278 Adventures in Scenery 



have made possible the movement of oil from whatever its orig- 

 inal source upward into the porous sandstone. Had it not been 

 for the joint cracks it would seem to have been impossible for 

 oil to pass through the impervious beds and so become concen- 

 trated in pools in the higher porous sandstone formations. 



Location of Kancho La Brea 



About seven miles west of the business center of Los 

 Angeles, in what is known as the Salt Lake oil field, on Wilshire 

 Boulevard west of La Brea Road, are located the far-famed tar 

 pits or asphaltum lakes of Rancho La Brea. These are pools or 

 seepages of petroleum tar or pitch-like oil oozed from depths 

 in the rocks probably by gas pressure. The pits or oil pools are 

 distributed over an area embracing 32 acres, and known as 

 Hancock Park, from the donors who gave the grounds to Los 

 Angeles County. 



These pools are noted for the great number of relics of ani- 

 mals and plants that have been recovered by excavation from 

 the deposits of asphaltum. Between 400 and 500 kinds of ani- 

 mal remains (species, genera and families) , and many fragments 

 of trees, and seeds and leaves of plants, have been recovered, 

 many of them representing species that no longer live upon the 

 earth. 



The pools have existed during and since Pleistocene time. 

 Animals that lived in the long past were entrapped in the sticky 

 mire of the pools, and skulls and bones, hard parts of many 

 species, have been recovered, and are now preserved in the Los 

 Angeles Museum, the Museum of the University of California, 

 and in other institutions. 



Asphalt Beds Formed in Oil Pools 



Pools of oil, into which dust and other debris have been 

 borne by the winds, formed during Pleistocene time, the geo- 

 logic age preceding Recent or modern time, have developed into 

 beds of asphaltum, thousands of tons of which have been re- 



