Valmiki Ramayana Bala Kanda Sarga 37 Shloka 21
Original Shlokaनिक्षिप्तमात्रे गर्भे तु तेजोभिरभिरञ्जितम्। सर्वं पर्वतसन्नद्धं सौवर्णमभवद्वनम्।।1.37.21।।
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गर्भे when that embryo, निक्षिप्तमात्रे had been just placed, सर्वम् all, पर्वतसन्नद्धम् sprouted on the mountain, वनम् forest, तेजोभि: with lustre, अभिरञ्जितम् reddened, सौवर्णम् अभवत् rendered golden.
When the embryo was placed (in Ganga) it spread on all sides of the forest on the mountain. Irradiated with lustre the forest appeared golden.