Scientists from China and Canada said Thursday that they unearthed a mass grave of sheep-size baby dinosaurs who were apparently buried during a sandstorm 75 million years ago.

Philip Currie, of the Tyrrell Museum of Paleontology in Alberta, said the joint team excavated the skulls of five baby Pinacosaurus in the wastelands of southern Inner Mongolia.He said they found a sixth baby on the last day of their summer expedition, "and it appears likely there are a number of other specimens."

One adult, which in life was "about the size of an extremely heavy bull," was also discovered nearby, he said.