The skeleton(s) found recently in Thayer may date to 500 B.C.
Which means the musketball presents us with an interesting enigma.
My three best explanations:
1. It's not a musketball, but something else. Maybe a petrified horse turd.
2. The native Americans had muskets before the Anglo-Saxon invasion, but somehow the technology was lost in the sands of time before Whitey arrived.
3. The musketball contaminated the scene later.
I am waiting patiently for the phone call asking me for suggestions on what to do with the remains of my ancestors.
I'll tell them to do a forensic analysis to confirm the skull has Native American features*, then make resin duplicates of the remains, place those duplicates in the Thayer Information Center with a respectful display, then make your best guess at what tribe(s) inhabited the area 2500 years ago, and return the remains to that tribe to do what they want with them.
And, of course, make a documentary film about the archaelogical dig and have the opening at the old theater in Thayer. Just don't put too much butter on the popmaize.
* - If it's not Native American, maybe the dating is a little off and it's Jesus. This would prove the Mormons right in their belief that Jesus came to the New World after his little experience in the Middle East. Or maybe, just maybe, it would prove that there were European-looking people here before the Native Americans, people who the Native Americans committed genocide upon, which would of course, on the grounds that they are pro-genocide, remove their moral standing to object to the genocide attempted upon them. Oh, wait. That already happened.