EXTINCTION OF THE SAURIANS. 439 
existence. Fancy a crocodile twenty-seven feet long, with the 
fins of a whale, the long and flexible neck of a swan, and a 
comparatively small head. With the appearance of this new 
tyrant, the last hope of escape is taken from the trembling 
_ fishes; for into the shallow waters, inaccessible ‘to the more 
bulky Ichthyosaurus, the slender Plesiosaurus penetrates with 
ease. 
A race of such colossal powers seemed destined for an immor- 
ta] reign, for where was the visible enemy that could put an end 
to its tyranny? But even the giant strength of the saurians 
was obliged to succumb to the still more formidable power of 
all-changing time, which slowly but surely modified the cireum- 
stances under which they were called into being, and gave birth 
to higher and more beautiful forms. 
In the tertiary period, the dreadful reptiles of the mesozoic 
seas have long since vanished from the bosom of the ocean, and 
cetaceans, walruses, and seals, unknown in the primitive deep, 
now wander through the waters or bask on the sunny cliffs. 
With them begins a new era in the life of the sea. Hitherto it 
has only brought forth creatures of base or brutal instinct, but 
now the Divine spark of parental affection begins to ennoble its 
more perfect inhabitants, and to point out the dim outlines of 
the spiritual world. 
During all these successive changes the surface of the earth 
has gradually cooled to its present temperature, and many 
plants and animals that formerly enjoyed the widest range must 
now rest satisfied with narrower limits. The sea-animals of the 
north find themselves for ever severed from their brethren of 
the south, by the impassable zone of the tropical ocean; and 
all the fishes, molluscs, and zoophytes, whose organisation 
requires a greater warmth, confine themselves to the equatorial 
regions, 
As the tertiary period advances towards the present epoch, 
the species which flourished in its prime become extinet, like the 
numberless races which preceded them; new modifications of 
life, more and more similar to those of the present day, start 
into existence; and, finally, creation appears with increasing 
beauty in her present rich attire. 
Thus old Ocean, after having devoured so many of his chil- 
dren, has transformed himself at last into our contemporancous 
