Sentence:  It was even larger than the mirage made it look—a dozen miles across and a thousand feet deep, with fins and towers and <WSD>hoodoos</WSD> like observation posts, mesas and minor buttes, springs flowing brightly in the red rock. 
Meaning of the word marked with <WSD> tags:  A tall thin spire of rock that protrudes from the bottom of arid basins and badlands.