ZURICH, Switzerland (Reuters) -- An amateur paleontologist in Switzerland may have unearthed Europe's largest dinosaur mass grave after he dug up the remains of two Plateosaurus.

The dinosaurs' bones came to light during house-building in the village of Frick, near the German border.

"A hobby paleontologist looked at a construction site for a house and happened to discover the bones," said Monica Ruembeli from the Frick dinosaur museum.

The finds show that an area known for Plateosaurus finds for decades may be much larger than originally thought.

"It could be that the area extends for 1.5 kilometers (0.9 miles) and in that case, you could certainly say it's the biggest site in Europe," said Martin Sander, a dinosaur paleontologist at the university of Bonn in Germany.

The Frick area contained the bones of one animal per 100 square meters, Sander said, so the entire area might contain bones of 100 more Plateosaurus.

The peaceful herbivore -- measuring up to 10 meters from head to tail -- roamed river deltas in large herds some 210 million years ago, according to some scientists, when most of Switzerland was covered with desert and its landscape may have looked much like the estuary of the Nile now.

There are two other large Plateosaurus sites in Germany, Sander said. It is not known how big they are because one is covered by the town of Halberstadt and the other, near Trossingen, by a forest. E-mail to a friend

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