When they were finally able to get back on land (on Mount Parnassos), they gave thank offerings to Zeus and consulted the oracle of Themis how they might replenish the earth with humans once again. They were told to throw the bones of their mother behind their shoulder and the human race would reappear. Since the mother of all is Earth, they threw stones and reformed the human race. The stones thrown by Pyrrha became women, those thrown by Deucalion became men.
Deucalion is the son of Prometheus and Clymene. When Zeus punished humankind for their lack of respect by sending the deluge, Deucalion and his wife Pyrrha were the sole survivors. They were saved because of their piety. Prometheus advised his son to build an ark and they survived by staying on the boat.