The park features a castle built from prehistoric logs, some weighing more than 10,000 pounds each, and composed of more than 300 tons of petrified rock, including many pieces of rose quartz from the Black Hills of South Dakota. A waterfall added to the park in 1989 was built by Olheiser Masonry as a tribute and dedicated to the park’s original builders, Mr. Rafferty, his sons, and his sons-in-law. The site also includes cannonball concretions, natural geologic formations often mistaken for dinosaur eggs, which formed outward from a small central core through chemical and mechanical forces in sandstone and mudstone deposits. These cannonballs were gathered from the Cannonball River in Hettinger County, North Dakota, where an exceptionally thick sandstone layer helps create them, and were cemented together during the park’s construction.