Each of the sedimentary basins of the Rocky Mountain province is geologically unique. All have been structurally controlled but by different episodes and styles of tectonic activity. At least some of the structures have been reactivated one or more times during the Phanerozoic.

Because of the great geologic diversity, no one worker could be authoritative about the geology of the province. Consequently, each basin in this chapter has its own specialist authors. They are identified with their appropriate texts and listed at the beginning of this chapter. Although an attempt has been made to standardize the format of the basin subchapters, some differences in style and geological focus appropriately reflect the differences among the various authors. Little attempt was made to force uniformity in details of approach to the basin analyses.

Organization of the chapter is geographic. Basins west of the Rio Grande Rift system are stratigraphically more closely related to the Cordilleran miogeocline than to the craton and are treated first. These basins are described in order by age, and geographically from south to north. Those basins lying east of the Rio Grande Rift and more closely related to the craton are presented in order from south to north.

Prior to Pennsylvanian time, the site of the modern Rocky Mountains was largely that of a broad, shallow marine shelf at the inner margin of the Cordilleran miogeocline. Late Paleozoic basins developed concurrently with the uplift of the Ancestral Rocky Mountains as the Precambrian basement structural fabric was strongly reactivated