The limestone rocks of the interior of the Peloponnesus abound as much in chasms, which swallow up the rivers, as do Bœotia and the western portion of the whole of the Balkan peninsula. Some of these katavothras are mere sieves, hidden beneath herbage and pebbles, but others are wide chasms and caverns, through which the course of the underground waters may be readily traced. In winter wild birds post themselves at the entrances of these caverns, in expectation of the prey which the river is certain to carry towards them; in summer, after the waters have retired, foxes and jackals again take possession of their accustomed dens. The water swallowed up by these chasms on the plateau reappears on the other side of the mountains in the shape of springs, or kephalaria (kephalovrysis). The water of these springs has been purified by its passage through the earth, and its temperature is that of the soil. It bursts forth sometimes from a crevice in the rocks, sometimes in an alluvial plain, and sometimes even from the bottom of the sea. The subterranean geography of Greece is not yet sufficiently known to enable us to trace each of these kephalaria to the katavothras which feed them.

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Fig. 19.—LAKES PHENEA AND STYMPHALUS.

From the French Staff Map. Scale 1 : 500,000.

The ancients were most careful in keeping open these natural funnels, for, by facilitating the passage of the water, they prevented the formation of swamps. These precautions, however, were neglected during the centuries of barbarism which overcame Greece, and the waters were permitted to accumulate in many places at the expense of the salubrity of the country. The plain of Pheneus, or Phonia, a vast chasm between the Aroanian Mountains and the Cyllene, has thus repeatedly been converted into a lake. In the middle of last century the whole of this basin {61} was filled with water to a depth of more than 300 feet. In 1828, when this sheet of water had already become considerably reduced, it was still 6 miles long and 150 feet in depth. At length, a few years afterwards, the subterranean sluices opened, the waters disappeared, and there remained only two small marshes near the places of exit. But in 1850 the lake was again 200 feet in depth. Hercules, we are told, constructed a canal to drain this valley and to cleanse its subterranean outlets, but the inhabitants content themselves now with placing a grating above the “sink-holes,” to prevent the admission of trunks of trees and of other large objects carried along by the floods.

To the east of the valley of Pheneus, and on the southern foot of Mount Cyllene, there is another lake basin, celebrated in antiquity because of the man-eating birds which infested it, until they were exterminated by Hercules. This is the Stymphalus, alternately lake and cultivated land. During winter the waters cover about one-third of the basin; but it happens occasionally, after heavy rains, that the lake resumes its ancient dimensions. There is only one katavothra through which the waters can escape, and this, instead of being near the shore, as usual, is at the bottom of the lake. It swallows up not only the water of the lake, but likewise the vegetable remains carried into it, and the mud formed at its bottom; and this detritus is conveyed through it to some subterranean cavity, where it putrefies slowly, as may be judged from the fetid exhalations proceeding from the katavothra. The water, however, is purified, and when it reappears on the surface, close to the seashore, it is as clear as crystal.

There are many other lake basins of the same kind between the mountains of Arcadia and the chain of the Gaurias. They all have their swamps or temporary lakes, but the katavothras, in every instance, are sufficiently numerous to prevent an inundation of the entire valley. The most important of these lake basins is formed by the famous plain of Mantinea, upon which many a battle was fought. From an hydrological point of view this is one of the most curious places in the world; for the waters which collect there are discharged into two opposite seas—the Gulf of Nauplia on the east, and in the direction of the Alpheus and the Ionian Sea towards the west. There may exist even some subterranean rivulet which discharges itself, towards the south, into the Eurotas and the Gulf of Laconia.

The disappearance of the waters underground has condemned to sterility several parts of the Peloponnesus, which a little water would convert into the most fertile regions of the globe. The surface waters quickly suck up and form subterranean rivers, hidden from sight, which only see the light again, in most instances, near the seashore, when it is impossible to utilise them. The plain of Argos, though surrounded by a majestic amphitheatre of well-watered hills, is more sterile and arid even than are Megara and Attica. Its soil is always dry, and soaks up water like a sieve, which may have given rise to the fable of the Danaids. But to the south of that plain, where there is but a narrow cultivable strip of land between the mountains and the seashore, a great river bursts forth from the rocks. This is the Erasinus.

Other springs burst forth at the southern extremity of the plain, close to the defile {62} of Lerna, which, like that of the Erasinus, are supposed to be fed from Lake Stymphalus. Close to them is a chasm filled with water, said to be unfathomable. It abounds in tortoises, and venomous serpents inhabit the adjoining marsh. These are the kephalaria, or “heads,” of the ancient hydra of Lerna, which Hercules found it so difficult to seize hold of. Still farther south there is another spring which rises from the bottom of the sea, more than three hundred yards from the shore. This spring—the Doinæ of the ancients, and Anavula of modern Greek mariners—is, in reality, but the mouth of one of the rivers swallowed up by the katavothras of Mantinea. When the sea is still it throws up a jet rising to a height of fifty feet.