Evidence Found of Lake, Catastrophic Flood on Mars
angkor points to this article on spaceflightnow.com, excerpting: "Scientists 'have discovered a large former lake in the highlands of Mars that would cover an area the size of Texas and New Mexico combined.'"
The BBC website has a related article about the formation of the Ma'adim Vallis. It can be found at News.BBC.Co.Uk
Just you're average nitpicker.