Courtesy Charles KnightA couple of nature lovers hiking through a meadow in France’s Jura Mountains discovered some very large dinosaur tracks. The 20 or so tracks measuring between 4.6 and 4.9 feet in diameter are some of the largest ever found, and date back 150 million years ago to the Late Jurassic period (which by the way was named after rocks found in the same mountains). The couple reported their find to scientists who think there could be hundreds or maybe thousands of footprints still to be uncovered. So far, the evidence points to giant sauropod dinosaurs (such as the diplodocus pictured) as the probable track-makers. The study of trace fossils, such as dinosaur tracks, is called ichnology.