Complex sentence: Oil was found on her land in October, 1929, with the drilling of the "Erburu No.1" well by General Petroleum Corporation, and the El Capitan oil field became one of the richest in the state; production at the field peaked in 1946.
Split into simpler sentences: Oil was found on her land in October, 1929, with the drilling of the "Erburu No.1" well by General Petroleum Corporation. The El Capitan oil field became one of the richest in the state; production at the field peaked in 1946.