From looking at those pictures It appears to be the base of an old cliff sticking out of the hillside,looking at the pic of the rock pile its either been blasted to make the road bed and fallen that way,or maybe even and old grazing spot for cattle,The rocks were stacked commonly to herd cattle in the opposite direction as they will tend to not walk over a pile of stone,instead they`ll go around them.As far as the rusted lock goes,Unless its on posted property it isnt breaking and entering if you open it,Its more or less litter left beside of a road,Its worth checking out if the property isnt posted,But im betting its more than likely nothing due to the location,Id like to see a photo of the lock,I could give you an idea of the time period as ive recovered a bunch of mid 1800` railroad locks and im quiet knowledgable of the time period padlocks generate from. Good Luck ,Hope its a confederate gold bullion stash,But im thinking its most likely and old explosives box from when they made te road bed based on the rock pictures posted here. Just be careful when you examine it next time.As old dynamite is quiet unstable.
