Fossils and Geologic Time Topics


Ichnofossils are traces of ancient life that are not actual organism parts.  They include tracks, trails, and burrows.

Tracks are fossilized footprints that ancient animals left in soft materials.  Dinosaurs left numerous footprints in ancient deposits.

Dinosaur tracks
(Photograph courtesy of the Virginia Division of Geology and Mineral Resources)

MapDinosaurs that walked in the Culpeper Basin left tracks, as shown in the photograph above.  Thousands of dinosaur footprints have been found in the Culpeper Basin.



Trails are fossilized structures created by ancient animals moving around on soft material.  Worms and worm-like animals left trails in ancient deposits. The fossil trails on this rock in the photo below were made by a crawling animal.

Ichnofossil trails
Fossil trails (Photograph by Parvinder Sethi)

Burrows are once-hollow structures filled with sediment that represent the burrowing activity of ancient animals. In the photo below, the burrow was made by a segmented animal.  It is preserved on the underside of a sedimentary layer.  This ichnofossil is common in Paleozoic sandstones in western Virginia. 

570 to 245 million years ago

(Photograph by Parvinder Sethi)