Depends on where it was found. If Montana, maybe a fossil. If eastern Pennsylvania, go with a fossilized seed pod from the Pennsylvanian period. All depends on location.
1st - I noticed this was your very first post CONNERS - so, Welcome Aboard! You didn't list your state (or country) in your profile. So, you might consider jumping over to Sub-Forums: Select Your Area.... and selecting location information (i.e., clubs, hunts, finds, legends, maps, etc.) directly related to your state (or country).
2nd - I moved this thread from HELP! over to Forum: What Is It? for more exposure.