Philip Jose Farmer 
Lavalite World 

The lavalite world is a world of slow but constant change. Here mountains rise from plains, or sink into rifts; new oceans form as vast hollows collapse and seas rush in. There is only one escape from this world where the very landscape moves. The one gateway to other universes is in the palace of the Lord Urthona. Paul Janus Finnegan – also known as Kickaha – must reach it if he is to survive. And he must do so despite the Lords Urthone and Red Orc, the hired thug Mc Kay, flesh-eating vegetation on the run, beasts of prey and planetary pseudopods.