from 101 Castalian Spring on Livius.org:
"The same author records several ancient traditions about the origin of the name, one of them being that the source was called after a local lady. The Carian poet Panyassis, who is quoted by Pausanias, appears to have called Castalia a daughter of the river Achelous, while others -- including the lyrical poet Alcaeus -- believed that the spring was connected to the Cephissus river.
According to legend, Apollo planted here a shoot of the laurel that he had brought to Delphi from theTempe Canyon, which was all that had been left of the woman he loved, Daphne. There may indeed have been an ancient cult for a tree; there appears to have been a statue for Ge, Mother Earth, as well. The Greek researcher Herodotus of Halicarnassus states that close to the Castalian Spring, one could find a sanctuary that was dedicated to Autonous, a local hero who helped to push back the Persian invaders in 480 BCE.note
Today, one can see a rectangular square basin of about 9x3 meters, hewn out in the hard soil. Next to it is a long reservoir in which the water from the Pheriads was collected, before it was fed to seven jets, which had the shape of lion heads. This monument dates back to the Hellenistic (or Roman) period, and is not the oldest building on the site: a fountain house from the Archaic period has been discovered as well.
The source was well-known throughout the ancient world, and the word "Castalia" could be used as a synonym for Delphi.note In the Roman age, the word could be a way to describe poetic inspiration.noteIt could even be a synonym for wisdom . . . "