The Devil’s Slide: A massive limestone chute in Utah’s Weber Canyon

Paul Revere
 
 
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Devil’s Slide is one of the more unusual natural formations located in northern Utah’s Weber Canyon. It lies just outside the town of Croydon, Morgan County, and is readily visible from Interstate 84.

It features a giant rock chute that extends several hundred feet down the side of the mountain.

Left - Devil's Slide photo by Carleton Watkins, c.1874. Right - Front view in March 2008 from the south parking area. 1-Wikipedia/Public Domain. 2- By Tricia Simpson/CC BY-SA 3.0.
Left – Devil’s Slide photo by Carleton Watkins, c.1874. Right – Front view in March 2008 from the south parking area

The sides are composed of hard, dense limestone layers around 40 feet high, 25 feet apart, and several hundred feet long that seem to slide down the hillside.

In between these two hard layers is a shaly limestone that is softer in comparison to the outer limestone layers, which makes it more susceptible to weathering and erosion, thus forming the chute of the slide.

Two limestone layers rise 40 feet above the canyon wall with 25 feet separating them. By Jeremybrooks/CC BY-SA 3.0.
Two limestone layers rise 40 feet above the canyon wall with 25  feet separating them. Photo credit

The Devil’s Slide is the tilted remnant of sediments deposited in a sea that once covered the whole of Utah. It is a classic example of how different rock layers, depending on their composition, are affected by weathering and erosion.

Front view in Fall of 2008. By J. D. Redding/CC BY-SA 3.0.
Front view in Fall of 2008. Photo credit

Approximately 170 to 180 million years ago, a shallow sea originating from the north spread south and east over areas of what are now Montana, Wyoming, and Utah.

This sea extended as far east as the present-day Colorado River and south into northern Arizona.

Massive amounts of sediment accumulated over millions of years and eventually formed layers of limestone and sandstone.

Together the rocks are lithified evidence of an ancient sea that covered parts of Utah, Wyoming and Montana 170 to 180 million years ago. By Ken Lund/Flickr/CC BY-SA 2.0
Together the rocks are lithified evidence of an ancient sea that covered parts of Utah, Wyoming and Montana 170 to 180 million years ago. Photo credit

The rock formations were tilted to the present near-vertical slant during a mountain-building episode that began about 75 million years ago.

A layer of shale between the limestone ridges eroded over time because it was less resistant, and thus the chute was formed, leaving the distinctive slide shape which we see today.