Weird Area On Map

[Kdense]

I am not sure if the Help! section is the right place for this but I have a question about an area I saw while looking at the map. There appears to be a large grey area on the map with what looks like maybe snow at the top? Any idea what this is? As far as I knew there wasn't any 'rocky' terrain or am I wrong. I have been up to this area and walked along it and in the game it appears to indeed be some kind of giant sheer cliff. It's not however the edge of the world. Just wondering if anyone has any insight to this.

[DarkNacht]

Its mountains.

[Kdense]

Thanks, I figured but I wasn't sure since it's not listed as a "biome"