Scientists say an excavation site in western Colorado is revealing an entire Ice Age ecosystem.

Crews from the Denver Museum of Nature and Science said Friday that bones from two more kinds of animals have been discovered near the resort town of Snowmass Village — an upper foreleg bone from a giant ground sloth, and the remains of a small deer-like creature. 

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The humerus (upper forelimb bone) of a giant ground sloth discovered Thursday at the Ziegler Reservoir excavation site near Snowmass Village, Colo. ((Rick Wicker, Denver Museum of Nature and Science))

Partial remains of five mastodons, three Ice Age bison and a juvenile Columbian mammoth, as well as plant matter and insects, have also been found. Crews haven't uncovered any human artifacts.

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Denver Museum of Nature & Science volunteer Jane Peterson excavates a juvenile Columbian mammoth. ((Denver Museum of Nature and Science))

"It is truly uncommon to get all parts of a fossil ecosystem preserved in one place," said Ian Miller, the museum's curator of paleontology and chair of the earth sciences department. "Instead of having just a piece of the ecosystem to tell the story, you've got all aspects of it. It's one of the most exciting scientific discoveries I've ever worked on." 

The discovery is attracting attention as there are very few sites in North America that contain both mammoth and mastodon remains in one location, according to the Denver museum. It added that the Columbian mammoth unearthed in October also appears to be the most complete mammoth fossil found at high elevation in Colorado.

The museum is bringing in more experts, including University of Michigan paleontologist Daniel Fisher, lead curator of a travelling exhibit on mammoths and mastodons assembled by the Field Museum in Chicago.