Regional structure in the Permian basin is due to the sinking of basins around positive elements. In the south the sinking was combined with uplift along the Marathon fold. These structures have been modified by post-Cretaceous deformation in the mountain areas. This is of the Basin Range or block-faulting type.

The limestone "highs" within the Permian basin are in part depositional and in part structural. The Getty "high" is a reef overlain by a typical compaction fold. The Winkler County "high" is a combination of a reef with a deformational "high." The varying relations of these two factors determine the character of production encountered from Winkler County north into Lea County. The Yates "high" is thought to be depositional whereas the Big Lake "high" is thought to be structural. The evidence for and against these conclusions is analyzed.

The final determination of the character of each limestone "high" in the basin is to be found in the structure of the beds below the "Big lime."