Virtual Villagers Tips & Tricks, Walkthroughs, Guides, Hints and HelpLast Day of Work Official Forums: Virtual Families, Virtual Villagers, Fish Tycoon
As for the moss-covered rocks, it seems that was just thrown in there haphazardly. What's the point if they aren't going to use it somehow to earn experience, or a huge food bonus?
You haven't finished the puzzles yet. The moss-covered rocks are part of the puzzles. That's all I'll say since this is a non spoiler thread.