佛祖歷代通載 2.20

2.20

(9) The God of the Soil (In ancient times Gonggong Shi had a son named Houtu, who was capable of leveling the Nine Provinces and was worshipped as the God of the Soil, master of the five soils. The five soils refer to mountains and rivers, marshes and pools, hills and mounds, tombs and alluvial plains, and high plateaus and lowlands. Because the earth is distant, wide, and moist, earth was heaped up to worship him in recompense for the earth's merits. In what generation he was first matched with Houtu is unknown, and awaits one who knows).