POPULAR GEOLOGY

Spectacular Pterosaur Track Slab Begins its Cross-country Journey

November 2013

A 900 lb. slab of rock with some of the best preserved pterosaur (flying reptile) tracks ever recognized was discovered on State Land in the San Rafael Swell near the town of Ferron by a team from Marietta College (Ohio). This slab of rock from the Jurassic Summerville Formation preserves at least 9 separate trackways of 2 different sizes of pterosaurs that were walking along a tidal flat near the shore of the Curtis Sea.

We know the tracks were made by pterosaurs because, in addition to the hind foot prints, there are tracks made by the wings. So, unlike birds that walk bipedally on their hind feet while folding their wings against their bodies, pterosaurs walked quadrupedally using their folded up wings to support the front of their bodies. This site and the tracks were documented in a scientific publication in 2004 (Mickelson and others, 2004).

Because of the scientific importance of this slab, a team from the Utah Geological Survey (UGS) collected it in 2004 so that it could be placed in the Natural History Museum of Utah (the repository for all of the fossils collected by the UGS from public lands in Utah). Due to its large size, this slab has been stored at the UGS’s Utah Core Research Center since collection.

The Natural History Museum of Utah agreed to loan the slab to the American Museum of Natural History in New York City for display in a new exhibit on pterosaurs. On November 14, 2013, a team from Terry Dowd Inc. (a fine art packing company) came to the UGS to package the slab in a custom crate so that it could be transported by truck to New York. The slab was cradled in ethafoam so that it will be well protected during the long drive to New York which began on November 19. Eventually, the slab will be returned to the Natural History Museum of Utah for display.