The Appalachian foreland lies north and west of a closely folded and faulted mountain zone. The search for oil and gas production from deeper formations has emphasized the importance of an understanding of the structure of this area. This structure is much more complex than was formerly supposed. That the stresses active in forming the foreland folds and faults represent principally the diminishing activity of the deforming thrusts of the associated mountains is the usual assumption, but little is known of the mode of transmission and application of these stresses.

The origin of the structures, the effects of rotational stresses, the dates of deformation, and the shape and downward change in position and intensity of the folds are discussed from the standpoint of problems which have received insufficient attention and on which more data are needed. It is thought that an appreciation of these problems and of the general structural complexity of the area may result in a search for, and analysis of, data that will lead to their solution.