Synthetic Men of Mars (Martian Tales, No. 9)
From Phundahl at their western extremity, east to Toonol, the Great Toonolian Marshes stretch across the dying planet for eighteen hundred earth miles like some unclean, venomous, Gargantuan reptile -- an oozy marshland through which wind narrow watercourses connecting occasional bodies of open water, little lakes, the largest of which covers but a few acres.