary
rocks, but at a prodigious depth under the solid ground, and by slow
crystallizing of molten substances. There must have been from two to
five miles of other rock lying upon the stuff that crystallized into
granite. A wrinkling in the skin of the earth exposed the granite, a
wrinkling so gradual that doubtless if generations of men had lived on
top of the wrinkle they would have sworn it did not move. But move it
did, and the superimposed rock must have been worn off at a rate of less
than a hundredth part of an inch every year in order to lose two or
three miles of it in twenty-five million years. As the granite was
wrinkled up by the movement of the earth's crust, certain cracks opened
and filled with lava, forming dikes. The geologist to-day can glance at
these dikes and tell the period of their formation as casually as a
jockey looking at a horse's mouth can tell his age. He could also tell
of the "faulting," or slipping down, of adjacent masses of solid rock,
which has occurred often enough to carve the characteristic Cohasset
coast.

The making of the rock bottom is a story which extends over millions of
years: the making of the soil extends over thousands. The gigantic
glacier which once formed all over the northern part of North America,
and which remained upon it most of the time until about seven thousand
years ago, ground up the rock like a huge mill and heaped its grist into
hills and plains and meadows. The marks of it are as easy to see as
finger prints in putty. There are scratches on the underlying rock in
every part of the town, pointing in the southerly direction in which the
glacier moved. The gravel and clay belts of the town have all been
stretched out in the same direction as the scratches, and many are the
boulders which were combed out of the moving glacier by the peaks of the
ledges, and are now poised, like the famous Tipping Rock, just where the
glacier left them when it melted. Few towns in America possess greater
geological interest or a wider variety of glacial phenomena than
Cohasset--all of which may be studied more fully with the aid of E.
Victor Bigelow's "Narrative History of the Town of Cohasset,
Massachusetts," and William O. Crosby's "Geology of the Boston Basin."

This, then, is briefly the first part of Cohasset's ledges. The second
part deals with human events, including many shipwrecks and disasters,
and more than one romantic episode. Perhaps this huma