My feeling is that "high fantasy" was the original and was used to distinguish Tolkienesque fantasy from whimsy or fairy tales. "Low fantasy" was a much later coinage. Is there anything in Rhetorics of Fantasy about the origins of the terms? I know that Farah defines her own categories, but was there anything in there about "high/low fantasy"?

Unfortunately, I honestly can't remember and also can't remember where my copy is. My books are very disorganised at the moment. :(