These things are foreshadowing because of what will happen up on the mountain in the later parts of the book.

Later in the book, Jack and his hunters will take over the top of the mountain.  That will be their heaquarters.  Remember that they stand for anarchy and savagery.  This is why the conch will not count up there on the mountain -- the conch represents civilization and that will be the place that is most against civilization.

Ralph's dislike of the area foreshadows that and the fact that Piggy will be killed up there.  It also foreshadows the fact that Ralph himself will be hunted and almost killed.