Caprock Coulee Nature Trail

A swath of tall green and yellow grass in front of colorfully striped badlands buttes

The Caprock Coulee Nature Trail is a 0.8 mile section of the Caprock Coulee Trail in the park's North Unit. The nature trail trail shows the natural and geologic variety of the badlands. It also provides a rare look at a densely wooded area of the park.

When you reach the end of the nature trail, turn back for a trip totaling 1.6 miles. Or, if you are prepared for a longer hike, continue on the Caprock Coulee Trail for a hike of 4.1 miles. Wear sturdy shoes and appropriate clothing. Carry extra water and a trail map.

As you hike, stop at each numbered trail post and read the corresponding text below. Remember to Leave No Trace; Help preserve the park for future generations by leaving everythign just the way you find it.

1 Coulees

Coulees are steep, narrow valleys like the one you are about to enter. Although they are formed by water erosion, coulees are usually dry in summer, except during thunderstorms. In the 1800s French fur trappers began referring to these valleys as “coulée” meaning “flow.” Since then the name has stuck.

Take a left where the trail forks. The trail to the right leads to the Buckhorn Trail.
small crevasses cascading down a sandy outcropping show evidence of water erosion

2 Rivulet Erosion

The pattern on the hillside is rivulet erosion. Rain carves a maze of channels over the face of the butte. These narrow rills merge to form a network of larger channels. Rivulet erosion is one of many never ending systems of erosion taking place in the badlands. With each rain shower, the land changes shape.
Three grass seed head. First, green needle with a long spike of seeds with short, curled hair-like awns. Second, green needle with a spray of long straight awns, last western wheat with tall clusters of stout seeds
From left: Green needle grass (Bouteloua gracilis); needle-and-thread (Stipa commata); western wheatgrass (Agropyron smithii)

3 Grasses

Rainfall influences the amount and type of plants that can grow in an area. This region receives only about 15 inches of precipitation each year, making it well suited for grasses. Prairie grass is an important food source for grazers like bison, deer, and other wildlife.

sprays of small white flowers grow from branches of dark green leaves with finely toothed edges
Chokecherry (Prunus virginiana)

4 Chokecherry

Dark purple chokecherries hang from these branches in late summer. Plains Indians enjoyed the fresh berries and also ground and dried them for winter use. Beware! The leaves, roots, and seeds are poisonous.


5 Badlands Slopes

Look for the differences in the vegetation patterns on the buttes around you. Notice the moist, cool, north-facing slopes supporting stands of juniper and other woody plants. South-facing slopes receive more direct sun rays making them hotter and drier. They are the ideal place for more desert-like plants. Explore these two plant communities on the trail ahead.
An illustration overtop an image of a butte shows the transition from shady, cool, moist north slopes to sunny, hot, dry, south slopes.

6 Differential Erosion

The thin layers of rust-red rock on the butte in front of you are iron-impregnated sandstone. Because they are harder than the soft gray sediments that make of up the rest of the butte, they erode more slowly. Notice how these hard layers form shelves that protect soft sediments below. This type of erosion, called differential erosion, is the main shaping force of the badlands.

Horizontal layers of hard, rust-colored rock protect softer rock layers below which show signs of water erosion
Three silvery blue/green sagebrush examples: long, slender leaves of silver sage, three-loped leaves of big sage, small tufts of fringe sage leaves
From left: silver sagebrush (Artemisia cana); big sagebrush (Artemisia tridentata); fringed sagebrush (Artemisia frigida)

7 Sagebrush

Silver-green sagebrush is a common sight throughout the western United States. Here, it grows abundantly on terraces above the Little Missouri River. Look closely at the leaves on several of the bushes as you walk along the trail. You should find three different shapes belonging to three different species. Notice how each species has a unique smell.
Small pieces of black lignite coal flake out of a hillside

8 Lignite

On the slope to your left is a thin black seam of lignite coal. Coal forms when vegetation is buried and subjected to great heat and pressure. Coal seams and other fossils tell us this region was once a lush, thickly vegetated swamp.
A closeup of blue-gray bentonite clay with a popcorn-like texture, and a hillside with swaths of bentonite that have flowed down when the clay was wet

9 Bentonite

The blue-grey sediment on the hillside across the coulee is bentonite clay. Bentonite contains volcanic ash and is common throughout the badlands. It can absorb several times its volume in water and has many industrial uses. After heavy rains or when soaked by melting snow, it expands and flows down hillsides. Notice the wildlife trails crossing the steep bentonite slope.
A yellow cactus bloom with numerous orange stamens atop a light green cactus pad with long white spines

10 Prickly Pear Cactus

Prickly pear cactus (Opuntia polyacantha) grows in clusters on the hill in front of you. It is one of few cactus species to grow this far north, and one of four in the park. Prickly pear is adapted to withstand periodic droughts. Its leaves have been reduced to spines to help preserve moisture and protect the plant.

