In July 1868, he joined Clarence King for his Geological Exploration of the Fortieth Parallel and stayed with him through 1872.
In 1872, Wilson accompanied King and others to investigate and eventually debunk a diamond hoax in the northwest corner of the Colorado Territory.
[2] Wilson's half-brother Franklin Rhoda was a key member of this survey team.
Wilson resigned from the USGS on September 30, 1881, in order to become chief topographer for the Northern Transcontinental Survey, organized by Raphael Pumpelly.
Pumpelly published part of that survey in his report for the Tenth Census, including at least one of Wilson's maps.