In North America all the indubitable signs of glacial action are found over the entire area of New England, the southern coast being bordered by a double line of terminal moraines. The outermost of these appears in Nantucket, Martha's Vineyard, No Man's Land, Block Island, and through the entire length of Long Island--from Montauk Point, through the centre of the island, to Brooklyn, N. Y., and thence across Staten Island to Perth Amboy in New Jersey. The interior line is nearly parallel with the outer, and, beginning at the east end of Cape Cod, runs in a westerly direction to Falmouth, and thence southwesterly through Wood's Holl, and the Elizabeth Islands--these being, indeed, but the unsubmerged portions of the moraine. On the mainland this interior line reappears near Point Judith, on the south shore of Rhode Island, and, running slightly south of west, serves to give character to the scenery at Watch Hill, and thence crops out in the Sound as Fisher and Plum Islands, and farther west forms the northern shore of Long Island to Port Jefferson. [Illustration: MAP SHOWING THE GLACIAL GEOLOGY OF THE UNITED STATES.] In these accumulations bordering the southern shore of New England, the characteristic marks of glacial action can readily be detected even by the casual observer, and prolonged examination will amply confirm the first impression. The material of which they are composed is, for the most part, foreign to the localities, and can be traced to outcrops of rock at the north. The boulders scattered over the surface of Long Island, for example, consist largely of granite, gneiss, hornblende, mica slate, and red sandstone, which are easily recognised as fragments from well-known quarries in Connecticut, Rhode Island, and Massachusetts; yet they have been transported bodily across Long Island Sound, and deposited in a heterogeneous mass through the entire length of the island. Not only do they lie upon the surface, but, in digging into the lines of hills which constitute the backbone of Long Island, these transported boulders are found often to make up a large part of the accumulation. Almost any of the railroad excavations in the city of Brooklyn present an interesting object-lesson respecting the composition of a terminal moraine.