Bridge of size?

Legend says the heroic giant Fionn mac Cumhaill built this geological marvel as a bridge from Ireland to Scotland. So how come the Giant's Causeway doesn't stretch across the sea? Well, another story tells of the even bigger giant Benandonner, who crossed the causeway to fight with Fionn—but rather than face the brute, Fionn had his wife Sadhbh disguise him as a baby. When Benandonner came to their house, Sadhbh told him her husband was away. Noticing the huge 'baby,' Benandonner realized its father must be truly gigantic. So he boogied back to Scotland over the causeway, smashing it as he fled so the fearsome Fionn couldn't follow.