Human Tracks from Quaternary Tufa Deposits,Cuatro Cienegas,Coahuila, Mexico

In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico, but for decades were not studied scientifically or deposited in any museum. Consequently, knowledge of the locality where they were found was lost. Once the two tracks were relocated they found their way to the Museo del Desierto, Saltillo (Coahuila) where they were placed on display with a tentative label suggesting an early Holocene age (10,000 B.C.). This inference was based only on the known antiquity of humans in the region determined from previous archaeological work and two dated sediment cores close to the footprint site. It was not until 2006 that the presumed footprint discovery site was rediscovered, revealing more than 20 additional well-preserved prints, in at least four trackways representing several different individuals with foot lengths ranging from about 23–27 cm. The tracks include one well-preserved trackway providing step and stride measurements. A poorly preserved cervid trackway and a possible duck footprint have also been identified. The footprints are preserved in hard tufa. Geochemical evidence suggests the tracks were made during periods of increased aridity.