Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
द्वीपस्य परिणाहं च ह्रस्वदीर्घत्वमेव च जम्बूद्वीपेन संख्यातं तस्य मध्ये वनस्पतिः //
dvīpasya pariṇāhaṃ ca hrasvadīrghatvameva ca jambūdvīpena saṃkhyātaṃ tasya madhye vanaspatiḥ //
The girth of the continent and likewise its shorter and longer dimensions are reckoned with reference to Jambūdvīpa; and in its very center stands a great tree (the central plant).
This verse is not about Pralaya; it belongs to cosmography, explaining how the world’s continental dimensions are computed with Jambūdvīpa as the reference and noting the central world-tree.
Indirectly, it supports dharma through knowledge of sacred geography—kings and householders are guided to understand the ordered cosmos that underlies pilgrimage, ritual orientation, and the cultural map of Bharata-varṣa within Jambūdvīpa.
Ritually, the “center” (madhya) and the idea of a central axis (world-tree) echo the principle of axial alignment used in sacred layouts; it can be cross-referenced when discussing Vastu concepts of center (brahmasthāna) and orientation, though no direct building rule is stated here.