Ginkgo Flow: Geologist Nick Zentner (of "Nick on the Rocks" fame) takes us on an entertaining road trip to explore the "ginkgo" lava flow that erupted in central Washington and flowed all the way to the Oregon Coast 16-million years ago. Columbia Slough: Exploring the surprising natural oasis in the most urban watershed in Oregon with the folks of the Columbia River Slough Watershed Council and a dedicated volunteer helping to clean it up.