Golden in Jefferson County, Colorado — The American Mountains (Southwest)

Cretaceous Time

Photographed by Jackson Perrie, August 25, 2018

1. Cretaceous Time Marker

Inscription. The tan sandstone of the Dakota Group form the crest of Dinosaur Ridge and were deposited more than 100 million years ago during Cretaceous time along the western shore of the Western Interior Seaway. At that time, only low hills existed to the west because the present Rocky Mountains had not yet been formed. At its fullest extent, the Seaway extended from the Gulf of Mexico to Canada. Sediments characteristic of beaches, swamps, and coastal plain wetlands were deposited on the shores of the Seaway as it grew and receded. The plants and animal whose traces and tracks are preserved in the rocks today lived in those ancient nearshore and intertidal environments.

Erected by Friends of Dinosaur Ridge.

Topics. This historical marker is listed in this topic list: Paleontology.

Location. 39° 40.566′ N, 105° 11.639′ W. Marker is in Golden, Colorado, in Jefferson County. It can be reached from County Road 93. The marker is on the Dinosaur Ridge Trail which is a 1.1 mile wide paved section of West Alameda Parkway that is closed to traffic. This marker is found 450 yards

Paid Advertisement

Click or scan to see
this page online

southeast of the parking area located at the junction of 93 (Hog Back Road) & West Alameda Parkway. Touch for map. Marker is in this post office area: Golden CO 80401, United States of America. Touch for directions.

Regionally, this marker is in Colorado’s Front Range.

It is also in the American Mountain West.

Globally, it is in North America,

the Rocky Mountains,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once the Louisiana Purchase.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Volcanic Ash (about 600 feet away, measured in a direct line); The Rocky Mountains (about 600 feet away); Brontosaur Bulges (approx. 0.2 miles away); Rock Deformation (approx. 0.2 miles away); Morrison Fossil Area (approx. 0.2 miles away); Late Jurassic Time (approx. 0.2 miles away); Theropod Track (approx. 0.2 miles away); West Alameda Parkway/Dinosaur Ridge (approx. ¼ mile away). Touch for a list and map of all markers in Golden.

Also see . . .
1. Cretaceous Time. (Submitted on October 23, 2018, by Alan M. Perrie of Unionville, Connecticut.)
2. Dakota Group.

The 100 million year old sandstone of Dinosaur Ridge. image. Click for full size.

Photographed by Abigail Perrie, August 25, 2018

2. The 100 million year old sandstone of Dinosaur Ridge.

(Submitted on October 23, 2018, by Alan M. Perrie of Unionville, Connecticut.)
3. Western Interior Seaway. (Submitted on October 23, 2018, by Alan M. Perrie of Unionville, Connecticut.)

Credits. This page was last revised on February 8, 2026. It was originally submitted on October 23, 2018, by Alan M. Perrie of Unionville, Connecticut. This page has been viewed 390 times since then and 18 times this year. Photos: 1, 2. submitted on October 23, 2018, by Alan M. Perrie of Unionville, Connecticut. • Andrew Ruppenstein was the editor who published this page.