Matsya Purana — Ekoddiṣṭa Śrāddha
पितृष्वेव तु दातव्यं तत्पिण्डो येषु संस्थितः ततः प्रभृति संक्रान्ताव् उपरागादिपर्वसु //
pitṛṣveva tu dātavyaṃ tatpiṇḍo yeṣu saṃsthitaḥ tataḥ prabhṛti saṃkrāntāv uparāgādiparvasu //
That piṇḍa-offering is to be given only to the Pitṛs, in whom that offering is understood to abide; and from that time onward it should be performed on Saṅkrānti days and on festival occasions such as eclipses and the like.
This verse is not about Pralaya; it focuses on Pitṛ-rites (śrāddha/piṇḍa) and specifies proper recipients (Pitṛs) and auspicious ritual timings (Saṅkrānti, eclipses, and other parva days).
It sets a clear householder duty: piṇḍa offerings are to be directed to the Pitṛs and repeated on key calendrical occasions (solar ingresses and eclipse-related festivals), reinforcing regular ancestral obligation as part of dharma.
The significance is ritual (not architectural): it links śrāddha/piṇḍa-dāna to specific high-merit times—Saṅkrānti and eclipse/parva days—indicating when ancestral offerings are especially prescribed.