The cave with the really hidden entrance above Lafayette is Johnson's Crook, and the drop is more like 25 feet (and vertical). You can't get into (or out of) that cave without climbing rope (and the know how to use it). It's an amazing cave, and you can literally stay in there all day exploring. Not for beginners. One of the passages is really tight, like, you have to exhale to be able to slither forward 6 inches, but it leads to a room called the Devils Dungeon. It's like a cathedral with a really tall waterfall. I hear it's posted property now.
Petty John's on Pigeon Mountain is pretty