Periodic Bedrock Ridges (PBRs) are features of the surface geomorphology of Mars and formerly unknown on Earth, first described in a paper in the Journal of Geological Research - Planets, in March 2012,[1] by Professor David R. Montgomery, Joshua L. Bandfield, and Scott K. Becker of the University of Washington.
[2] Evidence for sediment transport and erosion by wind is widespread over the surface of Mars today and was likely a major geomorphic process for much of its geological past.
[1] The authors reported evidence based on High Resolution Imaging Science Experiment images flown on the Mars Reconnaissance Orbiter, that show some megaripple forms are eroded into cohesive substrate rather than being composed of loose granular material or fossilized dunes.
Thus, some surfaces on Mars previously considered to be covered by wind-deposited material are actually wind-carved exposures that offer insights into Martian history.
Recognition of these transverse aeolian erosional forms brings up the question of how widespread Martian PBRs are and how many have been misinterpreted as active or indurated (fossilized) sedimentary dunes.