Dakota Sandstone
Outcrop at Dinosaur Ridge

Named after the peculiar ridgelike nature of the backs of underfed pigs, the land-form called the Dakota Hogback parallels the front of the Rocky Mountains for hundreds of miles. It is made up of Dakota Sandstone, formed from near-shore and beach environments that immediately preceded the arrival of the Interior Seaway. The portion of the Dakota Hogback located west of Denver is called Dinosaur Ridge because of the abundance of dinosaur footprints in this area. The beds are Cretaceous, about 100 million years old, and are about 220 feet thick.

If you examine some of the outcrops in detail, you will find ripple marks of shallow seas solidified in the sandstone beds. Little burrows and feeding traces of crustaceans and other critters that lived by the shore show up in them, as do fossilized woody and leafy plant material, fragments of a well-vegetated shoreline.

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