Regional Geologic Relationships as Seen in the Bridal Veil Falls Area.

This Drone photo was taken along the broad curve in the highway just south of the Bridal Veil Fall's observation platform. looking in a northerly direction. The bluish-green Igneous rock that underlies the falls and dominates the right half of this photograph is comprised of a relatively uncommon igneous rock called phonolite – which is to say that it was once hot magma. This large body of phonolite, which is referred to as a Laccolith in geologic jargon,  actually extends across the highway to the left where exposures can be examined directly along the north end of the Bridal Veil parking area. When the hot magma migrated upward during Eocene Time, it lifted and tilted the overlying Cambrian Deadwood Formation which you can see in the photo above.  The Deadwood is comprised of an assortment of brownish sandstones, shales, limestones and conglomerates. The younger Mississippian Pahasapa Limestone can be seen in the distant cliff face. Although the falls itself is not visible in this photo, its waters enter Spearfish Creek through Rubicon Gulch near the cluster of trees just to the left of the label "Phonolite Laccolith.