 Cuvier at first thought it was a marsupial, but Buckland later realized it was a primitive placental mammal.Due to its small size and primitive nature, Buckland did not believe it invalidated the overall pattern of an age of reptiles, when the largest and most conspicuous animals had been reptiles rather than mammals.In 1828 Alexandre Brongniart's son, the botanist Adolphe Brongniart, published the introduction to a longer work on the history of fossil plants.