Tosefta su Salmi 50:78

There was a stone there from the days of the first prophets, and it was called foundation, elevated three fingers above the ground. In the beginning the ark was placed on it. Once the ark was taken away they would burn the incense which was offered in the inner chamber upon it. R’ Yose said that from it the world was founded as it says, “From Tzion, the perfection of beauty…appeared.” (Tehillim 50:2)