Paleontology in Washington, D.C.

The District of Columbia and Maryland are the only places where Early Cretaceous dinosaur remains are known to have been preserved east of the Mississippi River.

[2] A few decades later, in January 1898, a vertebra and some other fragmentary remains of a large theropod dinosaur were discovered by workers attempting to install a sewer line at First and F Streets SE.

[3] The fossils were donated to the Smithsonian by J. K. Murphy on the 28th of that month and assigned the specimen number NMNH 3049.

[2] In 1942, near the end of Gilmore's career, a sizable thigh bone belonging to Astrodon was discovered during construction at the McMillan Water Filtration Plant.

On the next anniversary of the discovery mayor Anthony A. Williams declared it a local holiday, "Capitalsaurus Day".