SOLENHOFEN LITHOGRAPHIC STONE, a famous deposit of limestone of upper oolite age, which from its fine-grained and homogeneous texture is admirably adapted for lithographic purposes. It occurs near Aichstadt in Bavaria, and has been extensively quarried since the invention of lithography. The quarrymen work upon the lines of stratification, which are beautifully parallel, and all the fossils are found upon the natural surfaces of the beds, and present an impression and cast in almost every instance. The rock is quarried to a depth of 80 or 90 feet. It is of special interest to the geologist from the singular assemblage of fossil remains which are preserved in it with wonderful min, uteness. The most delicate tracery of the wings of the dragon-fly is often as perfect as in livi LIZ specimens. The rock is of marine origin, and while lithologically it has a strong. resemblance-to the white lias of Britain, its fossils correlate it to the Kimmeridge.clay. These are chiefly ammonites, nautili, crustacea, winged insects, fishing. and pterodac tyles. But the most singular fossil is one which has only recently been brought to tight. A single feather was first found, and some mouths after, the bones of a feather-covered animal, which was considered by its first describers to be a lizard, but prof. Owen has recently shown, on incontrovertible grounds, that it is a true though very anomalous bird. The specimen which, with the exception of the head, is almost entire, is now in the British museum. It has formed the subject of an elaborate memoir by prof. Owen, published in the Philosophical Transactions. He has named it Archceopteryx 911CGCPUP U. It is certainly the oldest bird of which any remains have yet been found, but the rocks which contain the numerous ornithic foot-prints in Connecticut valley (see IcatcoLoox) are more ancient; the most careful examination has, however, hitherto failed to discover in them any indications other than the footprints. The Archcropteryx was about the
size of a rook. The anomalous structure which induced the earlier observers to make it a reptile, and sonic followed to imagine it as a transition form between the reptile w and the bird, is the tail, which, instead of consisting of a few shortened vertebra united together into a coccygean hone, as in all known birds, recent or fossil, was formed of twenty elongated vertebrae, each of which supported a pair of quill-feathers. But this departure from the bird type is not so anomalous as it at first sight appears, for in the early embryonic condition of the bird, the vertebrae are distinct and separate, and the anastomosis which invariably takes place in the subsequent development of the embryo, does not occur in the ArclueopteTye, so that it may be considered to exhibit the temporary embryonic condition of the bird as a permanent structure; and that this is the true posi tion of this singular fossil is further established by the existence of other features which are found only in birds. These are the ornithie structure of the wings and legs, the occurrence of feathers, which are yonfined to birds, and the existence of a merry-Souglit (furculum), which is found in no other class of animals. An elevation on the surface of the slab containing the fossil is believed by many to be the cast of the interior of the• skull, and it corresponds remarkably in size and form with the cast from the skull of a rook.