228 THE HISTORY OF CREATION. 
formation of their beaks and feet—are of an exceeedingly 
uniform organization, in much the same way as are the class 
of insects. The bird form has adapted itself on all sides to 
the external conditions of existence, without having thereby 
in any way essentially deviated from the strict hereditary 
type of its characteristic structure. There are only two 
small groups, the feather-tailed birds (Saururee) and those 
of the ostrich kind, which differ considerably from the 
usual type of bird, namely, from those with keel-shaped 
breasts (Carinatze), and hence the whole class may be divided 
into three sub-classes. 
The first sub-class, the Reptile-tailed, or Feather-tailed 
Birds (Saurure), are as yet known only through a single, 
and that an imperfect, fossil impression, which, however, in 
being the oldest and also a very peculiar fossil bird, is of 
great importance. This fossil is the Primeval Griffin, or 
Archzopteryx lithographica, of which as yet only one speci- 
men has been found in the lithographic slate at Solenhofen. 
in the Upper Jura system of Bavaria. This remarkable 
bird seems on the whole to have been of the size and form 
of a large raven, especially as regards the legs, which are 
in a good state of preservation ; head and breast unfortun 
ately are wanting. The formation of the wings deviates 
somewhat from that of other birds, but that of the tail 
still more so. In all other birds the tail is very short and 
composed of but few short vertebre ; the last of these have 
grown together into a thin, bony plate standing perpen- 
dicularly, upon which the rudder-feathers of the tail are 
attached in the form of a fan. The Archzeopteryx, however, 
has a long tail like a lizard, composed of numerous (20) 
long thin vertebrz, and on every vertebra are attached the 
