Fossils from the last Ice Age, including bones of ancient mammoths and a prehistoric bison, have been found at a Carlsbad construction site where hundreds of new homes are planned.

The fossils, 50,000 to 200,000 years old, were discovered earlier this summer during grading at Carlsbad's Quarry Creek, the San Diego Union-Tribune reported.

Work was halted while paleontologists carefully removed them.

"I said, 'Take your time, this is kind of cool,'" John Suster, the project superintendent for developer Cornerstone Communities of San Diego, told the newspaper in a story Thursday.

The fossils included horses, turtles and Columbian mammoths. The latter were larger than the better known wooly mammoth and stood as tall as 13 feet at the shoulders and weighed as much as 10 tons. A photo taken by Cornerstone Communities shows a huge mammoth bone being unearthed.

The bison fossil, which includes a skull and partial skeleton, will eventually go on display at the San Diego Natural History Museum.

Tom Deméré, curator of paleontology at the museum, said the animals lived during the Pleistocene Epoch or last Ice Age.

"It's really an exciting project in terms of the geology and paleontology," he said. "The fossils have the potential to tell us a great deal about the climate, the environment, the ecology of that time."

Meanwhile, grading on the housing project continued, and more fossils could be found.

Construction is expected to begin early next year.