A pit left by asphalt mining at La Brea in the late 1800s later filled with rain and groundwater to form a small lake whose bubbles, sheen, and odor come from a deep underground oil field that also creates tar patches on the ground. Shallow pools of tar in this area trapped Ice Age animals between 55,000 and 10,000 years ago, including dire wolves, saber-toothed cats, sloths, camels, Columbian mammoths, and American mastodons. The area was mined for asphalt in the 1870s, when Major Henry Hancock operated a mine at the Lake Pit on land acquired from Jose Jorge Rocha, whose family had owned Rancho La Brea as a Mexican land grant. In 1875, geologist William Denton examined a fossil found at the Lake Pit at Major Hancock's request and confirmed that it belonged to an ancient saber-toothed cat, the first confirmed fossil from La Brea. In 1901, George Allan Hancock drilled for oil on family land, and more than 70 productive wells and the many fossils found in the process confirmed earlier claims that the remains were ancient. In 1913, the Hancock family granted the Los Angeles County Museum a two-year exclusive right to excavate fossils there. In 1924, George Allan Hancock donated 23 acres of his family's ranch to the County of Los Angeles for a public park to protect the tar pits and their fossil treasure for future generations. In 1977, the Page Museum opened to the public, and today research at La Brea Tar Pits and Museum advances understanding of long-term climate change in the local environment.
