Valmiki Ramayana Ayodhya Kanda Sarga 46 Shloka 28
Original Shlokaतं स्यन्दनमधिष्ठाय राघव स्सपरिच्छदः। शीघ्रगामाकुलावर्तां तमसामतरन्नदीम्।।2.46.28।।
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सपरिच्छदः with his belongings, राघवः Rama, तं स्यन्दनम् that chariot, अधिष्ठाय having mounted, शीघ्रगाम् rapidly flowing, आकुलावर्ताम् agitated with whirlpools, तमसां नदीम् Tamasa river, अतरत् crossed.
Rama (along with others) mounted the chariot with his belongings, crossed the rapidly flowing Tamasa agitated with whirlpools.