John Burroughs

One of my favorite old naturalist/writers (and early conservationist) is John Burroughs (1837 - 1921)
Google books has a fair amount of Burroughs' work available for viewing (free) over at their site:

http://books.google.com/books?q=john+burroughs&btnG=Search+Books

Burroughs' material also available over at Project Gutenberg, here:

http://www.gutenberg.org/browse/authors/b#a1127

and Wikipedia entry for Burroughs here:

http://en.wikipedia.org/wiki/John_Burroughs

If you enjoy good nature-writing, Burroughs really set the stage (along with his contemporary John Muir) for much of the quality writing done since his day.