Matsya Purana — The Greatness and Procedure of the Aṅgāra
अत्राप्युदाहरन्तीमम् इतिहासं पुरातनम् विरोचनस्य संवादं भार्गवस्य च धीमतः //
atrāpyudāharantīmam itihāsaṃ purātanam virocanasya saṃvādaṃ bhārgavasya ca dhīmataḥ //
Here too they cite an ancient traditional account—namely, the dialogue between Virocana and the wise Bhārgava.
This verse does not describe Pralaya directly; it signals a shift into an ancient illustrative narrative (itihāsa) used to teach principles—often the method by which Purāṇas contextualize cosmic or ethical teachings.
By introducing a dialogue-based itihāsa, the text indicates that the coming episode is meant as a moral precedent; such dialogues typically clarify right conduct (dharma), decision-making, and restraint—core duties for kings and householders.
No Vāstu or ritual procedure is stated in this line; it functions as a narrative preface announcing an authoritative example (udāharaṇa) that may later support ritual, ethical, or governance instructions.