SILURIAN PERIOD 
Now other layers of rock take up the tale, 
And Nature's ceaseless industry unveil. 
No pause she knows ; at rest she cannot stand, 
Though vast may be the time at her command. 
Not but she needs immeasurable time, 5 
For step by step must she the ladder climb. 
No " royal roads " are running through her spheres, 
No power or gift of miracle are hers : 
And though through Cambrian years she laboured long, 
In humble forms still stands her living throng. 10 
Along the shore sand-hoppers merry rise, 
Romping about like swarms of dancing flies. 
Water-fleas, swimming snails, and trilobites, 
" Lamp-shells," cystoids, and fleshy graptolites 
Are in their zenith now ; never again 1 5 
O'er the wide world such glory to attain. 
Corals are spreading through the clearer seas, 
" Rugose " and " tabulate " of many species. 
Crinoids, strong stalked and tufted, lift their heads 
In jungled wealth about their briny beds. 20 
And though developed animals they be, 
Well are they named the " lilies " of the sea. 
'5 
