1 98 WHAT IS LIFE ? 



swarmed in some of the Cretaceous seas. But reptiles 

 were not so abundant as in the previous system. True 

 crocodiles frequented the rivers of the period. One 

 extraordinary reptile was of a huge snake-like form, 

 forty or more feet long, with a slim arrow-shaped head, 

 on a swan-like neck, rising twenty feet out of the 

 water. This formidable sea monster " ' probably often 

 swam many feet below the surface, raising the head to 

 the distant air for a breath, then withdrawing it and 

 exploring the depths 40 feet below without altering 

 the position of its body. It must have wandered far 

 from land, and that many kinds of fishes formed its food 

 is shown by the teeth and scales found in the position 

 of its stomach ' (Cope)." 1 Sea-serpents found in this 

 system measure more than seventy-five feet in length ; 

 their heads are large, flat and conic, with eyes directed 

 partly upwards. They swam by means of two pairs of 

 paddles, like the flippers of the whale. Like snakes, 

 they had four rows of formidable teeth. They possessed 

 a unique arrangement in order to swallow their prey 

 entire. Some of the monsters living in these times 

 had skulls exceeding six feet in length, exclusive of 

 the horny beak, and four feet in width. Birds lived, 

 remarkable for having teeth in their beaks, rudimen- 

 tary wings, powerful hind limbs, and a broad beaver- 

 like tail, which no doubt materially helped in steering 

 the creature through the water. These birds had long 

 flexible necks and powerful jaws, which would enable 

 them to catch the most agile fish. These are a few of 

 the marvellous creatures which lived in the Cretaceous 

 times. 



i "Text-Book of Geology," Sir Archibald Geikie, F.R.S., 3rd 

 edition, 1893, p. 933. 



