Matsya Purana — Description of Gomedaka and Puṣkara Dvīpas; the Lokāloka Boundary; Ocean Tide...
एतौ द्वौ पर्वतौ वृत्तौ शेषौ सर्वसमुच्छ्रितौ पूर्वेण तस्य द्वीपस्य सुमनाः पर्वतः स्थितः //
etau dvau parvatau vṛttau śeṣau sarvasamucchritau pūrveṇa tasya dvīpasya sumanāḥ parvataḥ sthitaḥ //
These two mountains are circular in form; the remaining ones are lofty and rise high above all. To the east of that island stands the mountain named Sumanas.
This verse is not about Pralaya; it belongs to cosmographic description, classifying mountains by form (circular vs. lofty) and locating the Sumanas mountain on the eastern side of a dvipa.
Directly, it does not prescribe dharma; indirectly, such cosmographic knowledge supports a king’s learned counsel and a householder’s sacred worldview, used in Purana-based instruction, calendrical orientation, and traditional pilgrimage understanding.
No explicit Vastu or ritual rule is stated; however, the emphasis on cardinal direction (east) reflects the broader Purana-Vastu habit of orienting sacred spaces and descriptions using directional cosmology.