In Arcadia, just before you get to Megara Bluffs, there is an area just to the West and below you, at the level of the beach before Megara, but before you actually descend to Megara Bluffs. The map indicates a cave, and there is a spot where you can see there are the two tiki torches indicating progression through the map on either side of the cave entrance. There are mobs down there too, crows usually. I have never found any way to get there, wondering if it's just a part of the game that was never implemented or I'm missing something.