The Florissant Fossil Beds of Teller County, Colorado were established as a national monument in 1969 by the U.S. federal government. The site is open to the public as well as scientific investigators and is an active research area into the plant and insect life of the Eocene. The area was the site of an ancient lake and the remains of the prehistoric life forms within the shale are preserved quite well due to the effects of volcanic ash and continued volcanic activity of the nearby Thirty-nine mile volcanic fields during the period.
Official mail from this national monument is reasonably difficult to find. This example from the mid-1980s, sent with ‘Certified Mail’ service is even more desired as not a great deal of official mail from national monuments receives special postal services. The airmail and certified mail fees were paid by the U.S. Department of the Interior.