America, the Cape of Good Hope, and Van Diemen's Land. But we need not build up a theoretical case in order to form an approximate idea of the great ice-sheet stretching over the northern part of this continent during the glacial period. It would seem that man was intended to decipher the past history of his home, for some remnants or traces of all its great events are left as a key to the whole. Greenland and the Arctic regions hold all that remains of the glacial period in North America. Their shrunken ice-fields, formidable as they seem to us, are to the frozen masses of that secular winter but as the patches of snow and ice lingering on the north side of our hills after the spring has opened; let us expand them in imagination till they extend over half the continent, and we shall have a sufficiently vivid picture of this frozen world. And a temperature which would bring the climate of Greenland down to the fortieth degree of latitude would not only render the field of ice far more extensive, but thousands of feet thicker than it is at present. The physical configuration of Greenland also confirms the possibility of a glacial period in America, for there we have at this moment a wide expanse of land unbroken by mountains, over which a uniform sheet of ice moves southward, with occasional variations of its trend according to the undulations of the surface. The interesting accounts of Dr. Rink show that in reality Greenland is a miniature picture of the ice-period. The immense number of icebergs breaking off and floating southward every summer gives us some idea of the annual waste and renewal of the ice. How can we doubt, that, when, under the same latitude, Norway, Sweden, Scotland, England, and Ireland were covered by sheets of ice many thousand feet in height, the ice-fields of Greenland must have shared in the same climatic influences, and have been much thicker and far more extensive than they are at present?