On a geologic map, synclines are recognized as a sequence of rock layers, with the youngest at the fold 's center or hinge and with a reverse sequence of the same rock layers on the opposite side of the hinge. If the fold pattern is circular or elongate, the structure is a basin. Folds typically form during crustal deformation as the result of compression that accompanies orogenic mountain building.
where are the oldest rocks found in a syncline
opposite side of the hinge