Sorry to burst your bubble but I don't really think it's gold. Gold would not have a layer of oxides (it won't tarnish) no matter how long it's been sitting there and it also won't be silver colored.
If it's heavy, silver colored, and in nugget shapes I think you might have a hunk of melted lead, maybe there was some sort of campsite there at some time? Old lead is usually white though so I don't know.