[DensaMensa]

>"A large man" would lean and help himself and a canoe to balance, jump out and help push or bail in emergencies,

I see your point, but I've been in canoes where the load of tents and supplies was more than 220lbs, and even though it didn't help balance or jump out and help push it made the trip OK. ha. I would classify the argument that it couldn't have been moved by a canoe (or otherwise) a pretty weak one.

[crystalk]

If you are right, it would increase the chance that the stone is legitimate.