Thorlof Mostbeard in Landnáma Part 2, Chapter XII

Thorolf, son of Ornolf (fishdriver), dwelt in Most Isle. He was called Mostbeard; he was much devoted to offering up sacrifices and believed in Thor. He emigrated to Iceland on account of the tyranny of Harald Fairhair, and sailed by the southern part of the land; but when he came west, off Broadfirth, he threw overboard the high seat posts, whereon Thor was carved. And he prayed thus over them that Thor as he called the posts or pillars might there come to land where the God wished him to settle, and he promised that he would dedicate all the land of his settlement (landnám sitt) to Thor, and name it after him. Thorolf then sailed into the Firth, and gave a name to the Firth, and called it Broadfirth (Breiðafjörd). He settled land on the south side, near the middle of the Firth. There he found Thor cast aland, upon a point of land which is now called Thorsness (Thorsnes), on that account.