Outside the Page Museum of Los Angeles, life-size replicas of several extinct mammals are featured at the Rancho La Brea in Hancock Park. Although commonly called the “tar pits,” the pools are actually comprised of asphalt.

“Tar pits” form when crude oil seeps to the surface through fissures in the earth’s crust and part of the oil evaporates.

The La Brea “tar pits,” discovered on August 3, 1769, by Spanish explorer Gaspar de Portola, exemplify the many natural petroleum seeps of southern California.

“We proceeded for three hours on a good road; to the right were extensive swamps of bitumen which is called chapapote,” Franciscan friar Juan Crespi noted in a diary of the expedition.

“We debated whether this substance, which flows melted from underneath the earth, could occasion so many earthquakes,” he added.

Crespi – the first person to use the term bitumen – described the sticky pools in southern California where crude oil had been seeping from the ground through fissures in the coastal plain sediments for more than 40,000 years. Read the rest of this entry »