- Concrete — Thumbnail History (historylink.org)
The town of Concrete in northern Skagit County is located on the Skagit River at the mouth of the Baker River. Nestled in the foothills of the Cascade Range, Concrete is known as the gateway to the North Cascades. A few homesteaders began settling the area in the 1870s and 1880s, and more arrived over the next couple decades as two communities grew up, Baker on the west side of the Baker River and then Cement City on the east side…
- Siderian (Wikipedia)
The Siderian Period ( /saɪˈdɪəri.ən, sɪ-/; Ancient Greek: σίδηρος, romanized: sídēros, meaning “iron”) is the first geologic period in the Paleoproterozoic Era and lasted from 2500 Ma to 2300 Ma. Instead of being based on stratigraphy, these dates are defined chronometrically.