Matsya Purana — The Attendant Hosts of the Sun and Moon: Monthly Gaṇas
सौम्याः सुतपसो ज्ञेयाः सौम्या बर्हिषदस्तथा अग्निष्वात्तास् त्रयश्चैव पितृसर्गस्थिता द्विजाः //
saumyāḥ sutapaso jñeyāḥ saumyā barhiṣadastathā agniṣvāttās trayaścaiva pitṛsargasthitā dvijāḥ //
Know that the Sutapas are Saumyas; and likewise the Barhiṣads are Saumyas. And the three classes called the Agniṣvāttas—these twice-born are established within the creation of the Pitṛs, the ancestral order.
It does not describe Pralaya directly; it maps the ordered creation (sarga) of the Pitṛs by naming their principal classes (Saumya/Sutapas, Barhiṣad, and the three Agniṣvātta groups), showing cosmic organization rather than dissolution.
By identifying Pitṛ classes, it underpins śrāddha and ancestral rites: a householder (and a king as guardian of dharma) must support correct ritual practice, offerings, and remembrance of ancestors in accordance with recognized Pitṛ orders.
The significance is ritual rather than architectural: terms like Barhiṣad point to sacrificial procedure (barhis, the sacred grass) and Agniṣvātta to fire-offerings—key categories used in explaining śrāddha, yajña contexts, and ancestral worship frameworks.