And nothing I cared, at my sky blue trades, that time allows
In all his tuneful turning so few and such morning songs
Before the children green and golden
Follow him out of grace,
Nothing I cared, in the lamb white days, that time would take me
Up to the swallow thronged loft by the shadow of my hand,
In the moon that is always rising,
Nor that riding to sleep
I should hear him fly with the high fields
And wake to the farm forever fled from the childless land.
Oh as I was young and easy in the mercy of his means,
Time held me green and dying
Though I sang in my chains like the sea.
This whole poem personifies and creates metaphors from trees, land animals, and farms. However, it ends in a simile of the sea, the total opposite of land. 
 Perhaps it is because all of the good times that has happened on the land, that now drowning seems like what is going on in his mind. Either way, Thomas made it purposely not fit in to this poem.
Fern Hill