It is intended in this paper to call attention to certain sides of glacial geology which have a bearing on the broader problems of geology in general, and which should receive consideration from workers in other departments of geology and in the related sciences which deal with the early history of the earth, such as physics and astronomy. Glacial geology will be construed in its widest sense, not as confined to Pleistocene phenomena, but as including glacial activity in all ages where ice has left widespread proofs of its work.
It will be necessary to give a summary of the evidence showing the extent of glaciation at various times in the earth’s history; and the question of interglacial periods will be taken up briefly also. Afterward general conclusions will be drawn from the evidence, and these will be used as tests of various theories.
Evidence of ice action on . . .