Valmiki Ramayana Yuddha Kanda Sarga 4 Shloka 96
Original Shlokaततश्शिखरमारुह्य रामो दशरथात्मजः । कूर्ममीनसमाकीर्णमपश्यत्सलिलाकुलम् ।।6.4.96।।
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ततः then, दशरथात्मजः Dasaratha's son, रामः Rama, शिखरम् top , आरुह्या on climbing, कूर्मामीनसमाकीर्णम् inhabited by tortoises and fish, सलिलाकुलम् ocean, अपश्यत् observed
Then Rama the son of Dasaratha on climbing to the top (of Mahendra mountain) observed the ocean inhabited by tortoises and fish.