http://www.nytimes.com/2015/09/29/science/space/mars-life-liquid-water.html
Dark narrow streaks, up to a few hundred yards long, are seen along many slopes on Mars including Garni Crater. The identification of waterlogged salts in these streaks fits with the idea that they are formed by the underground flow of briny water that wets the surface.
I played this game 3 or 4 times with my grade 4 son. He said he would enjoy it more…
Brad