These may be very old, but I'm pretty sure they are not indian artifacts. They are naturally occurring clay balls, called pisolites. I've picked up lots of these in south Georgia. They are made up mostly of the mineral gibbsite, which is aluminum hydroxide.

http://www.clays.org/journal/archive/volume%2028/28-5-397.pdf
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Everybody's had to fight to be free...Tom Petty

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