From a bluff-side vantage point 500 feet above the braids and twists of Alaska's Colville River, we notice that a line of brush along a distant gravel bed is, in fact, moving. "Caribou," someone says--hundreds of them, in fact, surging along the river in an improbably large, swirling mass. For expedition leader Anthony R. Fiorillo, it's enough to prompt a paleontological daydream: What if, 70 million years ago, a similar grouping of dinosaurs had passed this way? And what if those dinosaurs had met with a sudden, mass death, as caribou sometimes do? That might explain the bonanza of horned dinosaur fossils in the tundra underneath our feet--
possibly the densest concentration of saurian fossils in the world.
This article was originally published with the title Cretaceous Park.