s views and scientific enterprise,
offered him the situation of geologist and mineralogist to an exploring
expedition, which the war department was about dispatching from Detroit
to the sources of the Mississippi under the orders of Gen. Cass.

This he immediately accepted, and, after spending a few weeks at the
capital, returned in Feb., 1820, to New York, to await the opening of
the interior navigation. As soon as the lakes opened he proceeded to
Detroit, and in the course of two or three weeks embarked on this
celebrated tour of exploration. The great lake basins were visited and
explored, the reported copper mines on Lake Superior examined, and the
Upper Mississippi entered at Sandy Lake, and, after tracing it in its
remote mazes to the highest practical point, he descended its channel by
St. Anthony's Falls to Prairie du Chien and the Du Buque lead mines. The
original outward track north-westward was then regained, through the
valleys of the Wisconsin and Fox Rivers, and the extended shores of Lake
Michigan and Huron elaborately traced. In this he was accompanied by the
late Professor David B. Douglass, who collected the materials for a
correct map of the great lakes and the sources of the Mississippi.

It was late in the autumn when Mr. Schoolcraft returned to his residence
at New York, when he was solicited to publish his "narrative journal."
This he completed early in the spring of 1821. This work, which evinces
accurate and original powers of observation, established his reputation
as a scientific and judicious traveler. Copies of it found their way to
England, where it was praised by Sir Humphrey Davy and the veteran
geographer, Major Rennel. His report to the Secretary of War on the
copper mines of Lake Superior, was published in advance by the American
Journal of Science, and by order of the Senate of the United States, and
gives the earliest scientific account of the mineral affluence of the
basin of that lake. His geological report to the same department made
subsequently, traces the formations of that part of the continent, which
gives origin to the Mississippi River, and denotes the latitudes where
it is crossed by the primitive and volcanic rocks. The ardor and
enthusiasm which he evinced in the cause of science, and his personal
enterprise in traversing vast regions, awakened a corresponding spirit;
and the publication of his narratives had the effect to popularize the
subject of mineralogy and geology