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| | Has Mars Always Been Dry |
 | | The sub-surface topographic gradients would be shaped by the ground closest to the scarp edge being warmed to a slightly greater depth than that further away, resulting in a sub-surface, truncated shallow basin like very flat versions of the alcoves described by Malin and Edgett, but underground. |
| | The dense gas would flow to the crater or canyon edge, then tip itself downslope, taking loose light loose material with it, and in time undermining the large boulders, to decametre size, that have been seen to have tumbled down some slopes. |
| | Moreover, dune patterns converging on a breach at the top of one of the Gorgonum Chasm cliffs show that strong surface flows of air also tip themselves into the canyons, and probably contribute largely to erosion and transport below. |
| www.spacedaily.com /news/mars-water-science-00i14.html (1033 words) |
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