I just got this link emailed to me by my friend Norris. Looks promising.
alice in montana

http://memory.loc.gov/ammem/smhtml/smhome.html

Music for the Nation, American Sheet Music, 1870-1885
The Library of Congress provides another fine online resource with a new American Sheet Music site. Thousands of pieces of sheet music registered for copyright during the post-Civil War era. Search by author, title or subject.