Mahabharata 12.49.63

12.49.63

tataḥ kālena pṛthivī praviveśa rasātalam |
arakṣyamāṇā vidhivatkṣatriyairdharmarakṣibhiḥ || 63 ||

It behoveth thee not, O Rama, to reside within (what is) my dominion.' At these words, Ocean suddenly created for Jamadagni's son, on his other shore, a region called Surparaka. Kasyapa also, O monarch, having accepted the earth in gift, and made a present of it unto the Brahmanas, entered the great forest. Then Sudras and Vaisyas, acting most wilfully, began to unite themselves, O bull of Bharata's race, with the wives of Brahmanas. When anarchy sets in on earth, the weak are oppressed by the strong, and no man is master of his own property. Unprotected duly by Kshatriyas observant of virtue, and oppressed by the wicked in consequence of that disorder, the earth quickly sank to the lowest depths. Beholding the earth sinking from fear, the high-souled Kasyapa held her on his lap; and since the great Rishi held her on his lap (uru) therefore is the earth known by the name of Urvi. The goddess earth, for protection's sake, gratified Kasyapa and begged of him a king.