This paper is the result of field work done during the seasons of 1904 and 1905 It is designed mainly to furnish information regarding geologic structure and the prospects for underground water. The description of the formations of the Bighorn Mountain area is chiefly the work of N. H. Darton, under whose direction the exploration ·was made.
A general account of the surface waters is given, including a statement of their present and proposed uses for irrigation, and the economic products of a geologic nature are also described. The region considered comprises the Bighorn basin, a part of the Clark Fork basin, and the slopes of the adjoining mountain ranges, the entire area comprising 8,500 square miles. As shown on fig. 1, it is situated mainly in Bighorn County, in the northwestern part of Wyoming, and includes the greater portion of the area lying between meridians 107° 15' and 109° 15' and parallels 43° 40' and 45°. It is bounded on the north by Montana, on the east by the Bighorn Mountains, on the south by Bighorn and Owl Creek mountains, and on the west by Shoshone, Absaroka, and Beartooth mountains.
