MAKING TRACKS FOR COLORADO'S AWESOME DINOSAUR COUNTRY : ON LOCATION.

Byline: Scott Smith Colorado Springs Gazette Telegraph

As Jurassic safaris go, this one was a modest success.

Plenty of dinosaur tracks. But no dinosaurs. Not an allosaurus or brontosaurus in sight. Just birds and rabbits and chipmunks and lizards and pronghorns. It turns out our timing was off - by about 150 million years.

Still, even though we didn't see a living, breathing, barn-size reptile, the tracks made the 10.6-mile round-trip hike in the Picket Wire Canyonlands worthwhile.

Picket Wire, south of La Junta in the Comanche National Grassland, is the largest documented dinosaur-track site in North America. But you don't have to be a paleontologist to identify or appreciate these rock-bound footprints on the banks of the Purgatoire River - they're easily visible and awesome in scope. On the day we visited, many of the tracks were filled with mud from recent runoff, but the deep prints - some with claw marks - were still easy to see.

The continuous parallel tracks made by plant-eating sauropods (brontosaurus, also known as apatosaurus) are elephantine in shape, but they were made by an animal that would dwarf even the most robust pachyderm. Imagine a herd of 70-foot-long, 33-ton creatures ponderously marching side by side, taking time to smell - and perhaps eat - the prehistoric roses.

Tracks made by carnivorous theropods (allosaurus, a smaller T-rex wanna-be) also abound. They are large, three-toed tracks - sort of like those made by a gigantic chicken - set in limestone. These 4-ton packages of teeth and talons presumably preyed on the sauropods.

The track site, discovered in 1935 and studied in more detail in the 1980s, includes more than 1,300 footprints and 100 trackways (continuous tracks) in four layers of strata. About 40 percent of the tracks are attributed to sauropods and the rest to theropods. Because of trackways like the ones found in the Picket Wire area, it's believed that adult and young sauropods traveled together in herds.

It's hard to imagine the Picket Wire Canyon country as a site for such tracks. The area is encircled by bluffs, cliffs and prairie, festooned with cactus and juniper. Part desert, part canyon. Hot and dry.

But once upon a time, in the Jurassic period of the Mesozoic era, the climate was wet and warm; ferns, sequoias, pines and ginkgos flourished along the shoreline of a large, shallow lake. The sauropods ate the lush foliage; the theropods ate the sauropods. In the process, the dinosaurs tramped through the mud, squashing plants, snails, clams and anything else in their path - and left a mess of footprints to verify their existence.

So how hard is it to get to the dinosaur footprints?

A heck of a lot easier than it was a few million years ago. It's 5.3 miles from trailhead to dinosaur tracks, and hiking, mountain biking and horseback riding are permitted. The area, which was U.S. Army land until it became part of the Comanche National Grassland in 1991, is open dawn to dusk; overnight camping is not permitted.

The trail follows a dirt road, and except for a 500-foot elevation loss in the first quarter-mile (and a short, steep hike out of the canyon on the return trip), the walking or biking is relatively flat and easy.

The trail also provides a glimpse of more recent history. Traces of the Dolores Mission (built in the 1870s or '80s) and cemetery are evident about 3.7 miles into the canyon, reminders of the Mexican pioneers who first settled in the valley. The dinosaur tracks make an ideal destination for day hikers, but mountain-bikers might want to go the 8.7 miles to what's left of the Rourke ranch (a working ranch until 1971) at the southern end of the canyon. It's a 17.4-mile round trip.

After 5.3 miles, look for an informational sign about the dinosaur tracks. The clearest allosaurus tracks are between the sign and the river. The best brontosaurus tracks are in limestone about 200 yards upstream (south) from the first site and across the river. This requires wading across the Purgatoire.

If you visit on a Saturday in May, June, September or October, try to arrive at the dinosaur tracks around noon. That way, you can listen to a presentation about the tracks by Forest Service workers or volunteers who lead four-wheel-drive tours on those days.

In the realm of scenic canyons, Picket Wire falls somewhere between grand and bland. It's not a hike for wilderness purists, especially those who'd rather not see remnants of power lines or adobe structures. But there isn't a lot of traffic on the trail - on an average weekend day, you might meet 15 to 30 hikers or bikers.

There's not as much grass in Picket Wire's grasslands this season - the result of an April range fire that burned more than 9,300 acres, including 6,300 on Forest Service land. The fire created surrealistic scenery throughout much of the canyon: parboiled prickly pear and charred cholla interspersed with blackened tree snags and brand-new shoots of green grass.

``It burned off a lot of the old growth, which was much-needed,'' says Colleen Oquist, an information assistant for the Comanche National Grassland. ``It should benefit the land a great deal, as long as we get some moisture this year. The native grasses will reseed and be able to breathe again.''

The land along the trail's first mile is untouched by fire; it gives you a good idea of what the hike would look like in a typical year - lots of long, golden grass and healthy, green cactus.

However, the area is not devoid of danger. Tops on the hazards list: heat, rattlesnakes and cactus. Recreationists should bring at least one gallon of water per person; summer temperatures are often in the 90- to 105-degree range.

Three types of rattlesnakes live in the canyon - prairie, pygmy and massasauga - but Oquist says if you avoid tall grass and watch where you place your hands and feet, you likely won't be bitten.

``I always tell visitors to watch out for the cactus - that's usually more of a danger than rattlesnakes,'' Oquist says. ``I've been here 20 years and we've never had any visitors to the grasslands bitten by a rattlesnake in that time.''

To reach Picket Wire from La Junta, head south on Colorado Highway 109 for 13 miles. Turn right (west) on County Road 802 and continue for eight miles. Turn left (south) on County Road 25 and continue for six miles. Turn left (east) at Forest Service Road 500A and go for 2-3/4 miles (you'll pass through a wire gate at about three-quarters of a mile) until the road forks. Take the left fork to the parking sign and park your vehicle; if you are unable to access Road 500A, you may park your vehicle at the bulletin board at the start of the road and start your hike or ride there. Road 500A is not maintained; the Forest Service recommends high-clearance 4WD vehicles.

The U.S. Forest Service conducts four-wheel-drive guided tours to the dinosaur tracks in May, June, September and October. Cost of the tour is $7.50 for adults and $3.50 for children, and you must provide your own four-wheel-drive vehicle. Information: [phone].

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Photo: (1--Color) The upright, ferocious, meat-eating allosaurus left these footprints along the banks of the Purgatoire River in Colorado's Picket Wire Canyon.

Knight-Ridder Tribune Photo Service