In these shifting seas of sand, rich in stone evidences of primitive men, visitors find flint points, sandstone metates, and manos of peoples who were here as early as 10,000 years ago and as late as the 1870s. Bones of great mammoths and gigantic bison show that in post-glacial times this desert was a land of lakes and tall grasses. Cabeza de Vaca in 1535 and Antonio de Espejo in 1583 encountered Jumanos, a historic tribe that hunted here. In 1590 Castaño de Sosa found a tribe he called Vaqueros because they lived by hunting cows, or buffalo, the tribe later called Apaches. For more than 100 years this was a stop on the great Comanche War Trail extending into Mexico, where Apache fought Comanche for pools of water and acorns of dwarf shinnery oak. The California, or Emigrant, Trail through the Sand Hills began with the gold rush and was first mapped in September 1849 by Capt. Randolph B. Marcy of the U.S. topographical engineers, and in 1854 by Capt. John Pope, who explored a railroad route toward the Pacific Ocean. Three thousand acres of Sand Hills were designated in 1957 as a state park after acquisition and construction of a museum by Ward County.