500 Main Ave., Lemmon, South Dakota
Long ago tropical swamps covered the region around Lemmon. Gradual climatic and chemical changes and the passage of time turned the remnants of that distant era—trees, grasses, plants, and marine and animal life—into stone. In the 1930s O. S. Quammen, an amateur geologist, collected some of the best specimens of the petrified material for an unusual but artistic outdoor display.
The small park is studded with cone-shaped pyramids and piles of “cannonballs.” A fairy-tale castle, built with more than 300 tons of petrified material, including tree trunks more than 30 feet tall, is especially intriguing.
Teeth marks, petrified snakes, and fossilized marine life are eerily recognizable in many surfaces. The castle contains the fossils of enormous animals, while a circular museum built of petrified logs and slabs of petrified grass houses pioneer artifacts. The multiplicity of forms and the incredible range of colors make this a fascinating place to visit.
Park open year-round; museum open mid-May–mid-Sept.