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 throughout the country.

In 1821, he executed a very extensive journey through the Miami of the Lakes and the River Wabash, tracing those streams minutely to the entrance of the latter into the Ohio River.  He then proceeded to explore the Oshawanoe Mountains, near Cave-in-Rock, with their deposits of the fluate of lime, galena, and other mineral treasures.  From this range he crossed over the grand prairies of the Illinois to St. Louis, revisited the mineral district of Potosi, and ascended the Illinois River and its north-west fork, the Des Plaines, to Chicago, where a large body of Indians were congregated to confer on the cession of their lands.  At these important conferences, he occupied the position of secretary.  He published an account of the incidents of this exploratory journey, under the title of Travels in the Central Portions of the Mississippi Valley.  He found, in passing up the river Des Plaines, a remarkably well characterized specimen of a fossil tree, completely converted to stone, of which he prepared a descriptive memoir, which had the effect further to direct the public mind to geological phenomena.

We are not prepared to pursue minutely these first steps of his energetic course in the early investigation of our natural history and geography.  In 1822, while the lead-mine problem was under advisement at Washington, he was appointed by Mr. Monroe to the semi-diplomatic position of Agent for Indian Affairs on the North-west Frontiers.  This opened a new field of inquiry, and, while it opposed no bar to the pursuits of natural science, it presented a broad area of historical and ethnological research.  On this he entered with great ardor, and an event of generally controlling influence on human pursuits occurred to enlarge these studies, in his marriage to Miss Jane Johnston, a highly cultivated young lady, who was equally well versed in the English and Algonquin languages, being a descendant, by the mother’s side, of Wabojeeg, a celebrated war sachem, and ruling cacique of his nation.  Her father, Mr. John Johnston, was a gentleman of the highest connections, fortune, and standing, from the north of Ireland, who had emigrated to America during the presidency of Washington.  He possessed