Hi Alex, I can't find him in the Oregon Death Index.
You might want to contact the Sweet Home Genealogical Society, http://shgenealogy.com/http://shgenealogy.com/ , and ask if they have any information on him. There might be a research fee.
Did you know that there was also an Augustus Fellows b. abt. 1842, Ohio living in Washington D. C. who died abt. 1905 and is buried at Arlington National Cemetery? Stumbled across him while searching for your Augustus. Successful Searching!