Over the years, paleontologists have found the fossil remains of numerous mammals as well as bird and fish species there.

After approximately 1.7 miles (2.7 km), turn south onto a rough unmarked dirt road.

[1][2] The bedrock beneath the Fossil Lake area was created by basalt flows laid down during the Pliocene and Pleistocene epochs.

This basin filled with water during the wet climatic periods of the Pleistocene and post-Pleistocene to a depth of 200 feet (61 m).

Over the past 3,200 years, the surface water in the Christmas Valley basin including Fossil Lake has completely dried up, leaving a high-desert environment.

Pumice sands from Mount Mazama and Newberry Crater also appear in the surface soils throughout the Fossil Lake area.

The surface soils are underlain by a hard calcium carbonate caliche layer several inches thick.

This locally unique water-retentive sub-surface structure has helped the ponderosa pines in nearby Lost Forest Research Natural Area survive in the high-desert environment.

[3][5] In 1877, there were still two small seasonal ponds at the Fossil Lake site surrounded by a large dry lakebed.

[6] Today, the Fossil Lake site is a dry lakebed above fossil-bearing deposits in the Christmas Valley basin.

These dunes are made up of lacustrine sediments, aeolian deposits, and alluvial materials with large amounts of volcanic pumice and ash mixed into fine sand that have been blown off the surface of Fossil Lake.

[8] In June 1877, John Whiteaker (a former governor of Oregon) visited the Christmas Valley basin.

During the trip, Whiteaker explored the Fossil Lake area, where he found a large dry lakebed with two small alkali ponds in low spots.

Whiteaker reported that fossils were scattered across a large swath of desert running from southwest to northeast.

After his trip, Whiteaker delivered his fossils to Thomas Condon, a well-known paleontologist and professor at the University of Oregon.

[11][12][13] Other paleontologists who collected at Fossil Lake during the latter part of the 19th century include O. C. Marsh of Yale University; Charles H. Sternberg, an author and amateur paleontologist; Cope's pupil Jacob L. Wortman of the American Museum of Natural History; and Robert W. Shufeldt, curator of the Army Medical Museum.

[14][16] In 1977, the Bureau of Land Management placed a temporary ban on vehicles in the Fossil Lake area.

[7] In 2017, a team from the University of Oregon with the assistance of the Bureau of Land Management discovered a trail of Columbian mammoth footprints.

The site has produced more Holocene fossils than any other location in the world except the La Brea Tar Pits in California.

Some of the large mammal fossils found at the site include Columbian mammoths, ground sloths, dire wolves, giant beavers, pre-historic bison, three species of camels, several horse species, peccary, and an extinct bear.

Bird fossils include flamingos, pelicans, and swans, and large eagle species.

[4][7] The Bureau of Land Management has identified several environmental concerns with regard to the Fossil Lake site.

Perennial flowering plants found in the Fossil Lake area include prickly-phlox, lemon scrufpea common wooly sunflower, and Townsend daisy, and spiny hopsage.

[23][24] The animal population around Fossil Lake is typical of the high desert country of south-central Oregon.

Eventually, it was determined that the specimen was an unusually small American black bear stunted from malnutrition.

They include greater sage-grouse, black-billed magpie, pinyon jay, Brewer's blackbird, American robin, mountain bluebird, sage thrasher, Sagebrush sparrow, and loggerhead shrike.