Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
अथ तृतीयं वक्ष्यामि कुशद्वीपं च कृत्स्नशः कुशद्वीपेन क्षीरोदः सर्वतः परिवारितः //
atha tṛtīyaṃ vakṣyāmi kuśadvīpaṃ ca kṛtsnaśaḥ kuśadvīpena kṣīrodaḥ sarvataḥ parivāritaḥ //
Now I shall describe in full the third continent, Kuśadvīpa; and all around Kuśadvīpa lies the ocean called Kṣīroda (the Sea of Milk), encircling it on every side.
This verse is not about Pralaya; it belongs to the cosmographic mapping of the world (dvīpa–samudra scheme), stating that Kuśadvīpa is encircled by the Kṣīroda (Milk Ocean).
Directly it does not prescribe duties; indirectly, such cosmographic passages ground dharma in a sacred worldview, reminding rulers and householders that governance and ritual life are situated within a divinely ordered cosmos.
No explicit Vāstu rule is stated; however, the named Kṣīroda (Milk Ocean) is ritually symbolic of purity and auspiciousness, often invoked in Puranic imagination for sacred spaces and consecratory ideals.