HiRISE 3D: The Scouring
Scour pits are a poorly understood erosional feature that are nearby but distinctive from the Medusae Fossae Formation (MFF). At the southwest of the main MFF formation unit, there are systems of hundreds of scour pits.
https://www.uahirise.org/anaglyph/ESP_083046_1795_ESP_083191_1795_RED
NASA/JPL-Caltech/UArizona