_Ungulata._--Six extinct horses (_Equus_), and one _Hipparion_; the living South American tapir, and a larger extinct species; a _Dicotyles_, or peccary, and an allied genus, _Platygonus_; a species of the South American llamas (_Auchenia_), and one of a kind of camel, _Procamelus_; two extinct bisons; a sheep, and two musk-sheep (_Ovibos_); with three living and one extinct deer (_Cervus_), show an important increase in its Herbivora. _Proboscidea._--Two elephants and two mastodons, added to this remarkable assemblage of large vegetable-feeding quadrupeds. _Rodentia._--These consist mainly of genera and species still living in North America; the only important exceptions being a species of the South American capybara (_Hydrochoerus_) in South Carolina; and _Praotherium_, an extinct form of hare, found in a bone cave in Pennsylvania. _Edentata._--Here we meet with a wonderful assemblage, of six species belonging to four extinct genera, mostly of gigantic size. A species of _Megatherium_, three of _Megalonyx_, and one of _Mylodon_--huge terrestrial sloths as large as the rhinoceros or even as the largest elephants--ranged over the Southern States to Pennsylvania, the latter (_Mylodon_) going as far as the great lakes and Oregon. Another form, _Ereptodon_, has been found in the Mississippi Valley. _Marsupialia._--The living American genus of opossums, _Didelphys_, has been found in deposits of this age in South Carolina. _Remarks on the Post-Pliocene fauna of North America._--The assemblage of animals proved, by these remains, to have {131}inhabited North America at a comparatively recent epoch, is most remarkable. In Europe, we found a striking change in the fauna at the same period; but that consisted almost wholly in the presence of animals now inhabiting countries immediately to the north or south. Here we have the appearance of two new assemblages of animals, the one now confined to the Old World--horses, camels, and elephants; the other exclusively of South American type--llamas, tapirs, capybaras, _Galera_, and gigantic Edentata. The age of the various deposits in which these remains are found is somewhat uncertain, and probably extends over a considerable period of time, inclusive of the Glacial epoch, and perhaps both anterior and subsequent to it. We have here, as in Europe, the presence and apparent co-existence in the same area, of Arctic and Southern forms--the walrus and the manatee--the musk-sheep and the gigantic sloths. Unfortunately, as we shall see, the immediately preceding Pliocene deposits of North America are rather poor in organic remains; yet it can hardly be owing to the imperfection of the record of this period, that _not one_ of the South American types above numerated occurs there, while a considerable number of Old World forms are represented. Neither in the preceding wonderfully rich Miocene or Eocene periods, does any _one_ of these forms occur; or, with the exception of _Morotherium_, from Pliocene