Hamilton Dome oil field is located on an asymmetric anticline that displays strong thinning of Mesozoic shales on its steep limb. These shales have lost about 65 percent of their thickness by removal of discrete sections that are as much as 700 ft (200 m) thick in the Triassic Chugwater Formation, but a normal thickness of shale is present in the adjacent syncline. Total vertical displacement of Paleozoic rocks is about 6,000 ft (1,800 m) but these rocks are not present on the steep anticlinal limb. Based on fold geometry, the seemingly missing section of Paleozoic rocks is 2,700 ft (800 m) thick and about 5,000 ft (1,500 m) long. Thus a significant volume of Paleozoic rocks, as well as Mesozoic shales, must be present beneath the anticline and Precambrian basement rock m st have been uplifted along a reverse fault that has a northeast dip of 60° or less. During uplift, Mesozoic shales may have been deformed by plastic flow, and thick sections appear to have been lost from the steep flank by transfer to the adjacent syncline.