Originally posted by blade express:

I know they are rare in unexplored Mountains. 1. Does Bonemass need defeated in same seed ? 2. Must you be carrying Wishbone ? 3. Do Frost Caves spawn below Obsidion elevation ? any valid info appreciated

Most of the caves are on ledges so you are not really going to happen across one just walking the mountains. Keep an eye out for a sharp pointy looking rock. That will be the top of the cave.