Jane Langton on types of fantasy

I have recently acquired Fantasists on Fantasy. It's a good book, containing essays by several authors of fantastic literature, including C. S. Lewis, George MacDonald, and J. R. R. Tolkien. An author I wasn't familiar with is Jane Langton. She writes:
. . . I've been sorting and categorizing a lot of old and new favorites to see if I can make some sort of sense out of them. The result is a modest set of conclusions concerning the three primary questions which each fantasy asks and answers What if? Then what? So what?
. . . What if rugs could fly? What if pigs could talk? Every writer of fantasy poses a what-if question that is the theme of his book. He can ask it in many ways, and all of these ways are different approaches to the dividing line between truth (the real world) and fantasy (the unreal world). For E. Nesbit, the dividing line was a piece of cloth. - pp. 165-6, emphasis in original.

Her essay attempts to categorize fantastic literature. Here's my summary of her eight categories.
Her first category does not, as she puts it, go through the cloth from the real to the other side. In this category, which she calls tall tales, reality is exaggerated. I don't have a good example. Hers is from a story where someone invents a device that attracts mice, like the Pied Piper's.

Her second category is when the characters go through the cloth, from the real to the fantastic side, by use of some device, such as the wardrobe in The Lion, the Witch, and the Wardrobe by C. S. Lewis. As Langton says, sometimes it's not a device, but a person, like Mary Poppins. She also says that, in this kind of book, everything comes back to the real side at the end.

In the third type, the two worlds, fantastic and real, exist side-by-side, as in Norton's books about the Borrowers.

In the fourth, we are totally in the fantastic realm, in once-upon-a-time. Langton describes it:
If we were to place it vaguely in space and time, we would attach it to northern Europe and sometime between the fall of Rome and the invention of the internal-combustion engine, and populate it exclusively with wizards, witches, jesters, goose-girls, youngest sons, aristocrats of royal blood, absolute monarchs, and a scattering of peasantry. p. 169.

The fifth kind answers the what-if question "What if animals could talk?" The Wind in the Willows is an example.

In her sixth kind, characters go to a different time and return.

In her seventh, there are ghosts.

Her eighth category is science fiction, in which, she says "the curtain hangs between a finite present and a kind of infinite future, a time in which the possibilities of knowledge will be infinitely extended or in which nature itself will be discovered to be infinitely varied." p. 173.

-Jane Langton, "The Weak Place in the Cloth: A Study of Fantasy for Children" Fantasists on Fantasy, edited by Robert H. Boyer and Kenneth J. Zahorski. New York: Avon Books, 1984. pp. 163-179. Originally published in The Horn Book Magazine, October and December 1973, pp. 433-441 and 570-578. The material above is from the first part only.

Thanks for reading.