From the uncleared wilds that still occupy the shores of Lake Superior, south-eastward through the great lakes and rivers to the valley of the St. Lawrence, those drift deposits reveal to the geologist marvellous changes that have transpired in this extensive area of the North American continent. Along the low shores stretching away from the rapids of Sault Ste. Marie to Lake Superior, huge granitic boulders lie strewed like the wreck of some Titanic Babel; raised beaches at various levels on the shores of Lakes Huron, Erie, and Ontario, show traces of other revolutions; and wherever the waves of the St. Lawrence reopen the deposits along the lower portion of the valley, the bottoms of an ancient ocean are revealed, frequently with littoral or deep-sea shells imbedded at different levels in the stratified drift. But remote as is the antiquity, according to all human chronology, to which the fauna of these beds of marine detritus belong, the palæontologist detects among their post-tertiary fossils the phoca, balænæ of more than one species, fishes, articulata, and the shells of many mollusca still inhabiting the neighbouring ocean along the northern Atlantic coasts. The period, therefore, which embraces those relics of ancient life is the same to which man belongs; and they mark for it one of the phases of that last transitional era during which the continent was being prepared for his entrance upon it. Since the natica, fusus, turritella, and other marine animals of the post-pleiocene period, were the living occupants of the St. Lawrence valley, vast changes have been wrought on the physical geography of the continent. The relative levels of the sea and land have altered, so as to elevate old sea-margins to the slopes of lofty hills, and leave many hundred miles inland escarpments wrought by the waves of that ancient sea. The conditions of climate have undergone no less important changes, developing in a corresponding degree the new character and conditions of life pertaining to this bed of an extinct ocean: covered with successive deposits of marine detritus, and then elevated into the region of sun and rain, to be clothed with the umbrageous forest, and to become the dwelling-place through another dimly-measured period of the wapiti, the beaver, and the bison; and with them, of the Iroquois, the Huron, and the Chippewa: all alike the fauna of conditions of life belonging to a transitional period of the New World preparatory to our own.