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VERNAL, Utah (AP) -- Without any money to replace it, the National Park Service is watching a visitor center over a dinosaur bone quarry slowly split apart, making do with patchwork repairs as the building slowly deteriorates.
It's been taking place ever since the visitor center was built in 1957.
Gummy, clay soil under the building swells when wet and the concrete basement floor has warped into something like ocean rollers. When the bentonite clay soil dries, it crackles like popcorn and shifts parts of the building again.
"It's like a fun house," said Dan Chure, chief paleontologist at Dinosaur National Monument. "There's some everyday work that needs to be done to make sure the doors close."
The Quarry Visitor Center, about 20 miles east of Vernal, is considered safe -- for now. Officials keep it open with stopgap repairs, and keep track of a spider web of widening cracks on exterior walls using measuring templates that straddle each major crack.
The visitor center is shoehorned between a pair of sandstone ridges near the Green River but sitting on a bed of pliable, unstable clay. It houses some park offices, a gift shop, workshops for chiseling Jurassic-era fossils from rock and a glass atrium that extends over the bone graveyard.
The atrium is cracking open like a clamshell under relentless ground pressure, leaving a 4-inch gap that workers patched with insulating foam. Overhead, a ceiling beam hangs unsupported at one end, having pulled too far from a corner post to be reattached.
In time the building could be reduced to rubble, but most visitors are oblivious to the creeping damage, said Mary Risser, the superintendent of the monument on the border of Utah and Colorado. In the early 1900s this site became famous for supplying many of the country's museums with near complete skeletons of lumbering dinosaurs.
"The building has been moving since the day it was built," Risser said. "Over the last 50 years we've gone in and done some rehabilitation mainly to get rainwater and snowmelt away from it."
She said there was little the Park Service could do to shore up the visitor center for good.
The building isn't moving so much as shuffling in place, confused about which direction to take.
"Some parts of the building are moving one way and other parts are moving in another direction," said Chure, who has had to make adjustments for his own basement quarters.
To keep his desk level, he raised a plywood pedestal 5 inches above the rolling surface of the concrete floor.
In the West, bentonite clay soils are notable for causing pioneer cabins to collapse over time and buckling hard-surface roads. The clay expands considerably when wet and turns so pasty it can cling to shoes like a bowling ball.
The Quarry Visitor Center, on the Utah side of the monument, was built partly over a sandstone ridge where in 1909, Carnegie Museum paleontologist Earl Douglass spotted eight fossilized Brontosaurus tail bones.
Douglass spent 15 years excavating what turned out to be a bounty of bones from an area barely the size of a basketball court. He ended up shipping 700,000 pounds of packing crates of fossils to the Pittsburgh museum, Chure said.
In the 1930s, a WPA crew split open the ridge to reveal more dinosaur fossils, and the National Park Service reopened the quarry in 1953 for careful excavation. Today more than 2,000 bones are still embedded in a tilting slab of sandstone inside the visitor center's atrium.
Paleontologists believe the sandstone ridge once lay flat on a river bottom where floating dinosaur carcasses piled up on a sandbar, leaving a "bone logjam," Chure said.
The skeletons eventually were buried by river silt and fossilized. Later tectonic forces lifted up the rock bed at a 67-degree angle, letting erosion gradually expose a concentration of shoulder, hip and thigh bones, among other dinosaur parts.
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On the Net: Dinosaur National Monument: http://www.nps.gov/dino
(Copyright 2006 by The Associated Press. All Rights Reserved.) APTV-05-21-06 1218MDT
