the valley of the Ohio from its source at the junction of the Alleghany and the Monongahela to its mouth was thickly settled. At the junction just mentioned a flourishing town called Columbus was established, and became the seat of an extensive iron-smelting industry. The old trading-posts on the Ohio and the Mississippi had become large towns. New trading posts had been established far westward up the Mizouri, and northward up the Mississippi.
Lead in abundance had been discovered in the region west of the Mississippi, not far from that river, and considerable mining settlements had been formed. Zinc ore was also found in the vicinity of the lead ore.
The Indians who came to trade at the posts on the upper Mississippi had knives, hatchets, and arrow-heads cast of copper, evidently of native manufacture. Some of the Indians revealed the existence of large deposits of pure metallic copper, which they said were situated near the shores of a vast lake or fresh-water sea far to the north. These Indians were induced by rich presents to conduct an exploring party to the mines. With the party were experts in minerals and a mathematician to de-
