SB 5.20.2

jambūdvīpo ’yaṁ yāvat-pramāṇa-vistāras tāvatā kṣārodadhinā pariveṣṭito yathā merur jambv-ākhyena lavaṇodadhir api tato dvi-guṇa-viśālena plakṣākhyena parikṣipto yathā parikhā bāhyopavanena; plakṣo jambū-pramāṇo dvīpākhyākaro hiraṇmaya utthito yatrāgnir upāste sapta-jihvas tasyādhipatiḥ priyavratātmaja idhmajihvaḥ svaṁ dvīpaṁ sapta-varṣāṇi vibhajya sapta-varṣa-nāmabhya ātmajebhya ākalayya svayam ātma-yogenopararāma.
Word for word: 
jambū-dvīpaḥ — Jambūdvīpa, the island named Jambū; ayam — this; yāvat-pramāṇa-vistāraḥ — as much as the measure of its width, namely 100,000 yojanas (one yojana equals eight miles); tāvatā — so much; kṣāra-udadhinā — by the ocean of salt water; pariveṣṭitaḥ — surrounded; yathā — just as; meruḥ — Sumeru Mountain; jambū-ākhyena — by the island named Jambū; lavaṇa-udadhiḥ — the ocean of salt water; api — certainly; tataḥ — thereafter; dvi-guṇa-viśālena — which is twice as wide; plakṣa-ākhyena — by the island named Plakṣa; parikṣiptaḥ — surrounded; yathā — like; parikhā — a moat; bāhya — external; upavanena — by a gardenlike forest; plakṣaḥ — a plakṣa tree; jambū-pramāṇaḥ — having the height of the jambū tree; dvīpa-ākhyā-karaḥ — causing the name of the island; hiraṇmayaḥ — magnificently splendorous; utthitaḥ — rising; yatra — where; agniḥ — a fire; upāste — is situated; sapta-jihvaḥ — having seven flames; tasya — of that island; adhipatiḥ — the king or master; priyavrata-ātmajaḥ — the son of King Priyavrata; idhma-jihvaḥ — named Idhmajihva; svam — own; dvīpam — island; sapta — seven; varṣāṇi — tracts of land; vibhajya — dividing into; sapta-varṣa-nāmabhyaḥ — for whom the seven tracts of land were named; ātmajebhyaḥ — to his own sons; ākalayya — offering; svayam — personally; ātma-yogena — by the devotional service of the Lord; upararāma — he retired from all material activities.
Translation: 
As Sumeru Mountain is surrounded by Jambūdvīpa, Jambūdvīpa is also surrounded by an ocean of salt water. The breadth of Jambūdvīpa is 100,000 yojanas [800,000 miles], and the breadth of the saltwater ocean is the same. As a moat around a fort is sometimes surrounded by gardenlike forest, the saltwater ocean surrounding Jambūdvīpa is itself surrounded by Plakṣadvīpa. The breadth of Plakṣadvīpa is twice that of the saltwater ocean — in other words 200,000 yojanas [1,600,000 miles]. On Plakṣadvīpa there is a tree shining like gold and as tall as the jambū tree on Jambūdvīpa. At its root is a fire with seven flames. It is because this tree is a plakṣa tree that the island is called Plakṣadvīpa. Plakṣadvīpa was governed by Idhmajihva, one of the sons of Mahārāja Priyavrata. He endowed the seven islands with the names of his seven sons, divided the islands among the sons, and then retired from active life to engage in the devotional service of the Lord.