An excavation team has unearthed a major dinosaur-fossil discovery in southeastern Utah, the Bureau of Land Management announced Monday.

In three weeks of excavating the preserved river channel near Hanksville, a team from the Burpee Museum of Natural History in Rockford, Ill., found four long-necked sauropods, two carnivorous dinosaurs and a possible herbivorous Stegosaurus.

"We have not had a discovery of this magnitude in many, many years," BLM Utah Paleontologist Dr. Scott Foss said. "They're just scratching the surface. The potential is great."

The Hanksville-Burpee Quarry is at least 145 million years old and contains the fossilized remains of dinosaur skeletons, animal burrows and large petrified tree trunks, BLM Utah paleontologist Scott Foss said.

The sandstone quarry has kept the fossils "exceptionally well preserved," he said. Some fossils have had to be put back together, but many were preserved as complete pieces.

In Hanksville, local officials knew the site contained bones when the Burpee team began excavating last year, Foss said. "When they got out there, it was bigger than they anticipated."

No new species have been discovered, and Foss said he doesn't expect to find any at the Hanksville site.

"What this offers is a much broader context," he said. "We're able to understand the ancient ecosystem better based on these findings."

Officials plan to close the site Friday until next summer when the Burpee excavation team will return to Utah. During that time, the BLM will conduct an environmental assessment of the area, Foss said.

The Burpee Museum and the BLM are working together to develop long-term research initiatives as well as educational and recreation opportunities in the area.