Turning the turtle

At the edge of the foaming sea, behind the spent waves on the beach, shapes materialize in the night. They are ancient shapes that have appeared countless times over millions of years. They slowly pulse towards the shore, their domed shells barely showing at the surface. Under a waning gibbous moon, scaly flippers strike the sand. Wrinkled necks emerge, stretching beaked heads with unblinking eyes to survey the beach. Like time travellers from some primeval epoch, a great wave of sea turtles...