NEBULA TO MAN 
Gone too from long held mud beds off the coasts 45 
Are Belemnites wiped out as Xerxes' hosts. 
Pearl-mussels' yard-long shells lie in the seas, 
Mere relics of the past, and tenantless. 
The " Lamp-shell" hosts, long waning, now comprise 
But three or four old struggling families. 50 
Of Sponges too, whole genera are gone ; 
Nor has Sea-urchin life been left alone. 
Swept thus and cleared is Nature's fateful stage, 
As starts its course the wondrous Mammal Age. 
How came all this this widespread overthrow-- 55 
That gave to Death these life-groups high and low ? 
Earth's movements doubtless had extensive been, 
And great as those the world for long had seen. 
Beds of Cretaceous seas had been uplifted, 
And ancient coast-lines far and wide been shifted. 60 
Seas long encroaching had been brought to bay, 
And on new paths their currents forced to stray. 
Through fractures in the crust had waters pressed, 
And roused volcanic forces long at rest. 
Craters with pristine wrath had roared again, 65 
And clothed with lava many a verdant plain : 
And earthquake waves high mounting from the sea 
Had swept vast tracks of level territory. 
Death warrants must these changes oft have signed 
Of many lives : and with them came combined 70 
102 
