The coastal ice-blockage argument was revisited as geological evidence suggested that ice-free refugia may have existed along parts of the coast earlier than previously thought — that the coastal route was open, or intermittently open, earlier than the interior corridor.

Against this backdrop, the Arlington Springs revision placed a person on a California island approximately 13,000 years ago — near the boundary of the Clovis horizon, but on the island that required maritime capability, and in a location consistent with a coastal rather than an interior migration route.

A person arriving in California by a coastal route from the north would, by necessity, have maritime technology.

If that person or their immediate ancestors had traveled down the Pacific coast following marine resources, they would be exactly the kind of people who could cross a channel to an offshore island.