The fossils from near Santa Fe included the horse tooth which had puzzled Darwin as it had been previously thought that horses had only come to the Americas in the 16th century, close to a Toxodon tooth and a tooth of Mastodon andium (now Cuvieronius hyodon).
Os fósiles da zona de Santa Fe incluían o dente de cabalo, que desconcertara a Darwin, xa que anteriormente se pensaba que os cabalos chegaran ás Américas no século XVI levados polo home, ao lado dun dente de Toxodon e un dente de Mastodon andium (agora Cuvieronius hyodon).