The sliding rocks of Racetrack Playa. NOV 30 2007
These rocks can be found on the floor of the playa with long trails behind them. Somehow these rocks slide across the playa, cutting a furrow in the sediment as they move. Some of these rocks weigh several hundred pounds. That makes the question: "How do they move?" a very challenging one.
Includes some nice photos at the end. (via clusterflock)