Flagstone is a monolithic piece of andesite in the Willamette Forest between Blue River and Oakridge. It offers no natural protection, but by now has well over 50 sport routes between 5.6 and 5.14. The style varies from steep, thin friction to juggy overhangs.
Here is my log of the climbs I have done there since 2001. The west side of the monolith, with Hydrotube and Acne Problem visible.