​Tennessee native Robert T. Hill (1858-1941) moved to Comanche, Texas at age 16 and developed an interest in Texas Geology. Educated at Columbia University, he worked for the U.S. Geological Survey, the University of Texas and as State Geologist. Known as the father of Texas Geology, he identified many of the state's geological features and regions. In 1899, he and five others surveyed the Rio Grande. Beginning in Presidio, the team charted the river's path through steep canyons and perilous obstacles. After 350 miles of river travel, the men saw a landmark eagle's nest and at that point ended their trip and hiked into Langtry. Hill's work was the first to document the Rio Grande through the Trans-Pecos region of Texas. (2005)

The Robert Hill marker overlooks the canyon of the Rio Grande near Langtry (April 2012).