For those just tuning in to the story: Billy and them have been fossil hunting, and while Harley and Pete have found nice interesting fossils, Billy's found nothing but some rocks. Poor Billy. I suppose there's a lesson in this, kids - Don't spend the whole time complaining and not listening or you won't be able to find any fossils and you can't talk about them with your friends and instead you'll be interrupting the conversation with inappropriately loud sighs.
. . . I'm pretty bad at lessons.