Gullies on Mars vs. Earth

Gullies on Mars vs. Earth
Gullies on Mars vs. Earth (A) Gullies in the mid-latitudes of Mars with the three characteristics labelled: Alcove, channels, and apron. (B) A gully on Mount St. Helens, imaged by Michael C. Malin. Coloured bar is 30 cm long. Modified from MGS MOC Release No. MOC2-234. NASA / JPL-Caltech / MSSS