Dinosaur National Monument, located south of Wyoming astride the Utah/Colorado line, is a genuine Jurassic park, famous for its fertile fossil bone quarry. Likewise, it's also noted for its rugged river gorges, pioneer homesteads, and Native American rock art--and for its lack of crowds and development. Most visitors don't go beyond the fossil quarry north of Jensen, Utah, the only area in the park where the ancient bones can be seen. But unpaved backroads, easily accessible with a stock SUV, pickup truck, or well-outfitted car, lead to such lesser-known sites as the McKee Spring petroglyphs on the Utah side along the road to Rainbow and Island parks, pretty Echo Park, and the vast Yampa Bench.

Echo Park, a meadow at the confluence of the Green and Yampa rivers deep in the heart of the 210,000-acre park, is dominated by the imposing sandstone mass of Steamboat Rock. Located on Dinosaur's Colorado side, it's reached by 13-mile Echo Park Road. Visitors will find a campground, ranger station, water, grassy meadows, and soaring sandstone cliffs at the end of their adventure.

In the '50s, the U.S. Bureau of Reclamation tried to build a dam on the Green River that also would have backed up the Yampa and inundated Echo Park under tons of water, but the effort was defeated by the fledgling environmental protection movement in its first large victory. Today, the Yampa River remains the last free-flowing river in the Colorado River system.

You can spend a long weekend lounging at Echo Park, then driving Yampa Bench Road, which meanders for 42 miles along the rim of the Yampa River's stunning sandstone gorge. Visitors to the park's northern sector will find a campground on the Green River just north of the dramatic canyon dubbed the Gates of Lodore.

Dinosaur National Park's back-country dirt roads are easily driveable in good weather with a high-clearance vehicle. When wet, the roads become treacherously slick and impassable even with four-wheel drive, so always check with local authorities for weather updates. At certain times of the year, the weather can change in a few hours. Overall, the climate is semi-arid and weather can vary widely. September and October typically bring cool, sunny days. Summer days are hot, with afternoon thunderstorms common in July and August. Roads can be blocked by snow in winter. The park lies north of U.S. 40 and east of Vernal, Utah. Information is available by calling the park at 970/374-3000, or on its Web site at www.nps.gov/dino.

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Be Advised: The information presented in this column are, to the best of our knowledge, correct and accurate at the time of publication. However, because of our lengthy lead time, we recommend calling the proper authorities or local experts for confirmation before visiting.