Dinosaur Ridge

Dinosaur Ridge is a hogback, a ridge of tilted rock running north from Morrison along the foot of the Front Range, and its two faces belong to different ages. The west side is Morrison Formation, river and floodplain mud laid down about 150 million years ago, in the Late Jurassic. The east side is Dakota Group sandstone, roughly 100 million years old, left along the shore of the shallow sea that once split the continent.

In March 1877 Arthur Lakes, an English-born teacher in Golden, found bones in the west face. He wrote to O. C. Marsh at Yale and collected for him from quarries along the hogback until 1879, and those quarries gave up the first known remains of Stegosaurus and Apatosaurus. The rock layer took the town's name, so the Morrison Formation that later yielded skeletons from Como Bluff in Wyoming to eastern Utah is named for this place. Stegosaurus has been Colorado's state fossil since 1982.

The east face waited for a road. In 1937, blasting for West Alameda Parkway over the ridge exposed hundreds of footprints in the Dakota sandstone, most of them left by three-toed plant-eaters, along with smaller meat-eaters; later work turned up the first raptor track found in Colorado. Bones are signed along the west side and tracks along the east. Alameda Parkway is closed to public traffic across the ridge and is walked or ridden as a paved trail of about two miles, with guided bus tours from the visitor center. The quarry and the tracks were designated part of a National Natural Landmark in 1973, now the Morrison-Golden Fossil Areas.