The Federal geologic work thus started was soon continued in surveys of wider scope and more thorough accomplishment. The position of the Government as the proprietor of mineral lands in the Upper Mississippi Valley led to their examination. These Government lands containing lead had been reserved from sale for lease since 1807, although no leases were issued until 1822. The amount of illegal entry and consequent refusal of smelters and miners to pay royalty after 1834 forced the issue upon the attention of Congress, and in 1839 President Van Buren was requested to present to Congress a plan for the sale of the public mineral lands. In carrying out this policy Dr. David Dale Owen was selected to make the necessary survey. Owen had served as an assistant on the State Survey of Tennessee and as the first State geologist of Indiana, and he organized the new work promptly and effectively. Although suffering from the handicap unfortunately known by geologists of the present day—the receipt late in the season (August 17, 1839) of authority to begin work—within exactly a month he had his force of 139 assistants organized into 24 field parties, instructed in “such elementary principles of geology as were necessary to their performance of the duties required of them.” His plan of campaign provided for a northward drive at a predetermined rate of traverse for each party, with periodic reports to himself at appointed stations, “to receive which reports and to examine the country in person” he crossed the area under survey eleven times. The result of such masterful leadership was the completion of the exploration of all the lands comprehended in his orders in two months and six days, and his report on this great area—about 11,000 square miles—bears date of April 2, 1840. Eight years later Doctor Owen made a survey of an even larger area, continuing his examination northward to Lake Superior. Again his report was published promptly, and he continued for several years his examination of the Northwest Territory, submitting his final report in 1851. It is interesting to note that in his earlier report Doctor Owen subscribed himself as “Principal Agent to explore the Mineral Lands of the United States,” but that in the later report he was “U. S. Geologist for Wisconsin.” The two surveys together covered 57,000 square miles.