National Geographic : 1998 Dec
Walking on Eggshells On the second day of our search for fossils in a corner of Patagonia's vast Rio Colorado formation (bottom right), team member Carl Mehling handed me a porous gray rock. I realized immediately that I held a dinosaur eggshell. It turned out to be one among thou sands strewn across nearly a square mile and layered in mudstone 16 feet deep. As we explored the site, we were less stunned by its immensity than by its rari ties. It has RESEARCH yielded PROJECT the first Supportedin embryonic part by dinosaur your Society skin, the first dino saur embryos found in the Southern Hemisphere, and the first eggs that, because they contain embryos, can conclusively be identified as sauropod, a group of long-necked, elephant legged dinosaurs. The site-christened Auca Mahuevo after the area's volcano, Auca Mahuida, and its glut of eggs, or huevos is 55 miles from the nearest town and is as rough as it is remote. "There's no water, no shade," says my colleague, Argentine paleontologist Rodolfo Coria. "Just us, the Luis CHIAPPE is a paleontologist and MICK ELLISON is a senior artist at the American Museum of Natural History in New York City. This is photographer BROOKS WALKER'S first assignment for NATIONAL GEOGRAPHIC. badlands, and, if we are lucky, a dinosaur coming out of the ground." At Auca Mahuevo, our 12-person team has had the kind of luck most paleontolo gists only dream about. In the hillside quarry (above), Coria, at right, field technician Pablo Puerta, at left, and I unearth whole eggs, carefully open ing the shells to reveal tiny embryos. I' * - °mi 400 0km 400 NG MAPS Stli NATIONAL GEOGRAPHIC, DECEMBER 1998 FoilEgg,i e.