Oil and gas fields are widely developed in the southeast part of the Plains Border section—in the Smoky Hills, the Great Bend Plains, and the Red Hills.
The Plains Border section, like the Missouri Plateau, the Colorado Piedmont, and the Pecos Valley, is primarily a product of stream dissection. The differences in the outstanding landforms of the section are mainly the result of differences in the hardness of the eroded rocks.
EPILOGUE
The Great Plains, as we have seen, is many things. It contains thick layers of rock that formed in oceans, and younger layers of rocks deposited by streams. These rocks have been affected by earth movements and injected by hot molten rock, some of which reached the surface as volcanic rock. The rocks have been carved by streams, dissolved by ground water, partly covered by glaciers, and blown by winds. All of these agents have played important roles in determining the landscape and the landforms of the Great Plains. But the streams were the master agent. They formed the great depositional plain that was to become the Great Plains, and then began to destroy it—leaving only the High Plains to remind us of what it was. Those long miles we travel across the High Plains are a journey through history—geologic history.
ACKNOWLEDGMENTS
This narrative history of geologic and biologic events in the Great Plains had its origin in a study intended to identify potential National Natural Landmarks in the Great Plains, commissioned by the National Park Service. William A. Cobban, G. Edward Lewis, and Reuben J. Ross of the U. S. Geological Survey were collaborators in that study, and some of their contributions to the history of life on the Great Plains have been incorporated into this narrative, which was undertaken at the urging of Wallace R. Hansen.
The photographic illustrations, other than those obtained from the film library of the U. S. Geological Survey, were provided by the interest and effort of my friends and colleagues of the Geological Survey—including C. R. Dunrud, V. L. Freeman, C. D. Miller, R. D. Miller, F. W. Osterwald, R. L. Parker, W. H. Raymond, III, Kenneth Shaver, and R. B. Taylor—and by Eugene Shearer, Intrasearch, Inc., Denver, Colo. Without their help this publication would not have been possible.
SOME SOURCE REFERENCES
Alden, W. C., 1932, Physiography and glacial geology of eastern Montana and adjacent areas: U. S. Geological Survey Professional Paper 174, 133 p.
Bluemle, J. P., 1977, The face of North Dakota—the geologic story: North Dakota Geological Survey Education Series 11, 73 p.