Plesiosaur patrol

Carter County Museum employees visited a friend last Friday when they dug into a plesiosaur buried in the southern part of the county. Even with GPS coordinates, they had difficulty finding the fossil in the tall grass. I know it's here, said Stew Cook, "I can feel it in my bones."

The search exhibited just how difficult it is finding a known fossil, let alone discovering a new one, in the 40,000 square miles of Southeastern Montana. Erosion, ice melts and heavy rain can expose bones that were not present last year, last month or last week; It is like refreshing a webpage. It can pay off to cover the same areas every year.

After hanging out with the plesiosaur, the crew hiked across fields, over hills and through trenches. A few lonely vertebrae were found, exposed in the middle of hills. Kolbe White gave a fossil hunting tip: If you find a bone halfway down a hill, start walking up. The bone could be washout from a larger specimen at the top of the hill.

One hundred million years ago Montana was part of the Western Interior Seaway. Besides the aquatic plesiosaur, other clues indicate a dried-up, inland sea. The crew found brittle baculites and spiraled nautilus fossils; animals in the same scientific class as squids, the cephalopods. The scenery has changed over millions of years, but paleontology is a young science and the detective work is just getting started. "We're trying to piece together an ecosystem," said White.