Bone up on the past at Utah's fossil sites

The bluffs and hills of this mountain biking hub were as red as a sunburn and barren, save for a few juniper trees and clumps of rabbit brush.

As I hiked to a flat stretch of sandstone, I saw them – bigger and more clearly defined than I had expected: dinosaur tracks.

I ran my fingers along the curve of the claw and pressed my palm inside the hubcap-size impression. It was a creepy feeling occupying the same spot as an SUV-sized lizard.

When the giant meat eater, probably an allosaurus, walked across this spot about 150 million years ago, the landscape was a tropical environment on the shores of an inland sea, lush with ferns, cycads, conifers and ginkgo trees.

Here, the beast's feet sank into a sandbar. Over time, seismic forces buried, solidified and then pushed that sandbar to the surface, retaining in astonishing detail the prints of that long-extinct monster.

A happy geological fluke has made Utah one of the world's best spots to hunt for dinosaurs.

Throughout the rest of the U.S., this fossil-rich layer of sedimentary rock is buried under prairies and forests. But in the badlands of Utah, the stratum rests near the surface, even along hiking trails like this one.

I consulted Utah's top paleontologists on the best way to make a four-day road trip to see the state's dinosaur exhibits. They told me the best time to visit is now, during an era of astounding discoveries. Thanks to improved technology and exploding interest in the field, paleontologists are digging up new dinosaur species around the world at a rate of 10 to 20 each year.

Utah's quarries have been at the forefront of this trend, producing such discoveries as a strange duck-billed herbivore, a new horned quadruped, plus evidence that some dinosaurs fished.

Here are my favorite stops.

St. George Dinosaur Discovery Center,

Johnson Farm

Eight years ago, Sheldon Johnson, a retired optometrist, was prepping land for resale when he spotted something in the soil. He uncovered thick mudstone slabs imprinted with thousands of dinosaur prints, including skin impressions and tracks from what paleontologists believe was the lanky, fast-moving coelophysis of the early Jurassic period.

Johnson notified paleontologists and city officials, who later built a museum around the impressions, which are 200 million years old. Among the exhibits is the world's largest slab of stone containing dinosaur prints, weighing more than 26 tons.

From bones, paleontologists learn about the size, anatomy and diet of dinosaurs. From track prints, experts get clues on how they sat, ran, turned and hunted. Andrew C. Milner, the city's paleontologist, believes scratch marks on several slabs suggest some dinosaurs swam in the shallows pursuing fish.

Details: St. George is in the southwest corner of Utah, a two-hour drive from Las Vegas via Interstate 15. Hours: 10 a.m.-6 p.m. Monday-Saturday. Admission: $5; $2 for children. Info: 435-574-3466; www.dino

Mill Canyon Dinosaur Trail

and Copper Ridge

Dinosaur Trackway

I drove 13 miles north of Moab to a hiking trail on U.S. Bureau of Land Management territory in Mill Canyon.

There, exposed to the elements were dozens of dinosaur bones, black, gray and grainy, like wood. The disjointed bones jutting out of a sandstone shelf were the vertebrae of a 20-ton camasaurus. A diamond-shape bone embedded in rock was the femur of an allosaurus, a smaller cousin of Tyrannosaurus rex.

The BLM installs interpretive markers on sites but doesn't post road signs for fear that too many visitors will “love the fossils to death,” according to BLM officials. Damaging or removing a dinosaur or other vertebrate fossil from state or federal land without a permit is illegal.

The nearby Copper Ridge Dinosaur Trackway was slightly easier to find. After hiking from a parking lot, I came to several 150 million-year-old prints on a flat rock path, as clear as if they had been made that week.

The three-toed allosaurus prints cross the path diagonally, but the bigger prints, probably made by an apatosaurus, seem to make a sharp right turn, a move that paleontologists say is unusual.

Details: Drive Interstate 70 across Utah from St. George to Moab. Don't rush past chocolate hoodoos, sherbet-colored mesas and the spectacular vista of Castle Valley at a rest area near mile marker 104.

Both track sites are open year-round.

For Mill Canyon, take U.S. 191 north from Moab for 13 miles to reach the general vicinity. Info: 435-259-2100.


