Farming was still America's main occupation. Scientists improved seeds. New machines did some of the work that men had done. American farmers produced enough grain, meat, cotton, and wool to ship the surplus overseas. The western regions still had room for exploration and for new settlements. Miners found ore and gold in mountains. Sheep farmers settled in river valleys. Food farmers settled on the Great Plains. Ranchers let their cattle graze on the vast grasslands. Cowboys drove great herds of cattle to the railroad to ship to the east. The "Wild West" pictured in many cowboy books and movies lasted only about 30 years.