Pitch Lake, pool of pitch (asphalt), c.114 acres (46 hectares), SW Trinidad island, Trinidad and Tobago, near La Brea. The lake is believed to be formed and supplied by the seepage of natural pitch, a form of petroleum, from the surrounding oil-rich region. The pitch, hard around the edges of the pool, becomes more viscous toward the center. The seemingly inexhaustible supply has yielded millions of tons of pitch since the 16th cent. Fossils of prehistoric animals have been found in Pitch Lake, which has also become a tourist attraction.