The size of this bird, inferred from that of its egg, would be vastly superior to that of the ostrich. But if we notice the comparative size of the trochleated extremity of the tarso-metatarsal bone, we shall see that its height would be greatly exaggerated by adopting such a basis for its establishment; in fact, it would not probably exceed a height double that of the ostrich. And, though it must have been superior to that of the Dinornis maximus of Prof. Owen, it might perhaps excel it only by the difference of two or three feet. A bird of twelve or thirteen feet in height would, however, if we stood in its presence, appear enormous, and must have greatly astonished and terrified the natives of Madagascar. Whether it now exists is uncertain, as it may possibly have a habitation in the wild recesses of the island, which have never yet been visited by any European traveller. The credit of most of the observations and discoveries relating to this remarkable bird is attributable to French naturalists;[A] and it seems to be a duty devolving on English and American navigators to complete the history thus happily begun, and to tell us whether the Epyornis still exists in the mountain-forests of Madagascar, or at least present us with its extraordinary relics. [Footnote A: The following are the names of French travellers, who have been supposed to have seen the eggs of the Epyornis in the Island of Madagascar: M. Sganzin, in 1831; M. Goudot, in 1833; M. Dumarele, in 1848; and M. Abadie, in 1850.] FOSSIL IMPRESSIONS.--I. Ichnology, a newly created branch of science, takes its name from the Greek word _ichnos_, a _track_ or _footstep_, and the tracks themselves have been denominated Ichnites, or, when they refer to birds only, Ornithichnites, from _ornis_, a _bird_. And this last term has by custom been generally applied to ancient impressions, though not correctly. Geology has revealed to us not only the remains of animals and vegetables, but the impressions made by them during their lives, and even the impressions of unorganized bodies. The first notice of these appearances was, as often happens, regarded with indifference or scepticism; but their number and variety enlightened the public mind, and opened a new source of information and improvement. The first remarkable observation made on fossil footsteps was that of the Rev. Dr. Duncan, of Scotland, in 1828. He noticed, in a _new red sandstone_ quarry in Dumfriesshire, impressions of the feet of small animals of the tortoise kind, having four feet, and five toes on each foot. They were seen in various layers through a thickness of forty feet or more.