Peloponnesus, in a physical point of view, is a very remarkable country: it rests upon a volcanic foundation; and although our history knows nothing of any eruptions, still we hear of formidable earthquakes. The island of Thera, in the Greek Archipelago, is the central point from which a volcanic chain extends below the sea to Peloponnesus, and as far as Epirus and Thesprotia, while on the other side, it proceeds to Sicily, Ischia and Mount Vesuvius. Hence earthquakes were very frequent and eventful occurrences in the physical history of the peninsula. When you come down from the precipitous heights of Arcadia, or from the opposite heights of Parnassus and Helicon, you at once see that the country falls off, and has been formed by the ground sinking in consequence of this volcanic nature; and I have no doubt that the Corinthian Gulf was likewise the effect of such causes, for the land on both sides of it breaks down abruptly. The range of Taygetus, of which Taenarus forms the southern extremity, is particularly renowned for its internal convulsions; the most fearful ravages are nowhere so frequent as there, and about the time of the 80th Olympiad, in particular, the earth was there in violent agitation: whether this is still the character of that district, I do not know. The Peloponnesian coast of the Corinthian Gulf is another scene of earthquakes; there Helice and Bura were swallowed up by the earth, and as far as history can be traced, one town after another was destroyed by convulsions of the earth, whence Ποσειδῶν Ἐνοσίχθων was specially worshipped there, and on Mount Taenarus. Those earthquakes give rise to lakes discharging their waters through subterraneous canals, which at times are filled up, and at others are opened again; hence the lakes are of varying extent, as for example, the Stymphalian lake in Arcadia. Another effect is, that several rivers of Peloponnesus are interrupted in their course: they sometimes continue it under ground, as, for example, the Ladon, while at other times they change their beds, or disappear entirely in caverns or lakes. Hence also the quantity of water in some districts is different at different times; this was the case especially in Argolis, which in the days of Aristotle had lost all its waters.