AMBIVALENCE often attends that poor literary relative, the novella - are we confronting a rambling short story, or a novel without sufficient ambition? Two novellas by Caterina Edwards do nothing to clear up the ambiguity, and though both have moments in which their form has some validity, in the end, A Whiter Shade Of Pale/Becoming Emma (NeWest, 220 pages, $14.95 paper) would be greatly improved by some judicious pruning. That pruning would profitably remove a lot of stylized literary "structure" - fractured and often tediously random jottings in the former story, "litcrit" quoting in the latter - to allow the narratives some air in which to breathe. In "A Whiter Shade of Pale , the lesser of the two novellas, a hospital stay is the catalyst prompting the central character, George, to embark on some much needed self-analysis and self-discovery. Edwards has the makings of a decent short story here, but loses it to inflated rhetoric and portentousness, when she might better have concentrated on ensuring the development of her characters and the story she tells about them. "Becoming Emma," the account of a woman who uses a love affair to search for her identity and the meaning in her life, is much stronger. Edwards can - and frequently does - write well, and nowhere I better than in her detailing of the growth, prosecution, and sudden, humiliating ending of the affair. Closely observed and welldescribed, this is very affecting material that almost works on its own terms, if it weren`t for its burden of self-consciously literary decoration, wherein the author muddies the water by exploring her character`s putative relationship with Flaubert`s Emma Bovary, Jane Austen`s Emma Woodhouse, art, literature, philosophy, and a mare`s nest of other intellectual concerns. Edwards`s first novel, The Lion`s Mouth, was praised for its "bright talent" and "clear, elegant prose." She should forget about this present unfortunate book and set about recovering those qualities.