Cretaceous rocks in the northern Great Plains can be divided into four chronostratigraphic intervals. The intervals consist of marine and nonmarine shale and sandstone. Thickness patterns for each interval show subtle and distinct linear trends that have been interpreted to reflect movement of basement faults and fault blocks. Recurrent movement has occurred throughout Paleozoic and Mesozoic time. Reactivated faults are propagated upward, deforming overlying sediments by faulting and probably by drape or force folding. Thickness trends of four intervals and trends of sandstone thicknesses are generally oriented northeastward and, more rarely, northwestward. A northeast-southwest pure and/or simple shear stress system during Cretaceous time created a structural style in th northern Great Plains that consisted of a series of grabens, half-grabens, and horsts. The strike of these features was predominantly northeast-southwest. Relief on these structures was small, ranging from a few feet to tens of feet. Translated stress from continental margins to the northern Great Plains during Cretaceous time created a definite structural style for the area. That style was later enhanced as part of the Laramide orogeny by reactivated Precambrian (basement) faults and fault blocks.