Dinosaur Quarry

In the 1930s, near Cleveland, about 30 miles south of Price, paleontologists uncovered the densest collection of fossils in the world – more than 12,000 bones in one-quarter of an acre.

More surprising was the mystery of why there were so many bones in one spot, most from juvenile and adolescent carnivores such as the allosaurus. Fewer than 30 percent were herbivores, and paleontologists have been unable to find an intact skull.

Some suggest the land was a bog that trapped herbivores and attracted predators. But that doesn't explain a preponderance of predator bones.

It looked like a mass grave, except for the fossilized dinosaur egg found in 1987.

Details: Take Utah 10 south to the Cleveland/Elmo turnoff and follow the signs. The quarry is 12 miles from Cleveland, Utah, via unpaved roads. A four-wheel drive vehicle is recommended. Hours: 10 a.m.-5 p.m. Friday-Saturday in fall and spring; longer hours in summer; closed November-mid-March. Admission: $5; 16 and younger, free. Info: 435- 636-3600.

Utah Field House

of Natural History

In northeastern Utah, the visitor center at Dinosaur National Monument in Jensen is one of the state's premier fossil viewing sites. Unfortunately, the center was closed indefinitely in 2006. I headed instead to nearby Vernal to see the Utah Field House of Natural History.

The star of the museum is a 90-foot-long diplodocus skeleton. The field house was designed as an educational center, with hands-on exhibits for kids.

A 15-minute movie explained the Morrison Formation – the fossil-rich sedimentary layer that stretches 600,000 square miles from Canada to the American West.

Details: Drive about seven miles outside Vernal along U.S. 191 to Red Fleet State Park and dinosaur tracks on the northern shore of the lake. These prints, at the end of a 1.5-mile hike, are not as distinct as the impressions on Copper Ridge but are impressive. Open 9 a.m.-5 p.m. daily (closed holidays). Admission: $6; $3 for seniors and children. Info: 435-789-3799.

BYU Earth Science Museum

Brigham Young University Earth Science Museum, in Provo, is a research center. Students behind a glass partition clean bones, and the dinosaur displays are magnificent.

Highlights include the skeleton of a torvosaurus, a predator with teeth that hang like stalactites. Bones of museum skeletons are reproductions because fossils are too fragile to mount.

One fossil under glass is the 4-foot-tall leg bone of a Utahraptor, the nasty larger cousin of the turkey-sized velociraptor.

Details: Drive through Manti-La Sal National Forest along U.S. 6. Open 9 a.m.-5 p.m. Monday-Friday. Admission is free; donations accepted. Info: 801-422-3680; http://cpms.byu .edu/ESM/information.html.

North American Museum

of Ancient Life,

Thanksgiving Point

This place in Lehi brings the dinosaur era to life, complete with spooky lighting and eerie sound effects. The 86,000-square-foot museum – the world's largest collection of life-size dinosaur skeleton casts – is part of a 700-acre commercial development that includes gardens, golf greens, shops, animal park, farmers market and more.

Thanksgiving Point museum has benefited from the backing of Alan Ashton, co-founder of WordPerfect, one of Forbes magazine's 400 wealthiest Americans in 1995.

The $20 million museum was built in 2000. A two-story-tall torvosaurus is the museum's doorman. It's just the opening act.

Home to more than 60 complete dinosaur skeletons, the museum is divided into four sections, each representing a period of Earth's history: the Precambrian age, when Earth was a bubbling caldron of single-cell critters, and the Triassic, Jurassic and Cretaceous periods.

The sounds of prehistoric birds echo from hidden speakers.

The supersaurus, one of the world's largest dinosaurs, stretches 110 feet from head to tail. The neck of the supersaurus is so long it extends into the next exhibit hall.

Details: From Provo to Lehi, follow Interstate 15 past industrial warehouses and strip malls. Open 10 a.m.-8 p.m. Monday-Saturday (closed Thanksgiving and Christmas). Admission: $10; $8 for children. Admission plus a 3-D dinosaur battle movie: $15; $12 for kids. Info: 888-672-6040; www