The only thing I remember from my original 2008 review of this book was that the Pliocene served as a basic backdrop for this story, and not much more: that still stands. For this reading, I found this book was too long and paced too slowly, which I am sure continues with the remaining two books in the trilogy, The Golden Torc and The Nonborn King. This is a quest, so I think it is written strongly, but the genre throws me off, even clothed in science fiction rather than fantasy.
Julian May, born in 1931, had written a lot of series, and is still writing!
I think the gigantic battle-ending on many stories (including ones I've written) is not needed, and gets to be too much of a trope. I spared myself this time and skimmed through the last twenty pages.