How is Jerry's beach different from his mother's?

Jerry's mother's beach seems "safe" to him, like a place for children to go and be looked after by their parents. His beach, however, is "wild" and rocky. Rocks lie like "monsters" on the ocean floor, and the water is colored like bruises. The "rough, sharp rock" of Jerry's beach contrasts with his mother's much more typical, vacation-like beach where she sits with her umbrella, which looks like a "slice of orange" to Jerry from his dangerous beach. The water of his beach is shocking to the limbs due to the "irregular, cold currents" that seem to come in from the much deeper waters. Local boys who are several years older than he swim at his beach, splashing and playing, and they seem like "men, to Jerry." Jerry's mother's beach becomes associated, at least in his mind, with children and safety, and he associates his wild beach with independence and adulthood.