The Unicorn By Shel Silverstein, The Unicorn (#7 in 1968)

A long time ago when the earth was green,
There were more kinds of animals than you've ever seen,
They'd run around free while the earth was being born, but the loveliest of all was the Unicorn.
There were
    Green alligators, and long necked geese,
    Some humpty-back camels and some chimpanzees,
    Some cats and rats and elephants, but sure as your born,
    The loveliest of all was the Unicorn.

Now God seen some sinning and it gave him pain, and he said stand back I'm going to make it rain.
He said hey brother Noah I'll tell you what to do, build me a floating zoo...
And take some of them
   Chorus  (“but don’t you forget my Unicorn”)
Well Noah was there to answer the call,
And he finished making the ark just as the rain started to fall.
He marched in the animals two by two,
And he called out as they went through... Hey Lord
I got your 
Chorus  (“I just can’t find no Unicorn”)
Well Noah looked out through the driving rain,
The Unicorns were hiding and playing silly games.
They were kicking and a-splashing while the rain was pouring,
Oh them silly Unicorns.
Noah cried close the door, because the rain is pouring,
And we just can't wait for no Unicorn.

Well the ark started moving and it drifted with the tide.
The Unicorns looked up from the rocks and they cried,
And the waters came down and sort of floated them away,
And that's why you've never seen a Unicorn - to this very day
There were