All we have to do is to say--not "Open Sesame," like Ali Baba in the tale of the Forty Thieves--but some word or two which Madam Why will teach us, and forthwith a hill will open, and we shall walk in, and behold rivers and cascades underground, stalactite pillars and stalagmite statues, and all the wonders of the grottoes of Adelsberg, Antiparos, or Kentucky.
Am I joking?
Yes, and yet no; for you know that when I joke I am usually most in earnest.

At least, I am now.
But there are no caves in chalk?
No, not that I ever heard of.

There are, though, in limestone, which is only a harder kind of chalk.

Madam How could turn this chalk into hard limestone, I believe, even now; and in more ways than one: but in ways which would not be very comfortable or profitable for us Southern folk who live on it.

I am afraid that--what between squeezing and heating--she would flatten us all out into phosphatic fossils, about an inch thick; and turn Winchester city into a "breccia" which would puzzle geologists a hundred thousand years hence.