 This discovery was later explained as part of the evolution of the horse.The "soft as cheese" "Mastodon" bones at the Paraná River were identified as two gigantic skeletons of "Mastodon andium", and mastodon teeth were also identified from Santa Fe and the Carcarañá River.The pieces of spine and a hind leg from Port S. Julian which Darwin had thought came from "some large animal, I fancy a Mastodon" gave Owen difficulties, as the creature which he named "Macrauchenia" appeared to be a "gigantic and most extraordinary pachyderm", allied to the "Palaeotherium", but with affinities to the llama and the camel.