When it is considered that, along with the mica of the Alleghanies, the shells of the Gulf of Mexico, and obsidian from the ancient centre of American civilisation, the copper of Lake Superior is one of the most abundant materials found in the Mississippi mounds: we are tempted to trace some intimate relation between the warlike occupants of the Ohio and Scioto valleys and the singular race who dwelt in peaceful industry on the well-watered and plentifully stocked plains to the south of the copper region, and there constructed their strange colossal memorials of imitative art. The country seems peculiarly adapted by nature as a central neutral land for the continent to the east of the Rocky Mountains. On the east it is guarded by Lake Michigan, and on the north by the great inland sea which constitutes the fountain of the whole lake and river chain that sweeps away on its course of twenty-five hundred miles, over Niagara, and through the islands and rapids of the St. Lawrence, to the Atlantic. On the west, with its infant streamlets originating almost from the same source, the Mississippi rolls onward in its majestic course, receiving as its tributaries the great rivers which rise alike on the western slope of the Alleghanies and the eastern declivities of the Rocky Mountains, and loses itself at length in the Gulf of Mexico. This wonderful river system, and the great level contour of the regions which it drains, exercised a remarkable influence on the extinct civilisation of America, as well as on later Indian nomad life, making its primitive eras so different from any phase of Europe’s history. The Indians who traded with Cartier at Tadousac, on the lower St. Lawrence, and those whom Raleigh met with on the coast of Carolina, obtained their copper from the same northern region towards which the head-waters of the Mississippi and the St. Lawrence converge; while the world of Europe between the Rhine and the Baltic remained, even in its late Roman era, almost as much apart from that on its Mediterranean shores as the America of centuries before Columbus. It seems, therefore, not inconceivable that the prairie land of Wisconsin derives some of its archæological characteristics from its relation to the physical geography of the region between the Rocky Mountains and the Atlantic, possibly as a sacred neutral ground attached to the metallurgic region of Lake Superior, like the famous pipe-stone quarry of the Couteau des Prairies.