Mbh 9.39.3b

The assembled Rishis, having heard his words, bestowed the name of Kapalamochana on the tirtha. The great Rishi Mahodara, repairing once more to that foremost of tirthas, drank its water and attained to great ascetic success. He of Madhu's race, having given away much wealth unto the Brahmanas and worshipped them, then proceeded to the asylum of Rushangu. There, O Bharata, Arshtishena had in former days undergone the austerest of penances. There the great Muni Vishvamitra (who had before been a Kshatriya) became a Brahmana. That great asylum is capable of granting the fruition of every wish. It is always, O lord, the abode of Munis and Brahmanas. Baladeva of great beauty, surrounded by Brahmanas, then went to that spot, O monarch, where Rushangu had, in former days, cast off his body. Rushangu, O Bharata, was an old Brahmana, who was always devoted to ascetic penances. Resolved to cast off his body, he reflected for a long while. Endued with great ascetic merit, he then summoned all his sons and told them to take him to a spot where water was abundant. Those ascetics, knowing their sire had become very old, took that ascetic to a tirtha on the Sarasvati. Brought by his sons to the sacred Sarasvati containing hundreds of tirthas and on whose banks dwelt Rishis unconnected with the world, that intelligent ascetic of austere penance bathed in that tirtha according to due rites, and that foremost of Rishis conversant with the merits of tirthas, then cheerfully said, O tiger among men, unto all his sons, who were dutifully waiting upon him, these words, 'He that would cast off his body on the northern bank of the Sarasvati containing much water, while employed in mentally reciting sacred mantras, would never again be afflicted with death!' The righteous-souled Baladeva, touching the water of that tirtha and bathing in it, gave considerable wealth unto the Brahmanas, being devoted to them.