Who is the boy who finds the conch?

Ralph discovered the conch. Piggy explained what it was.

Ralph had stopped smiling and was pointing into the lagoon. Something creamy lay among the ferny weeds.
"A stone."
"No. A shell."
Suddenly Piggy was a-bubble with decorous excitement.
"S'right. It's a shell! I seen one like that before. On someone's back wall. A conch he called it. He used to blow it and then his mum would come. It's ever so valuable--"