Ferdinand Vandeveer Hayden was born on September 7, 1829, in Westfield, Massachusetts to Asa Hayden and Melinda Hawley. He graduated from Oberlin college in 1850 and Albany medical college in 1853. In 1856, Ferdinand was appointed the assistant to Lieutenant G.K. Warren in the exploration of the Yellowstone and Missouri Rivers and the Black Hills. He was a surgeon and naturalist for Captain W.F. Reynolds' expedition to the upper tributaries of Yellowstone, which resulted in his Geological Report of the Explorations of the Yellowstone and Missouri Rivers in 1859-60. Hayden was a surgeon during the Civil War in the Federal army from 1862-1865. While serving, he rose to the role of Chief Medical Officer of the Army of the Shenandoah and received a brevet to lieutenant colonel. After the war, he became a professor of mineralogy and geology at the University of Pennsylvania where he worked until 1872. In 1867, Hayden was appointed geologist in charge of the U.S. geological and geographical survey of the territories. He married Emma Copper Woodruff on November 2, 1871, in Philadelphia, Pennsylvania. Together they had one child. Also in 1871, Hayden led America's first federally funded survey into the Yellowstone region with a group of fifty men, including Thomas Moran, painter, and William Henry Jackson, photographer. This expedition resulted in his five-volume publication titled Department of the Interior: United States Geological Survey of the Territories which was instrumental in convincing Congress to establish Yellowstone as the first U.S. National Park. Hayden died on December 22, 1887, in Philadelphia, Pennsylvania.

William Henry Jackson was born April 4, 1843, in Keeseville, New York. He was a man of great energy and love for the outdoors and especially the breadth and heights of the mountain West. His life spanned the first century of the new visual art of photography and the great era of westward expansion. He began his photography career in 1858 in New York as a photographic retouching artist in the burgeoning photography industry and ended it in New York City with his death in 1942. In between these years he became increasingly proficient in his chosen field through his studio and field work in Omaha, Nebraska, his nine year odyssey as the official photographer with Ferdinand Vandeveer Hayden’s United States Geological Survey of the Territories, his 15 years in Denver, Colorado, 17 months of Asian and Pacific travel with the World Transportation Commission, his 27 years in Detroit associated with the Detroit Photographic Company and its successor the Detroit Publishing Company, and finally his highly productive "so-called" retirement years from 1924 to 1942. He died on June 30, 1942, in New York, New York at the age of 99.

Aleksei Petrovich Pavlov (A.P.) was born on November 19, 1854, in Moscow, Russia. A.P. graduated from Imperial Moscow University in the natural department of the Faculty of Physics and Mathematics. In 1880, he was invited to be a curator of the Geological and Mineralogical offices at Moscow University. He rose from curator to head of the department of geology and paleontology in 1884 and professor emeritus of the university in 1909. He was an academician of the St. Petersburg Imperial Academy of Sciences. While attending lectures, A.P. met his future wife, Maria Vasilevna Gortynskaya (M.V.) who was a graduate of the Sorbonne. They were married on May 26, 1885, in Moscow, Russia. She became an honored paleontologist and academician. A.P. participated in eight sessions of the International Geological Congress. He published over 160 works in the fields of stratigraphy and paleontology. They immigrated to the United States in 1893. Together, A.P. and M.V. were awarded the medal of A.Godri, the highest award of the Geological Society of France. The work of the Pavlovs grew into a large Geological-Paleontological Museum, which was named after them in 1926. A.P. died on September 9, 1929, in a town called Bad Taurz, which is present day Germany, Bavaria.