Parfrey's Glen, Wisconsin's first State Natural Area, is a spectacular gorge deeply incised into the sandstone conglomerate of the south flank of the Baraboo Hills. The exposed Cambrian strata provide excellent opportunities for geological interpretation. The walls of the glen - a Scottish word for a narrow, rocky ravine - are sandstone with embedded pebbles and boulders of quartzite. The moss-covered walls are moist from seepage, cool and shaded. As a result, they support a flora more typical of northern Wisconsin with yellow birch, mountain maple, and red elder and several rare plant species. Parfrey's Glen Creek, a fast, cold, hardwater stream flows through the gorge and harbors a very diverse insect fauna including a rare species of diving beetle and a rare caddisfly. Parfrey's Glen is owned by the DNR and was designated a State Natural Area in 1952. Visitors must remain on the designated trail. At the point where the designated trail ends, visitors may proceed into the glen but must remain within 20 feet of the bed of the creek and may not venture past the base of the waterfall. Pets, food, and beverage are not allowed in the natural area. A State Park sticker is required to park in the parking lot.