Matsya Purana — Description of Gomedaka and Puṣkara Dvīpas; the Lokāloka Boundary; Ocean Tide...
एतैः पर्वतपादैस्तु स देशो वै द्विधाकृतः दक्षिणार्धं तु द्वीपस्य धातकीखण्डमुच्यते //
etaiḥ parvatapādaistu sa deśo vai dvidhākṛtaḥ dakṣiṇārdhaṃ tu dvīpasya dhātakīkhaṇḍamucyate //
By these mountain-foot ranges, that region is indeed divided into two. The southern half of the island-continent is called Dhātakīkhaṇḍa.
This verse is not about Pralaya; it belongs to the Matsya Purana’s cosmography, explaining how mountain ranges mark boundaries that divide a dvīpa into named regions.
Indirectly, it supports dharmic governance by defining sacred geography and territorial divisions—background knowledge used in Purāṇic thought for understanding realms, pilgrimage networks, and the ordered structure of the world.
No direct Vāstu or ritual rule is stated; the key takeaway is geographical classification (khanda/region naming), which can inform pilgrimage orientation and the Purāṇic “mapping” of sacred space.