Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
शाल्मलो द्विगुणो द्वीपः क्रौञ्चद्वीपस्य विस्तरात् परिवार्य समुद्रं तु दधिमण्डोदकं स्थितः //
śālmalo dviguṇo dvīpaḥ krauñcadvīpasya vistarāt parivārya samudraṃ tu dadhimaṇḍodakaṃ sthitaḥ //
Śālmala-dvīpa is twice the extent of Krauñca-dvīpa; and surrounding it lies the ocean whose waters are like dadhimaṇḍa (the whey or thin buttermilk of curd).
This verse is not describing Pralaya; it presents cosmography—how the world is structured into dvīpas and oceans—by giving the relative size of Śālmala-dvīpa and naming the surrounding ocean as dadhimaṇḍa-like.
Directly it does not prescribe royal or household duties; indirectly, such cosmographic knowledge supports a king’s role as protector of dharma by grounding ritual calendars, pilgrim routes, and the Puranic worldview used in public instruction.
No explicit Vāstu or temple rule appears here, but the dvīpa–samudra scheme is often used in ritual imagination (mandala-style world visualization) and in Purāṇic sacred geography that informs temple narratives and pilgrimage mapping.