Some rivers, from a real hatred of the sea, pass under it, as does Arethusa, a fountain of Syracuse, in which the substances are found that are thrown into the Alpheus; which, after flowing by Olympia, is discharged into the sea, on the shore of the Peloponnesus[644]. The Lycus in Asia[645], the Erasinus in Argolis, and the Tigris[646] in Mesopotamia, sink into the earth and burst out again. Substances which are thrown into the fountain of Æsculapius at Athens[647] are cast up at the fountain of Phalerum. The river which sinks into the ground in the plain of Atinum[648] comes up again at the distance of twenty miles, and the Timavus does the same in Aquileia[649]. In the lake Asphaltites, in Judæa, which produces bitumen, no substance will sink, nor in the lake Arethusa[650], in the Greater Armenia: in this lake, although it contains nitre, fish are found. In the country of the Salentini, near the town of Manduria, there is a lake[651] full to the brim, the waters of which are never diminished by what is taken out of it, nor increased by what is added. Wood, which is thrown into the river of the Cicones[652], or into the lake Velinus in Picenum, becomes coated with a stony crust, while in the Surius, a river of Colchis, the whole substance becomes as hard as stone. In the same manner, in the Silarus[653], beyond Surrentum, not only twigs which are immersed in it, but likewise leaves are petrified; the water at the same time being proper for drinking. In the stream which runs from the marsh of Reate[654] there is a rock, which continues to increase in size, and in the Red Sea olive-trees and green shrubs are produced[655].