Possible evidence for the association of early people and extinct late Ice Age animals resulted in two investigations at Tule Springs in Southern Nevada. The first was undertaken intermittently between 1933 and 1956 by Mark Raymond Harrington and Ruth DeEtte Simpson of the Southwest Museum, Los Angeles.
A second investigation occurred when the Nevada State Museum mounted large-scale excavations in 1962 and 1963. Their methods ranged from bulldozer-cut trenches totaling 7,000 feet in length to the most careful recovery of tiny amounts of shell and carbon for radiocarbon dating. Richard Shutler directed the project, and C. Vance Haynes led the study of the sedimentary sequence and dating.
Researchers recovered bones of extinct mammoth, bison, horse, ground sloth, and camel as they eroded out of the sides of Las Vegas Wash, northeast of Tule Springs. The site now forms a lake at Floyd Lamb State Park in Clark County. With the advent of radiocarbon dating in the 1950s, Harrington and Simpson obtained dates of 23,800 years ago and 28,000 years ago on organic material from bone-bearing layers.
Then as now, any proof that people were in North America prior to about 11,500 years ago (Clovis times) was subject to intense scrutiny. The Nevada State Museum's four-month project sought to verify Harrington and Simpson's claims that evidence, such as tools and hearths, indicated people were there in association with the early dates.
Despite the promise of the site, the Nevada State Museum found no evidence of human occupation prior to about 11,000 years ago. What Harrington and Simpson thought were hearths turned out to be the cross-sections of slow-moving streams with organic mats. Associated iron oxide deposits looked like evidence of burning. In addition, stone tools that appeared to be from layers containing Ice Age mammal bones had fallen into secondary association with the earlier deposits. The tools were from a later period, either Lake Mojave to early Pinto, and were from sites on the surface above. Erosion of the sides of Las Vegas Wash had undercut these tools, letting them slide down to come to rest on the margins of much earlier Ice Age layers.
Three excavated sites at Tule Springs did show that people were there at the same time as the later Ice Age mammals. A few well-dated stone and bone tools were dated to approximately 9,000 to 11,000 years ago.
None at this time.