The Monte Cristo area is a 7 1/2-minute quadrangle located in the southeastern. part of the Bear River Range, northern Utah. It is within the Middle Rocky Mountain province and is 10 miles east of the Basin and Range province. Previous to this investigation little was known about the detailed geology of the area except for a reconnaissance study and general geologic map of the Cache County part included in the Geologic Atlas of Utah, Cache County, published by Williams (1958). The purposes of this investigation were as follows: (1) to determine the formations present in the area and their relation to regional stratigraphy, (2) to determine the structure of the area and its relation to regional.structure, and (3). to produce a geologic map of the area (Plate 1).