William B. Logan
"Reresentatives Dawes and Senator John Logan. . . placed relatives with the survey. . . Young Logan proved an admirable collector of butterflies, and he assisted Stevenson with the paperwork." 
- "U.S. Geological Survey Photographic Library," U.S. Geological Survey Photographic Library, 1871, accessed November 21, 2012, photo by W. H. Jackson, http://libraryphoto.cr.usgs.gov/htmllib/btch111/btch111j/btch111z/btch111/jwh00499.jpg
- F. V. Hayden, Preliminary Report of The United States Geological Survey of Montana and Portions of Adjacent Territories; Being A Fifth Annual Report of Progress (Washington: Government Printing Office, 1872), pg.4.
- Mike Foster, Strange Genius: The Life of Ferdinand Vandeveer Hayden (Niwot, CO: Roberts Rinehart Publishers, 1994), pg. #227.