Never seen one quite like that. I have seen a few eagle backamarks from the late 1700's, though.
I think your button is from 1783. Rotate your pic 90 degrees left and the scene appears to be Jacques Charles first manned hydrogen balloon flight at Place de la Concorde, Paris France.
I know NOTHING about buttons. With that being said, if it is a balloon scene, the first balloon flight in America went from Philly to Deptford. Connection?