- Sunset Mine (washingtonminerals.com)
Index Batholith (Oligocene) - Uplift and erosion of the Old Cascade Volcanic Arc exposed plutonic rock of the Index Batholith near Index, Washington. Intrusive rock types found within the Index Batholith range in composition from granodiorite to tonalite.
- Cottonwood Island Wildlife Area Unit (wdfw.wa.gov)
The Cottonwood Island Unit is a unique forested property that is representative of a historic habitat type that would have been more widespread along the lower Skagit River Valley. It provides valuable mature cottonwood forest habitat for a variety of forest birds and raptors, primarily buteos and eagles. The remnant of Cottonwood Slough also provides off-channel habitat for salmonids during certain times of the year and has been evaluated for potential habitat restoration projects.