Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
प्रदक्षिणोपचारेण दध्यक्षतफलोदकैः प्राङ्मुखो निर्वपेत्पिण्डान् दूर्वया च कुशैर्युतान् //
pradakṣiṇopacāreṇa dadhyakṣataphalodakaiḥ prāṅmukho nirvapetpiṇḍān dūrvayā ca kuśairyutān //
Facing east, one should offer the piṇḍas with the clockwise reverential procedure (pradakṣiṇa), using curds, akṣata (unbroken rice-grains), fruits, and water; and the piṇḍas should be accompanied by dūrvā grass and kuśa blades.
This verse does not describe pralaya; it gives procedural instructions for ancestral offerings (piṇḍa-dāna) within dharma/śrāddha practice.
It outlines gṛhastha-dharma: a householder (and by extension a king as an ideal patron of dharma) should properly perform śrāddha by offering piṇḍas with prescribed substances and orientation, honoring the Pitṛs through correct ritual conduct.
The ritual significance is explicit: face east (prāṅmukha), perform offerings with pradakṣiṇa-style reverence, and use standard śrāddha materials—curds, akṣata, fruits, water—along with kuśa and dūrvā grasses, which are traditional purificatory and rite-defining implements.