National Geographic : 1940 Sep
314 The National Geographic Magazine Leisurely "Lightning" Takes Mrs. Stirling for a Ride The wife of the expedition's leader, herself an accomplished mathematician, borrows one of the bulls used by workmen to ride from Tres Zapotes to excavation sites near by. It was dubbed the camp "motorcycle." These Figurines May Reveal a New Chapter in Early American Engineering Skill With this smiling clay dog (left), conventionalized turkey, and laughing jaguar were found eight small clay disks. Tubes pierce the feet of the dog and jaguar. Perhaps the ancient people inserted wooden axles in these tubes and used the round disks as wheels. If so, the early inhabitants of Tres Zapotes had discovered the use of the wheel, generally believed to have been unknown to American Indians.