Like the Anoplotherium and the Palaeotherium, therefore, Archaeopteryx tends to fill up the interval between groups which, in the existing world, are widely separated, and to destroy the value of the definitions of zoological groups based upon our knowledge of existing forms.

After the appearance of Archaeopteryx Lithographica, the first known bird, the myriad species descended from it. It is hard to isolate when the first owls evolved. The first owl may have come out of the Cenozoic era of 70 to 40 million years ago if not the latter part of the Mesozoic era, which was 135 to 70 million years ago.

Cassian Beds to the Triassic Periods. Discovery of new organic Types. Feathered Archaeopteryx of the Oolite.

The skull of this solitary specimen is unfortunately wanting, and it is therefore uncertain whether the Archaeopteryx possessed teeth or not. But the remainder of the skeleton is so well preserved as to leave no doubt respecting the main features of the animal, which are very singular.

Thus the genus Orthoceras has been for the first time recognised in a Mesozoic deposit, and with it we find associated, for the first time, large Ammonites with foliated lobes, a form never seen before below the Lias; also the Ceratites, a family of Cephalopods never before met with in the Upper Trias, and never before in the same stratum with such lobed Ammonites. Archaeopteryx macrurus, Owen.

Darwin to an extent which could hardly have been anticipated. In 1862, the specimen of Archaeopteryx, which, until the last two or three years, has remained unique, was discovered; and it is an animal which, in its feathers and the greater part of its organisation, is a veritable bird, while, in other parts, it is as distinctly reptilian.

In the living representatives of the class Aves, the tail-feathers are attached to a coccygian bone, consisting of several vertebrae united together, whereas in the Archaeopteryx the tail is composed of twenty vertebrae, each of which supports a pair of quill-feathers.

These insects, among which is a libellula, or dragon-fly, must have been blown out to sea, probably from the same land to which the pterodactyls, and other contemporaneous air-breathers, resorted. Tail and feather of Archaeopteryx, from Solenhofen, and tail of living bird for comparison. A. Caudal vertebrae of Archaeopteryx macrura, Owen; with impression of tail- feathers; one-fifth natural size.

New Genera of fossil Mammalia in the Middle Purbeck of Dorsetshire. Dirt-bed or ancient Soil. Fossils of the Purbeck Beds. Portland Stone and Fossils. Kimmeridge Clay. Lithographic Stone of Solenhofen. Archaeopteryx. Middle Oolite. Coral Rag. Nerinaea Limestone. Oxford Clay, Ammonites and Belemnites. Kelloway Rock. Lower, or Bath, Oolite. Great Plants of the Oolite. Oolite and Bradford Clay.

The Archaeopteryx macrurus, Owen, recently acquired by the British Museum, affords a second example of the discovery of the osseous remains of a bird in strata older than the Eocene. It was found in the great quarries of lithographic limestone at Solenhofen in Bavaria, the rock being a member of the Upper Oolite.