Hunter Shea said this quote

Which grave are we in? she said. The oldest. She felt Eddie's puzzlement. That can't be possible. He looks like he was just buried. There must be something at work in the chemistry of the island that's preserving his body. It's like the incorruptibles, bodies that weren't preserved in any special way that don't decay. Catholic saints like Bernadette and Padre Pio are said not to have decomposed even though they died a long, long time ago. Environmental factors can cause a kind of mummification. Jessica said, or thought, This is bizarre. I'm getting a lesson on mummification while in the coffin of a dead man.