From the May trip with Dana, this is the feature that locals call "The Wall." It really is an imposing feature: tall, vertical, and harder than Tyee sandstone normally is. It's also quite linear- the apparent bowing is due to assembling the panorama. Unfortunately, weathering and the growth of a shrubbery over the last couple of decades have largely obscured the clues you need to answer the puzzle, "what is the origin of this feature?" Location is uncertain, but if you drive from Harlan to Elk City along the Harlan Road, keeping an eye to the right side of the road, it's easy to find.
Panorama stitched in HugIn, otherwise unmodified. May 6, 2013.