I came across this last night in Lolita. Humbert has momentarily lost Lo in fictional Wace, Colorado, situated upon the continental divide.
"The noncommittal mauve mountains half encircling the town seemed to me to swarm with panting, scrambling, laughing, panting Lolitas who dissolved in their haze. A big W made of white stones on a steep talus in the far vista of a cross street seemed the very initial of woe."
(See also Narnia)