After grueling work that required the removal of a 9 ton block of sandstone, Utah state paleontologist James Kirkland and his team have made a remarkable fossil discovery.

125 million years ago the land that now makes up the state of Utah was much wetter than it is currently. Marine seas inundated the area and were surrounded by wetlands and, sometimes, quicksand. Researchers believe that, during this time, an iguanodont stumbled into one of these quicksand pits. As it struggled, trying to free itself, it attracted predators.

The quicksand, now in the form of sandstone, has recently been unearthed revealing the bones of the iguanodont along with six Utahraptors. The Utahraptor ostrommaysorum is the largest known member of the Dromaeosauridae family. It is believed that they were covered in feathers and that an adult would have been about 23 ft long, weighing slightly more than 1,000 pounds. The second toe on the Utahraptor’s feet had large curved claws roughly eight to nine inches in length.

In 2001, Kirkland was approached by a geology student who found what looked like a human arm bone. Kirkland located the site and determined that the bone was in fact a dinosaur foot and that foot was just the tip of the iceberg. The more the team dug, the more they found. The researchers found the bones of a 16 foot long Utahraptor along with the skeletons of five younger dinosaurs.

The team also found the remains of a iguanodont, a large duck-billed dinosaur, which lived from the Middle Jurassic to the Late Cretaceous period.

These bones, however, may only represent a small fraction of what is still lying in the sandstone. Kirkland believes that this find represents the first example of dinosaurs trapped in quicksand en mass.

In order to ensure that the find was properly excavated, the decision was made to remove the entire block from the mountainside. This turned out to be a much larger job than the researchers had anticipated.

“We didn’t want to take out a nine-ton block, every time we tried to cut in, we kept hitting legs and vertebral columns,” Kirkland told National Geographic.

In all the project took more than a decade. It proved too expensive to remove the rocks with helicopters so the team was forced to work with heavy machinery and their hands to get the sandstone block to Salt Lake City’s Department of Natural Resources.

The discovery of the raptors may put to rest a long running controversy. In the Jurassic Park films, raptors were depicted as cooperative-pack hunters. That idea was based on a single find, which included the remains of several predators and an herbivore. That assumption, however, has never been confirmed and remains somewhat controversial.

The Utah find may show whether the animals were part of a pack or family or whether they were individually drawn to the quicksand pit. As the rock is carefully chipped away and more fossils are exhumed it may provide even more answers about one of histories largest predators.

Kirkland is currently searching for a new home for the bones. The paleontologist’s facilities at the Department of Natural Resources aren’t large enough for the excavation. He is currently searching for a venue where the work can be done in public view.