“Alas for our friend, it does not. Over here, where the mud is pushed every which way, is where poor Patty falls. Wham! Leaving one hell of a nice body print, incidentally. This and this are definitely tail thrashes. She’s a game creature, is Patty. But the fight is all over now, however much longer it lasts. Once the apatosaur is down, that’s it. These little beauties are never going to let her get up again.”

He zoomed outward again, revealing yet more of the mudstone that had once been ancient lakeside. The trackway was, all told, over half a mile long. His back still ached at the thought of all the work it had taken first to uncover it—unearthing representative samples for the first two-thirds, skipping and sampling until at the end it got exciting and they had to excavate the whole damned thing—and then, when their photographs were taken and measurements done, to rebury it under layers of Paleomat and sterile sand in order to protect the tracks from rain and snow and commercial fossil hunters.

“And then, over here—” This was the exciting part, and involuntarily his voice rose. There was nothing he loved so much as a scientific puzzle, and this trackway was the mother of all brain-teasers. Besides the allosaur prints, there were also traces of secondary scavengers—birds, smaller dinos, even a few mammals—criss-crossing one another in such exuberant profusion that it seemed they might never be untangled. He welcomed the challenge. He looked forward to the work. “—this section is where our unfortunate Patty dies, and is eaten by the allosaurs.

“The incredible thing, though, is that some of the scattered bones were pressed into the mud deeply and firmly enough in the process to leave clean impressions. We made rubber molds from them—an ulna, parts of a femur, three vertebrae—enough to make a positive identification. The first direct, noninferential identification of a dinosaur footprint ever!”