Valmiki Ramayana Yuddha Kanda Sarga 22 Shloka 58

महाकायाः of huge body, महाबालाः strong, हस्तिमात्रान् like elephants, पाषाणान् stones, पर्वतांश्च mountains, समुत्पाट्य collecting and lifting up, यन्स्रैः by machines, परिवहन्तिच transported.

The Vanaras of huge body size and strong like elephants collected stones and mountains, lifted them, and transported into the sea.