SB 5.16.19

evaṁ jambū-phalānām atyucca-nipāta-viśīrṇānām anasthi-prāyāṇām ibha-kāya-nibhānāṁ rasena jambū nāma nadī meru-mandara-śikharād ayuta-yojanād avani-tale nipatantī dakṣiṇenātmānaṁ yāvad ilāvṛtam upasyandayati.
Synonyms: 
evam — similarly; jambū-phalānām — of the fruits called jambū (the rose apple); ati-ucca-nipāta — because of falling from a great height; viśīrṇānām — which are broken to pieces; anasthi-prāyāṇām — having very small seeds; ibha-kāya-nibhānām — and which are as large as the bodies of elephants; rasena — by the juice; jambū nāma nadī — a river named Jambū-nadī; meru-mandara-śikharāt — from the top of Merumandara Mountain; ayuta-yojanāt — ten thousand yojanas high; avani-tale — on the ground; nipatantī — falling; dakṣiṇena — on the southern side; ātmānam — itself; yāvat — the whole; ilāvṛtam — Ilāvṛta-varṣa; upasyandayati — flows through.
Translation: 
Similarly, the fruits of the jambū tree, which are full of pulp and have very small seeds, fall from a great height and break to pieces. Those fruits are the size of elephants, and the juice gliding from them becomes a river named Jambū-nadī. This river falls a distance of 10,000 yojanas, from the summit of Merumandara to the southern side of Ilāvṛta, and floods the entire land of Ilāvṛta with juice.
Purport: 

We can only imagine how much juice there might be in a fruit that is the size of an elephant but has a very tiny seed. Naturally the juice from the broken jambū fruits forms waterfalls and floods the entire land of Ilāvṛta. That juice produces an immense quantity of gold, as will be explained in the next verses.