A fossil snake, embedded in one of the stones Rob's father has had delivered so he can build a wall, breaks free and grows in Rob's room, sleeping with him when it's cold and dancing obediently to the boy's recorder. There are bits of humor, such as the snake's appearances to a gang of louts engaged in tearing down the wall and, later, to the drunken parson, but the dominant mood is quiet, steady suspense stemming from the boy's attempts to protect his find from a grasping museum curator and then the police. This slight, but finely crafted story projects a nice sense of a child's secret life and, most important, makes you share Rob's proper awe of the snake's natural majesty. (However, the author's unspoken equation of bad manners with evil smacks of elitist assumptions that she can't expect all her readers to share.) On the whole, this is less impressive than The Sea Egg (1967), if only because it comes after, but it has some of the same virtues and is probably less special in appeal.