On October 29, 1926, Mid-Kansas Oil and Gas Company, a subsidiary wholly owned by the Ohio Oil Company, later renamed Marathon Oil Company, brought in the I. G. Yates "A" No. 1 well, opening one of the greatest oil fields in the world. At a shallow depth of 1,150 feet, the well had a rated potential daily flow of 72,869 barrels. Although oil men had said that no oil would be found west of the Pecos, Mid-Kansas Oil and Gas Company and its partner, Transcontinental Oil Company, later acquired by Marathon Oil Company, continued their work, and the strike was sensational. Scarcely more than a year later, the Yates field had 100 wells, two of which had higher yields than Yates No. 1. Beneath the 20,000-acre Ira G. Yates ranch and adjoining lands lay one of the largest oil reserves in the world. The many developers voluntarily adopted proration, and their plans for allocating and restricting Yates field production were approved by the Texas Railroad Commission in 1928 as the first complete proration of an oil field in the state and an important milestone in petroleum conservation. The Yates field now has 607 wells.