- A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers.
- Stillwater Bridge (St. Croix River) (Wikipedia)
The Stillwater Bridge (alternatively known as the Stillwater Lift Bridge, St. Croix River Bridge at Stillwater, Mn/DOT Bridge #4654, and Wis/DOT Bridge #M-61) is a vertical-lift bridge crossing the St. Croix River between Stillwater, Minnesota, and Houlton, Wisconsin, United States. It formerly connected Minnesota State Highway 36 and Wisconsin Highway 64. Around 18,000 vehicles crossed the bridge daily. The new St. Croix Crossing bridge crossing the St. Croix river valley to the south of Stillwater replaced its purpose, having opened to highway traffic on August 2, 2017, leaving the Stillwater Lift Bridge to be preserved and to be converted to bicycle/pedestrian use.