Some reference books are good only because of all the citations they provide to related first and secondary source works. This is one of them.
The Adventures of a Treasure Hunter, 1951 by Charles P Everitt – Ironically this is NOT about treasure, it is about a man who is a book finder and book hunter. However he mentions several important historical Americana books. From these books they are useful for treasure hunting leads. Narrative and critical history of America – A very rare book and dense compendium of American books in 1800’s and back. Written 1889. Leads galore.