Gustavus Doane%2C 2nd Lieutenant in the Second Cavalry%2C fourth in from left %28standing%29 at Fort Ellis outside Bozeman in 1870. Earlier that same year%2C in January%2C Doane was an officer who was instrumental in carrying out the Marias Massacre that killed more than 200 Piegan Blackfeet. Photo taken by William Henry Jackson%2C the photographer who accompanied painter Thomas Moran to Yellowstone and whose imagery%2C together%2C helped persuade Congress to create Yellowstone as the world%27s first national park