In July 1945 (although some accounts say 1944), a German immigrant to Mexico, Waldemar Julsrud (1875/6-1952), a hardware merchant, discovered a number of clay figurines at the foot of El Toro Mountain on the outskirts of Acámbaro (Guanajuato, Mexico). Charles Hapgood (1904-1982), the historian of science from Keene College (New Hampshire, USA) who first made the impossible claims about the Piri Re’is map, also promoted claims that the figurines are genuinely ancient artefacts showing extinct animals, including dinosaurs. On the other hand, he was troubled by the near-perfect condition of what are often very delicate objects and the complete absence of any sort of patination that might have developed during centuries (or even millennia) of burial.
It has been claimed that radiocarbon dates from organic materials on their surfaces are around 6,500 years old, based on three samples: sample 1 has a date of 3590±100 bp (I-3842), sample 2 of 6480±170 bp (I-4015) and sample 3 of 3060±120 bp (I-4031). It has been suggested that many, if not all of them, are modern souvenirs made for the tourist industry. Even if they are genuine, there is debate about what they depict. None of the published examples really resembles any known dinosaur. Instead, it has been suggested that they are stylised representations of living reptiles of the region or are composite fantastical monsters.
Excavation of the objects was observed by a trained archaeologist, Charles di Peso, who found that they were only retrieved from hollows in middens with loose black soil quite unlike the rest of the middens. He also recognised that their lack of patination and surface damage was quite unlike that of other materials recovered from the same middens; moreover, they were recovered whole, while other objects were broken. There is little doubt that the figurines are of recent date; thermoluminescent tests would be sufficient to establish their approximate date of manufacture and although dating was attempted in 1972 by Froelich Ramey of the Pennsylvania Museum, who obtained results suggesting that they were around 4500 years old. Subsequent tests in 1978 were unable to replicate these dates; indeed, they were unable to obtain any dates from the figurines, showing that they are of very recent manufacture. This does not prevent fringe writers from complaining that archaeologists have dismissed them as fakes without taking the trouble to examine them.
For another deconstruction of the figurines, see this site [NB The original site has been down since October 2012 and the link takes you to a cached version of the page from the Internet Archive Wayback Machine dated 8 September 2012].