The Cimoliornis Diomedeus, described by Professor Owen, is the only specimen of the order Aves or bird-tribe that as yet appears over this waste of waters. The term _cimoliornis_ means simply the chalk-bird, and is allied, in some of its osseous processes, to the albatross, but also differs in too many points to be regarded as the ancestor of that courageous storm-braving animal. The claims of this fossil, indeed, to its true place in the system, have not yet been fully established. “Of the few actually fossilized remains of birds,” says Professor Owen, “that have been discovered in England, the most complete and characteristic are those from the London clay. Some fragmentary Ornitholites have been discovered in the older pliocene crag, and in the newer pliocene fresh water deposits and bone caves. Extremely scanty have hitherto been the recognizable remains of birds from the chalk formations. The fossil from the wealden, which I formerly believed, with Cuvier and Dr. Mantell, to belong to a wading bird, I have since adduced reasons for referring to the extinct genus of flying reptiles called Pterodactyle.” The fossil bones of the Cimoliornis were obtained by the Earl of Enniskillen from the chalk beds near Maidstone, and resemble the humerus of the albatross in form, proportions and size; there are no distinct traces of the attachments of the quill-feathers in any of the fragments; but in other points there are analogies to the osseous structure of birds; and there are bones so gigantic as will assign them a place, if the proofs are completed, among the enormous foot-print class of the permian age, and go almost to realize the fabulous “roc” of the Arabian romance.