Devil's Kitchen
A few miles north of Highway 14 between Greybull and Shell is a real “hole in the ground”, dubbed Devil’s Kitchen. This features covers roughly 128 acres. While some might view it as a desolate place, to geologists it is a heavenly paradise. Hundreds of students studying geology, enrolled in some of the nation’s best universities and colleges, have walked over and mapped this area for decades. Devil’s Kitchen exhibits classic “badlands” topography. Badlands typically form in arid environments where easily eroded clay-rich mudstones and sandstones are dissected by many little gullies and rills. Badlands topography will have steep slopes with very little vegetation.
Most of Devil’s Kitchen is made up of the Cloverly Formation with a little bit of Greybull Interval and Sykes Mountain Formation at the very top of the rim. These are all units that were deposited in the early part of the Cretaceous Period. If you do decide to visit Devil’s Kitchen please be aware that this road is used to haul bentonite (a type of clay that has a variety of uses including cosmetics, a food additive, paint, kitty litter, etc.) to a nearby processing plant. Please give these trucks plenty of room and don’t drive on these road when they are wet!
Directions to Devil's Kitchen
From Shell
Follow US-14E west to Davis Road (7.8 mi). Continue north on Davis Road (1.1 mi). Turn left on Co. Ln. 33 (2.8 mi). Turn left towards Devil’s Kitchen (0.7 mi). Total drive is ~20 min.
From Greybull
Follow US-14 E to Davis Rd. (7.4 mi). Continue north on Davis Road (1.1 mi). Turn left on Co. Ln. 33 (2.8 mi). Turn left towards Devil’s Kitchen (0.7 mi).. Total drive ~ 21 minutes
Where Are You Stratigraphically?
This chart is a simplified summary of the geological formations that exist in the Big Horn Basin. The numbers to the left are the ages of the rocks in millions of years. The Cloverly Formation is highlighted in yellow.
While this chart may look a bit intimidating to a non-geologist, it is a geologist’s attempt to simplify what they see in the outcrops around them. The generalized section on the right indicates the stratigraphic level of the Cloverly (in yellow). The different patterns reflects the rock types that occur in the Cloverly Formation in the area around Devil’s Kitchen but not necessarily in Devil’s Kitchen.
Why Is Devil’s Kitchen Here?
Figure is modified from http://pages.geo.wvu.edu/~kammer/g100/StructuralGeology.pdf
​
This diagram shows a conceptual cross section through the area around Devil’s Kitchen. The circled area denotes where Devil’s Kitchen is located at the very north end of Cherry Anticline. Devil’s Kitchen is a classic example of “inverted topography” formed when the area was folded into an anticline (formation of rocks that when they were squeezed together to form a broad arch by tectonic forces starting ~ 70 million years ago. Think of a rug or a stack of colored paper that is pushed and distorted into wrinkles. In geology each page is a formation or type of rock, like sandstone or mudstone or limestone. Imagine the top page is hard, like a sandstone. Then imagine that the “hard” page overlies a “soft page” composed of mudstone. As the fold was exposed by erosion, the hard sandstone was eroded off the top of the fold exposing the soft mudstone below it. At that point, the center of the fold exposed the softest rocks composed of clay-rich mudstones which were susceptible to weathering and erosion. Around the rim today are most the resistant sandstones. The center of the fold now erodes faster than the rim creating a depression in the center of the fold.
If you look west of Devil’s Kitchen you will notice a ridge of silica-cemented sandstone that overlies black mudstone. This ridge is in the Mowry Formation and it forms part of Poverty Flat Syncline, a fold that was down-warped by the same tectonic forces that created Cherry Anticline.
This Google Earth image shows the structural axes of Cherry Anticline and Poverty Flats Syncline. Devil’s Kitchen is at the very north end of Cherry Anticline and is only a small part of a much larger structure that extends southeastward towards Red Gulch Dinosaur Tracksite.
What Can You See?
The Cloverly Formation is comprised of two main units. The lowest is the Little Sheep Mudstone Member and it occurs in the bottom of the depression. In the Devil’s Kitchen area it is dominated by battleship grey and purplish mudstones and whiteish somewhat more resistant siltstones and mudstones. These units were deposited in ancient ephemeral lakes (termed playas) and mudflats in what were, at least seasonally, arid environments.
The upper Cloverly Formation unit is called the Himes Member and it is composed of reddish and greenish sandstones and mudstones that contain abundant volcanic grains. It was deposited in rivers and floodplains that drained volcanic highlands to the west. It is more resistant to erosion and forms part of the cliffs that rim Devil’s Kitchen.
On top of the Himes member are a series of stacked fossil soils (termed paleosols). They form a transition from the underlying Himes Member to the overlying Greybull Interval. For those of you who really want to geek out here, please notice the white “tongues” of sediment that extend down into the top of the Himes Member. There are two schools of thought regarding these features. The first is that they are the remains of fossilized vertisols, organic poor clay-rich soils that shrink and swell during pronounced wet and dry seasons. The second school of thought is that they are the remains of fossilized crayfish burrows.
This paleosol complex marks a major change in paleocurrent drainage towards the end of Cloverly time. During the Himes Member time, the rivers flowed eastward. When the Greybull Intervals was being deposited, the rivers flowed westward. Over tens of thousands to several hundreds of thousands of years the landscape changed from eastward dipping to westward dipping. When the thick paleosols formed, the gradient was essentially flat with few rivers crossing it.
Some Paleontology
The sediments that make up the core of Devil’s Kitchen constitute most of the Cloverly Formation. It was deposited near the beginning of the Cretaceous Period about 110 to 120 million years ago. This was millions of years after the Jurassic dinosaurs Allosaurus, Diplodocus, Stegosaurus, and Camarasaurus were dead and gone. In their places were the plant-eating ornithopod Tenontosaurus, armored tank-like herbivores like Sauropelta and Tatankacephalis (buffalo head) and the fierce little (about 3 feet tall) predators called Deinonychus aka “wolf of the Cretaceous”. If you look around in the Little Sheep Mudstone in the basin you will likely find dinosaur bones weathering out, perhaps the remains of one of these Cretaceous animals.
Bones of an unknown dinosaur weathering out of the Little Sheep Mudstone Member of the Cloverly Formation
Deinonychus Bayla Arietta Watercolor 2016 ©Bayla Arietta from https://peabody.yale.edu/article/deinonychus
Within the Greybull Interval, researcher Dr. Nathan Jud has discovered some of the oldest flowering plant fossils found in North America (for example, this poppy-like leaf). Prior to this the landscape was the exclusive domain of conifers, cycads (palmlike plants), ginkgoes, ferns and large horsetails.