Low-gravity, high-viscosity oil occurring in discontinuous sandstone bodies is present at shallow depths in at least 21 western Missouri counties. Asphaltic sandstones extend vertically from lower Cherokee in Barton and Vernon Counties to upper Pleasanton in Lafayette and Carroll Counties.

Since 1950 interest in asphaltic sandstone ("tar sand") deposits has kept pace with development of thermal recovery techniques and demand for reserves. Pilot thermal recovery projects in Vernon and Cass Counties have produced a composite oil product of 15°-26° API gravity compared with 10° or less API gravity for the original reservoir oil.

A north-south cross section shows a change form recoverable oil of 24°-28° API at depth in the northern parts of the area to the highly viscous, low-gravity oil in the southern parts where the reservoir rocks are approaching the outcrops. Other cross sections show the discontinuous nature of the sandstone bodies.

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