Glaciologists have uncovered large valleys in the ocean floor beneath some of the massive glaciers flowing into the Amundsen Sea in West Antarctica. (eos.org)
In those moments I am willing even to indulge his somewhat romanticized view of himself: a figure in the twilight, at the end of a long journey through a large valley and into wooded hills, perhaps pausing on a low ridge that affords him a last narrow glimpse of the paths he has followed, watching the evening descending over the mountains and down toward darkening lakes and fields, trying to fix in memory the shape of a world soon to be lost in night. (firstthings.com)
However, these valley networks are less developed than typical terrestrial drainage systems, with the Martian examples lacking small - scale streams feeding into the larger valleys. (solarviews.com)