In the early 1900s, Aleš Hrdlička and William Henry Holmes of the Smithsonian Institution became the chief advocates of the view that man had not lived in the Americas for longer than 3,000 years.

[6][7] Hrdlička and others made it "virtually taboo" for any archaeologist "desirous of a successful career" to advocate a deep antiquity for inhabitants of the Americas.

[8] On August 27, 1908, 15 in (380 mm) of rain fell on Johnson Mesa in New Mexico causing downstream floods along the Dry Cimarron River.

A local African-American cowboy, George McJunkin, surveyed the damage in Wild Horse Arroyo and found bones uncovered by the flood.

In 1895, at the 12 Mile Creek site in western Kansas, an archaeologist found a projectile point in conjunction with the bones of extinct bison.

In 1922, shortly after McJunkin's death, a Raton blacksmith, Carl Schwachheim, and a banker, Fred Howarth, both amateur naturalists visited the Folsom site.

In 1924, at Lone Wolf Creek in Texas, excavators reported to Figgins that they found three projectile points associated with a bison skeleton.

As the date of the extinction of the ancient bison had not yet been determined, archaeologists at a meeting of the American Anthropological Association in December 1927 speculated that man had arrived in the New World 15 to 20 thousand years ago.

[20] Authorities differ as to whether the extinctions of megafauna were caused by climate change (the Younger Dryas) or over-hunting by Paleo Indians or both.

[21] The Folsom culture flourished over a large area on the Great Plains of the United States and Canada, eastward as far as Illinois and westward into the Rocky Mountains.

[23][24] In addition to individual kills, a practice of Folsom hunters was to ambush groups of bison by driving them into narrow ravines and gullies where they could be slaughtered.

The sparse remains of Folsom settlements are usually found near kill sites and steams or springs where bison and other animals congregated.