A recent thread about the effects of another ice age reminded me of something. A very long time ago I read a story (I can’t even remember now if it was science fiction or fantasy) about a lost civilization that existed in the last interglacial period in what’s now Britain; all traces of which were completely obliterated by the most recent glaciation. Can anyone come up with a title?
Lord of the Rings? 
Clan of the Cave Bear?
The Saga of the Pleistocene Exile? http://en.wikipedia.org/wiki/Saga_of_Pliocene_Exile
The Chronicles of Prydain? http://en.wikipedia.org/wiki/The_Chronicles_of_Prydain
This would be my guess, if the “Britain” part of the OP is a misremembering. Pliocene saga is set mostly in what would become the Mediterranean and France.
Possibly Anvil Of Ice and it’s sequels by Michael Scott Rohan?
It was a trilogy which he then wrote 3(?) more sequels to. I think it started in northern Europe but ended in the Med. area…
Tell us if we guess right, Lumpy.
Something by A Merrit?
Or Clark Ashton Smith?
Might be one of these, I’ll have to find a copy and see.
Weren’t Robert Howard’s Conan stories set in Hyperborea, a pre-glacial European civilization?
No, Conan was set between “the sinking of Atlantis” (end of most recent glaciation) and the rise of Sumeria, approx 8000-9000 Y.A.
This is a dorky cover, but was it The Many Colored Land by Julian May?