RULERS OF THE ANCIENT SEAS 41 



sharks of later days, all these voracious, highly special- 

 ized creatvires passed out of existence. 



And then there came a change; to the south, to the 

 west, to the north, the land was imperceptibly but surely 

 rising, perhaps only an inch or two in a century, but 

 still rising, until "The Ocean in which flourished this 

 abundant and vigorous life was at last completely 

 inclosed on the west by elevations of sea-bottom, so 

 that it only communicated with the Atlantic and 

 Pacific at the Gulf of Mexico and the Arctic Sea." 



The continued elevation of both eastern and western 

 shores contracted its area, and when ridges of the sea- 

 bottom reached the surface, formiag long, low bars, 

 parts of the water-area were included, and connection 

 with salt-water prevented. Thus were the living beings 

 imprisoned and subjected to many new risks to life. 

 The stronger could more readily capture the weaker, 

 while the fishes would gradually perish through the con- 

 stant freshening of the water. With the death of any 

 considerable class, the balance of food-supply would be 

 lost, and many large species would disappear from the 

 scene. The most omnivorous and enduring would 

 longest resist the approach of starvation, but would 

 finally yield to inexorable fate — the last one caught by 

 the shifting bottom among shallow pools, from which 

 his exhausted energies could not extricate him."i 



Like the "Fossil man" the sea-serpent flourishes 

 perennially in the newspapers and, despite the fact that 

 he is now mainly regarded as a joke, there have been 

 many attempts to habilitate this mythical monster 

 and place him on a foundation of firm fact. The most 



'Cope: "The Vertebrata of the Cretaceous Formations of the West,'' 

 p. 60, being the "Report of the United States Geological Survey of the 

 Territories," Vol. II. 



