In this interesting VIS image, taken by the NASA - Mars Odyssey Orbiter on August, 24h, 2015, and during its 60.745th orbit around the Red Planet, we can (actually, barely) see some Dark Streaks on the Slopes of small Hills (look at the Surface Features found on the upper portion of the frame) and Unnamed Crater Rims (look at the lower portion of the pciture) which are located in the Martian Region known as Amazonis Planitia.
It is (generally, by Planetary Scientists) thought that the removal of (large quantities of) Dust by Downslope Movements (due, perhaps, to the occurrence of either Gravity Wasting and/or strong Aeolian Actions) reveal, in - usually, a VERY long - time, the darker Rocks that lie beneath the Dust itself.
Latitude (centered): 13,620° North
Longitude (centered): 191,678° East
This image (which is an Original Mars Odyssey Orbiter b/w and Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 20072) has been additionally processed, magnified to aid the visibility of the details, extra-contrast enhanced and sharpened, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.