It was quickly seen - even by those who held Archaeopteryx to be a reptile - that it was a form intermediate between existing birds and existing reptiles; while those who were convinced by Sir R.
The clawed slender fingers did not make Archaeopteryx any more quadrupedal or bat-like in its habits than is a kestrel hawk, with its equally large, or even larger thumb-claw.
The separation of the Ratitae from the other birds, and their seemingly fundamental differences, notably the absence of the keel and of the power of flight, induced certain authors to go so far as to derive the Ratitae from the Dinosaurian reptiles, whilst Archaeopteryx (q.v.) and the Carinatae were supposed to have sprung from some Pterosaurian or similar reptilian stock.
Owen com municated a detailed description of them to the Philosophical Transactions (1863, pp. 33-47), proving their bird-like nature, and referring them to the genus Archaeopteryx of Hermann von Meyer, hitherto known only by the impression of a single feather from the same geological beds.
A wide gap separates Archaeopteryx from the next order of fossil birds of the Cretaceous epoch, and, since freshwater deposits of that age are rare, bird remains are uncommon.
The importance of Archaeopteryx justifies the following descriptive detail.
Marsh states that he had fully satisfied himself that Archaeopteryx belonged to the Odontornithes, which he thought it advisable for the present to regard as a subclass, separated into three orders - Odontolcae, Odontotormae and Saururae - all well marked, but evidently not of equal rank, the last being clearly much more widely distinguished from the first two than they are from one another.
The name of Archaeopteryx litho graphica was based by Hermann von Meyer upon a feather (Gr.irrEpv, wing) found in 1861 in the lithographic slate quarries of Solenhofen in Bavaria, the geological horizon being that of the Kimmeridge clay of the Upper Oolite or Jurassic system.