Animal sculptor Louis Paul Jonas built the two fiberglass dinosaur models of a 70-foot Apatosaurus and a 45-foot Tyrannosaurus Rex for the Sinclair Oil Company’s "Dinoland" exhibit of 1964 - 1965 New York World’s Fair.

In September of 1966, the nine models that made up the "Dinoland" exhibit made a stop in Fort Worth on their nationwide tour. The Somervell County Chamber of Commerce had a booth at the show, and interest in what would happen to these models was sparked.

In 1969 the Sinclair Oil Corporation merged with Atlantic Richfield Company, and plans were made to abandon the dinosaur mascot. Citizens of Glen Rose immediately sought to acquire the models. At-the-time Governor Preston Smith wrote a letter to Atlantic Richfield Company asking for the dinosaurs to be retired at Dinosaur Valley State Park. Initially, all nine dinosaurs were promised to the park, but that fell through when word got around and everyone wanted a piece of "Dinoland." In the end, the park acquired the two most impressive statues in July of 1970 just in time for the parks dedication on Oct. 2, 1970.

*Information gathered from "Dinosaur Highway" written by Laurie E. Jasinski. This book and many others are for sale at the park gift shop.