JURASSIC PERIOD 
With them compete along the life-filled shores, 
With paddle limbs, the long-necked plesiosaurs. 100 
These have indeed advanced from strength to strength, 
And far surpass their ancestors in length. 
But lanky necks and small-brained heads in life 
Must have their drawbacks in a time of strife ; 
And new breeds now are coming to the fore, 105 
Less necked and bigger headed than of yore : 
And these new forms, with brains of larger size, 
Have hopes of better times than their allies. 
The Turtle groups, by Trias heralds foretold, 
Along the coasts a growing power hold ; no 
Proud with their shields, bequeathed a legacy 
From some obscure old reptile family. 
Great is their future : for indeed from them, 
As branches breaking from a vigorous stem, 
Families will come, that will in time command 115 
An empire stretched from sea far over land ; 
And whilst much other life runs out its span, 
These will survive, and see the rise of Man. 
Thus in warm seas, extending far and wide, 
In depths and shoals have fishes multiplied : 120 
And mollusk groups have spread along the shore, 
And prospers crusted life as ne'er before ; 
Whilst swimming reptiles, oft to giants grown, 
Keep, with the sharks, the population down. 
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