Roll Over, Clovis, or: Kilroy Was Here, Used the Facilities, Nobody Go In There for a While
For a long time (by my standards, not the Earth's) the Folsom point was the oldest evidence of human arrival in America, so rare they're expertly forged by flintknappers and sold as genuine. Then the Clovis culture with their fluted points (sounds un-American, downright effete) pushed the calendar back even farther. Oh, there are 15,000 year-old settlements in Chile, 14,000 year-old butcher's marks on mammoth bones in Wisconsin, 18,000 year old artifacts in Pennsylvania-- but there's always the danger that artifacts can be "seeded" on an archeological site (see Tony Hillerman's mystery novel, Dance Hall of the Dead.)
Now archeologists have irrefutable proof that human beings strode the American continent at least 1,000 years before Clovis: a fossilzed turd.
The coprolites from Paisley Caves in Oregon date at 12,500 BCE. The traces of DNA concealed therein are related to Native Americans and come originally from East Asia. It might be my years of working in a hospital, or hanging out too much with a gastro-enterologist, but I find it funny that our arrival on any landscape-- cue the Hollywood backlighting and inspirational music-- would be marked not by a pyramid or a handprint but by our most humbling shared experience. Now that's a closing shot that might have saved Zardoz.