NEBULA TO MAN 
Of weaker parts subsiding. Lands are lifted, 
Large seas locked in, and ancient coast-lines shifted. 
Big rivers from the rocky continents 100 
Fast flowing bring down gritty sediments, 
Worn from the weathered rocks of hills and moors, 
To spread them on the limestone shallowed floors 
Of seas enclosed. Truly with might and main 
Labours the land her balance to retain. 105 
And then, in time, as at a slackened rate 
The rivers flow, their seaward debris freight 
Perforce grows light. Coarse grit soon finds a bed, 
But silts and shales are still borne far ahead : 
And muddy banks, amassing by degrees, no 
Lift up their breasts above the shallowed seas. 
Life lies in wait, all ready to advance, 
By sea and land, at every opening chance. 
And muddy banks, new basking in the sun, 
By leafy life ere long are overrun. 115 
Soon creep the calamites upon the scene, 
Hard though their struggle oftimes is, and keen, 
On shifting treacherous beds to keep their hold : 
(But Life is nothing if it is not bold). 
And other growths the rising land befriend. 120 
Club-mosses tall their frontier lines extend, 
And sigillarias. Ferns too break forth, 
With cordaite shrubs, in tangled undergrowth. 
34 
