Valmiki Ramayana Yuddha Kanda Sarga 76 Shloka 85
Original Shlokaततःकुम्भनिपातेनजलराशिस्समुत्थितः । व्निध्यमन्दरसङ्काशोविससर्पसमन्ततः ।।6.76.85।।
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ततः then, कुम्भनिपातेन by the fallen Kumbha, समुत्थितः from the ocean, जलराशिः ocean, व्निध्यमन्दरसङ्काशः form of Vindhya and Mandara, समन्ततः all over, विससर्प flowed.
By Kumbha falling into the ocean, it got swollen to the form of Vindhya and Mandara mountain and water flowed all over.