Matsya Purana — Saptamī Sacred Bath and the Mṛtavatsābhiṣeka Rite for Pacifying Misfortune an...
गजाश्वरथ्यावल्मीकात् संगमाद्ध्रदगोकुलात् संशुद्धां मृदमानीय सर्वेष्वेव विनिक्षिपेत् //
gajāśvarathyāvalmīkāt saṃgamāddhradagokulāt saṃśuddhāṃ mṛdamānīya sarveṣveva vinikṣipet //
Having brought well-purified earth from places such as an elephant-stable, a horse-stable, a chariot-road, an anthill, a river-confluence, a pond, or a cattle-settlement, one should deposit (apply) it in all the required spots (of the site/works).
This verse is not about Pralaya; it belongs to Vāstu/ritual procedure, prescribing how purified earth should be gathered and applied during site preparation.
It frames proper construction and ritual work as dharmic responsibility: a king or householder should follow prescribed methods for preparing a site—using purified materials—so that building, consecration, and domestic rites are performed correctly.
It gives a Vāstuvidyā rule for sourcing and distributing purified soil/clay from specified locations, implying standardized material selection for consecration, ground-rites, or plastering/filling in ritual construction.