The Krance family rose before dawn, drove 25 miles from Cranberry and wandered bleary-eyed into the Jurassic period.

"Three kids want to see the dinosaurs, so we're here first thing in the morning," Crissy Krance said yesterday.

"T-rex," said 2-year-old Katie. "He has a big tail."

When a kid wants to look at a carnivore tail, what parent says no?

They ate doughnuts in the car. They snagged a primo parking spot right next to the Carnegie Museum of Natural History. Their journey was untroubled by crowded highways, busy side streets and common daylight.

They were at the museum at 6 a.m.

That is to say at six o'clock in the morning. As in the prehistory of weekends, when homo sapiens are snug abed, still evolving, as it were, into something presentable at a more godly hour, say, 10 a.m.

T-rex, as it turns out, is in a rather literal body shop in Jersey being detailed for the opening next spring of Phase 2 of the museum's new hall. His bony compatriots, Diplodocus, Stegosaurus, Allosaurus and every other manner of eat-you-uppicus, were waiting in their new digs at The Carnegie.

Waiting for them were 200 Carnegie members, hard-core paleo-tourists who, like the Krances, entered the museum's draw for premier tickets to the new dinosaur hall. Back came the answers -- noon Saturday; 10 a.m. Sunday; 3 p.m. Sunday.

And, to the slightly astonished few, came a summons for 6 a.m.

"We asked ourselves, 'Are we really going to do this?' " Aaron Krance said, towing sons Ryan and Jake with one hand, signaling surrender with another. "We said to the kids, 'Guys, these tickets are really early.' They said 'We're gonna go.' It's a great adventure."

The adventure was guaranteed by a lottery designed to challenge the laws of time and space. The Carnegie had time for 2 1/2 days of opening for the new hall. It had space for 20,000. Someone did the math and 6 a.m. became the opening hour.

Ellen James, the museum spokeswoman, led what she described as a "weirdly cheerful" staff in greeting the undead yesterday.

"I actually grew up on a dairy farm. My first thought was, 'I only have to wake up this early to milk cows,' " said Miss James.

Juan Jorge Schaffer doesn't milk cows. He's a mathematician at Carnegie Mellon University. He knew exactly what time it was.

"What got us up at this hour? The ticket," Mr. Schaffer said. With his wife, Ines, he held the curious honor of being the Buzz Aldren of opening day -- the second visitors to put foot in the place.

First to cross over was Stephen Glass, a little boy who, the night before, rose from the dinner table, politely took his plate into the kitchen and informed his parents he was headed to bed so they'd be ready to rise for their early conference with the Cretacious .

Given that history moves in cycles, it seemed fitting he be first.

"We were here the day the hall closed, the last day, so we wanted to be here the first day," said Karen Glass, Stephen's mom. "And this was the time our ticket came up."

As for the Krances, they were in and out in about 90 minutes. They drove home, where Aaron and Crissy figured the kids would conk out for a few hours.

They gathered on the couch, watched a movie and were still revved at midday.

"It's going to be an early night," Mr. Krance said.

And an epoch of a day.