While browsing on Archive.org, I came across these American heraldic publications which I thought might be of interest :

* Edward S. Holden’s Primer of Heraldry for Americans, published in 1898.  While a lot of the content is fairly generic, some of it is specific to the USA.

http://archive.org/details/PrimerOfHeraldryForAmericans

* Vol 1 of the American Heraldic Journal, published in 1901.  The contents include the arms and pedigree of Gen Robert E. Lee;  the seal of the Cathedral of St John the Divine, New York;  the arms of the city of East Liverpool, Ohio;  and two pages of ecclesiastical seals (some of them armorial).

http://archive.org/stream/americanheraldic00whay#page/n19/mode/1up