While reading Penelope Lively's Dancing Fish and Ammonites, I came across "palimpsest" - "Something having usu. diverse layers or aspects apparent beneath the surface" - in the context in which she places it.
For that matter, I didn't know what Ammonites were - "A member of a Semitic people who in Old Testament times lived east of the Jordan between the Jabbok and the Arnon".
edit - I'm just finishing reading the Penelope Lively book and Find that she uses ammonite with it's alternative meaning - a type of fossil.
I had assumed she would be using the first meaning I posted, since she lived in the mid-east as a child.