DEFINITION OF BIEDS. 



63 



ichnites, — the fossils so called ))ecause supposed to indicate the presence of Birds by their 

 foot-pririts, were discovered about the year 1835 in the Triassic formation in Connecticut. 

 But the creatures which made these trades are now reasonably believed to have been all 

 Dinosaurian Reptiles. The oldest ornitholUe, or fossil certainly known to be that of a true 

 Bird, is the famous ArchcBopteryx, found by Andreas AVaguer in 1861 in the Oolitic slate of 

 Solenhofen in Bavaria. This has a long lizard-like tail of twenty vertebrte, from each of which 

 springs a weU-developed feather on each side ; feathers of the wings are also well preserved ; 



Fig. 15. — Restoration of Hesperornis regalis. After Marsh. 



bones of the hand are not fused together, as they are in recent Birds ; and the jaws bear true 

 teeth. This Bird has served as the basis of one of the primary divisions of the class Aves ; 

 though it has many reptilian characters, it is a true Bird. The great gap between this ancient 

 Avian and latter-day birds has been to some extent bridged by Marsh's discovery and splendid 

 restoration of Birds from the Cretaceous formations of North America, suoli genera as 

 Ichfhyornis and Hesperornis forming types of two other primary divisions of the class, Odon- 

 totormce and Odontolcce, or Birds with teetli in sockets, and those with teeth in grooves. In 

 both genera the tail is short, as in ordinary birds. In IcMhijornis, though the wings are 



