Mosaic

Mosaic is a condensed mixture of biomes in the game.

Mosaic "biomes" are observably rare, and contain a random patchwork of all other biomes within them. A signature of the Mosaic biome is the presence of lakes (several small holes of ocean), identical to the edges of islands, in the appearance of a circular shape or other obscure polygon.

Mosaic biomes would make excellent homes, if not for the uncommonness of signature biome benefits, such as Tallbirds and Beefalos, due to the considerably small area of each biome region.

Mosaic biomes are also the only place where you can find natural spawned cobblestone, usually near ocean holes.