Top photo—View is to northwest, looking across southeastern parts of ‘The Breaks’ at the northeastern corner of Wyoming's Hanna Basin. Shirley Mountains dominate the left skyline. Camera is placed at dead center of the W ½ of sec. 10, T. 23 N., R. 80 W., featuring lower Paleocene strata of the >4.8 km-thick Hanna Formation. Photographer stands on steeply southwest-dipping lower parts of hanging wall of the out-of-the-basin Dragonfly (thrust) Fault. As per usual for thrusts around the eastern half of the Hanna Basin, the Dragonfly Fault puts younger strata onto older, leading to structurally thinned sections around basin margins. On opposite side of the ephemeral drainage in the photo's center is the top of the Dragonfly's footwall. The steeply northeast-dipping rusty sandstone at the ridge's top is the southwestern edge of the fault's footwall syncline (the ‘Great Tortilla’ of Lillegraven et al., 2004, fig. 4B, RMG, v. 39,
Lower-left photo—Shown is a roughly 30 cm-wide band of tightly folded, alternating siltstone and coal found low in the hanging wall of the Dragonfly Fault (camera is directed northwest). This style of intense deformation is common at all scales adjacent to thrust faults around margins of the Hanna Basin, especially in hanging walls.
Lower-right photo—Shown are prosaic yet essential tools that greatly aided the field research included in the following article.