Late Triassic Footprint Fauna from the Culpeper Basin, Northern Virginia (U.S.)

Thousands of footprint impressions, probably of Norian age, have been discovered on a single bedding plane in a quarry in the Culpeper Basin of N. Virginia. About 830 tracks on this bedding surface, contained in 32 recognizable trackways, were studied in detail. The other tracks were too obscure for meaningful analysis. Herbivores greatly outnumber carnivores, & small herbivores are more abundant than large ones. The order of appearance of these trackmakers suggests that smaller & less agile species preferred soft ground, whereas larger carnivorous forms preferred a firmer substrate. From the measured print sizes, stride lengths, & pace angles, it was possible to estimate the hip height, body length, Froude numbers, & speed of each trackmaker. Illus.