A. M. White W. N. Sharp 1957 <p>The Pumpkin Buttes area comprises about 450 square miles in Campbell and Johnson Counties that includes several prominent buttes known as Pumpkin Buttes.&nbsp; The area is near the center of the Powder River Basin, a large physiographic unit of prairie and sculptured terrain that occupies approximately 12, 000 square miles of northeastern Wyoming.&nbsp; The basin is bounded on the east by the Black hills, on the south by the Laramie Mountains, and on the west by the Big Horn Mountains.&nbsp; The northern end is more or less open into Montana.&nbsp; Much of the basin ranges in altitude from 4,000 to 5,000 feet above sea level; but in the central part, about 40 miles southwest of Gillette, the Pumpkin Buttes rise abruptly to an altitude of 6,000 feet.</p><p>Secondary uranium minerals were discovered in the vicinity of Pumpkin Buttes in October 1951 (Love, 1952).&nbsp; The following spring, a study of the area and the uranium occurrences was begun by the Geological Survey on behalf of the Division of Raw Materials of the U. S. Atomic Energy Commission.&nbsp; The accompanying map, which shows distinguishable lithologic units and occurrences of uranium in outcrop, is a result of the continuation of this study.</p> application/pdf 10.3133/mf98 en U.S. Geological Survey Preliminary geologic map of the Pumpkin Buttes area, Campbell and Johnson Counties, Wyoming, showing location of uranium occurrences reports