11 Petrified Wood

Light-colored pieces of petrified wood dot the far hillside. They are the fossilized remains of trees that grew here 55 million years ago. Parts of the trees were covered by sediment which prevented decay. Ground water slowly filled the cell spaces with minerals. The minerals hardened, preserving the trees as rocks. Much later in time, erosion exposed the petrified wood. The trees, likely cypress or magnolia, are further evidence of the area’s swampy past.
A mound of earth with diagonal rock layers
This example of a slump formation is visible along the North Unit Scenic Drive.

12 Slump

Across the coulee to the right is a small slump. Notice its layers are diagonal instead of horizontal. Unlike a landslide where earth and rock break up as they tumble down, slump blocks remain whole as they slide. Match the colors in the slump to the rock layers on the wall above to find where the slump came from.


13 Piping

The vertical “pipes” in the coulee walls are formed by a type of erosion called piping. Rainwater enters small surface openings, like rodent burrows or tree root tracks, and saturates the ground. The saturated ground then collapses, forming a pipe. The size of some pipes, up to several feet deep and wide, makes them a significant force of change in the badlands.
Three types of juniper needles are shown along with the plant's shape/habit.
Top: Rocky Mountain juniper (Juniperus scopulorum), an upright tree with scale-like needles. Middle: common juniper (Juniperus communis), a shrub-size plant with sharp needles. Bottom: creeping juniper (Juniperus horizontalis), a low ground-cover type plant with scale-like needles.

14 North-facing Slopes

The next part of the trail explores a north-facing slope. Notice the difference in temperature. Animals and hikers alike appreciate these pockets of vegetation for the shade and protection they provide. Three types of juniper grow on north-facing slopes. See if you can locate them all.
long delicate stems of rabbit brush covered in long, slender green leaves.

15 Rabbitbrush

Rabbitbrush is the last flower of the season to bloom, hinting at the arrival of winter. During the hot summer, rabbitbrush provides shade and shelter for small animals. In the winter it serves as food for deer and elk.

16 Active Slump

A slump that begins on the butte ahead has completely blocked the coulee. Water from the seep above you saturated a layer of bentonite clay. The force of gravity on the wet, slippery clay was too much and a section of land gave way, sliding into the coulee. While the seep water is unfit for human use, animals welcome it in this semi-arid country. Watch your footing - seep water can make this area slippery.

17 Wildlife Tracks

Small sources of water, like the one you just passed, become gathering places for wildlife. Seeps and springs draw bison, coyotes, and other animals looking for a drink. Look for signs of their presence, such as tracks or scat, on the trail.

Bison and deer tracks have a two-toed appearance but are quite different in size and shape. bison tracks are up to 6 inches long and the toes are curved inwards. Deer tracks are about 3 inches long and the toes are straight.

Canine and feline tracks are also quite distinct, once you know what clues to look for. Coyote tracks are about 2.25 inches wide, oval-shaped and nearly symmetrical. The foot pad has two lobes at the bottom and the tracks always have claw marks. Mountain Lion tracks are larger at 3.5 to 5 inches across. They are circular in shape and asymmetrical with one leading toe. The foot pad has 3 bottom lobes and claw marks are usually absent.
Large bison track with two toes that curve in. A smaller deer track with two straight toes, an oval-shaped coyote track with claw marks, and a large, circular mountain lion track with no claw marks.
Tracks from left: bison, deer, coyote, mountain lion

18 Forest Litter

Forest “litter,” made of fallen leaves, trees, and other dead plant matter, is an important part of the north-slope habitat. Many animals use forest litter for food, shelter, or nesting places. As time passes, the dead plant materials decay into the ground to nourish a new cycle of plant growth.
clusters of yellow, oblong seeds hang from a branch with bright green simple shaped leaves

19 Green Ash

Green ash grows in ravines and coulees throughout the park. Songbirds build their nest in the ash tree’s shady branches. Bison use trees as scratching posts. Can you feel where their scratching has rubbed the bark smooth?
A rough, curly coating of mint-green lichen growing on grey tree bark

20 Lichens

The bright-colored splashes on the tree trunks are lichens (pronounced li-kens). Lichens consist of two different organisms – fungi and algae. The two live together in a balanced relationship as if they were one organism. The alga makes food, while the fungus gathers and holds water for both organisms. Lichens can be indicators of changes in the environment; some species are sensitive to changes in air quality.

21 Trail's End

You have reached the end of the Caprock Coulee Nature Trail. The shortest way back to your car is to turn around here. If you continue ahead you will have to hike another 3.3 miles to return to where you started. Only continue if you are prepared with extra water, appropriate clothing, and a map.

Last updated: November 29, 2018

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