Castlewood Canyon provides high-quality, easily accessible exposures of the upper Dawson Formation and Castle Rock Conglomerate that provide an understanding of the geologic history of the Front Range. Canyon walls and adjacent caprock are excellent exposures of the Castle Rock conglomerate member of the White River Formation, coarse, erosion-resistant cobble cemented by volcanic ash.
In the northwestern portion of the park, a loose alluvium known as the Dawson Formation lies exposed. The scenic topography of the canyon is a direct result of the characteristics of the bedrock. As Cherry Creek cut down into bedrock, cliffs formed in the resistant, well-cemented Castle Rock Conglomerate. The broad, lower slopes of the canyon resulted from erosion of the soft upper Dawson Formation.
Read more about Castlewood Canyon's geology.