This subimage highlights a feature that resembles a terrestrial glacier, indicating that material has viscously flowed at this location. It appears that water ice has collected at the head of the valley (at bottom), allowing glacier-like flow toward the top of the subimage.
At the top right of the subimage, the flow appears to have slowed down and stopped, forming ridges perpendicular to the flow direction. Similar features are observed on terrestrial glaciers, but Martian examples are not as bright as many on Earth. The Martian glaciers appear to be covered by dust and other debris, hiding the ice below. Such debris-rich flows on Earth are called "rock glaciers" and may be good analogs for the flow seen here.
Photo credit: NASA/JPL/University of Arizona
Note: This photo was taken in the Protonilus Mensae region, which is located between the northeastern-most tip of Arabia Terra and Vastitas Borealis. The location of this glacier is roughly halfway between the craters of Moreux and Renaudot, being slightly closer to Renaudot.