Lyons Sandstone is a geological layer formed during the Paleozoic Era, Middle Permian Period about 250 million years ago. This layer is also referred to as the Lyons Formation. It is the result of fine-grained quartz sand dunes compressing into sandstone. This layer is visible along the Front Range of the Colorado Rocky Mountains.
References
External links Colorado Mountain Presentation Geology of Colorado (Boulder Valley) Geologic History of the Boulder Area The Horsetooth Quadrangle Virtual Geological Field Trip USGS Geolex Database: Lyons Roxborough State Park Geology