Kurkar is a brittle stone composed of sand and lime. Several kurkar ridges run on a north-south pattern up the coast. (In fact, they are ancient coastlines.) North of Jaffa are three. Counting from west to east, between the first and the second swamps formed. The third and broadest was thickly forested. Given the straight coastline, the swamps and forests, the ancient Israelites preferred not to live in the Sharon plain (the coastal plain between the Yarkon River and Mt. Carmel). This was why they viewed the sea as something hostile (as in Psalm 104). The Phoenicians to their north, with little farmland and excellent harbors, posed no economic competition and became their natural allies (Hiram and Solomon, Jezebel and Ahab).