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

Front Range Foothills

Photographed by Kevin W., July 5, 2012

1. Front Range Foothills Marker

Inscription. You are looking out over the edges of tilted and eroded layers of sandstone and shale that lie upon much older rocks in the mountains behind you. If the eroded layers were restored to where you stand they would be more than two miles thick. The sandstone and shale were deposited as flat layers of sand and mud in streams, lakes and shallow seas during a time that began about 300 million years ago and ended about 70 million years ago. Later, the flat layers were bent upward during the rise of the Front Range of the Rocky Mountains. Since then, they have been eroded to their present form. The sandstone layers are hard, and their eroded edges form great ridges but the soft shale layers are hard, and their eroded edges from great ridges but the soft shale layers from valley which extend far to the north and south.

The rock on which you stand, and in which the Red Rocks Theater is carved, belong to the Fountain Formation. In places, these rocks contain fossil remains of tiny animals that lived in the sea about 300 million years ago (fossil 1).

Alon the highway that crosses the ridge in front of you there are maroon and gray

Paid Advertisement

Click or scan to see
this page online

shales of the Morrison Formation. These rocks – – about 130 million years old – – have yielded the remains of the largest dinosaurs that ever lived (fossil 2).

The ridge, known as the Dakota Hogback, is composed of hard Dakota sandstone, which lies above the Morrison Formation. The Dakota sandstone contains fossil clams (fossil 3) and is a valuable source of artesian water and of oil in the plains region east of the hogback. Afew miles south of here it contains uranium.

Mount Carbon, farther east, has seams of coal but consists mainly of clay used for bricks. It also contains fossil seashells and dinosaur bones about 100 million years old (fossils 4 and 5).

After these deposits were laid down, volcanic debris, partly preserved at Green Mountain, was deposited by streams.

Gravel along the creeks was washed down during the ice age only a few thousand years ago, when mammoths (fossil 6) roamed the Denver Plains.

Erected 1962 by Colorado Scientific Society and the Rocky Mountain Association of Geologists.

Topics. This historical marker is listed in these topic lists: Natural Features • Paleontology.

Location. 39° 40.331′ N,

Picture of cut away on lower front of Front Range Foothills Marker image. Click for full size.

Photographed by Kevin W., July 5, 2012

2. Picture of cut away on lower front of Front Range Foothills Marker

105° 12.225′ W. Marker is in Morrison, Colorado, in Jefferson County. It can be reached from Plains View Road. Touch for map. Marker is in this post office area: Morrison CO 80465, United States of America. Touch for directions.

Regionally, this marker is in the 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: Red Rocks Amphitheatre (approx. half a mile away); Red Rocks Trading Post (approx. 0.6 miles away); Red Rocks Park (approx. 0.6 miles away); Cretaceous Time (approx. 0.6 miles away); The Rocky Mountains (approx. 0.6 miles away); Brontosaur Bulges (approx. 0.6 miles away); Rock Deformation (approx. 0.6 miles away); Volcanic Ash (approx. 0.6 miles away).

Also see . . . Front Range. Wikipedia entry. (Submitted on September 13, 2020, by Larry Gertner of New York, New York.)

Red Rocks Amphitheatre from the Marker image. Click for full size.

Photographed by Kevin W., July 5, 2012

3. Red Rocks Amphitheatre from the Marker

Front Range Foothills Marker Wide View image. Click for full size.

Photographed by Leslie Eudy, October 31, 2025

4. Front Range Foothills Marker Wide View

Credits. This page was last revised on November 18, 2025. It was originally submitted on July 28, 2012, by Kevin W. of Stafford, Virginia. This page has been viewed 1,020 times since then and 37 times this year. Photos: 1, 2, 3. submitted on July 29, 2012, by Kevin W. of Stafford, Virginia. 4. submitted on October 31, 2025, by Leslie Eudy of Golden, Colorado.