It is certainly very much out of stratigraphical order to jump from the fossil bird-remains of the Stonesfield Slate to those of the Tertiary beds of the Paris basin ; nor is such a step in any accordance with historical order. We aro simply compelled to take it, through the necessity of saying a few words in explanation of certain plates which have been issued with the previous numbers of this volume. The gap, however, in the historical series is not so very wide; and it is by no means useless in this place to run over afresh the review which the great Cuvier made of the labours of his predecessors. A section of vol. iii. of his famous work, ‘Recherches sur les Ossements Fossiles,’ published in 1812, was devoted to the remains of birds. “Naturalists,” he begins, “ are agreed that, of all animals, birds are those whose bones or other relics are the most rarely found in the fossil state. Some even absolutely deny that any have ever been met with; and indeed, by one of those singular accidents reserved for the beds of gypsum of our neighbourhood, there are scarcely any other well preserved fossil bones of birds than those they have furnished.” He then, to show the correctness of this statement, and the then recent knowledge even of the fossil birds of the platriàres of Paris, glances over the statements of Walch, Hermann, Camper, Blumenbach, Faujas, Lamanon, Gesner, Luid, Wallerius and Linnaeus, Davila and others, the accounts of most of which have been already given in our previous articles.