In 1817 he was attracted to go to the Valley of the Mississippi. A new
world appeared to be opening for American enterprise there. Its extent
and resources seemed to point it out as the future residence of
millions; and he determined to share in the exploration of its
geography, geology, mineralogy and general ethnology, for in this latter
respect also it offered, by its curious mounds and antiquities and
existing Indian tribes, a field of peculiar and undeveloped interest.

He approached this field of observation by descending the Alleghany
River from Western New York to the Ohio. He made Pittsburgh, Cincinnati,
and Louisville centres of observation. At the latter place he published
in the papers an account of the discovery of a body of the black oxide
of manganese, on the banks of the Great Sandy River of Kentucky, and
watched the return papers from the old Atlantic States, to see whether
notices of this kind would be copied and approved. Finding this test
favorable, he felt encouraged in his mineralogical researches. Having
descended the Ohio to its mouth one thousand miles, by its involutions
below Pittsburgh, and entered the _Mississippi_, he urged his way up
the strong and turbid channel of the latter, in barges, by slow stages
of five or six miles a day, to St. Louis. This slowness of travel gave
him an opportunity of exploring on foot the whole of the Missouri shore,
so noted, from early Spanish and French days, for its mines. After
visiting the mounds of Illinois, he recrossed the Mississippi into the
mineral district of Missouri. Making Potosi the centre of his survey and
the deposit of his collections, he executed a thorough examination of
that district, where he found some seventy mines scattered over a large
surface of the public domain, which yielded, at the utmost, by a very
desultory process, about three millions of pounds of lead annually.
Having explored this region very minutely, he wished to ascertain its
geological connection with the Ozark and other highland ranges, which