Researchers back at a fossil dig near Aspen have found more than 100 bones in the last week.Excavation began at the site last fall after a bulldozer operator uncovered a bone while working on expansion of Ziegler Reservoir. Work stopped for the winter, but resumed in mid-May.Since then, the crews with the Denver Museum of Nature and Science have uncovered two Mastodon skulls, two Mastodon pelvises, three Mammoth tusks along with bones from an Ice Age camel, a sloth, a bison and a deer."Its extremely rewarding work, thanks to these amazing finds so far," said Kirk Johnson, the leader of the Museums excavation team and vice president of the Research and Collections Division. "With only 40 days to go, we are shoveling like mad in a race against time, and we continue to bump into bone after bone."Museum officials said 43 people are at the site each day. The crew is divided into five teams, each working on a specific location including the peat bison, the clay mammoth and the Snowy site where the original mammoth was discovered.To date, scientists have discovered eight to 10 American mastodons, four Columbian mammoths, two Ice Age deer, four Ice Age bison, one Jeffersons ground sloth, one Ice Age camel, many tiger salamanders, as well as evidence of beaver, insects, snails and microscopic crustaceans. reservoir are large quantities of well-preserved wood, seeds, cones, and leaves of sub-alpine white spruce, subalpine fir, sedges, pollen and other plants.On July 1, the site will be handed back over to the water district and work on the expanded reservoir will be completed. However, a small excavation crew will remain onsite.The fossils discovered at Ziegler Reservoir are being preserved in the museums conservation lab in preparation for scientific study and are not on public display. Because the fossils were encased in wet sediments for so long, they must dry out in a very slow, controlled manner or they may crack and fall apart.Get the latest on the project on the Denver Museum of Nature & Science's Snowmastodon Project website. .