佛祖歷代通載 2.20

2.20

（九）　社神（昔共工氏有子。曰后土。能平九州。祀為社神五土之主。五土者。謂山川陂澤丘陵墳衍原隰也。土遠廣潤封土祀之以報土功。不知何代配乎后土。更俟知者）。

(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).