Here are lyrics for the song I'm singing at the Singaround today. The waterfall was one of the elaborate hairdos of the 1860's. Rats and mice are pads of hair used to add volume. I came across the song on the Lester Levy site. It's completely trivial but I liked it.

THE GIRL WITH THE WATERFALL
(Nancy's Waterfall)
by Frank Wilder, Boston, 1865.

There's songs a-bout most ev-ry-thing that one could name or call.
But un-til this, none has been wrote a-bout the Wa-ter-fall.
CHO: O Nan-cy's wa-ter-fall, it looks so ve-ry fine.
It hangs so grace-ful on her neck, she al-most seems di-vine.

Ni-ag-a-ra and all the falls that ev-er I did see
can-not com-pare with Nan-cy's hair, it looks so splen-did-ly!

A Ro-man said, "O what a fall was there, my coun-try-men!
Were he a-live to see our girls, he's say as he did then!

What next the girls will wear a-bout I'm sure I can-not tell.
With rats and mice they fix their hair, so goes the mo-dern belle.

Our Nan-cy is a char-ming girl, she's so gen-teel and tall,
when-e'er you see her on the street, just twig her wa-ter-fall!

https://levysheetmusic.mse.jhu.edu/collection/052/013