Besides the outdoor park, the site has a museum, also built out of petrified wood, which hosts smaller collections of fossils.

[3] An amateur geologist, Quammen also collected samples of petrified wood he discovered across Perkins County, which has an abundance of the fossils.

[2] Quammen employed up to 40 men in two teams: one to locate and move the fossils to the park via wagon, and one to construct the monuments according to his instructions.

[7] In 1961, the Lemmon Chamber of Commerce donated a 200-pound petrified log to White Gardens in St. Petersburg, Florida, for inclusion in its Walk of States mosaic.

[11] Three buildings exist on the site, likewise constructed out of petrified fossils: the Castle, the museum, and a now-disused gas station.

[2] The octagonal Castle sits at the center of the park and was created out of 300 tons of material, and its surfaces feature the fossilized remains of dinosaurs, snakes, and bird tracks.

[12] Inside are displays of fossil bones and teeth also collected by Quammen, as well as relics of Lemmon's pioneer past, including firearms, saddles, taxidermy and hunting trophies, and other 20th-century artifacts.

[4] During the Mesozoic era,[2] about 252–66 million years ago (Ma), this area of the Great Plains was a freshwater swamp with thick jungles of vegetation.

[7] The Mesozoic plant—and some animal—matter, buried underneath the sea, was concreted and preserved by mineral deposits carried underground by the seawater.

[4] Other speciments collected by Quammen and his team include preserved dinosaur, bison, and other faunal bones; invertebrate shells; and fossilized leaves.