15mm, excavated Federal Eagle "I" Infantry officer jacket button without shank. Substantial silver plating remains (button has only been rinsed). The button is of the low convex type, but is also dented.   It bears the rare "Floyd/Extra" backmark. McGuinn and
Bazelon report that George Floyd was listed as a gilt button-maker in the City Directory for 1842-1844 only.  Understood to have been found at Buena Vista, Mexican War site.