The more they dig, the more mastodon remains they find in Orange County, New York.

The Ice Age mammals, which may have weighed up to six tons, went extinct 11,000 years ago. But they've been a longtime source of fascination in these New York City suburbs. 

"George Washington left an encampment in Newburgh and came to Middletown to see a tooth that a farmer had encountered," Dr. Cory Harris of SUNY Orange said. 

Harris recently led students on a weeks-long excavation in a back yard in Wallkill after the homeowner found mastodon teeth. The painstaking dig recovered more pieces. 

"We found quite a few vertebrae. We found some ribs," Harris said. 

The so-called "atlas bones" are perhaps 13,000 years old. 

"Where we found it, based on the sediments, the sediments indicated that the remains were in a former lake formed by a retreating glacier," geologist Anthony Soricelli said. 

A nearly complete mastodon skeleton dating to 8,000 B.C. was found in Orange County in 1972. It's named Sugar. Continued exploration for remains of these Ice Age mammals helps answer questions about our natural history and our ever-changing environment. 

"We're providing opportunities to our students at SUNY Orange. We're recovering real and important natural history for New York, and for Orange County," Harris said. 

Their finds will be further studied at the New York State Museum in Albany. 

In total, mastodon remains have been found at 150 sites in New York, and a third of them have been in Orange County. 

• New York