RULERS OF THE ANCIENT SEAS 55 
Hesperornis (see page 83), while over the 
waters flew pterodactyls, with a spread of 
wing of twenty feet, largest of all flying 
creatures; and, not improbably —nay, very 
probably—fish-eaters, too ; and when each and 
all of these were seeking their dinners, there 
were troublous times for the small fry in that 
old Kansan sea. 
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 com- 
pletely 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, 
forming long, low bars, parts of the water-area 
were included, and connection with salt-water 
prevented. Thus were the living beings im- 
prisoned and subjected to many new risks to 
