Dingus and mouse, you flatter me! Thanks. The child has fared well, although she does not like scary movies in the least.
Like all good quests, today's involved a collection of rumors and mixed information to make a whole. I think this story about a crevice up in Hidden Valley was melded with the cave that was sealed story to make the whole idea that they were connected. It's not possible from what I observed. But this is the sealed entrance.
Some caves are sealed to keep things out, while others are sealed to keep things in.