Board Thread:Bug Reports/@comment-25565811-20160920194234/@comment-27516710-20160920202019

The problem is that it's not the biome but the algorithm that creates the boundary between biomes. There is a 128 block variance in where the white mountains can be with regard to the Pelennor Field biome, so, it's impossible to generate the wall without either cutting it short, or, having it generate inside the mountain (which would make a nasty cut into the mountains). It stops generating when it determines it is near the mountains.