One of the manifestations of Mercurius in the alchemical process of transformation is the lion, now green and now red. Khunrath calls this transformation ‘luring the lion out of Saturn’s mountain cave.’
Jung identifies the mountain cave as the alchemical locus from which Mercurius-as-lion must be drawn forth, linking leonine transformation to Saturn’s dark, subterranean domain.
, Alchemical Studies, 1967thesis