well if it's pewter (which it looks like to me) that would date it to the 1700's.unfortunatly pewter doesn't hold up that well underground as you can tell.coat it with hairspray or some clear polyurethane spray before it crumbles any further.good luck in IDing the design.cool find!
2012 LARGE COPPERS 16 1/2* SILVERS 9 * IH'S 9
2011 large coppers 80 3/4*SILVERS 49* IH'S 73
"2010" LARGE COPPERS 34
Maybe a crude, unmarked, rising phoenix button facing the opposite way. The dotted edge border is quite similar to the Liberty Cap Rattle Snake buttons made by the French around the Rev War period, so maybe it's kind of the same idea. Maybe not French but the same era.
AMERICAN DIGGERS ON SPIKE: THE TRASH WE WOULD LIKE TO DISCRIMINATE OUT!
Pewter was used in button manufacturing up through the 1820's and maybe even a bit latter. The break point on the back is very small compared to what we would expect to see for a shank (or remains thereof) in most Rev War period buttons. Therefore, an 18th century rule is nothing that is concrete for pewter (not that I'm saying concrete and pewter are relative, as that was just an adjective for the rule.) Although both concrete (cement) and pewter become a bit crumbly with age
Deciphering the design on this particular example, is akin to looking at clouds in the sky.
So far I've seen a butterfly, or a physicians mortar and pestle. No, maybe it is two sheep, or is that crossed flags?
A bit of rotation and imagination, close one eye and squint, and soon all kinds of ideas come in.
My impression is the button is likely early 1800's. Toss in the site context as well, brings a newer perspective.