Tarzan creator Edgar Rice Burroughs penned the adventures of a group of Americans who, wandering in uncharted seas, make their way into the weird island of Caprona. There they find a strange country teeming with grotesque animal life that, in the known world, has been extinct for countless ages. In the steaming rivers and amid the lush growth of the jungle, gigantic reptiles peer at them with gleaming eyes. Huge, hideous, deadly monsters—a veritable Mesozoic nightmare. In the months that follow they learn some of the secrets of this lost land, and make some interesting friends among its peculiar inhabitants. It is a tale that only the author of the famous Tarzan stories could write.