Bhagavatapurana 9.17.3

9.17.3

kāśyaḥ kuśo gṛtsamada iti gṛtsamadādabhūt /
śunakaḥ śaunako yasya bahvṛcapravaro muniḥ //

2. & 3. O great king, hear of the line of Kshatravridha, (the sinless); his son Suhotra had three sons named Kasya, Kusa and Gritsamada and Gritsamada's son was Sunaka, and his son Saunaka, a sage most important of the followers of Rig Veda.