The modern assault on the “bad road” dinosaur began in September 1989, when State Paleontologist David Gillette joined Fran and Terby Barnes for a ten-day reconnaissance. Unlike standard digs, where fossils are gently brushed from soft clay, this sandstone had cured over 156 million years into something as unyielding as highway concrete. If you’re lucky, fieldwork in a dinosaur quarry can be a gentle process of clearing dirt to leave a fossil perched atop a neat pedestal of sediment. Still, the rock at the quarry had cured over 156 million years into something more unyielding than highway concrete. Modern dating technology from the quarry has set the age of the individual dinosaur at 156.1 million years, crowning it the oldest sauropod found to date in all of North America.