North Dakota History Geology of the South Unit, Theodore Roosevelt National Memorial Park

How the Badlands Are Formed

The history of the Little Missouri has been outlined in the preceding part of this report. Now it would be well to consider just how the actual formation of these unusual scenic land forms took place.

First and most important to the formation of badlands is the action of water. This may seem unreasonable to the casual visitor who drives through the Park on a hot summer day with little or no water in sight anywhere. It must be remembered, however, that these erosional features were not formed in a day and that the erosive agencies have been at work for a long time. Furthermore, when the rain does come in this area, it frequently comes in the form of sudden showers and downpours which cause very rapid cutting in a short period of time.

In addition to the erosive work of short quick downpours of rain, the formation of the badlands is aided by the type of material being eroded. In the Paleocene rocks exposed in the Park area, it is found that poorly cemented sands, clays and siltstones are in the majority. These materials are easily eroded into gullys which can be seen on the sides of each of the buttes. This extensive gullying is the beginning of the badlands and therefore, each butte side shows the badlands in miniature.

Another factor in the formation of the badlands is the action of the burning lignite beds. The results of this burning can be seen through the Park by the great outcrops of the fused and burned rock which originally were shales, clays and sands overlying the lignite prior to its burning. These clinker beds are locally called "scoria." However, from the standpoint of erosion the most important thing that the burning lignite beds did was to open the ground above the lignite and break it up so that erosion was accelerated by these irregularities when the water did fall on the land.

The clinker also affects the land forms in that it is more resistant to erosion than some of the softer beds and therefore, where it caps, the buttes, the highest areas of the Park are frequently found. This relationship of the clinker beds to the topographically high areas can be seen everywhere in the Park.