The Louisiana Purchase was the acquisition by the United States of America in 1803 of 828,000 square miles (2,144,000 square kilometers or 529,920,000 acres) of France's claim to the territory of Louisiana. The U.S. paid 50 million francs (...
Dr. Ferdinand Vandeveer Hayden was an American geologist noted for his pioneering surveying expeditions of the Rocky Mountains in the late 19th century. He was also a physician who served with the Union Army during the Civil War.
In 1871...
