linguistic:paraphrasing
Lithic evidence of pre-Clovis migrations

Geological findings on the timing of the ice-free corridor also challenge the notion that Clovis and pre-Clovis human occupation of the Americas was a result of migration through that route following the Last Glacial Maximum. Pre-LGM closing of the corridor may approach 30,000 BP and estimates of ice retreat from the corridor are in the range of 13,000 to 12,000 years ago. Viability of the corridor as a human migration route has been estimated at 11,500 BP, later than the ages of the Clovis and pre-Clovis sites. Dated Clovis archaeological sites suggest a south-to-north spread of the Clovis culture.

Pre-LGM migration into the interior has been proposed to explain pre-Clovis ages for archaeological sites in the Americas, although pre-Clovis sites such as Meadowcroft Rock Shelter, Monte Verde, and Paisley Cave have not yielded confirmed pre-LGM ages.

There are many pre-Clovis sites in the American Southwest, particularly in the Mojave Desert. Lake Mojave quarries dating back to the Pleistocene hold lithic remains of Silver Lake projectile points and Lake Mojave projectile points. This indicates an interior movement into the region as early as 13,800 BP, if not earlier.