- Dinosaur National Monument Expansion - Dinosaur COIn 1909, an abundance of dinosaur fossils were discovered by a team of paleontologists collecting for the Carnegie Museum of Natural History, near Jensen, Utah. It was one of the most important dinosaur excavation sites in the United States at the time. In 1915, President Woodrow Wilson set aside 80 acres around the fossil discovery site as a National Monument. President Franklin Roosevelt expanded the monument to its present size of nearly 200,000 acres in 1938. About 3/4th of the enlarged monument lies in Colorado, making this one of the few bi-state national parks or monuments. It is administered by the...