In "Lord of the Flies", what is the symbolic meaning of the rocks and shelters?

Rocks symbolize primitive human instincts and destruction. Jack's power base is located on Castle Rock. Throughout the novel, the boys roll rocks down the mountain and hills to witness the awesome destruction they cause. Roger rolls a large boulder towards Piggy, which ends up killing him. While Ralph is hiding in the brush, the savages roll a massive boulder that forces him to leave his hiding place. Rocks are used as weapons and cause destruction throughout the novel. The earliest humans used rocks as tools and weapons to survive. Jack and his band of savages parallel these Neolithic humans by rejecting civilization and embracing primitive human instincts. Much like Jack's band of savages, rocks are callous, sharp, and dangerous. Golding associates the destructive nature of rocks with Jack's tribe throughout the novel.

Shelters symbolize civilization and protection throughout the novel. Ralph and Simon work on the shelters alone after the rest of the boys leave to bathe, play, eat, and hunt on the island. Ralph and Simon share an affinity for civilization, structure, and morality. The shelters are built to house and protect the littluns from not only the forces of nature but also the "beast." Jack, who represents anarchy and primitive human nature, dismisses the importance of shelters and refuses to help build them. The fact that the shelters become progressively unstable and shaky foreshadows the boys descent into barbarism on the island. The shelters represent the degree in which civilization diminishes throughout the novel.