The pre-Morrow sediments of the Delaware basin were deposited uniformly over a cratonic shelf in a marine environment. During early Morrow time an orogenic movement began which reached its zenith during post-Morrow time. The area was severely eroded and peneplaned. During Strawn and later time, the area began to subside with definite depositional troughs forming. Generally, four facies were deposited simultaneously--the arkose and conglomerate facies on the flanks of the highlands, the lagoonal facies of light-colored limestones and shales in the marginal areas, local reef type or carbonate buildup facies, and the dark-colored basinal facies of limestones, shales, and sands. In some locales, the carbonate buildup facies tended to separate the lagoonal from the basinal fac es. These conditions persisted until late Wolfcampian-early Leonardian time.

At this time, the area experienced a broad epeirogenic movement. This movement resulted in a change of regional strike and in many areas resulted in a change in the nature of the sediments being deposited. The sea, during Leonardian time, reached its maximum extent, and for the first time since pre-Morrow time, completely inundated the area. A well defined, barrier type reef developed which separated the light-colored lagoonal facies from the dark-colored basinal facies.

The sea began to recede by late Leonardian or early Guadalupian time. Reef growth continued until Ochoan time when an evaporitic basin was forming due to further restriction of the sea. The basin continued to subside as the continent emerged, resulting in a thick evaporate sequence. The end of the Permian was marked by the advent of the Triassic redbeds filling in the basin. This was followed by the complete uplift of the area during late Triassic and Jurassic time.

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