Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
संवत्सरं तु गव्येन पयसा पायसेन च रौरवेण च तृप्यन्ति मासान्पञ्चदशैव तु //
saṃvatsaraṃ tu gavyena payasā pāyasena ca rauraveṇa ca tṛpyanti māsānpañcadaśaiva tu //
By cow’s milk—whether as milk itself or as sweet rice (pāyasa)—they are satisfied for a full year; and (those in) Raurava are satisfied for fifteen months.
This verse is not about pralaya; it teaches karmic recompense and ritual efficacy—how specific offerings (milk/pāyasa) yield measurable relief or satisfaction in post-death states such as Raurava.
It supports the householder (and ruler) duty of dāna and śrāddha-type rites: offering cow’s milk or milk-based food is presented as a meritorious act that brings sustained benefit (a year or fifteen months), aligning with dharma of care for ancestors/spirits and social-religious order.
The significance is ritual, not architectural: milk and pāyasa are specified as effective offerings, with a stated duration of appeasement/satisfaction, and Raurava is named as the relevant naraka context.