Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
उद्भिदान्युदकान्यत्र गिरिप्रस्रवणानि च भोजनं षड्रसं तत्र तेषां स्वयमुपस्थितम् //
udbhidānyudakānyatra giriprasravaṇāni ca bhojanaṃ ṣaḍrasaṃ tatra teṣāṃ svayamupasthitam //
There, plants and waters abound, and mountain springs flow forth; and for them, food of all six tastes (ṣaḍ-rasa) presents itself spontaneously.
It does not describe Pralaya directly; it depicts a merit-born realm where nature is abundantly ordered—waters, springs, and food arise without effort.
It implies the karmic ideal that righteous living and dharmic duties culminate in effortless well-being—symbolized by self-appearing, well-balanced nourishment (ṣaḍrasa).
No explicit Vāstu rule is stated; however, the emphasis on pure water sources and springs aligns with Purāṇic ideals of auspicious site qualities (abundant, sweet waters) valued in settlement/temple environs.