76 CORNWALL These plates of slate, for they are nothing else, have had all the angles scoured off them by the scourging surge. The village people collect them, picking out all that are of one size, to form neat pavements. You also see them set like some strange mosaic on the fronts of the houses, stuck in mortar, and making a deep frieze ; the effect is not beautiful. But the ruined castle on the island is not all that remains of man's handiwork here, for high on the mainland, on the great boss of earth fronting the island, are the remains of another castle, now falling piecemeal into the gulf below as the cliff crumbles. Some hold that the " island " was originally an island in reality, and that the slender neck of rock now linking it to the mainland is the result of cliff-falls and debris. But whether that was so or not the purpose of the landward castle can only be guessed. It may have been an out- work, though that seems rather unnecessary. Over it hover screaming jacks, who love the sheltering crevices of artificial walls, and occasionally may be seen a red-legged and beaked Cornish chough which here alone on the Cornish coast is not extinct, and is supposed by the children to re-embody the spirit of King Arthur.