Edited sentence: The Rhine Graben is a major extensional basin.The amount of uplift decreases with distance from the basin, causing the highest range of peaks to be immediately adjacent to the basin, and the increasingly lower mountains to stretch away from the basin.There is a remarkable similarity between the Black Forest and the corresponding range of the Vosges Mountains on the other side of the Rhine: both lie within the same degrees of latitude, have similar geological formations and are characterized by forests on their lower slopes, above which are open pastures and rounded summits of a rather uniform altitude; furthermore, both exhibit steeper slopes towards the Rhine and a more gradual descent on the other side.This occurs because both the Black Forest and the Vosges were formed by isostatic uplift, in a response to the opening of the Rhine Graben.When such basins form, the thinning of the crust causes uplift immediately adjacent to the basin