Fossil Cycad National Monument

A reconstructed fossil cycad

Fossil Cycad National Monument was a national monument in the U.S. state of South Dakota beginning in 1922. The site contained hundreds of fossil cycads, one of the world's greatest concentrations. Because vandals stole or destroyed all of the visible fossils, it was withdrawn as a national monument in 1957. It is located in northwestern Fall River County, on U.S. Route 18, northeast of the city of Edgemont.

Discovery

Cycas rumphii, a modern cycad

The fossilized cycad beds were discovered in 1892 by F. H. Cole of Hot Springs, South Dakota, in the 120-million-year-old Dakota Sandstone Formation, near Minnekahta. Cole sent photographs of the fossils to Professor Henry Newton, a geologist at the Smithsonian Institution. Professor Thomas MacBride of the University of Iowa published the first description of the site in 1893. There were believed to be large deposits of Cretaceous cycad fossils. (Cycads are plants resembling ferns, although not related to them. The ones at this site were tree-sized.)

In 1920, Yale paleobotanist George Reber Wieland obtained the fossil cycad-rich land under the Homestead Act "in order that the cycads might not fall into unworthy hands". Two years later he offered to return the land to the federal government if a national monument could be established to protect the fossils.

Establishment of the national monument

The original monument was established on October 21, 1922 by proclamation of President Warren G. Harding. It encompassed 1.3 km² (320 acres) at the south entrance to the Black Hills of South Dakota. It was said to be "probably one of the most interesting fossil-plant beds yet discovered, with the most perfectly preserved specimens, and is known to scientific people throughout the world."

The superintendent at Wind Cave National Park was given jurisdiction over the new national monument, but day-to-day supervision was left to local ranchers.

Deauthorization of the monument

Even before formal approval of the new national monument, all of the visible fossils had been removed. Excavations in 1935 uncovered many new fossils. The site was retained for some years in the expectation that erosion would uncover new fossils. This did not happen, however, and on September 1, 1957 Fossil Cycad National Monument was transferred to the Bureau of Land Management. In 1980, construction of a highway through the site uncovered more fossil cycads.