Valmiki Ramayana Bala Kanda Sarga 34 Shloka 8

भर्तारम् her husband, अनुवर्तिनी following, सशरीरा with human body, स्वर्गम् heaven, गता had gone, परमोदारा highly generous, कौशिकी named Kausiki, महानदी sacred river, प्रवृत्ता च flowed.

Following her husband my highly generous sister reached heaven with her human body and down assuming the form of a sacred river, flowed Kausiki.