Matsya Purana — Procedure for Going to Prayaga and the Greatness of the Ganga
ततो भोगवतीं गत्वा वासुकेरुत्तरेण तु दशाश्वमेधकं नाम तीर्थं तत्रापरं भवेत् //
tato bhogavatīṃ gatvā vāsukeruttareṇa tu daśāśvamedhakaṃ nāma tīrthaṃ tatrāparaṃ bhavet //
Then, having gone to Bhogavatī, and to the north of Vāsuki, there is another sacred ford there, known as Daśāśvamedhaka (the ‘Ten Horse-Sacrifices’ Tīrtha).
This verse is not about Pralaya; it belongs to a tīrtha-māhātmya passage mapping sacred places and their ritual merit.
It points to dharmic life through pilgrimage (tīrtha-yātrā) and honoring great Vedic rites (like Aśvamedha), ideals traditionally supported by kings and pursued (as capacity allows) by householders for merit.
The ritual significance is the association with “ten Aśvamedhas,” implying exceptional sanctity and merit; the verse functions as a geographic pointer to a named tīrtha rather than a Vāstu/temple-building rule.