Matsya Purana 273.76

273.76

na śakyo vistarasteṣāṃ santānasya parasparam.
tatpūrvāparayogena vaktuṃ varṣaśatairapi .. 273.75

These Kṣatriyas were pious-minded and charitably disposed. Thousands of similar Râjarshis have disappeared. In the present Manwantara the dynasty of Vaivaswatamanu appeared and disappeared and with it many races came and went.—73-75 Even in one hundred years it is not easy to describe that dynasty fully Twenty eight families have disappeared with the Devas What remained I am relating—76-77