Dakota Group 112—100 Ma: This grayish-tan ridge (covered in large boulders) was formed in a coastal flood plain and beach sand environment during the Cretaceous period.

Keep a lookout as this ridge is also a favorite spot for Rocky Mountain Bighorn Sheep.

The Dinosaur Ridge just west of Denver is part of the Dakota Group. At Dinosaur Ridge, footprints can be seen of the dinosaurs that migrated along the western edge of this ancient sea.