At the request of Cass mineralogists and geologists had been sent with him, and they made such discoveries as he had expected of copper and other minerals. So valuable were they that the attention of the whole United States was turned toward this rich region. Part of the company, led by Cass, returned by way of Chicago, a village of only ten or twelve houses outside the limits of a well-garrisoned fort, but with a location in what seemed to Cass “the most fertile and beautiful country that could be imagined.” Six years later Cass was back on Lake Superior making on the site of Duluth important treaties with the tribes of Wisconsin and Minnesota. In all these treaties with the Indians he insisted on three points. The chiefs should understand fully what they were doing; just remuneration should be made by the Americans; and the promises made should be faithfully observed on both sides. The flag that he carried into the lake region remained during his administration the symbol of justice and honor, and won the respect of all. CHAPTER XVI THE BLACK HAWK WAR The settlement of northern Illinois and Wisconsin by American colonists brought on in 1832 the last serious Indian outbreak in the lake region. The white men had been pushing the Indians farther and farther west. On the banks of the Mississippi the red men turned and made a desperate attempt to keep possession of the lands which held the homes and the graves of their ancestors. Between Rock River in Illinois and the Wisconsin River there lay on the eastern bank of the Mississippi a region which had been known to the white men ever since the visit of Nicholas Perrot in 1690 because of its extensive deposits of lead. Mines had been worked there by the Indians and Frenchmen for two centuries and had yielded a considerable output, which had been bought by French-Canadian traders and in later years by the British. The United States concluded in 1804 a treaty with the Sauk and Fox Indians, who occupied this country, by which they ceded to the Americans the territory east of the Mississippi River from the mouth of the Illinois at the south to the mouth of the Wisconsin at the north. It had been agreed that so long as the lands remained the public property of the United States the Indians might live and hunt there, but when they were bought by settlers the Indians must move. [Illustration: Map: “From Lake Michigan to the Mississippi”]