No further effort was made to explore the sources of the Mississippi, for several years. In 1820, Gov. Cass, then administering the government of Michigan Territory and exercising jurisdiction over Indian affairs, obtained the sanction of the general government to visit the region. He left Detroit, with a party of thirty-eight men, including the gentlemen composing his suit, during the latter part of May. He was supplied for a journey of four months. After traversing the coasts of Lake Huron, and visiting Michilimackinac, he proceeded north-westward, by ascending the primitive summit at the Falls of St. Mary, went through the extended and picturesque basin of Lake Superior, and first struck the waters of the Upper Mississippi at Sandy Lake. To this point he was accompanied by the military escort, and by the train of larger canoes employed to transport stores and baggage. But the fatigues which the men had undergone in crossing portages, added to the low state of the water, induced him to form a permanent encampment at this place. And he proceeded with a select party, in canoes to explore the Mississippi. It was the middle of July when the expedition reached Sandy Lake, and the difficulty of subsisting so large a party in so remote a position, with the constant claims of suffering and hungry tribes, who presented themselves at every point, began to be severely felt. The exploring party, which was now organized, went out, under a sense of these circumstances, and with a feeling of the responsibility pressing upon the claims of the expedition in other quarters, which limited the time applicable to the ascent. They entered the Mississippi on the 17th of the month, and found a strong current, with alluvial banks, and a vegetation indicative of a fertile soil. For the distance of about one hundred and fifty miles, above this point, the party found no diminution in the average strength of the current, which was frequently accelerated by rapids. The latter then assumed a more formidable aspect for ten or a dozen miles, at the end of which they were terminated by the falls of Peckágama. At this cataract, the river, which below has its course through alluvial banks, densely wooded, is compressed between rocks of granulated quartz, over which it rushes with a velocity, which would seem to threaten destruction to any species of craft that should attempt the descent. It became necessary, at this point, to transport the canoes and baggage from two to three hundred yards over land.