Pausanias Description of Greece 1.26.5

[5] There is also a building [ oikēma] called the Erekhtheion [/Erechtheum]. In front of the entrance is an altar [ bōmos] of Zeus Hypatos [‘the Most High’], on which they never sacrifice [ thuein] anything alive [ empsūkhon] but they deposit [ tithenai] baked-goods [ pemmata], and they follow-the-custom [ nomizein] of not using any wine either. As one goes inside, there are altars [ bōmoi], one belonging to Poseidon, on which in following up on an oracular-pronouncement [ manteuma] they sacrifice [ thuein] also to Erekhtheus; the second [altar belongs] to the hero [ hērōs] Boutēs; and the third to Hephaistos. On the walls are paintings [ graphai] that depict the Boutadai [‘descendants of Boutēs’]; there is also inside—the building [ oikēma] is double—sea-water in a well [ phrear]. This is no great wonder [ thauma], since other inhabitants of any midland region [ mesógaia] also have such wells, in particular the Carians who inhabit Aphrodisias. But this particular well [ phrear] [in Athens] lends itself to a scientific-write-up for this reason: it makes the sound of waves when a south wind blows. And on the surface of the rock is the outline [ skhēma] of a trident [ triaina]. It is said that these things appeared [ phanēnai] as evidence [ marturia] in support of Poseidon’s claim to the land.