The English language is rich with terms to describe the outdoor world (many of which have been borrowed from other languages), such as coteau and coulee, jaral and jetty, savanna and sawtooth. The worlds of most fantasy novels use natural settings where the features of the landscape may help or hinder the protagonists, or set the mood for the plot. When an author is creating a fantasy world where she needs to construct these settings, how can she find the best descriptors?
Home Ground: Language for an American Landscape (2006, Barry Lopez, ed.) is essentially an encyclopedia of terms to describe geographical features. The book includes a number of illustrations. I guarantee, if you browse through Home Ground you will find many things you've never heard of before, as well as accurate descriptions to accompany terms you always believed you knew but might not have quite right. (Note, the focus here is on the American countryside; I recently wanted to look up "moors", but since we don't have moors in America, it wasn't listed.)