Complex sentence: The physical features include three rivers: the San Juan, Animas, and La Plata rivers; also, the Chuska Mountains and Shiprock Pinnacle to the west, volcanic structures, buttes, mesas, badlands, and fertile river valleys.
Split into simpler sentences: The physical features include three rivers: the San Juan, Animas and the La Plata rivers. Also the Chuska Mountains and Shiprock Pinnacle to the west, volcanic structures, buttes, mesas, badlands, and fertile river valleys.