There's an adage in the business that the best places to look for oil and gas are where they have already been found. But notable exceptions certainly exist: one is the Raton Basin, in southeastern Colorado and northeastern New Mexico. This basin failed to produce from traditional reservoirs, but has grown to become a coalbed-methane powerhouse. Now, another basin with a frustrating history may find a bright future in unconventional gas production, this time from shales. At least that's the hope of a new cadre of explorers working in the Marfa Basin. The little-known Marfa is tucked along the great Ouachita Thrust trend, which stretches 1,500 miles from Mexico, through Texas, Oklahoma and Arkansas and into Mississippi. The Marfa is a deep, tectonically complicated basin that's largely covered in Tertiary volcanic sediments. But, it contains some 15,000 feet of Paleozoic sediments, and is a little brother to the prolific Delaware Basin of West Texas. Big and small companies have broken picks in the Marfa attempting to find fields like those in the mighty Delaware. Wildcats were drilled between the 1940s and 1980s by operators including Gulf Oil, Arco, Exxon and Amoco. But, results were acutely disappointing. There were lots of structures, but fresh-to-brackish water and dead oil were pervasive in the potential reservoir rocks. For more on this, see the October issue of Oil and Gas Investor. For a subscription, call 713-260-6441.