The island supported forests, wetlands, and the fresh water systems implied by the very name Arlington Springs.

The channel between Santarosae and the mainland, despite being narrower than today, was still a rich marine environment: kelp forests grew in the cold upwelling water, and the marine mammals, fish, and shellfish that depend on kelp-forest ecosystems were abundant.

The person who reached the island 13,000 years ago arrived in a landscape of considerable ecological richness, separated from the mainland by a minimum of miles of open water, accessible only to someone who already knew how to cross open water.

The Pygmy Mammoths And The Late Pleistocene Context