Who finds the conch shell and whose idea is it to use to call a meeting?

Ralph and Piggy find the conch shell together in the first chapter of Lord of the Flies while they are looking around the lagoon and learning about their new environment. They spot the shell in the water, and Ralph bends a palm sapling to bring the conch up to the surface of the water to a place where Piggy can grab the shell. Piggy explains to Ralph that the conch is an exciting find because it can be used to make a loud noise when someone blows into it. While describing the monetary value of the conch to Ralph, Piggy gets very animated and suddenly realizes that the conch has potential value for them: Piggy tells Ralph that they can use the conch to make a noise that will summon the others to a meeting.