CHAPTER VI.

THE FEATHERED CONQUERORS OF THE AIR--PART I. THEIR WANDERINGS OVER SEA AND MARSH, DESERT AND PLAIN 123

PICTURE-HEADING--Toothed Water-birds of the Cretaceous Period. Swimming and standing, _Hesperornis_; flying, _Ichthyornis_. (Restored from Marsh’s Skeletons.)