Badlands are regions dissected into steep hills and deep gullies by the action of wind, rain, and ﬂash ﬂoods. The name was originally applied to a semiarid area in South Dakota east of the Black Hills, called les mauvaises terres à traverser by the French because it was so difﬁcult to cross; the term is now generally applied to similar lands throughout the continent. In All the Strange Hours, Loren Eiseley writes: “I will never forget my ﬁrst day of registration at the University of Pennsylvania. I had come directly from the Mauvaises terres, the Tertiary badlands of western Nebraska, into a great city of banging, jangling trolleys, out of a silence as dreadful as that of the moon.” The friable topography of the Badlands, composed primarily of shales, clays, and sandstones, has been sculpted into a maze of barren ravines and tunnels, and grassy-topped tables. (The sparse vegetation is deceptive; while puny on the slopes, it can be comparatively lush on the ﬂat tops.) The average slope angle in the heart of this desiccated world often exceeds thirty-ﬁve degrees— steep enough to drive rain from seasonal summer thunderstorms downhill with scouring force, leaving the sides of the tables looking barren and peeled. The Lakota Sioux name for the Dakota Badlands is Mako Sica, meaning “eroded land,” a region they were wary of. During the Ghost Dance conﬂicts of the late 1800s, diehard Lakota warriors assembled on remote tables in the depths of the Badlands, out of sight of white authorities who feared the dancing would foment an outbreak of violence.