Leather, too, they learned how to make from the skins of some of the animals they found in the sea; great creatures, like walrus, or seals, that they fought and killed on the rocks along the coast. Living as they did more in the open air than the valley people, sleeping in huts instead of caves, wearing few furs, they grew tougher and stronger than the people in the valley, and were very brave and hardy and daring. With their cords of grass, they learned before long to make nets, with which they caught fish in the river, wading in the water and pulling the nets between them. They lived on fish and wild fowl; they knew little of the fruits, nuts or roots which the valley tribes ate. Sometimes hunting parties went up the river, and brought back fresh fruits, but not often. It was toward the sea that they turned for new adventures. CHAPTER XVI MA-YA BUILDS A CANOE FOR a long time after Ka-Ma and his wife came to live beside the sea, his children and his children's children continued to use rafts, made of logs tied together, for floating on the waters of the river. They never ventured on the ocean with these rafts, because of the heavy waves, and surf. Once or twice a raft was swept from the river into the sea, but the waves dashed over it, washing the men upon it into the water, and finally tossed it like a cork through the foaming surf and left it, battered and broken, on the beach. Some of the sea people were drowned in this way, and this made them very careful when they used their rafts upon the river. There was a young man in the tribe named Ma-Ya, who used to sit for hours on the beach, looking out across the ocean, and wondering what was on the other side. He thought the ocean was a very wide river, too wide for him to see across, but he believed that if he could find some way of reaching the other side, he might find a new country, filled with strange adventures. The early men who lived by the sea always felt this call to cross its wide surface, and find new lands. It was the spirit which drove the early Norsemen, the Vikings, to Iceland, and later on, all the way across the Atlantic to the shores of North America, many centuries before Columbus made his first voyage. It sent these same Norsemen southward, around the shores of Spain to the coast of Africa, and into the Mediterranean Sea until they came to Italy, and even to the shores of Asia. But all this was thousands of years later, when man had learned how to build stout ships out of wooden planks, driven by long rows of oars, and sails.