Just a theory that popped in my head while reading this:
What if there is a skeleton down there with a wooden box, but it's just the skeleton of an early settler who got caught in the naturally occuring sinkholes of Nova Scotia? Not treasure, but his belongs? The artifacts things that have been brought up with other sinkholes causing the floods to lift them up, then get stuck in the dirt as the water eventually 'seepedl back into the soil and the walls started caving in? The wood, slate and other things could be there because they were at the top of that current flood of their time before the dirt fell in on top of the sink hole agian?
Just something I was thinking about...It would be much more fun to have it be treasure, but who knows if we will ever know...it's already a few of my lifetimes, generally speaking, old.
I will remain happy to think of it as a mystery until someone else wants to pay to prove me right or wrong...