WHEN THE WOBLD WAS YOUNG 191 



the reptiles had mostly died out) were a good deal less 

 numerous than the creatures who had gone before 

 them. But this may be partly accounted for by the 

 fact that their bodies, being lighter, would more easily 

 float on the surface of lakes and rivers, and would be 

 eaten by fishes, or decomposed by the air, instead of being 

 sealed up in mud, like those of larger and heavier 

 animals. 



The very earliest kind of bird that has so far been 

 found at all — it was in a Bavarian rock of late limestone, 

 and is known as the Archaeopteryx — resembles, in many 

 respects, the family of reptiles. It has, to be sure, a long 

 jointed tail, and teeth in its jaws, and other features in 

 common with them ; but then it possesses feathers, even on 

 its tail, and the brain of a bird. Teeth were not at all un- 

 common in the jaws of these early birds, and the long- 

 billed, fish-eating, Hesperornis, of North America, had a 

 whole set that grew afresh when the old ones fell away. 

 The Hesperornis was between five and six feet high, 

 and is found in the chalk rocks. It was a famous diver, 

 and had -wings of a sort ; but whatever use they may have 

 been on land, they certainly could have been of none 

 either in air or water. 



In New Zealand there existed, until comparatively 

 lately, several ' running ' birds, of the kind of which the 

 ostrich, the cassowary and the emu are the last specimens 

 surviving in the world. The most celebrated of these is the 

 Moa, whose bones are found only along the banks of streams 

 at present flowing, showing that the surface of the land has 

 not changed since they were buried there. The Moa could 

 not have been less than fourteen feet, as its leg bone is 

 nearly three times as long as that of a man. Some of the 

 tribe were slight and swift, others like the Dinornis 

 Elephantopus, shorter and stronger. The wing bones of all 

 were so small as to be hardly noticeable, and their bills 

 were invariably short. Whether they could sing or not 

 we do not know — probably not. In some cases a few 



