)Erosion of the region to give present topography. 10. RELATIVE AGES OF BEDS ) In case of an unconformity, younger beds overlap older rocks. (i) The outcrops of dipping beds in a valley will always point upstream unless the dip is in the same direction as the slope of the valley, and at a greater angle. In this case progressively older beds occur in the upstream direction. (IT) In anticlines the older beds outcrop toward the centre of the fold and in synclines the reverse applies. (iv) Out of two adiacent beds outcropping on opposite side of a fault, the younger bed is always on the down-throw side. /hen ieneous intrusions or faults cut through older rocks, they 1hen they r than the strata they cut.