Jurassic Park

BUT COOK WAS INTERESTED. He made it his business to know everything about his property, but he knew nothing about dinosaurs. Never thought about them, never studied them, wouldn't know a dinosaur bone if he saw one.

So he, too, contacted the University of Wyoming, which sent a graduate student named Kelli Trujillo out to Spring Creek. She didn't have a scintillometer, so she had to search the hard way -- tramping around the rocks with her head to the ground.

And there they were.

She knocked on Cook's door and told him: You've got a big piece of the Morrison Formation on your property about 150 million years old. The Morrison is a footprint of shale, mud rock and sandstone laid down by an ancient, semitropical river system in what is now the western United States. Besides in Wyoming, outcrops can be found from western Montana into northern New Mexico and the tip of Oklahoma. It is the most famous dinosaur bed in North America, Trujillo told Cook, and one of the most famous in the world. It's known for big sauropods -- plant-eaters.

You've got plenty of those, but your piece of the Morrison is special for another reason, she continued. You've got little critters, too, and fossilized fish, birds, turtles and even plants. Other parts of the Morrison, like Como Bluff down the road, probably had all that stuff once, but back in Wyoming's dinosaur glory day, the bone hunters kicked the small fossils aside so they could mine the apatosaurus, the diplodocus and the other monsters that the museums were looking for.

Things are different now, she explained. Today scientists want to know everything about a site -- not only the dinosaurs but the rest of the animals, as well as the plants, the ancient weather and what the world was like. And nobody has so much as stuck a pick in the ground in Spring Creek, she said. You've got "Jurassic Park" in your back yard. Untouched. The real thing.

She took Cook out to the ridge to show him. Cook realized he'd walked past dinosaur bones before but hadn't recognized them. The bones are petrified, literally turned to stone, and that's what the untrained eye sees.

There was no obvious reason for Spring Creek to have escaped the pickax for so many years, but Cook had a pretty good idea: "Private owners always controlled it, and they had heavy hands that didn't allow much access."

Cook's property was a classic case. For decades, it served as the headquarters of the Swan Land and Cattle Company, one of the biggest ranches that ever existed, and one with an unforgiving landlord. Along with other self-help techniques, rustlers were discouraged with bullets. In the 1890s Swan hired the notorious gunman Tom Horn to perform this service, and he did well. His tragic flaw, however, was excessive zeal, not a good trait for the frontier equivalent of a paid enforcer. Wyoming hanged him in Cheyenne in 1903 for murdering the 14-year-old son of a homesteader.

Southeastern Wyoming today is less cutthroat, but it's still not a good place to wander unasked onto somebody's land, then compound the insult by trying to intimidate the owner into getting rid of it. Especially Allen Cook. That somebody would even think of it is almost inconceivable to anyone who knows the rancher. Trujillo, now an independent paleontologist and Cook's fast friend, noted that "Allen doesn't like anyone telling him what he should do with his property." Indeed.

But after Trujillo showed him the Spring Creek dinosaurs, "I was intrigued," Cook acknowledged. "I started to realize the magnitude of the find."

Maybe the dinosaurs were worth something, and he could sell them. He knew Spring Creek was the most "logistically difficult" part of his ranch. Grass was good, but there weren't many roads. Hard to reach the cattle. He didn't have to keep that piece, and somebody might pay a premium for it. He'd check it out further, then decide.