Spawns patches of Clay, Sand, and Dirt, within the Ocean type biome floors (spawning in the sand/gravel surface layers of the ocean floor, as well as some gravel below ocean biomes. applies to all temperatures)
1.16 example: https://github.com/Lothrazar/OceanFloorControl/blob/trunk/1.16/oceanfloor.toml
Spawn rates and sizes controlled in the config file. 1.12 example:
I:clay_chance=65
I:clay_size=32
I:dirt_chance=30
I:dirt_size=18
I:sand_chance=45
I:sand_size=22