 Viability of the corridor as a human migration route has been estimated at 11.5k cal years BP, later than the ages of the Clovis and pre-Clovis sites.Dated Clovis archaeosites suggest a south-to-north spread of the Clovis culture.Pre-Last Glacial Maximum migration into the interior has been proposed to explain pre-Clovis ages for archaeosites in the Americas, although pre-Clovis sites such as Meadowcroft Rock Shelter, Monte Verde, and Paisley Cave have not yielded confirmed pre-LGM ages.