Minecraft wiki entry for Mountains, associated text: The jagged peaks biome generates in regions with snowy, cold and temperate biomes and is more likely to generate in taller and more jagged and pointy peaks that often pass the clouds and can peak at y=256. It is covered by a single layer of snow blocks with stone underneath often exposing ores such as coal, iron and emerald, and just like the snowy slopes, stone cliffs can generate in some sides of the mountain. Only goats spawn in this biome.