Doubly plunging folds involving the Carys Mills, Smyrna Mills, and Madrid formations in the northeastern part of the study area are interpreted as an interference pattern caused by refolding of early recumbent folds by later upright structures.
The recumbent folds and thrusts shown in Figure 10 caused considerable crustal shortening but their effect on the current outcrop patterns of Central Maine and Aroostook-Matapedia lithofacies cannot be understood fully without more detailed mapping.
The recumbent folds
verge in the opposite direction to the generally southward-verging orogen and may have been generated in response to top-to-the-north motion along the underlying South Tibetan detachment.
These structures include recumbent folds, breccia zones, extension veins, and normal faults, and occur at all sites exposing the Macumber Formation limestone.
However, deformation is evident towards the base of the Macumber Formation where a series of large inclined to recumbent folds are developed that resemble the slump structures at MacIsaacs Point.