The Katabothra of the lake Kopaïs, are a specimen of the phenomenon so frequent in Greece,—lakes and rivers finding for themselves subterranean passages through the cavities in the limestone rocks, and even pursuing their unseen course for a considerable distance before they emerge to the light of day. In Arcadia, especially, several remarkable examples of subterranean water communication occur; this central region of Peloponnesus presents a cluster of such completely inclosed valleys, or basins.[335] [335] Colonel Leake observes (Travels in Morea, vol. iii. pp. 45, 153-155), “The plain of Tripolitza (anciently that of Tegea and Mantineia) is by far the greatest of that cluster of valleys in the centre of Peloponnesus, each of which is so closely shut in by the intersecting mountains, that no outlet is afforded to the waters except through the mountains themselves,” etc. Respecting the Arcadian Orchomenus, and its inclosed lake with Katabothra, see the same work, p. 103; and the mountain plains near Corinth, p. 263. This temporary disappearance of the rivers was familiar to the ancient observers—οἱ καταπινόμενοι τῶν ποταμῶν. (Aristot. Meteorolog. i. 13. Diodor. xv. 49. Strabo, vi. p. 271; viii. p. 389, etc.) Their familiarity with this phenomenon was in part the source of some geographical suppositions, which now appear to us extravagant, respecting the long subterranean and submarine course of certain rivers, and their reappearance at very distant points. Sophokles said that the Inachus of Akarnania joined the Inachus of Argolis: Ibykus the poet affirmed that the Asôpus, near Sikyon, had its source in Phrygia; the river Inôpus of the little island of Delos was alleged by others to be an effluent from the mighty Nile; and the rhetor Zôilus, in a panegyrical oration to the inhabitants of Tenedos, went the length of assuring them that the Alpheius in Elis had its source in their island (Strabo, vi. p. 271). Not only Pindar and other poets (Antigon. Caryst. c. 155), but also the historian Timæus (Timæi Frag. 127, ed. Göller), and Pausanias, also, with the greatest confidence (v. 7, 2), believed that the fountain Arethusa, at Syracuse, was nothing else but the reappearance of the river Alpheius from Peloponnesus: this was attested by the actual fact that a goblet or cup (φιάλη), thrown into the Alpheius, had come up at the Syracusan fountain, which Timæus professed to have verified,—but even the arguments by which Strabo justifies his disbelief of this tale, show how powerfully the phenomena of the Grecian rivers acted upon his mind. “If (says he, _l. c._) the Alpheius, instead of flowing into the sea, fell into some chasm in the earth, there would be some plausibility in supposing that it continued its subterranean course as far as Sicily without mixing with the sea: but since its junction with the sea is matter of observation, and since there is no aperture