In this role he led federal surveys from 1839 to 1840 and from 1847 to 1851 of the Midwestern United States , which included Iowa , Missouri , Wisconsin , Minnesota , and part of northern Illinois .
In July 1839 Owen received an appointment as the U.S. geologist .
In this role Owen led federal surveys from 1839 to 1840 and from 1847 to 1851 of the Midwestern United States , which included Iowa , Missouri , Wisconsin , Minnesota , and part of northern Illinois .
In July 1839 Owen received an appointment as the U.S. geologist .