is 250-450 feet wide and is composed of irregular quartzite cliffs. Spectacular unconformable contacts with younger Cambrian sandstone can be seen on both the north and south sides of the Precambrian Baraboo quartzite. The exposures of the unconformity between the ancient quartzite and the overlying sandstone are world famous. The site tells a fascinating geological story of changing conditions in an ancient sea that first rose quietly against a cliff of quartzite and then, as layers of sediments gradually decreased the relief between sea floor and land, surged against the top of the cliff, wearing away quartzite and depositing a layer of cobbles and boulders across its upturned edge. Erosional forces and a former quarrying operation in the southern part of the natural area have re-exposed these long buried layers. Nowhere in the Midwest is such a sequence of events so displayed. The cool, moist, north-facing slopes shelter plants more typical of northern Wisconsin, including hemlock, yellow birch, mountain maple and Canada yew. The groundlayer contains numerous ferns and includes species such as Virginia water-leaf and Canada mayflower. The area is widely used for geology research and a plaque honors researcher Charles Van Hise, who formulated some of his principles of structural deformation and metamorphism here. Ableman's Gorge is owned by the DNR and the University of Wisconsin and was designated a State Natural Area in 1969.