These three excavated buttons were found in the Savannah, Georgia vicinity.  The 20^th Regiment is French and we know that they were involved in the surge in Savannah in September/October 1779.  The 20 mm. button has a nice appearance with shank.  The button (also 20 mm.) with the 3 cannons is a British Royal Artillery button probably from the War of 1812.  The 67^th French button (18 mm.) probably came from the West Indies.  A nice grouping of early excavated buttons for one price!