La Brea Tar Pits is an active paleontological research site in urban Los Angeles. Natural asphalt (asphaltum, bitumen, pitch, or tar) was found near Hancock Park. Dating from at least 3500 BC, the tar preserved the bones of trapped Neolithic animals.

Bitumen lines, from the crude oil, seep up along the 6th Street Fault from the Salt Lake Oil Field, which underlies much of the Fairfax District north of Hancock Park. Oil reaches the ground and forms pools, near modern day downtown Los Angeles, becoming asphalt as the the petroleum biodegrade or evaporate. It usually hardens into stubby mounds. The pools and mounds can be seen at the Museum. Below is a picture.

History

Aboriginal ‘Chumash and Tongva’ lived in La Brea building boats and neolithicly through time. Pulling fallen large tree trunks and pieces of wood from the ocean, they learned to seal the checks between the boards and wood by using the stagnant liquid. An expedition, led by Gaspar de Portolá, led the first documented visit to the tar sands by Spanish in 1769.

By the 1880’s, land was purchased by a Countess of Dundonald. A formal excavation began by Messrs Turnbull, Stewart & Co in 1886.

In 1901 a oil geologist was finally credited with recognizing that fossilized prehistoric animal bones were preserved in pools. John C. Merriam, and the university of California begin a major portion of the early anthropological work. In search of large skeletons, between 1913 and 1915, explorers excavated more than 100 sites finding thousands of specimens. These excavations though, while being examined, have gradually been filled, by an accumulation of asphaltum, dust, leaves, and water.

Only one human has been found, a partial skeleton of the La Brea Woman dated to around 10,000 years. She is estimated to have been 17 to 25 years old, and found associated with remains of a domestic dog.

Bibliography: “La Brea Tar Pits History | La Brea Tar Pits”.

Seaman, Florence Josephine (1914) A Brief History of Rancho La Brea, Historical Society of Southern California, Vol IX, pp 253-256

Map of old Spanish and Mexican ranchos in Los Angeles County

James Miller Guinn (1915). A history of California and an extended history of Los Angeles and environs, Volume 2. Historic Record Co.