HuffPost Science: Incredible Fossil Find; Two-Headed Shark; Mars Rover

March 26, 2013 Subscribe · Forward Show & Tell Object Turns Out VERY Old Ever brought in something this good for show-and-tell? An unusual rock, which a 10-year-old student presented to his classmates, has turned out to be an incredibly rare, 320 million-year-old fossil of a horseshoe crab's footprints. Continue reading...