CC Ādi 5.110

nārāyaṇera nābhi-nāla-madhyete dharaṇī
dharaṇīra madhye sapta samudra ye gaṇi
Word for word: 
nārāyaṇera — of Lord Nārāyaṇa; nābhi-nāla — the stem from the navel; madhyete — within; dharaṇī — the material planets; dharaṇīra madhye — among the material planets; sapta — seven; samudra — oceans; ye gaṇi — they count.
Translation: 
The material planets rest within the stem that grows from the lotus navel of Lord Nārāyaṇa. Among these planets are seven oceans.