A few problems with the cave gold you mentioned. Everyone nows that these caves were guarded by the Sasquatch nation. As our population grew and took over land belonging to the Sasquatch Nation, the Squatchs' removed the treasure and took it deep into the high Adirondacks where they buried it under the site of an ancient outhouse once used by George Washington shortly after his victory at Yorktown. It hasn't been found yet because (as everyone knows) of the squatch's greatly advanced physics and engineering capabilities. They used this knowledge to prevent metal detector signals and other electronic locating devices from working by covering it with Sasquatch fur before filling in the hole. Their fur, of course, being well known for it's ability to prevent magnetic fields, radar signals, and other locating technologies.
Unfortunately, the government has discovered technology that detects buried Sasquatch fur with UV light frequencies yet unknown to man and have used it to locate Sasquatch treasures. Typically, the government secretly excavates these finds at night in total secret while nearby citizens are sprayed with sleeping drugs from an invisible drone who's technology is from an alien spacecraft that crashed in secret 57 years ago in the Nevada desert.
OR, it could be a myth born out of an ongoing practical joke originally designed to keep fools on an errand so they wouldn't bother the rest of us.