Solnhofen Formation in the context of "Eichstätt"

Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used (see below).

Archaeopteryx lithographica, from the late Jurassic Period Solnhofen Formation of Germany, is usually considered the earliest known avialan which may have had the capability of powered flight; a minority of studies have suggested that it might have been a deinonychosaur instead. Several older (but non flight-capable) possible avialans are known from the late Jurassic Tiaojishan Formation of China, dated to about 160 million years ago.

The Black Jurassic or Black Jura (German: Schwarzer Jura) in earth history refers to the lowest of the three lithostratigraphic units of the South German Jurassic, the latter being understood not as a geographical, but a geological term in the sense of a lithostratigraphic super group. Formerly and even occasionally today in the popular scientific literature, this term is equated to the chronostratigraphic series of the Lower Jurassic. This is however not quite correct, because the Black Jura does not exactly coincide with the chronostratigraphic boundaries of the Lower Jurassic. In addition, the term lias, which was formerly frequently used (and sometimes is today) as a synonym, should no longer be used in connexion with the South German Jurassic. Instead, the term lias, or North German Lias, should be reserved for the roughly equivalent lithostratigraphic unit in the North German Jurassic. The deposition of the Black Jurassic took place about 199 to 175 million years ago. The Black Jurassic follows the lithostratigraphic unit of the Keuper and is superimposed on the lithostratigraphic group of the Brown Jurassic.