This chapter is an elaboration on the shadow which to which we were introduced in the prior chapter. It explains the baleful effect of the shadow, which appears to be two-fold: first, it brings about death (by killing the flowers on which the shadow lay) and second and similar to the first, it kills the magic of other people or things. You see that when the shadow destroys Anodos's joy in the vista and destroyed the magic of the boy with the kaleidoscope. It reminds me of the effect of the father in the house that Anodos stayed in, where the father disbelieved in Fairy Land and his skepticism and very laugh had the effect of making Anodos doubt in Fairy Land. In this case, though he did not doubt, the shadow has the effect of taking anything he sees and removing from it the power of Fairy Land, leaving only the "commonplace".
The shadow seems to have the power of disenchantment, removing the glory and beauty of life and leaving only the material, the mundane. I can't help but think of it as a subtle jab at scientific naturalism.
I don't have a clear idea what kind of symbol the maiden with the globe is. I believe this character is referenced later in the book so perhaps that will shed some additional light on it.
The last part of the chapter (the village where appearances change when you get close to someone) defies any attempt at my analysis. I think it makes for a cool story though. :)